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Annealing is a heat treatment process in the processing of stainless steel pipe fittings. The pipe is slowly heated to a certain temperature for a sufficient period of time and then cooled at a suitable speed. The brightness of the product after the production of stainless steel pipe fittings determines the quality of the product. The process of annealing in the stainless steel market is quite mature. The following three advantages of stainless steel affect the brightness of stainless steel in actual production: 1. Whether the annealing temperature reaches the specified temperature, the heat treatment of stainless steel pipe fittings is generally carried out by solid solution heat treatment, which is commonly called “annealing”, and the temperature range is 1040~1120 degrees (Japanese standard). You can also observe through the observation hole of the annealing furnace. The stainless steel pipe fittings in the annealing zone should be in an incandescent state, but the softening spreader does not sag. 2. The annealing atmosphere generally uses pure hydrogen as the annealing atmosphere, and the purity of the atmosphere is preferably 99.99% or more. If another part of the atmosphere is an inert gas, the purity can be lower, but it must not contain too much oxygen or water vapor. 3. The furnace sealing bright annealing furnace should be closed and isolated from the outside air; using hydrogen as the shielding gas, only one exhaust port is open (used to ignite the discharged hydrogen). The method of inspection can be applied to the gaps of the joints of the annealing furnace with soapy water to see if the gas is running. The most easy place to run the gas is the place where the annealing furnace enters the pipe and the place where the pipe is discharged. The sealing ring in this place is particularly prone to wear. Always check frequently to change. 4. Protective gas pressure In order to prevent micro-leakage, the protective gas in the furnace should maintain a certain positive pressure. If it is hydrogen protective gas, it generally requires more than 20kbar. 5. In the furnace, the water vapor on the one hand checks whether the material of the furnace body is dry. When the furnace is first installed, the material of the furnace body must be dried. Second, whether the stainless steel pipe entering the furnace has excessive water stains, especially if there is a hole in the pipe, Don’t leak into it, or else destroy the atmosphere of the stove. Generally, if it is normal, the stainless steel pipe that should be retreated 20 meters after opening the furnace will start to brighten, and the kind that is reflective. The most important thing to note is the knowledge we mentioned above. I hope everyone is producing. You can pay attention when you are…. Source: China Stainless Steel Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

What is a flat welding flange? A flat welded flange is a type of flange that is joined to a vessel or pipe by a fillet weld. It is an arbitrary type of flange. According to the degree of integrity of the connection between the flange ring and the straight section, the design is checked according to the integral or loose flange. The flange ring is available in both neck and neck. Compared with the neck-welded flange, the flat-welded flange has a simple structure and is material-saving, but the joint is not as good as the neck-welded flange. Flat welded flanges are widely used in the connection of medium and low pressure vessels and pipes. Flat welding flange is suitable for steel pipe connection with nominal pressure not exceeding 2.5MPa. The sealing surface of flat welding flange can be made into smooth, concave and convex and grooved. The application of smooth flat welding flange is the largest. It is mostly used in cases where the medium condition is moderate, such as low pressure non-purified compressed air and low pressure circulating water. Type of flat welding flange: Plate flat welding flange Advantages: easy to take, simple to manufacture, low cost, widely used Disadvantages: Poor rigidity, so it should not be used in chemical process piping systems with high and extreme hazard requirements for supply, demand, flammability, explosive and high vacuum. The sealing surface type has a flat surface and a convex surface. Neck flat welding flange Advantages: It is convenient to install on site, and the process of welding seams can be omitted. Disadvantages: The neck of the flat welded flange has a low neck height, which improves the rigidity and load carrying capacity of the flange. Compared with the butt welding flange, the welding work is large, the welding rod consumption is high, and the high temperature and high pressure and repeated bending and temperature fluctuation cannot be withstood. Flat welding ring loose flange The flat welding ring loose flange is a movable flange. It is usually matched on the water supply and drainage fittings (the most common on the expansion joint). When the factory leaves the factory, there is a flange at each end of the expansion joint, directly in the project. The pipes and equipment are bolted. The purpose of using a flat welding ring to loosen the flange is generally to save material. The structure is pided into two parts. One end of the pipe is connected to the pipe, one end is made into a flange, and the flange is partially placed on the flange. The flanges are made of low-grade materials, and the tubes are made of the same material as the pipes to save material. Flat welding flange features: The flat welded flange not only saves space, reduces weight, but more importantly ensures that the joint is not leaked and has good sealing performance. The reduced size of the compact flange is due to the reduced diameter of the seal which will reduce the cross-section of the seal face. Second, the flange gasket has been replaced by a seal ring to ensure that the seal faces the sealing surface. In this way, only a small amount of pressure is required in order to press the cover tightly. As the required pressure is reduced, the size and required number of bolts can be reduced accordingly, so a new design that is small in size and light in weight (70% to 80% lighter than conventional flanges) is designed. product. Therefore, the flat welding flange type is a relatively high quality flange product, which reduces the quality and space and plays an important role in industrial use. Sealing principle of flat welding flange: The two sealing faces of the bolt press each other against the flange gasket and form a seal, but this also causes damage to the seal. In order to maintain the seal, it is necessary to maintain a huge bolt force, for which the bolt is made larger. Larger bolts are matched to larger nuts, which means that larger diameter bolts are needed to create the conditions for tightening the nuts. However, the larger the diameter of the bolt, the more suitable the flange becomes, the only way to increase the wall thickness of the flange. The entire device will require a great size and weight, which becomes a special problem in the offshore environment, because weight is always a major concern for people in this situation. Moreover, fundamentally, the flat weld flange is an ineffective seal that requires 50% of the bolt load to be used to squeeze the gasket, while the load used to maintain the pressure is only 50%. The main design disadvantage of flat welded flanges is that they are not guaranteed to be leak free. This is the design flaw: the connection is dynamic, and cyclic loads such as thermal expansion and undulations cause movement between the flange faces, affecting the function of the flange, thereby impairing the integrity of the flange and ultimately leakage. It is impossible for any product to have no defects, but to minimize the shortage of the product as much as possible, so the company should try to improve the performance of the product when producing flat welding flanges, so that it can play its biggest role. What is a butt weld flange? A butt weld flange is a type of pipe and refers to a flange with a neck that has a transition of a round pipe and is butt welded to the pipe. Butt welding flange is not easy to be deformed, sealed, widely used, has corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition, the welding joint is away from the joint surface, the joint surface is protected from welding temperature deformation, it takes more complicated It is suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines. It is generally used for the connection of pipelines and valves with PN greater than 2.5MPa. It is also used for expensive, flammable and explosive transportation. On the tubing of the media. Classification of welded flanges Welding Neck Flanges The sealing faces of the neck butt weld flange are: face (RF), concave (FM), convex (M), face (T), groove (G), full plane (FF). Advantages: the connection is not easy to be deformed, the sealing effect is good, and the application is wide. It is suitable for pipes with high temperature or pressure fluctuation or pipes with high temperature, high pressure and low temperature, and also for conveying expensive medium, flammable and explosive medium and toxic gas. on Disadvantages: The neck-welded flange is bulky, heavy, expensive, and difficult to install. Therefore, it is easier to bump during transportation. Butt ring loose flange The loose flange of the welding ring is a movable flange. It is usually matched with the water supply and drainage fittings. When the factory leaves the factory, there is a flange at each end of the expansion joint, which is directly connected with the pipeline and equipment in the project. Function: The purpose of loosening the flange of the welding ring is generally to save material. The structure is pided into two parts. One end of the pipe is connected to the pipe and the other is made into a butt weld ring. The flanges are made of low-grade materials, and the tubes are made of the same material as the pipes to save material. Advantages: cost saving and easy construction. Disadvantages: low pressure. Low strength at the weld ring (especially when the thickness is less than 3mm) The difference between the welding flange and the flat welding flange Different weld joint forms: welded welds with neck welded flanges and flanges are in the form of fillet welds, while welded welds with neck butt welds and pipes are in the form of girth welds; The material is different: the neck flat welding flange material is made of ordinary steel plate machine with the thickness meeting the requirements, and the material with neck butt welding flange is machined by forging steel parts; The nominal pressure is different: the nominal pressure of the neck flat welding flange is: 0.6—4.0MPa, and the nominal pressure of the neck butt welding flange is: 1–25MPa grade. Another point is that the weld with the neck butt weld flange and the joint is a type B joint, and the weld with the neck flat weld flange and the joint is a type C joint, and the non-destructive testing after welding is different. The neck flat welding flange and the neck butt welding flange can not be replaced casually, in terms of manufacturing angle, the neck flat welding flange (SO is SLIP ON abbreviation), the internal diameter is large, which means the weight is small, the cost is low, and The neck-welded flange with a nominal diameter of more than 250 mm (WN is the abbreviation of WELDING NECK) is to be tested. The flange of the SO does not need to be tested, so the cost is low. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The causes of hydrogen crack formation in welding arc welding of stainless steel are mainly caused by three factors, namely, the brittle and brittle hard and brittle structure of hydrogen produced by the welding process, the tensile stress acting on the welded joint, and often when the temperature is up to the normal environment. In practice, for a given situation (material composition, material thickness, joint type, electrode composition and heat input), the risk of hydrogen cracking can be reduced by heating the joint. Reducing the cooling rate by preheating can diffuse some hydrogen and reduce the hardness of the stainless steel plate, that is, the hardness of the microstructural area sensitive to the crack, which causes the plate to break easily. When thick walled steel with high carbon equivalent (IIW CE) value is welded, the preheating level can be as high as 200 degrees. Because there are few cracks above the ambient temperature, it is also important to keep the temperature of the weldment of the stainless steel plate in the manufacturing process. For susceptible steels, it is appropriate to keep the preheating temperature at a given time, usually between 2 and 3 hours, so that hydrogen diffuses from the welding area. Under the condition of sensitive crack, such as high IIW CE steel welded or under high constraint conditions, temperature and heating time should be increased, usually at 250-300 C three to four hours. For many kinds of steel, post weld heat treatment (PWHT) can be used immediately after welding, i.e., no preheating temperature is allowed. But in fact, since inspection can only be carried out at ambient temperature, it is only after PWHT that the “disposable” defect can be found. In addition, for high hardness steel, second heat treatments may be needed to adjust the hard microstructure after the first PWHT. In some cases, in order to avoid cracking, more stringent procedures are required (higher preheating temperature and / or lower hydrogen content in welding metal). It includes the following: height constraints, including the weld of section thickness above 50mm, and the operation of the root in the double inclined joint; the thick part (more than 50mm); the low carbon equivalent steel (C < 0.1% and IIWCE < 0.42 C-Mn steel); "clean" or low sulfur steel (S less than 0.008%) because of low sulfur and oxygen content It will increase the hardenability of steel. The alloyed weld metal, where the preheating level to avoid HAZ cracking may not be enough to protect welding metal. Low hydrogen technology and consumables should be used. For predicting the preheating requirements to avoid welding metal cracking, the diffusion hydrogen level of welded metal and tensile strength of welded metal are usually required as input. The use of austenitic stainless steel and nickel alloy welding metal can also effectively prevent cracking. Austenitic consumables should be used in case of poor preheating or no cracking prevention. Austenitic stainless steel and nickel alloy electrodes will produce a welding metal, and the solubility of hydrogen to iron at ambient temperature is higher than that of ferritic stainless steel. Therefore, any hydrogen formed during welding is locked in the welding metal and rarely diffuses to HAZ when cooled to ambient temperature. The commonly used austenitic MMA electrode is 23Cr:12Ni, such as EN 1600:1997. However, because nickel alloy has lower thermal expansion coefficient compared with stainless steel, nickel alloy electrode is preferred to reduce shrinkage strain. When welding up to 0.2%C steel, it is usually not necessary to preheat. However, at a temperature above 0.4%, the minimum temperature of 150 C will be needed to prevent HAZ cracking. The best way to avoid hydrogen cracking is to reduce the hydrogen content of weld metal, that is, to reduce the amount of hydrogen generated by consumables, that is, using low hydrogen technology or low hydrogen electrode. According to the amount of welding metal hydrogen produced in the standard test block, the welding process can be pided into high, medium, low, extremely low and ultra-low. MMA is likely to produce more hydrogen content. Therefore, in order to achieve a lower value, the base electrode must be used and roasted according to the manufacturer’s advice, or removed from the special package immediately before use, and the time of exposure to the environment is not more than the specified time by the manufacturer. For the MIG process, cleaner wires are needed to achieve very low hydrogen content. The following general guidelines are recommended for all types of steel, but the requirements for specific steels should be inspected according to EN 1011-2:2001. Low carbon steel is easy to weld. If low hydrogen technology or electrode is used, it usually does not need preheating. When welding thick cross section material, it may need preheating, high binding force and more hydrogen. The thin part of medium carbon and low alloy steel can be welded without preheating, but the thicker part needs lower preheating level. Low hydrogen technology or electrode should be used. Higher carbon and alloy steels require preheating, low hydrogen processes or electrodes, post weld heating and required slow cooling. It is recommended that the following practical technologies be used to prevent hydrogen cracking, clean joint surface, remove paint, cutting oil, grease and other pollutants. If possible, use the low hydrogen process, roast electrode (MMA) or flux (submerged arc), then store them, or limit the time exposed to environmental conditions. The stress on the weld is reduced by avoiding large root gap and height constraints. If preheating is specified in the welding procedure, it should also be applied when the temporary attachment is glued or used, and the joint is preheated to at least 75mm from the seam line to ensure that the thickness of the material is heated evenly and the preheating temperature of the measurement and the reverse side of the heating phase is measured. In acceptance, because the hydrogen crack is a linear defect with sharp edges, it is not allowed to conform to the weld of the quality grade B, C and D according to the requirements of EN ISO 5817. There are several main aspects of detection and remedial measures, because hydrogen cracks are usually very fine and may be subsurface. Source: China Stainless Steel Plates Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

What is a rolled flange? The rolled flange is cut into slats by the middle plate, and then rolled into a round welded joint and then processed by a flattening process. The coil is made up of cold and hot coils. After processing into a circle, the water line, bolt holes, and stops are processed. This is generally a large flange, which can be up to 7 meters in one shot. Most of the plate type flat welding flanges are connected by welding. If the production process is produced in stages, it can be made to specifications of 12 meters to 15 meters or more. This type of flange has a good quality guarantee. Because the raw material is medium plate, the density is good. The welding process at the interface of the rolled flange is a top priority, and X-ray or ultrasonic film inspection is required. The interface is done, and the material of the entire flange is no problem. Relatively speaking, the product is thinner, lighter in weight, narrower in one side of the product, and has a higher sealing price, and some of the thicker, heavier, and less cumbersome processing flanges are available. It is lower. When the bolt hole is machined, it is not allowed to hit the bolt hole to the place where the weld is made. Such flanges are made of carbon steel, stainless steel, alloy steel, etc. Lpipe.com is capable of producing products up to 7 meters. Rolling flanges of more than 3 meters must first consider the transportation problem when signing the contract. Because the height limit of the overpass on the highway is 4.5 meters. The height of the car’s trunk is about 1.5 meters, and the height of the flange is too high. Ultra-high and ultra-wide coiled flanges can be applied to the local traffic management department for bulk transportation. However, the transportation cost of large parts is too high, it is recommended to produce in sections and go to the site for installation. Algorithm for theoretical weight of carbon steel coiled flanges: 1. First use (outer diameter – inner diameter) pided by 2 to get the result. 2. Reuse (outer diameter – above result) multiplied by the above result X0.0246615X thickness 3. After the above two steps, the theoretical weight of the carbon steel coiled flange is obtained. For example, the calculation method of the rolled flange with an outer diameter of 3000 mm, an inner diameter of 2800 mm and a thickness of 70 mm is as follows: 1.(3000-2800)/2=100. 2.(3000-100)X100X0.0246615X0.07=500.63KG After calculation, the theoretical weight of the flange is 500.63kg. In the machinery industry, many manufacturers use flanges (also known as reinforcement rings) only as a connection or support, so steel strips (flat steel) can be directly rolled onto the flanged equipment directly into the required ring. The circle can be used, this processing method saves labor and materials, and greatly saves costs. Classification of rolled flanges: Cold rolled flange The cold coil flange is a disc-shaped part that is commonly used in boiler piping engineering. The cold coil flange is mainly used for pipe connection. At the pipe joints to be connected, one roll flange is installed, and the low pressure pipe can use a wire-wound flange. The pressure of 4 kg or more is used to weld the cold-roll flange. A seal is placed between the two cold-roll flanges and then bolted. Cold-rolled flanges of different pressures have different thicknesses and use different bolts. Cold-rolled flanges increase with the percentage of carbon content. They are also called ordinary carbon steels. Nowadays, steels that are common in drunk are relatively low-priced, cold-rolled. Flange quotations provide relevant material properties to the cold-roll flange, what the cold-roll flange means, which is acceptable for many applications. The cold coil flange contains approximately 0.05 – -0.15% carbon, which enhances its toughness and plasticity. The rolled flange has a relatively low tensile strength, non-standard flange, but the rolled flange is relatively cheaper and easier to form. Coiled flanges often use a large amount of steel, and the hardness of the rolled flange can be increased by the carburized surface. The density of the rolled flange is approximately 7.85 grams per cubic centimeter. Hot coil flange The hot-roll flange blank is carried out by rolling a steel slab into a flat steel by a hot-rolling machine and rolling it into a circle. It is a relatively advanced flange blank manufacturing form in China, and the traditional flange manufacturing process. Compared to the following, there are obvious advantages: (1) All raw materials are made of standard billet, and the material is stable and reliable; (2), the flatness and ovality of the blank can be precisely controlled to minimize the processing volume; (3) The processing precision of the blank is high and the machining efficiency is increased by 50%; (4), the finished product rate is high, the material ratio reaches 1.25-1.35; (5) The newly developed convex flange blank product saves about 24% of raw materials compared with the traditional process; (6), energy saving and consumption reduction, the new process can produce 60% coal consumption per ton of flange compared with the traditional process, and the power consumption is 40%; (7), can be adjusted according to customer requirements. The difference between a cold coil flange and a hot coil flange is: The cold coil flange is formed at a low temperature (below the recrystallization temperature); The hot coil flange is formed at a high temperature (above the recrystallization temperature). Rolling flange processing technology: The middle plate is first cut into suitable slivers, and the length of the sliver is determined according to the specifications of the large flange. Then, the ring is rolled into a circle, and the joint is welded firmly with the electrode. Then use the press to flatten it, and then use the lathe to process the waterline, chamfering, etc. Finally, the indexing disc is used in conjunction with the drilling machine to process the hole of the bolt hole. The cost of a rolled flange is lower than that of a forged one. But some oversized flanges are forged. Most of these products are weighed by the theoretical weight. In the calculation, the weight of the water line, the stop, the bolt hole and the chamfer are not reduced. The price of a flat product is lower, but if a large flange with a process such as a dovetail is expensive, the price will be higher. The theoretical weight is calculated according to the above formula. The rolled flange replaces the original steel plate blanking, docking correction, lathe processing and other complicated processes, and saves oxygen, acetylene, labor, raw materials, etc., and the process is simpler. As a connection and support, the products are widely used. In the wind turbine, bridge last class, chemical equipment, cable racks, centrifuges and other industries. The rolled flange is a ring or arc that is directly cold-formed into the required diameter. The roundness is determined according to the customer’s requirements. The customer can directly use it on the cylinder or in the cylinder as a connection. Flange, talking about the support ring, etc., is convenient and inexpensive. The welding process at the interface of the rolled flange is a top priority, and X-ray or ultrasonic film inspection is required. The interface is done, and the material of the entire flange is no problem. Relatively speaking, the product is thinner, lighter in weight, narrower in one side of the product, and has a higher sealing price, and some of the thicker, heavier, and less cumbersome processing flanges are available. It is lower. Lpipe.com is a professional manufacturer of stainless steel coiled flanges, which produces rolled flanges of various materials such as super duplex stainless steel, duplex stainless steel, alloy steel and stainless steel. Source: China Stainless Steel Flange Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

High-pressure butt-welded flanges are suitable for pipelines with high pressure or temperature fluctuations or for high-temperature, high-pressure and low-temperature pipelines, as well as for pipelines that are expensive, flammable, and explosive. The high-pressure butt-welding flange is not easy to be deformed, has good sealing and is widely used. The nominal pressure PN is about 16 MPa. Butt weld flanges are suitable for pipelines with high pressure or temperature fluctuations or for high temperature, high pressure and low temperature pipelines, as well as for pipelines that are expensive, flammable and explosive. The welding flange is not easy to be deformed, sealed well, and widely used. The nominal pressure PN is about 16 MPa. The butt joint size of the flange changes with the nominal pressure, which makes the equal-diameter flange often unable to dock. The actual work of ordering, manufacturing, storage, installation, overhaul and maintenance is very troublesome. It is adopted for 0.25 and 0.6 MPa flanges. The 1.0 MPa butt size and the thickness are still in the original three specifications, thus simplifying the docking size. Production standard for high-pressure butt-welded flanges: Since the nominal diameter of the container cylinder and the nominal diameter of the pipe represent different sizes, the container flanges and pipe flanges of the same nominal diameter are also different in size. Can not substitute for each other. In addition to flat welding and butt welding flanges, there are cast steel flanges, cast iron flanges, looper flanges, threaded flanges, etc. In addition to GB9119.7-88, the standard for pipe flanges is: Standards of the Ministry of Chemical Industry HG20592~HG20602-97; Sinopec Standard SH3406-96. Among them, the Ministry of Chemical Industry is pided into the European system and the American system. The European system is commonly used in China. Because the operating pressure is not high, the diameter is not large, A-type flat welding flange, flat sealing surface can be used, and the gasket material is made of asbestos rubber sheet. The connecting bolt is made of Q235-A and the 2″ and 4″ flanges are used. High-pressure butt-welded flanges, also known as split flanges, are a type of flange. The flange is a part that connects the pipe to the pipe and is connected to the pipe end. There are holes in the flange, and the bolts make the two flanges tightly connected. Butt weld flanges and their gaskets and fasteners are collectively referred to as flange joints. Flange joints are an essential component in equipment and equipment components, and are also indispensable parts in piping design and pipe fittings. A butt weld flange is a flange that has a neck and is transitioned by a round pipe and is butt welded to the pipe. Butt weld flange is one of the flanged pipe fittings. It is widely used and promoted in different fields and industries. The applicable range is different in use, and the environment to be used is different. It needs to be used according to certain conditions. The welded flange is suitable for steel pipe connections with a nominal pressure not exceeding 2.5 MPa. It plays an important role and value in the link of the pipe, but the nominal pressure must be guaranteed to be within a certain range. The processing of high-pressure butt-welded flanges is called “five-step walk”. By strictly monitoring the precise five steps, we can produce high-quality butt weld flanges. Let’s take a look at the five steps. In the first step, the annealing temperature has reached the specified temperature. The welding flange treatment is generally a solution heat treatment, which is commonly referred to as “annealing”. The temperature range is generally 1040 degrees Celsius to 1120 degrees Celsius. It can also be observed through the observation hole of the annealing furnace. The flanged pipe fittings in the annealing zone should be It is in an incandescent state, but there is no softening sagging. In the second step, the welding flange is used to process the water vapor in the casting furnace. On the one hand, check whether the material of the furnace body is dry. When the furnace is installed for the first time, the material of the furnace body must be dried. Second, is there any excessive water stain on the flanged pipe fittings entering the furnace, especially if the flanged pipe fittings are free? Don’t leak into it, or else destroy the atmosphere of the road. The third step is the sealing of the furnace body. The soldering flange bright annealing furnace should be sealed, isolated from the outside air, using hydrogen as a shielding gas, and only one exhaust port is open. The inspection method can be applied to the joint gap of the annealing furnace with soapy water. Look at whether to run, the most easy place to run is the place where the annealing furnace enters the pipe and the place where the pipe is discharged. The sealing ring in this place is particularly easy to wear, and it is often checked frequently. The fourth step is to protect the gas pressure. In order to prevent micro-leakage on the welding flange, the protective gas in the furnace should maintain a certain positive pressure. If it is hydrogen shielding gas, it is generally required to be above 20kBar. The fifth step is to anneal the atmosphere. For the welding flange, pure hydrogen is generally used as the annealing atmosphere, and the purity of the atmosphere is preferably 99.99% or more. If another part of the atmosphere is an inert gas, the purity can be slightly the first point. But absolutely must not contain too much oxygen and water vapor. Butt welding flange is one of the flanges, and it has been applied in various fields. According to the range applicable to the welding flange e in use, the environment to be used is different, and it needs to be used according to certain conditions. . Butt welding flange has corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition, the welding joint is away from the joint surface, the joint surface is free from the welding temperature deformation, it adopts a more complicated squat body structure, suitable for pressure Pipes with high temperature fluctuations or pipes with high temperature, high pressure and low temperature are generally used for the connection of pipes and valves with PN greater than 2.5 MPa; they play an important role and value in the links of pipes, but must be guaranteed in use. The pressure is in a certain range. The sealing surface of the welding flange e can be made into a smooth type, a concave-convex type and a groove type, and the smooth type butt welding flange e has the largest application amount. Mostly used in the case of moderate media conditions, such as low pressure non-purified compressed air, low pressure circulating water, it has the advantage that the price is relatively cheap. Butt weld flange e is suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines, and also for pipelines that are expensive, flammable and explosive. The welding method used for the flange and pipe connection of the welding flange e is butt welding. The welding is similar to the welding of the pipe and the pipe. Generally, the pipe diameter is small, the argon arc welding is used to make the bottom, the cover is hand welded, and the pipe diameter is large. Only double-sided welding is used. Butt weld flanges are typically made using forging or forging processes. When made of steel or steel, the following requirements must be met: 1. The welding flange should be ultrasonically flawed without delamination defects; 2. It should be cut into strips along the rolling direction of the steel, bent into a ring by bending, and the surface of the steel forms a cylindrical surface. The steel plate shall not be directly machined into a neck butt weld flange; the butt weld of the ring shall be subjected to post-weld heat treatment and 100% ray or ultrasonic inspection, and the radiographic inspection conforms to the Class II requirements of JB4730, and the ultrasonic flaw detection conforms to JB4730. Level I requirements. In the actual application process, the high pressure butt welding flange is used for pipe connection, which is usually suitable for pipe connection with pipe diameter of 32-315 mm. When installing the socket type telescopic short pipe joint, it must be fixed by using the anchor pipe clamp to avoid the position of the socket pipe due to the influence of thermal expansion and contraction. If it is used in vertical vertical pipe, long-distance collection pipe network and buried pipeline between floor and floor, at least one socket type telescopic short pipe part shall be installed. If it is used on the pipe, it can be easily disassembled by loosening the screws and then rotating the pipes on both sides and then tightening. The reason is that the socket type telescopic short tube can not only eliminate the thermal expansion and contraction caused by the temperature change of the drainage process, but also facilitate the reliable connection with the branch pipes of each floor, so that the installation of the pipeline is more Simple and convenient. This high-pressure butt-welded flange is a flange product with good performance, which can show good performance and function in practical use, and can overcome the shortcomings of the traditional butt-welded flange. This high-pressure butt-welded flange is a reliable connection for two large-diameter pipes, usually consisting of two flanges plus several fastening bolts. It is actually made of carbon steel. Low carbon steel has good plasticity and weak strength. It can be added with carbon to make it harder. At this time, the plasticity will decrease and the strength will increase. This high-pressure butt-welded flange plays a good value and role in use. Use in the right way and method can effectively avoid a series of quality problems during use. This type of flange may have a corresponding size reduction problem during use because the diameter of the seal is reduced and the cross section of the seal surface is reduced. At present, such a high-pressure butt-welded flange is sealed with a sealing ring to ensure a good match between the sealing surface and the sealing surface. Source: China High Pressure Butt-Welded Flange Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The difference between the stainless steel elbow and the carbon steel elbow is mainly due to the difference in material. The chemical composition of the elbow will keep the surface of the elbow from rusting for a long time and will not be corroded. In a piping system, an elbow is a pipe that changes the direction of the pipe. According to the angle, there are three most commonly used 45° and 90°180°, and other abnormal angle elbows such as 60° are also included according to engineering needs. ​ The stainless steel elbow processing is based on the power of a conventional or special stamping device, so that the sheet material can directly withstand the deformation force and deform in the mold, thereby obtaining the production skill of the commodity parts of a certain shape, scale and function. Sheets, molds and their devices are the three elements of stamping. Because the stainless steel elbow pipe has the advantages of inner wall lubrication, low heat medium activity resistance, acid and alkali resistance, long service life and convenient installation. The stability of the stainless steel pipe can effectively prevent the pollution caused by the material. The stainless steel pipe has high strength, can withstand strong vibration and impact, has the characteristics of no water leakage, no bursting, fireproof and earthquake resistance, and is widely applicable. Besides disinfection and sterilization, it is not necessary to control the water quality. At the same time, there is no corrosion and dirty exudate. If the water stays in the pipeline for a long time, it will not affect the water quality and prevent secondary pollution. Obviously, this is a health barrier. Development trend of stainless steel elbow pipe: GB stamping elbow material not only has a qualified creep breaking curve, but also the price of the pipe is moderate, the construction is quick and convenient compared with other varieties, and the connection method is attributed to the most reliable mutual fusion hot melt fusion in the current period. The method, the hole diameter of the pipe part is larger than the inner diameter of the same standard pipe, and the system fluid resistance is relatively small because there is no mechanical connection method of local shrinkage in the system. Use and maintenance of stainless steel elbow In the process of home decoration, stainless steel elbows are used and maintained in a correct and reasonable way, which can prolong the service life. The main methods are: Long-term storage of stainless steel elbows should be checked on schedule. The exposed surface should be kept clean, dirt removed, and stored neatly in a place where the air is dry and dry. It is strictly prohibited to be stacked or stored in the open air. Always keep the stainless steel elbow dry and ventilated, keep the cleaner clean and tidy, and store it according to the exact storage method. The stainless steel elbow ball valve, stop valve, gate valve use, only for full or full closure, so as to avoid erosion of the sealing surface, accelerate wear. The gate valve and the upper thread stop valve have a reverse sealing device, and the hand wheel is screwed to the uppermost position to prevent the medium from leaking from the packing. When installing, the stainless steel elbow can be directly installed on the pipeline according to the connection mode, and installed according to the position used. Under normal circumstances, it can be installed at any position of the pipeline, but it is easy to check the operation. Keep in mind that the flow direction of the stainless steel elbow should be upward from the longitudinal valve. The stainless steel elbow can only be installed horizontally. Stainless steel elbows should be carefully sealed during installation to prevent leakage and affect the normal operation of the pipeline. Source: China Stainless Steel Elbows Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Duplex stainless steels require good overall mechanical properties. These properties are achieved by the selection of steel with the appropriate composition and by heat treatment by quenching and high temperature tempering. In the quenched and tempered state, the dual-phase steel has low carbon content, high plasticity and toughness, but low strength; the high carbon content is opposite, the strength is higher, and the plasticity and toughness are lower; if the carbon content is medium, At the same time, it has the proper strength, ductility and toughness. Therefore, in general quenched and tempered parts, most of the carbon content is in the range of 0.25 to 0.55%. The carbon content of carbon steel is biased to the upper limit (0.035-O.055%). This is because the alloying elements in duplex stainless steel have a strengthening effect instead of a part of carbon. The higher the alloying element content, the lower the carbon content. For example, S31803 stainless steel can be used as both quenched and tempered steel and carburized steel. Effect of Metal Elements Chromium and Nickel on Mechanical Properties, Logistics Properties and Corrosion Characteristics of Duplex Stainless Steel: Chromium The addition of chromium is primarily intended to provide corrosion resistance to duplex stainless steels. This is particularly effective in oxidizing environments such as those containing nitric acid. After the addition of chromium, an oxide having a stoichiometric ratio of iron oxide is formed on the surface of the steel. Because the affinity of chromium and oxygen is much higher than that of iron; the presence of chromium increases the stability of this oxide. Steels with a mass fraction of chromium greater than 10.5% are considered to be stainless in the atmosphere. Oxides that are stable in more aggressive environments require higher chromium levels. Chromium is also a ferrite forming element. An Fe-Cr alloy containing more than 12% Cr is an alloy of all ferrite. Increasing the chromium content in Fe-Cr-C or Fe-Cr-Ni-C alloys promotes the formation and retention of ferrite in martensitic stainless steel, austenitic stainless steel and duplex stainless steel. In ferritic alloy steels, chromium is the main alloying element for stabilizing ferrite structure. Chromium is also a strong carbide-forming element. The most common chromium-rich carbide is M23C6. Among them, M is mainly chromium, but sometimes some iron and molybdenum appear. In duplex stainless steel, the chemical formula of M23C6 is adopted and the default chromium is the main element in M. This carbide is actually found in all stainless steels. Cr7C3 type carbides may also form in duplex stainless steels, although this type of carbide is not common. Other composite carbides and carbonitrides M23CN6 may also form. Chromium can also form nitrides with nitrogen, the most common being Cr2N, which is observed in both ferritic and duplex stainless steels. Chromium is also an important component in the formation of intermetallic compounds, and intermetallic compounds have a tendency to embrittle duplex stainless steels, the most common being phase a, which is a temperature below 815 ° C in Fe-Cr systems. The (Fe,Cr) compound formed underneath. In fact, the sigma phase can be formed in any stainless steel, but is most common in high chromium austenite, ferrite and duplex stainless steel: chromium is also present in the yttrium phase and Laves phase intermetallic compounds. Since chromium can be used as a replacement atom in body-centered cubic (BCC) and face-centered cubic (FCC) lattices, chromium can be solid solution strengthened to some extent from the viewpoint of mechanical properties. However, in ferritic alloy steels, especially when carbon and nitrogen are present in the steel, high chromium content makes the toughness and plasticity poor. High-chromium ferritic steels must be carefully treated or have a low carbon and nitrogen content to achieve acceptable mechanical properties after welding. The determination of the alloy composition in the duplex stainless steel elbow takes into account the following factors: To ensure corrosion resistance, especially resistance to pitting corrosion, crevice corrosion resistance, stress corrosion corrosion resistance. To ensure the characteristics of the dual-phase steel, that is, after the solution treatment can have two phases, and one of the phases is not less than 25%. Has a certain strength, plastic toughness. Consider the same or different effects between different alloying elements. Consider the feasibility of material casting, heat treatment and processing. According to the above principle, the main alloying elements in the duplex stainless steel elbow are chromium, nickel, molybdenum, nitrogen, tungsten and the like.   (1) Chromium. Chromium is the most important element to ensure corrosion resistance. Chromium can form a passivation film and has good self-repairing ability to the damaged passivation film. As the chromium content increases, the passivation ability of the steel increases. Chromium has a significant solid solution strengthening effect on the matrix. As the amount of chromium increases, the yield strength of the steel increases. However, it causes σ to be precipitated equally, which reduces plasticity and toughness. Nickel Nickel is an important alloying element in stainless steel that is second only to chromium (which will be learned later). In order to resist the corrosion of reducing acid and alkali medium, it is not enough to contain only chromium in steel. Nickel must be added to chromium (see Figures 1 and 2). Nickel promotes the stability of the stainless steel passivation film and improves the thermodynamic stability of the stainless steel. Therefore, the coexistence of chromium and nickel in stainless steel can significantly enhance the stainless steel’s rust and corrosion resistance. Nickel is beneficial to the high temperature oxidation resistance of stainless steel, but is harmful to high temperature oxidation resistance. Because nickel and sulfur act to form low melting point sulfides. The formation of low melting point sulfides can significantly reduce the hot workability of steel. If the nickel content is too low, the ferrite phase content in the steel is too large, and the brittleness is easily increased. If the nickel content is too high and the ferrite content is small, the ferrite is more enriched with alloying elements such as chromium and molybdenum. Promote the precipitation of brittle phase, also reduce the toughness of steel. The low ferrite content, ie the austenite content, will affect the yield strength of steel. Therefore, considering the mechanical properties, the nickel content is suitable between 4.5% and 7.5%. Quenching and tempering process during heat treatment of duplex stainless steel In the heat treatment process of duplex stainless steel, the effect of cooling and quenching is very important. It should be correctly selected according to the hardenability of duplex steel, the shape and size of the workpiece and the specific conditions of production, usually under the premise of ensuring hardening. Slow cooling methods should be used to reduce quenching stress, reduce deformation and prevent cracking. Duplex stainless steel has low hardenability and requires oil quenching when stainless steel tubes smaller than 8 mm in size. When a larger diameter duplex stainless steel tube is quenched with two liquids, the residence time in water can be estimated from 3 to 5 mm/sec. In order to reduce quenching stress and deformation and reduce the tendency of quenching, S31803 stainless steel pipe with diameter ≤12 mm can be graded quenching, usually in a hot alkaline bath or molten nitrate salt at 170-200 °C for short time (3~5) Minutes) until silent, then air-cooled. Due to the high hardenability of duplex steel, in addition to water quenching of inpidual grades, it is generally quenched in oil, and can be quenched in alkali bath or nitrate salt. The residence time at the classification temperature can be extended to 30-60 minutes. The deformation is reduced by appropriately increasing the amount of retained austenite. After quenching, the duplex stainless steel should be tempered at low temperature to minimize internal stress, improve the plasticity and toughness of the steel, stabilize the performance and size of the steel, and prevent it while maintaining high hardness, high strength and high wear resistance. Grinding cracks. The tempering temperature of the dual-phase steel material is usually 150 to 160 ° C, the hardness after tempering is HRC 61–63, and the tempering degree of the smaller steel tube should be higher (180 ~ 2000 ° C) to increase the strength and keep Sufficient hardness (HRC 60 ~ 61). The tempering temperature of the duplex steel is slightly higher, often 160 to 180 ° C, and has a hardness of HRC 61-63 after tempering. During the actual operation, the duplex tempering temperature of the duplex stainless steel is higher, and the troostite structure is obtained to improve the toughness. For example, the hardness of S32205 stainless steel after tempering at 300-325 ° C is HRC 52-57; the hardness after tempering at 440–460 ° C is HRC 44-48. The tempering holding time is usually taken for 1 to 2 hours. For duplex stainless steel materials with good wear resistance, it is often necessary to pass tempering at 140-160 ° C for 30-60 minutes after grinding to eliminate the processing stress. The primary role of alloying elements is to increase the hardenability of duplex stainless steels. Comparing the hardened and unhardened specimens, if the tempering to the same hardness, the tensile strength is very small, while the yield strength and impact toughness of the unhardened specimen are lower. Therefore, all hardened duplex stainless steel materials can achieve high overall mechanical properties after quenching and high temperature tempering, and uniform performance over the entire cross section, while unhardened parts have poor performance. Since the alloying elements improve the hardenability, the mechanical properties of the duplex steel are improved and the process performance is improved. For example, oil quenching can be used to reduce the deformation and cracking tendency after quenching. The larger the cross section, the more pronounced the beneficial effect of the alloying elements. The use of a single element such as chromium, manganese, silicon, boron, can improve the hardenability of duplex steel, but in the quenching and high temperature tempering process, some defects often occur, such as increasing the tendency of overheating or increasing the high temperature Tempered brittleness. To overcome these drawbacks, certain elements such as tungsten, molybdenum, titanium, etc. may be added to the duplex stainless steel. From the performance of the duplex steel after tempering, in the quenching and tempering temperature range, the obtained tempering stability is higher, and the strength is lower. When tempering to the same strength, the stability is large, the tempering temperature needs to be higher, and the obtained plasticity and toughness are correspondingly higher, that is, the comprehensive mechanical properties are better. The small stability results in poor overall mechanical properties. In order to improve the tempering stability of the duplex stainless steel, alloying elements such as tungsten, molybdenum, vanadium, etc. may be added to the duplex steel. Compared with the carbon steel with the same carbon content, the duplex stainless steel has higher plasticity and toughness at the same strength, and the strength of the duplex steel is higher at the same plasticity and toughness. In addition, since the duplex stainless steel obtains an austenitic structure after high-temperature tempering, in which the ferrite content is large, the properties of the duplex steel can also be affected by changing the properties of the ferrite. Change process of carbide after tempering of duplex stainless steel After the tempering treatment of the duplex stainless steel, the a-phase recrystallization process in the material includes two aspects. On the one hand, the phase a and the carbide are in association with each other, so that the phase a is broken; on the other hand, the phase a is broken. Crystallization, forming polygonal ferrite grains. As this process progresses, intergranular stress (ie, the second type of stress) gradually disappears. Therefore, the influence of alloying elements on the above process is also manifested in two aspects, namely, on the one hand, delaying the destruction of the a phase and the carbide, and on the other hand, increasing the recrystallization temperature of the a phase. When discussing the influence of alloying elements on martensite decomposition, it has been pointed out that most of the alloying elements have different degrees of delayed martensite decomposition, ‘this directly proves that the alloying elements destroy the coherent relationship between phase a and carbide. Deferred. Because this process is actually a diffusion process, and the presence of alloying elements hinders the progress of diffusion, so that coherent damage and ferrite fragmentation can occur at higher temperatures. As the tempering temperature increases, the shredded ferrite, ie, the a-phase insert will gradually grow. This is a recrystallization process. This process is also a diffusion process, and the presence of alloying elements not only spreads itself. It is very low, and it also reduces the diffusion rate of iron atoms, thereby increasing the recrystallization temperature of phase a, which can be indirectly confirmed by the influence of alloying elements on the recrystallization temperature after cold deformation processing. For example, when various iron alloys are subjected to 90% cold working deformation, the recrystallization temperature is listed in Table 1-2 for each 1% (atomic) different element. As can be seen from the table, various elements are for ferrite. The body recrystallization temperature is improved to varying degrees. The combined action of several elements at the same time will more significantly increase the recrystallization temperature of phase a. In addition, if the tempering temperature is above the alloying element enrichment temperature, the non-carbide elements will be enriched in the ferrite, causing the ferrite to solid solution and strengthen, and the carbide elements diffusing into the carbide, possibly leading to carbides. The transformation, the precipitation of highly dispersed special carbides to produce dispersion strengthening, can greatly improve the mechanical properties of duplex stainless steel. In the test duplex stainless steel, alloying elements such as tungsten, molybdenum and niobium have the strongest hindrance to the recrystallization process of phase a, and aluminum, silicon, vanadium, chromium, manganese, nickel, copper and cobalt have less influence. The alloying elements can increase the recrystallization temperature of phase a to varying degrees, leaving the martensite morphology of phase a and the mosaic structure in which it is shredded to a higher temperature, which maintains the strength of the tempered structure and increases the steel. The heat and so on have important contributions. The alloying elements have a great influence on the formation, transformation and aggregation of carbides during tempering, especially the carbide forming elements, and the effect is more remarkable. The alloying elements affect the aggregation growth of carbides in two aspects. On the one hand, due to the aggregation process of carbides, it is essentially a diffusion process. The alloying elements change the diffusion coefficient of carbon in phase a, and thus change. The rate of aggregation of carbides; on the other hand, the aggregation of carbides is carried out by means of small particles dissolved and large particles grow, while alloying elements change the stability of carbides, so that small particles dissolve and large particles grow. The speed has changed, which has changed the rate of carbide accumulation. The non-carbide forming elements nickel and cobalt promote the aggregation of carbides, while the formation of silicon and carbide elements hinders the aggregation and growth of carbides, as shown in the figure for the content of each alloy element and the average of carbides during high temperature tempering. The relationship between the diameters, as can be seen from the figure, the average diameter of carbides increases only with the increase of cobalt and nickel elements, and decreases with the increase of other elements. In addition, in addition to affecting the aggregation and growth of carbides, alloying elements also produce two new processes for tempering of duplex stainless steels compared to carbon steels, which are described as follows: When carbon phase transitions in duplex stainless steel tempering X-ray analysis and electron microscopy observations show that when tempering duplex stainless steel is tempered, as the tempering temperature increases, during the formation of carbides, there is a process of converting alloy cementite into alloy carbide. A process is a secondary process that is not available when carbon steel is tempered. The transformation process of the alloy carbide can be clearly illustrated by the following diagram. It can be seen from the above diagram that the transformation process of the alloy carbide is also a diffusion process, that is, on the basis of the analysis of the carbide of the martensite fraction, the alloy cementite is formed by the diffusion of iron, carbon and alloy element atoms, and then converted into Alloy carbide. There are two ways for this transformation. One is to form an alloy carbide nucleus at the phase boundary between the alloy cementite and the ferrite, and grow up by the consumption of the alloy cementite; Second, the alloy carbide nucleus is directly precipitated from the ferrite matrix, and grows by relying on the alloy cementite to continuously dissolve into the matrix. This latter transformation will make the alloy carbides highly diffuse and difficult to aggregate and grow because it requires the diffusion of atoms of carbon and alloying elements over long distances. Effect of alloying elements on mechanical properties of duplex stainless steel The influence of alloying elements on the mechanical properties of duplex stainless steel is closely related to the heat treatment mode. In the annealed state, the alloying elements mainly act by solid solution strengthening of ferrite and changing the distribution state and relative content of carbides. In the annealed state of duplex stainless steel, the basic constituent phases are ferrite and carbide. The strength of the iron body plays a decisive role in the strength of the steel. Experiments have shown that all alloying elements can strengthen ferrite, but they are not strengthened to the same extent. Silicon, manganese and nickel have a greater strengthening effect. Silicon and manganese have strong effects and are rich in resources. They are the most commonly used elements for strengthening ferrite. China’s ordinary low-alloy duplex stainless steel is made of silicon and manganese as the main alloying elements. Tungsten, molybdenum and vanadium are the second, and chromium and cobalt have the least effect. Source: China Stainless Steel Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Pipe reducer for connection between pipes of two different pipe diameters. According to the shape, it is pided into two types: concentric small head and eccentric reducer. The different diameter pipe material includes stainless steel reducer (alloy steel, carbon steel reducer). The calculation method of the expansion arc length of the different diameter reducer: Concentric reducers, with a large head radius of R1, a small head radius of R2, and a height of H, these three data are known on sheet metal drawings. Decomposition of the expansion arc length of the reducer: For the convenience of calculation, the radius of the large arc is RD, the angle of expansion is α, the radius of the arc of the small head is RX, (R1—R2)=(ΔR), and L is the length of the side projection of the reducer. (RD-RX)=L=[(H)^2+(ΔR)^2]^(0.5) RD = (R1 × L) ÷ (ΔR), RX=(R2×L)÷(ΔR), The angle of expansion is α = [180 × (ΔR)] ÷ (L × π), and the unit is degree. The heterocentric reducer should be developed according to the sheet metal drawing. Concentric reducers, with a large head radius of R1, a small head radius of R2, and a height of H, these three data are known on sheet metal drawings. Production of seamless reducer A reducer (reducing pipe) is a type of pipe used for pipe diameter. The forming process usually adopted is a reduction press, a diameter expansion press, or a reduction and diameter expansion press. For certain sizes of different diameter pipes, press forming can also be used. Reduced diameter / expanded diameter forming The reduction forming process of the reducer is to put the blank of the diameter of the large end of the reducer into the forming die, and the metal is moved along the cavity and contracted by pressing along the axial direction of the blank. The reduced diameter forming process of the reducer is to put the blank of the same diameter as the large end of the reducer into the forming mold, and the metal is moved along the cavity and contracted by pressing in the axial direction of the blank. According to the size of the reducer of the reducer, it is pided into one or more press forming. The diameter reduction of the concentric reducer is to use a tube blank smaller than the diameter of the large end of the reducer, and the inner die is formed along the inner diameter of the tube. The diameter expansion process mainly solves the problem that the reducer having a large reduction diameter is not easily formed by the diameter reduction, and sometimes the method of expanding the diameter and reducing the diameter is used according to the material and product forming requirements. In the process of reducing or expanding the deformation and deformation, it is determined according to different materials and the diameter of the diameter to determine the use of cold or hot pressing. In general, cold pressing is used as much as possible, but in the case of severe work hardening caused by multiple reductions, thick wall thickness or alloy steel material, hot pressing is suitable. Stamping forming of reducer: In order to make the service life of the reducer longer, the quality of the product is better. Many people usually use the following techniques in the production of the reducer. Let me introduce the stamping method for the reducer: (1) Because the die guarantees the size and shape accuracy of the stamping part during stamping, and generally does not damage the surface quality of the stamping part, and the life of the die is generally long, so the quality of the stamping is not disordered, the interchangeability is good, and it has the same “Characteristics. (2) Stamping is generally free of chip scraps, material consumption is less, and no other heating equipment is needed, so it is a material-saving, energy-saving processing method, and the cost of stamping parts is lower. (3) Stamping can process parts with large size range and complicated shape, such as stopwatch from small to clock, large to automobile longitudinal beam, cage parts, etc., plus cold deformation hardening effect of material during stamping, strength of stamping And the stiffness is higher. (4) The production efficiency of the different diameter pipe stamping processing is high, and the handling is convenient, and it is easy to realize mechanization and automation. This is because the stamping relies on the die and the punching equipment to complete the processing, and the number of strokes of the ordinary press is up to several tens of minutes per minute. Second, the high-speed pressure can reach hundreds or even thousands of times per minute, and each punching stroke may get a punch. The internal pressure of the concentric reducer: Under the action of internal pressure, the bending moment caused by the area pressure difference at the end of the concentric reducer causes the big end to be relatively open and the small end is relatively contracted. (2) The inner surface of the eccentric side of the eccentric reducer under the internal pressure and the eccentricity The hoop stress on the outer surface of the side central portion is the largest. 5 The above theoretical results have been verified by finite element numerical analysis and experiments. The experiment also shows that the bending radius and the tube section radius of the ring shell increase under the action of internal pressure, while the tube wall thickness changes little. The concentric diameter reducer is formed by using a tube blank smaller than the diameter of the large end of the reducer, and is formed by expanding the inner diameter of the tube with the inner die. The diameter expansion process mainly solves the problem that the reducer having a large reduction diameter is not easily formed by the diameter reduction, and sometimes the method of expanding the diameter and reducing the diameter is combined according to the material and product forming requirements. The hoop stress formula and the meridional stress formula of the concentric reducer under internal pressure are derived. Under the corresponding structural parameters, the hoop stress formula of the different diameter elbow can be transformed into the hoop stress formula of the concentric reducer, the eccentric reducer, or the equal diameter bend. Based on this, the ultimate pressure type of the reducer is derived. The entire process is formed by the radial compression of the tube blank and the stretching process of the branch portion. Different from the hydraulic bulging tee, the metal of the hot-pressed three-way branch pipe is compensated by the radial movement of the tube blank, so it is also called the radial compensation process. In the process of reducing or expanding the diameter of the concentric reducer, it is determined according to the different materials and the diameter of the pipe, and cold or hot pressing is determined. Under normal circumstances, cold pressing is used as much as possible, but in the case of severe work hardening caused by multiple reductions, thick wall thickness or alloy steel material, hot pressing is preferred. Concentric reducer hot press forming is to pide the tube blank larger than the diameter of the three-way, about the diameter of the three-way diameter, and open a hole in the portion of the stretched branch pipe; the tube blank is heated, placed in the forming mold, and The tube is filled with a die of a tensile branch pipe; under the action of pressure, the tube blank is radially compressed, and in the process of radial compression, the metal flows toward the different diameter pipe member and forms a branch pipe under the drawing of the die. Eccentric reducer process pipe flow design: The eccentric reducer is internally cut at the ends of the nozzle, and is generally used for horizontal liquid pipes. When the eccentric pipe reducer is cut upward, it is called top flat installation. It is generally used for pump inlet, which is good for exhausting. The cut point is down to the bottom. It is generally used for adjusting the valve installation and using the drain. The concentric reducer facilitates fluid flow and has less interference with the fluid flow regime when the diameter is reduced, so the gas and the vertically flowing liquid conduit use concentric reducer diameter reduction. Because the eccentric reducer is flat on one side, it is good for exhausting or draining, which is convenient for driving and overhauling. Therefore, the horizontally installed liquid pipeline generally uses an eccentric reducer. The roundness of the reducer shall not be greater than 1% of the outer diameter of the corresponding end, and the allowable deviation shall be ±3 mm; the allowable deviation of the reducer size shall comply with the provisions of Table 4.2.2-3. The flowmeter of the corresponding caliber can be selected according to the actual flow rate of the process pipeline corresponding to the flow rate in the above table, and the flowmeter with the same caliber specification as the process pipeline can be selected as much as possible. The inlet of the pump inlet reducer should be installed so that the gas does not accumulate at the variable diameter to avoid cavitation due to improper installation. When the horizontal inlet pipe of the pump is reduced in diameter, an eccentric reducer should be used. When the pipe is pumped horizontally from bottom to top, the reducer should be “flat”; when the pipe is pumped horizontally from top to bottom, the reducer should be “bottom flat” to prevent gas from being at the pump inlet reducer. Accumulation, eccentric reducers are also installed in a “top flat” manner, even if the pipe is pumped horizontally from top to bottom. The pump that transports the medium with impurities at the end or side suction, when the suction speed is lower than the sedimentation speed of the impurities, the diameter of the reducer should be the same as the diameter of the nozzle that is inserted into the tank. The stress distribution of the reducer: The bending moment caused by the area pressure difference at the end of the different diameter tube causes the big end to be relatively open and the small end to shrink relative to each other. The standard of the reducer: There are two main systems for the international pipe flange standard, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by the American ANSI pipe flange. In addition, there are Japanese JIS pipe flanges, but they are generally only used for public works in petrochemical plants, and have little impact internationally. Now introduce the national pipe flanges as follows: European system pipe flange represented by Germany and the former Soviet Union American system pipe flange standard, represented by ANSI B16.5 and ANSI B 16.47 British and French pipe flange standards, the two countries have two casing flange standards. In summary, the internationally accepted pipe flange standard can be summarized as two different, non-interchangeable pipe flange systems: a European pipe flange system represented by Germany; the other is represented by the United States. American pipe flange system. IOS7005-1 is a standard promulgated by the International Organization for Standardization in 1992. This standard is actually a standard for pipe flanges that combines two series of pipe flanges from the United States and Germany. Classification of different diameter pipes Divided by material Carbon steel: ASTM/ASME A234 WPB, WPC Alloy: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H Low temperature steel: ASTM/ASME A402 WPL3-WPL 6 High Performance Steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70 Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC, PPR, RFPP (reinforced polypropylene). Divided by production method Can be pided into push, pressing, forging, casting and so on. Divided by manufacturing standards Can be pided into national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, Russian standard and so on. The products of the reducer have the following characteristics: The strength of the reducer is generally higher than that of the straight welded pipe. It can produce elbows with larger diameters with narrower blanks, and can also produce welded pipes with different pipe diameters with blanks of the same width. The strength of the reducer is generally better than that of the straight seam. The welded pipe is high, and the elbow with larger diameter can be produced with a narrow blank, and the welded pipe with different pipe diameter can be produced with the same width of the blank. The different diameter pipe production process is simple, the production efficiency is high, the cost is low, and the development is fast. The main raw materials for the production of different diameter pipes account for a large proportion of the production cost of different diameter pipes, and the price changes directly affect the changes in production costs. If the same type of stainless steel stamping elbow is used for welding, it is necessary to carry out preheating at 300 °C or more and slow cooling at around 700 °C after welding. If the weldment cannot be post-weld heat treated, a reducer electrode should be used. Application range of stainless steel reducer: First, Application in mining and coal industry (1) Mine: Mine filling, concentrate powder and tailings transportation are serious to the pipeline. The used powder conveying pipelines such as Panzhihua and Daye Mine have been used for less than one year. About 5 times. (2) Coal: The coal transportation and long-distance pipeline coal transportation are generally carried out by wet method. It is required that the conveying pipe is both wear-resistant and corrosion-resistant. The pipe can be used as a long-life conveying pipe with considerable economic benefits. Second, the application of different diameter pipe metallurgy and power industry The transportation of pulverized coal, ash, mud, lime gypsum slurry, etc. in the metallurgical and electric power industries requires a large amount of metal pipes to be consumed each year. The ceramic composite pipe is used to replace other pipes, and has the characteristics of high wear resistance, long service life, convenient installation and remarkable economic benefits. Introduction to anti-cracking technology of stainless steel reducer: The production of stainless steel reducers is mainly based on pressing, but the pressing process will make the hardness and density of the steel larger, but if it is not heated, cracks will easily occur. In the control of the variable diameter range, in general, the processing range of the stainless steel reducer is within one stage. For example, the reducer of 325-159 basically needs to be heated several times. First, the tube of 325 is pressed. The pressure of 325 is pressed into 273. This pressing also needs to be heated. The second diameter is 273 variable diameter 219. This time it is necessary to heat the tube to the specified temperature and then press. Then there is the process of 219 changing to 159, and each time the diameter is required to be heat treated. Various materials have their own hardness and tensile strength, so it is determined that the pressing strength of each material is also different. The same type of stainless steel reducer, the material processing method and the program will be very different. For example, the reducer of ordinary carbon steel is formed after three heat treatments. However, the greater the hardness of the reducer of the alloy material, the more the number of presses and the number of times of heating, and the more complicated the forming process. How to choose a reducer? If the diameter of the different diameter pipe does not match the inner diameter of the process pipe, the corresponding diameter reduction or expansion process should be carried out. If the pipe is to be reduced, it should be considered whether the pressure loss caused by this will affect the process flow. In order to prevent the distribution of the flow field after the installation of the reducer, the pressure loss, and thus the measurement accuracy of the electromagnetic flowmeter, the required central cone angle α is not more than 15°, and the smaller the better. Source: China Stainless Steel Reducer Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

In the piping system, the stainless steel elbow is a pipefitting that changes the direction of the pipe. According to the angle, there are three kinds of most commonly used 45° and 90°180°, and other abnormal angle stainless steel elbows such as 60° are also included according to engineering needs. Stainless steel elbows are made of cast iron, stainless steel, alloy steel, malleable iron, carbon steel, non-ferrous metals and plastics. The way to connect to the pipe is: direct welding (the most common way) flange connection, hot melt connection, fused connection, threaded connection and socket connection. According to the production process, it can be pided into: welded stainless steel elbow, stamped stainless steel elbow, push stainless steel elbow, cast stainless steel elbow, butt weld stainless steel elbow. What are the main differences between stainless steel elbows and carbon steel elbows? Stainless steel elbows and carbon steel elbows are mainly made of different materials. The chemical composition of stainless steel elbows will keep the surface of stainless steel elbows from rusting for a long time and will not be corroded. The main difference between stainless steel elbows and carbon steel elbows What is it? According to the standard production points are as follows: 1. According to the manufacturing standards, it can be pided into national standard, ship standard, electric standard, water standard, American standard, German standard, Japanese standard and Russian standard. 2. Divided by the production method can be pided into push, press, forge, casting and so on. The 90° stainless steel elbow is mainly used for a connecting pipe in pipe installation for the connection of the pipe bend. The advantage of the stainless steel elbow is that it is resistant to corrosion. In the case of corrosive chemicals such as chemical papermaking, stainless steel must be used, and the cost is generally high. The processing method of stainless steel elbow is as follows: Forging method: The end of the pipe or a section is punched by a swaging machine to reduce the outer diameter. The common forging machine has a rotary type, a link type and a roller type. Rolling method: Generally, the mandrel is not used, and it is suitable for the inner edge of the thick-walled tube. The core is placed in the tube, and the outer circumference is pressed by a roller for round edge processing. Stamping method: The pipe end is expanded to the required size and shape with a tapered core on the punching machine. Bending forming method: There are three methods that are more commonly used. One method is called stretching method, the other method is called pressing method, the third method is roller method, there are 3-4 rollers, two fixed rollers, one adjusting roller, and adjustment. With the fixed roll distance, the finished pipe is curved. Inflating method: one is to place rubber in the tube, and the upper part is compressed by a punch to make the tube convex and convex; the other method is to form a hydraulic bulge, fill the middle of the tube with liquid, and the liquid pressure drums the tube into the required The shape, the bulk of the production of bellows is used in this way. Welded stainless steel elbow The welded stainless steel elbow is called “shrimp bend”, which can be welded after cutting and cutting on the pipe or steel plate, and its specifications can be very large. The number of bends and the bend radius are freely determined by the producer. The welding bend is not very round, and the bending radius of both is not large, generally about 1 times the diameter of the pipe. The classification method of welded stainless steel elbows can be pided into long-radius stainless steel elbows and short-radius stainless steel elbows according to its radius of curvature. The long radius stainless steel elbow refers to the outer diameter of the tube whose radius of curvature is equal to 1.5 times, that is, R = 1.5D. The short radius stainless steel elbow refers to its radius of curvature equal to the outer diameter of the tube, that is, R = D. D in the formula is the diameter of the stainless steel elbow, and R is the radius of curvature. The most commonly used is the 1.5D stainless steel elbow. If it is not indicated in the contract as 1D or 1.5D, then the 1.5D should be optimized. The most commonly used implementation standards in China are GB/T12459-2005, GB/13401-2005, GB/T10752-1995. Pressure class classification If there are about seventeen types according to the pressure level, they are the same as the American pipe standards: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; 80, Sch100, Sch120, Sch140, Sch160, XXS, the most commonly used are STD and XS. According to the angle of the stainless steel elbow, there are 45° stainless steel elbows, 90° stainless steel elbows and 180° stainless steel elbows. In this way, there are many types of stainless steel elbows. Orders are often indicated as follows: “LR STD 90° 8″, which means long radius, pressure grade STD, 90° 8” stainless steel elbow; , “SR XS 45° 4″ means a 4” stainless steel elbow with a short radius and a pressure rating of XS, 45°. The above is the approximate classification of stainless steel elbows. There are two types of tees. The three ports are equal in diameter and have the same diameter tee. The diameters of the two ends are the same, but the diameter of the confluent end is different from the other two diameters. The representation is as follows: For equal-diameter tees, such as “T3” tee, the outer diameter is 3 inches of equal-diameter tee. For the reducer tee, for example, “T4 x 4 x 3.5” means a reducer with a diameter of 3.5 inches and a diameter of 3.5 inches. The pressure rating and the pressure level of the stainless steel elbow are the same, and the specification range is the same. Stamped stainless steel elbow Stamping and welding stainless steel elbow, which is stamped into a semi-annular stainless steel elbow with a stamping die of the same material as the pipe, and then two pairs of semi-annular stainless steel elbows are assembled and formed. Due to the different welding standards of various types of pipes, it is usually fixed by semi-finished products by group-to-spot welding. The on-site construction is welded according to the grade of pipe welds. Therefore, it is also called two-semi-welded stainless steel elbows. Advantages of stamping stainless steel elbows The stamping process has high production efficiency and is easy to operate, and is easy to realize mechanization and automation. This is because the stamping relies on die and punching equipment to complete the processing, and the number of strokes of the ordinary press is every minute. Up to several dozen times, high-speed pressure can reach hundreds or even thousands of times per minute, and each stamping stroke may get a stamping. Stamping generally has no chip waste, less material consumption, and no need for other heating equipment, so it is a material-saving, energy-saving processing method, and the cost of stamping parts is low. Stamping can process parts with large size range and complicated shape, such as stopwatches as small as watches, as large as car longitudinal beams, covering parts, etc., plus the cold deformation hardening effect of materials during stamping, the strength and rigidity of stamping Higher. Since the die ensures the size and shape accuracy of the stamping part during stamping, and generally does not damage the surface quality of the stamping part, and the life of the die is generally long, the quality of the stamping is stable, the interchangeability is good, and the characteristics are “ exactly the same”. . The forming process of stamped stainless steel elbows is complicated, and it needs to be welded according to different materials and uses, and gradually formed under a certain pressure. The forming of the stamped stainless steel elbow needs to be carried out according to a certain process, and the corresponding process is strictly followed, otherwise the produced stamped stainless steel elbow will have quality problems. A circular shell can be cut into four 90 ° stainless steel elbows or six 60 ° stainless steel elbows or other stainless steel elbows as needed. This process is suitable for Any large-scale push-to-stain stainless steel elbow with a stainless steel elbow and a stainless steel elbow with an inner diameter ratio greater than 1.5D is an ideal method for making large stainless steel elbows. This process molding method is used in the production of different stainless steel elbows, showing good use value in different fields, so that the process has a good value in the production of different stainless steel elbows. The advantages of the forming process of large-scale stamped stainless steel elbows are mainly reflected in the following aspects: It is not necessary to use the tube blank as a raw material, which can save the cost of the pipe making equipment and the mold, and can obtain a push stainless steel elbow of any large diameter and relatively thin wall thickness. The raw material of the stamped stainless steel elbow is special, and it is not necessary to add the raw material of the tube blank, and it is easy to control during processing. The billet of the stamped stainless steel elbow is flat or expandable surface, so the material is simple to cut, the precision is easy to guarantee, the assembly and welding are convenient, the raw materials are easy to control during processing, the operation is relatively simple, there is no complicated process, and the welding and assembly are convenient. . Due to the above two reasons, the manufacturing cycle can be shortened and the production cost is greatly reduced. Because it does not require any special equipment, it is especially suitable for on-site processing of large stamped stainless steel elbows. Hot pressed stainless steel elbow The hot-pressed stainless steel elbow is formed by heating the pipe and then forming it with professional equipment. Then it is cut and heated to a critical temperature. After being kept for a period of time, it is put into the quenching agent quickly, and the temperature is suddenly lowered. The cooling is faster than the critical cooling rate. Method made of stainless steel elbows. Manufacturing method of hot-pressed stainless steel elbow The specific production method is as follows: the hot-pressed stainless steel elbow is formed by heating the pipe and then forming it with professional equipment, and then cutting and heating to a critical temperature. After being kept for a period of time, it is quickly put into the quenching agent, and the temperature thereof is suddenly lowered to be greater than the critical value. Stainless steel elbow made by rapid cooling method. One of the treatment methods: quenching Quenching is to heat the stainless steel elbow to above the critical temperature, keep it for a period of time, and then put it into the quenching agent quickly, so that its temperature suddenly drops, and it is rapidly cooled at a speed greater than the critical cooling rate, and martensite is obtained. Heat treatment method for unbalanced tissue. Quenching increases the strength and hardness of steel, but reduces its ductility. Quenching agents commonly used in quenching are: water, oil, alkaline water and salt solutions. Treatment method 2: normalizing Normalizing is a heat treatment method in which the hot-pressed stainless steel elbow is heated above the critical temperature to convert the hot-pressed stainless steel elbow into uniform austenite and then naturally cooled in the air. Normalizing can eliminate the reticulated cementite in addition to the eutectoid hot-pressed stainless steel elbow. For the hypoeutectoid hot-pressed stainless steel elbow normalizing, the crystal lattice can be refined to improve the comprehensive mechanical properties, and the less demanding stainless steel elbow It is more economical to replace the quenching process with a normalizing fire. Push stainless steel elbow Pushing the stainless steel elbow is a push-made stainless steel elbow. Nowadays, the most important type of stainless steel elbow forming production process when the stainless steel elbow is pushed into the shape is firstly because the push-made stainless steel elbow is also The production of stainless steel elbows is fast, and then the stainless steel elbows can be produced in batch production. The quality of the stainless steel elbows is good. The molding process of stainless steel elbows is now stainless steel bending. The process parameters that influence the geometry of the stainless steel elbow are: the material, wall thickness and outer diameter of the billet, the material and shape of the mandrel head, the heating temperature and its distribution, and the advancement speed.  If the actual outer diameter of the tube blank is smaller than the Dp value calculated according to the formula, the bonding performance with the mold is good, but the inner arc of the stainless steel elbow is easily unstable and wrinkled. If the actual outer diameter of the tube blank is larger than the Dp value calculated by the formula, the result is the opposite. According to the above principle, the push tube blank used for the push stainless steel elbow in this test is shown in Table 1 (A is the left part of the elbow). Stainless steel elbows can be pided into: According to the manufacturing standards, it can be pided into national standard, ship standard, electric standard, water standard, American standard, German standard, Japanese standard and Russian standard. Divided by the production method can be pided into push, press, forge, casting and so on. The 90° stainless steel elbow is mainly used for a connecting pipe in pipe installation for the connection of the pipe bend. Connect two pipes of the same or different diameters to make the pipe turn 90°. Stainless steel elbow manufacturing process: 1. Feeding: material re-inspection, identification and transfer. 2, cutting: material re-inspection, identification and transfer, size control mark transfer. First, the material is hot pushed, the pusher is a horn-shaped core or mandrel, the mandrel is thickened and thickened, and the process of pushing the stainless steel elbow is a process of expanding the diameter of the belt, and there is support at the back. The cutting pipe section penetrates the mandrel, and a rear arch frame fixes the mandrel. There is a small car in the middle, and some of the trolleys are hydraulically driven. Second, in the finishing process, after the shot peening, the scale of the inner and outer surfaces of the stainless steel elbow is removed, and the both ends are treated with a groove to facilitate welding. Third, we must first select the specifications, and propose the pipe material, for example, a 90-degree stainless steel elbow. Through its curvature, it can be calculated that the long material can be processed into a 90° stainless steel elbow, and then cut with the length as the fixed length. Fourth, after the push, the stainless steel elbow should be shaped in this hot state, because some stainless steel elbows will be distorted after improper handling, which is not allowed. 3. Inspection: size and appearance quality control. 4, molding: size, appearance control; logo transfer; pressure control. 5A, heat treatment: temperature control. 5B, inspection: hardness, shape and size inspection control. 5C, calibration: shape tolerance control. 6, gold processing: shape size control. 7. Groove inspection: fine groove size control. 8, pickling / passivation: pickling time appearance control. 9, surface treatment: internal appearance control. 10. Non-destructive testing: internal quality control. 11, pickling / passivation: pickling time and appearance control. 12. Logo: Control according to user requirements and standards. 13, finished product inspection: according to the standard for sampling inspection control. 14, packaging. 15. Storage and transportation: Quality control according to specifications and user requirements. Polishing tips and specific steps for stainless steel elbows: The first thing that the stainless steel elbow is to be formed is that it is polished. The grinding can make the surface of the stainless steel elbow more bright, and it can also remove some forged corners. When grinding stainless steel elbows, use 80-mesh louver grinding wheel. Black is better to use. Apprentices recommend using red. It must be slow. Do not press hard. When grinding, try to flatten the grinding machine. After all the mills have been worn, the 320-mesh louver grinding wheel will be re-grinded once. The 320-head grinding wheel must be polished very carefully, otherwise it will leave the scratch of the 80-mesh grinding wheel. After the 320-mesh louver grinding wheel has been polished, the stainless steel elbow is waxed, and the new hand is better. Then continue to polish with the red hemp wheel, then press hard with the force, the harder the better. After the stainless steel elbow is polished, remember to clean the wax, it is easier to use dust. How to choose stainless steel elbow? Stainless steel elbows buy more people and sell more people, but how do people who buy them know stainless steel elbows? Is the quality of the stainless steel elbow you purchased good? People who buy stainless steel elbows can check whether the material is stainless steel. The chemical composition of the stainless steel elbow will keep the surface of the stainless steel elbow from rusting for a long time and will not be corroded. The appearance of a good stainless steel elbow is beautiful, the texture performance is strong, you can use the eyes to see if it is smooth, not rough; Choose a good service to sell stainless steel elbow enterprises, problems can be resolved in a timely manner. Source: China Stainless Steel Elbows Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel tee is a chemical pipe fitting with three ports, one inlet and two outlets; or two inlets and one outlet. It has T-shaped and Y-shaped shapes, has equal diameter nozzles, and has different diameter nozzles. At the same or different pipeline collections. The main function of the stainless steel tee is to change the direction of the fluid. Stainless steel tee general purpose in the branch of the pipeline, mainly used to change the direction of the fluid, used in the branch pipe of the main pipeline. It is easy to use and widely used in civil construction, machinery manufacturing, chemical industry, shipbuilding industry and other fields. Classified by pipe diameter Equal-diameter stainless steel tee: stainless steel tee with the same diameter as the branch pipe. Reducing stainless steel tee: stainless steel tee with smaller pipe diameter than main pipe diameter. Classified according to the docking form Butt-welded stainless steel tee: It is a stainless steel tee pipe welded after connecting with the connecting pipe. Socket type stainless steel tee: It is a stainless steel tee pipe fitting which is welded or welded after the connecting pipe fittings are inserted into the ends of the stainless steel tee. Ferrule type stainless steel tee: that is, each end is a ferrule joint, the stainless steel tee pipe fittings are inserted after the pipe fittings are inserted. Threaded stainless steel tee: threaded way to connect the stainless steel tee fittings. Classified according to the form of branch pipe Positive stainless steel tee: It is the stainless steel tee pipe fitting of the vertical pipe of the branch pipe. Oblique stainless steel tee: It is a stainless steel tee pipe with a certain angle between the branch pipe and the main pipe. Generally low-pressure stainless steel can be made on the pipe in the field, but the high-pressure pipe must use the finished stainless steel tee. What is the molding process of stainless steel tee? A. Hydraulic bulging of stainless steel tee The hydraulic bulging of the stainless steel tee is a forming process for expanding the branch pipe by axial compensation of the metal material. The process uses a special hydraulic machine to inject a liquid into the tube blank equal to the diameter of the stainless steel tee, and the liquid in the tube blank becomes smaller as the volume of the tube blank becomes smaller and the pressure rises. The special hydraulic machine is used to inject liquid into the tube blank with the same diameter of the stainless steel tee, and the tube blank is synchronously centered by the two horizontal side cylinders of the hydraulic machine, and the volume of the tube blank becomes smaller after being squeezed, and the liquid in the tube blank is The volume of the tube blank becomes smaller and the pressure rises. When the pressure required for the expansion of the stainless steel three-way branch pipe is reached, the metal material flows along the cavity of the mold under the double action of the liquid pressure in the side cylinder and the tube blank to expand the branch pipe. Due to the relatively large tonnage of equipment required for the hydraulic expansion process, it is mainly used in the manufacture of standard wall thickness stainless steel tees smaller than DN400. The suitable forming materials are low carbon steel and low alloy steel with relatively low cold work hardening tendency. ,stainless steel. B. Hot press forming of stainless steel tee The stainless steel three-way hot press forming is to reduce the diameter of the stainless steel tee by a diameter of about three to the diameter of the stainless steel tee, and to open a hole in the portion of the tension branch; the tube blank is heated and placed in the forming mold, and A die of a tensile branch pipe is placed in the tube blank; the tube blank is radially compressed under the action of pressure, and the metal flows toward the branch pipe during the radial compression and forms a branch pipe under the drawing of the die. The entire process is formed by the radial compression of the tube blank and the stretching process of the branch portion. Different from the hydraulic bulging stainless steel tee, the metal of the hot-pressed stainless steel three-way branch pipe is compensated by the radial movement of the tube blank, so it is also called the radial compensation process. Due to the use of heated stainless steel tees, the tonnage required for material forming is reduced. The hot-pressed stainless steel tee has wide adaptability to materials, and is suitable for materials of low carbon steel, alloy steel and stainless steel; especially stainless steel tees with large diameter and thick wall, which is usually used. Stainless steel tee extrusion molding method: Prepare a stainless steel tube blank with a plastic film on its surface; Extrusion of the stainless steel tube blank of the product to obtain a semi-finished product of the stainless steel tee; Solid solution treatment, surface grinding and bevel processing on the semi-finished products of the stainless steel tee of the product. Nine characteristics of stainless steel tee: The stainless steel tee has a thin and strong thin oxide film (self-passivation film) with corrosion resistance (oxidizing acid, organic acid, cavitation), heat resistance and wear resistance. Stainless steel tee has high corrosion resistance whether it is buried or used for pipeline connection. Therefore, it is more used in various water quality and can be effectively disinfected and sterilized. Even if it is immersed in water for a long time, there will be no rust and spots. It will not corrode and exceed the standard exudate, can keep the water pure and hygienic, effectively prevent the polluted water source, and can withstand the high water flow impact of 30 meters per second. Stainless steel tees have corrosion resistance because of the alloying elements contained in the steel. Stainless steel three-way corrosion test data shows that stainless steel pipe can last up to 100 years and does not require daily maintenance. Stainless steel tee has good performance, low price and low operating and maintenance costs. Stainless steel tee has excellent mechanical and physical properties. Stainless steel tee has good insulation performance, especially suitable for hot water transportation. The strength of stainless steel tee is very high, it is 2 times of galvanized pipe, 3 times of copper pipe and 6-10 times of PP-R pipe. It can withstand vibration shock well, with no water leakage, no bursting, fire prevention, Anti-seismic and so on, so it is very safe and reliable; Stainless steel tee has good frost resistance and heat resistance, simple installation and connection, light weight and good flexibility. Stainless steel tee maintenance and maintenance: Stainless steel stainless steel tees are used and maintained in a correct and reasonable manner, which can prolong the service life. Stainless steel tee ball valve, stop valve, gate valve only when fully open or fully closed, do not allow to adjust the flow, so as to avoid erosion of the sealing surface and accelerate wear. The gate valve and the upper thread stop valve have a reverse sealing device, and the hand wheel is screwed to the uppermost position to prevent the medium from leaking from the packing. Second, the long-term storage of stainless steel tees, should be checked on schedule, often the exposed surface must be kept clean, remove dirt, neatly stored in a place where the room is dry and dry, no stacking or open storage. The stainless steel tee is often kept dry and ventilated, the retainer is clean and tidy, and stored in an accurate storage method. When installing, the stainless steel tee can be directly installed on the pipeline according to the connection mode, and installed according to the position used. Under normal circumstances, it can be installed at any position of the pipeline, but it is necessary to facilitate the inspection of the operation. Note that the flow direction of the stainless steel three-way medium should be upward from the longitudinal valve flap, and the stainless steel tee can only be installed horizontally. Stainless steel tees should pay attention to the sealing during installation to prevent leakage and affect the normal operation of the pipeline. Source: China Stainless Steel Tee Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The stainless steel reducer is one of the chemical stainless steel pipe fittings and is used for the connection of two different pipe diameters. It is pided into stainless steel concentric reducer and stainless steel eccentric reducer. 1 Process for manufacturing stainless steel reducer The stainless steel reducer has a Concentric Reducer, an Eccentric Reducer and a Reducing El-bow. The latter two stainless steel reducers are non-axisymmetric tubulars. , have to take some unique manufacturing process, in general, the current manufacturing process is guaranteed for the quality of stainless steel reducer. 1.1 Manufacturing method of seamed pipe fittings The concentric reducer and the eccentric reducer with larger calibers can be formed by rolling on the buckling machine. The stainless steel reducer has only one radial longitudinal weld. Concentric reducers and eccentric reducers with small calibers and reducers of any size and diameter can only be pressed into a half shape by a die, and then the two halves are welded into one integral pipe. Stainless steel reducers have two radial longitudinal welds. And the two halves of the eccentric reducer and the different diameter elbow respectively require two pairs of molds. When the sheet (rolling) is pressed and formed into a stainless steel reducer, cold pressing is generally employed. Hot pressing is only used when the capacity of the press is limited. The size of the mold for cold pressing and hot pressing will be slightly different. 1.2 Manufacturing method of seamless pipe fittings The manufacturing process of the concentric reducer is the simplest. The thicker tube is used as the blank, and the one-port diameter or the tube with the same thickness is used as the gross damage, and the diameter of one port can be reduced. Regardless of the flaring or shrinkage, it is generally pressed with a mold. At present, the eccentric reducer is widely used in China to suppress the eccentric reducer. The eccentric reducer of the third grade or above produced by this process will produce serious gaps at the eccentric end of the small head, tumors on the inner wall, uneven wall thickness and ellipse. phenomenon. When the eccentric reducer is replaced by the structure obtained by the truncated concentric reducer, since the oblique section is not a round surface but an elliptical surface, there is a problem that the end surface and the straight tube are misaligned and cannot be completely connected. If a new pressing process is adopted, the concentric reducer is first pressed with a concentric mold, and the pressed concentric reducer is placed in an eccentric die to press the shape into a desired eccentric reducer, then the inside and outside. The surface is smooth, the small head is flat, the wall thickness is uniform, the roundness is qualified, and the raw materials used are less. The different diameter elbow can be formed by the die shrinking step by step on the basis of the equal diameter elbow. In order to facilitate the shrinkage, an extra elbow wall is cut off in the area of the elbow that is convenient for manual welding, and the mouth is welded after the shrinkage, and the weld must be strictly inspected. Thus, the reducer elbow becomes a half-welded pipe, but the wall thickness is relatively uniform. When the tube blank is pressed and formed into a stainless steel reducer, the large-diameter tube is generally used for hot-pressing and forming, and it is not suitable to use a small-diameter tube for cold-rolling and flaring. 2 Product inspection of stainless steel reducer The test objects are shown in Table 1. The geometric shape of the eccentric reducer is slightly deviated from the standard. The orientation of the surface strain measurement point of a eccentric reducer specimen is shown in Figure 1 and Figure 2. The two methods of ultrasonic non-destructive thickness measurement and physical anatomy after vernier caliper thickness measurement The results are compared as shown in Table 2, and other data are shown in Table 3. The measured wall thickness distribution of the eccentric reducer is shown in Figure 3. Table 1 Theoretical table of detection Fig.1 Geometric deviation of part of eccentric reducer Fig. 4 Surface hardness distribution measured by eccentric reducer warp In Table 2, there are two wall thickness values in the eccentric reducer. The upper wall thickness value and the lower wall thickness value are measured when the ultrasonic thickness measuring probe transmits and receives the acoustic wave separation surface parallel to the elbow axis and the vertical axis. The value of the average value of the two wall thicknesses of the eccentric reducer is 2.16%. The same method and content were tested on other pipe fittings. The measured ellipticity of the stainless steel reducer was less than 2%, and the error of the radius bend of the reducer was also small. Surface hardness. In order to evaluate the uniformity of the strength and performance of the material, the hardness measurement is a simple and easy means, and the tube to be tested is not damaged during the measurement. The measurement method is stipulated in Article 33 of the “Safety Supervision Procedure for Ultra High Pressure Vessels (Trial)”: “There shall be 5 circular lines perpendicular to the cylinder on the outer wall of the cylinder, and 4 points shall be drawn on each loop line. For hardness inspection, the hardness value should conform to the design drawings or standards. The difference between the highest and lowest values of the hardness between the loops should be no more than 40, and the points on the same loop should be no more than 20′′. The test hardness tester is located at the warp line C at the center of the eccentric slope and the measurement point on the warp G at the opposite circumference. The result of the warp G is shown in Fig. 4. The results of other fittings are shown in Table 4. Strength performance. According to the empirical formula in GB1172-74 “Black metal hardness and strength conversion value” ≈ 3. 5378HB (MPa) converts Brinell hardness into tensile strength. Table 2 Comparison of wall thickness of eccentric reducer Table 3 No. 1 easurement of the length of the circumferential arc of each cross section of the eccentric reducer Table 4 Average results of different diameter tube hardness test and estimated intensity value Table 5 Performance of 20 steel pipe 168 × 6.0 and its reducer 3 Gometrical analysis of stainless steel reducers According to Table 2 and Figures 3 and 4, from the end face 1 of the large end face to the section 5 close to the small end, the wall thickness is from thin to thick, and from the section 5 to the end face 7 of the small end face, the wall thickness is thick to thin. Because the inner hole of the small end is turned after forming, part of the wall thickness is removed, and the section 5 is a smooth transition zone of the straight end and the inclined section of the small end. However, the wall thickness of the end face of the small end is thicker than the wall thickness of the end face of the large end, because the wall thickness of the straight pipe of the pipe is relatively uniform. And when the wall thickness changes along the axial section, the variation between the warp threads is uneven, but there is obvious regularity: the wall thickness of the straight surface zone composed of warp beams B, C, and D does not change much along the axial direction because the zone The degree of processing deformation is small; the wall thickness of the slope area composed of the warp beams F, G, and H varies in the axial direction because the degree of processing deformation in the area is large. In addition, the wall thickness distribution trends of the concentric and different diameter pipes of the two sizes are completely the same. From the end face of the big end to the section close to the small end, the wall thickness is from thin to thick, and from the transition cross section to the end face of the small end, the wall thickness is from floating to thin, because the small end inner hole is turned after forming. Part of the wall thickness was removed. However, the wall thickness of the end face of the small end is thinner than the wall thickness of the end face of the large end, which is exactly the opposite of the case of the eccentric reducer, which is caused by the manufacturing process. And when the wall thickness changes along the axial section, the change between the warp threads has obvious regularity, but also has a certain dispersion. Figure 5 Load displacement curve of the sample 4 Strength performance analysis The surface hardness distribution trends of the large and small eccentric reducers are about the same, but they are not completely consistent. The main difference is the hardness of the small end, the hardness of the small end of the small eccentric reducer is higher, and the large eccentric reducer is small. The hardness of the end has dropped. In Table 4, the tensile strength of the samples was 6.1% and 11% higher than the strength calculations of the empirical formula, respectively. From Table 5, the yield strength and tensile strength of Sample 1 were increased by 9.0% and 2.0%, respectively, before the start of production, and the yield strength and tensile strength of Sample 2 were increased by 26.4%, respectively, before the start of production. And 8.8%. Extrusion processing in the manufacturing process of pipe fittings, geometric shape repair, cold work hardening, uneven heat treatment, plastic deformation of different parts of the actual pipe parts, although the product is finally normalized, its mechanical properties will still be a certain direction The opposite sex has a certain adverse effect on the stress distribution. Some scholars have studied the elbow and the tee. The anisotropy of the pipe material is not obvious considering the dispersion of the test data, and the variation of the yield strength does not exceed ± 5%. The degree of deformation of the wooden eccentric reducer is larger than that of the three-way, so the change in the yield strength of the pipe may exceed this value. 5 Conclusion The geometrical dimensions of the large and small stainless steel reducers are more accurate, but the wall thickness is very uneven. For a stainless steel reducer with a straight section, the wall thickness of the end face of the eccentric reducer is thicker than the wall thickness of the end face of the large end, and the wall thickness of the end face of the concentric reducer is larger than the wall thickness of the end face of the big end. To be thin, the wall thickness of the different diameter elbow is relatively uniform. Therefore, when testing, the geometry of both the large and small ports should be measured the most. The thickness of the stainless steel reducer tube is too thick. It is recommended to carry out a comprehensive wall thickness test record before use. It provides a basis for online thickness measurement to judge the thinning star, in order to accurately reflect the corrosion speed and ensure the safe operation of the pipeline. The ultrasonic thickness measurement method is slightly larger than the caliper thickness measurement method, thereby making the result dangerous. When measuring the maximum wall thickness, the measured value when the probe separation surface is parallel to the axis of the tube is slightly larger than the measured value of the partition surface perpendicular to the axis of the tube. Although less than 0.5%, the result is also dangerous. The ellipticity of the stainless steel reducer is less than 2%, and the error of the bend radius of the reducer is also small and can be ignored. The surface hardness of both ends of the stainless steel reducer is about 35% lower than the surface hardness of the middle section. When the tensile strength is estimated according to the empirical formula of 3.5378HB (MPa) in GB 1172-74, the result is still conservatively 6.1%. After the final normalizing treatment, the stainless steel reducer formed by the hot-pressing of the large-diameter tube blank has significantly improved the yield strength and tensile strength. Source: China Stainless Steel Reducer Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

There are always some carbon elements in the stainless steel head, and carbon is iron. I believe that everyone has heard a saying that it is to take advantage of the heat to melt the iron in the high temperature and eliminate its magnetism. It is often said that the solution treatment. After hot working, the stainless steel heads are not single-phase austenite, but also have a small amount of carbide. In order to obtain single-phase austenite and improve corrosion resistance, it can be heated at about IlOO C, so that all carbides are dissolved in austenite, and then water quenched to room temperature, that is to obtain single-phase austenite. This heat treatment, namely solid solution treatment (SHT), can improve the corrosion resistance of the material and soften the steel. Because of its special shape, if the cooling method is improper, the stainless steel head may cause insufficient solid solution or serious deformation, which directly affects the quality of the product. Heat treatment specification for solid solution treatment of stainless steel head The heating rate should be as fast as possible. If the conditions are permitted, the air furnace can be heated to 1050 C, then the stainless steel head is placed in the furnace and then cooled. The holding time is usually controlled by 1mm/2 minutes, but at least 30 minutes, up to 60 minutes. If several stainless steel heads are heated together in the furnace, the second must rise again to 1050 degrees in the furnace, and then heat up for 5 minutes. From 950 to 550 C, it must be controlled within 3 minutes. Stainless steel head The operation method of solid solution treatment for stainless steel head The stainless steel head with a diameter of less than lOOOmm is cooled by lifting the lifting lug after driving. For stainless steel heads with larger diameters and openings on the curved surfaces, the opening of holes on the surfaces of stainless steel heads should be subject to customer’s consent. The diameter of the general hole should be more than 30mm. In order to achieve better cooling effect, several vent holes can be opened. After discharge, the lifting lug horizontal position is immersed in water to cool down. For a stainless steel head with a larger diameter and no opening, the exhaust pipe is usually welded with two seamless steel pipes with a diameter of 80mm. The pipe is immersed in the water with a crane and the top of the exhaust pipe must be exposed to the water. Among the above three methods, the function of the tooling board is to control the change of the size of the stainless steel head. The thickness of the plate plate should be more than 30mm, the thicker the stainless steel head, the thickness of the tooling board should be correspondingly thickened. The welding of the tooling plate and the stainless steel head must be firm. Once the welding is not stable, if the welding process is undone during the cooling process, it may cause the deformation of the stainless steel head. The strength of the hanging ear should also be considered, because the strength of the steel plate may be only 1/10 at normal temperature when heating to 1050 C. In order to prevent problems during the lifting process, the strength of the hanger and the welding of the hanger must be confirmed. After the stainless steel head is immersed in the water, the water on the surface of the stainless steel head should be continuously flowing to prevent the formation of water film on the surface of the stainless steel head and the cooling rate of the stainless steel head.   Source: China Stainless Steel Head Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)