Search Results

One: The development trend of the world’s production technology of stainless steel pipes 2.1 “Three-step method” steelmaking and continuous casting process The use of the “three-step method” for steelmaking and continuous casting to produce stainless steel pipe blanks has created conditions for improving the quality of stainless steel pipe blanks and reducing costs. Some of the world’s major stainless steel plants have studied and adopted the “three-step method” to smelt stainless steel on the basis of the “two-step method”. At present, most of the professional stainless steel plants in Japan have adopted the “three-step method” production process. Mannesmann Demag Metallurgical Technologies of Germany has developed a process equipment dedicated to the “three-step process”, which includes an ultra-high power electric furnace, an MRP-L converter and a VOD unit. The process is melted in an electric furnace, the MRP-L converter is quickly decarburized with an oxygen lance, and the VOD vacuum furnace is deeply decarburized. The basic starting point of this process is to combine and promote the advantages of both AOD and VOD processes, and overcome the shortcomings of AOD argon and refractory materials with large consumption and long processing time, achieving low consumption, shortening time and reducing cost. purpose. Of course, electric furnace-AOD “two-step method” smelting stainless steel is also feasible. At present, more than 60% of the world’s stainless steel is produced by the “two-step” process. Foreign stainless steel pipe blanks have been basically continuous casting and continuous casting machines with vertical and arc type, and horizontal continuous casting machines are also used. Compared with the traditional ingot billet, the stainless steel continuous casting billet has a metal yield increase of 10% to 15%, the pipe billet quality is better, energy saving and production cost are reduced. In the continuous casting process of stainless steel, some alloying elements are easily oxidized, which is easy to produce oxide inclusions. In addition, the viscosity of molten steel is large, which easily causes the nozzle to block. Due to the complicated solidification shape of stainless steel, the thermal conductivity of molten steel is poor, and the casting blank is prone to cracks. Therefore, the speed of cooling and casting is strict, and each tundish heating, non-oxidation protection casting, electromagnetic stirring, and liquid level automatic control are adopted. A series of new technologies have greatly improved the quality of the slab, enabling some difficult-to-cast steel grades, such as titanium-containing stainless steel, single-phase austenitic stainless steel and martensitic stainless steel, to be cast smoothly, expanding the stainless steel continuous casting steel. Kind. 2.2 Hot extrusion process The hot extrusion process is the main production process of the world’s current hot-processed stainless steel seamless pipes. With the development of technology, some types of hot-rolled steel pipe units can produce stainless steel pipes, but the extrusion unit is the main production unit of stainless steel seamless pipes in the world. At present, there are more than 60 sets of extrusion units in the world. Except for a few for profile extrusion, 70% of the units are used for the production of steel pipes. The main type is stainless steel pipes. Compared with the extrusion (rolling, cross-rolling) production method, the extrusion method is characterized by three-direction compressive stress during metal deformation. Under such a good stress state, a good internal and external surface quality and metallographic structure can be obtained for a stainless steel pipe with high deformation resistance. Due to the improvement of the vertical hydraulic perforation process equipment, the wall thickness deviation of the waste pipe after extrusion can be adjusted to an accuracy of 5% to 7%. Extrusion molds are easy to manufacture and replace, making them suitable for small-volume, multi-size stainless steel pipes. The extrusion unit can also produce a wide range of steel pipes. A 50 MN extrusion unit can produce steel pipes of @25-254 mm, which is much more suitable for market demand than other pipe rolling methods. The outstanding advantage of using the extrusion method to produce stainless steel pipes is that the continuous casting slab can be directly used as raw materials, the product quality is stable, the replacement varieties are flexible, and the hot extruded product pipes can be directly produced, and various shaped stainless steel pipes can also be produced. Obviously, the production of finished pipes by extrusion and the provision of waste pipes for cold processing are a more economical method widely used in the production of hot-processed stainless steel pipes abroad, with the adoption of high-speed, automated, large-tonnage extruders, and The development of related technologies such as glass lubricant, non-oxidation heating, high-strength and high-toughness hot work die, and the production of stainless steel seamless steel pipes by hot extrusion, especially the production of difficult-to-deform stainless steel and high-alloy steel pipes have been rapidly developed. The method of providing a waste pipe for cold processing by a single two-roll cross-rolling perforation has been basically not adopted abroad. 2.3 Cold processing is mainly based on cold rolling and cold drawing Cold-worked stainless steel pipes tend to adopt a combined production process mainly consisting of cold rolling and cold drawing, and cold rolling mills and cold drawing machines are developed in the direction of high speed, high precision, long stroke and multi-line. 50% to 80% of stainless steel pipes are finished by cold working. Therefore, more attention has been paid to the development of cold working equipment. There are basically three types of cold working processes, namely cold drawing process, cold rolling process, cold rolling and cold drawing combined process. Cold processing of stainless steel pipes Most of the foreign countries adopt the cold rolling and cold drawing combined process, and the processing method is mainly cold rolling and cold drawing. Modern cold rolling mills can achieve large reductions and large reductions in wall thickness, and 80% of the rolling deformation is done on cold rolling mills. It adopts cold rolling and wall fixing, supplemented by cold drawing to change specifications and control outer diameter to meet the requirements of different varieties and specifications. The advantages of cold rolling and cold drawing combined process are: good quality of steel pipe, high wall thickness precision and surface quality of cold rolled steel pipe, cold drawing to ensure outer diameter accuracy of steel pipe; short cold working cycle, reducing intermediate degreasing, heat treatment, shrinkage, and correction Straight processes, saving energy and reducing metal consumption; large-diameter pipes can be used to produce small-diameter steel pipes, simplifying the types of raw materials. At present, the world’s cold rolling and cold drawing process technology and equipment level have been greatly developed. The cold rolling mill develops in the direction of high speed, long stroke, ring L type and high precision. The characteristics of this rolling mill are: 1 using inertial force and inertia torque vertical balance mechanism, the number of round trips of the rolling mill is improved; 2 adopting annular hole type, The length of the rolling deformation zone is 70% longer than that of the short stroke mill, the uniformity of rolling deformation is improved, and the delivery volume is increased. 8 The long pipe blank is used, and the length of the raw material of the waste pipe can be increased to 12 to 15 m, which can produce long steel pipes and improve the utilization of the rolling mill. Rate, the effective utilization coefficient of rolling is up to 80% or more; 4 adopting curved mandrel and good parabolic face type, reasonable metal deformation and long tool life. The above characteristics make the production capacity and product precision of cold rolling mill greatly improve the production of stainless steel pipe. The structure of the cold pipe drawing machine is still mainly chain cold drawing machine, and there are also a few hydraulic cold drawing machines. Multi-line, high-speed and fully automatic are the development direction of the current cold drawing machine. 2.4 Multiple welding techniques Advances in welding process technology have accelerated the development of stainless steel welded pipe production, and the application of various welding methods has further improved welding quality and productivity. At present, the stainless steel welding methods applied in the industry mainly include tungsten argon arc welding (TIG), high frequency welding, plasma welding and laser welding. Several welding methods have their own characteristics, and the most used ones are argon arc welding and high frequency welding: 2.4.1 TIG welding Stainless steel welded pipe requires deep penetration welding, no oxide inclusions, heat affected zone as small as possible, TIG welding with tungsten inert gas protection has good adaptability, high welding quality and good penetration performance. Its products are in chemical industry. Widely used in the industrial fields such as nuclear industry and food industry. The welding speed is not high. It is the inadequacy of argon arc welding. In order to improve the welding speed, various methods have been developed in foreign countries. Among them, the development of single-electrode single torch to multi-electrode multi-torch has been applied in production. In the 1970s, Germany first used a multi-torch to line up along the direction of the weld to form a long heat flow distribution, and the welding speed was significantly improved. Generally, the argon arc welding of the three-electrode welding torch is adopted. The wall thickness of the welded steel pipe is s ≥ 2 ram, the welding speed is increased by 3 to 4 times than that of the single welding torch, and the welding quality is also improved. The combination of argon arc welding and plasma welding can weld steel pipes of larger wall thickness. In addition, the use of 5% to 10% hydrogen in argon, followed by high-frequency pulse welding power supply, can also increase the welding speed. Multi-torch argon arc welding is suitable for the welding of austenitic and ferritic stainless steel pipes. 2.4.2 High frequency welding High-frequency welding has been used in carbon steel welded pipe production for more than 40 years, but it is a relatively new technology for welding stainless steel pipes. The economics of its production make its products more widely used in the fields of architectural decoration, household appliances and mechanical structures. High-frequency welding has a large power supply, and it can achieve a higher welding speed for steel pipes of different materials, calibers and wall thicknesses (more than 10 times higher than the high welding speed of argon arc welding). Therefore, high-frequency welding produces general-purpose stainless steel pipes with high productivity because high-frequency welding speed is high, which makes it difficult to remove burrs in the welded pipe. This is also the current high-frequency welding of stainless steel pipes that cannot be accepted by the chemical industry and the nuclear industry. One of the reasons. From the perspective of welding materials, high-frequency welding can weld various types of austenitic stainless steel pipes. At the same time, the development of new steel grades and advances in forming and welding methods, ferritic stainless steel AISI 409 and other steel grades can also be welded. 2.4.3 Combined welding technology Various welding methods for stainless steel welded pipes have their own advantages and disadvantages. How to improve strengths and avoid weaknesses, combine several welding methods to form a new welding process to meet people’s requirements for stainless steel welded pipe quality and production efficiency, is a new trend in the development of stainless steel welded pipe technology. After several years of exploration and research, the combined welding process has made progress, and Japan, France and other countries have mastered certain welding techniques for the production of stainless steel welded pipe. Combination welding methods are: argon arc welding + plasma welding, high frequency welding + plasma welding, high frequency preheating + three torch argon arc welding, high frequency preheating + plasma welding + argon arc welding. Combined welding increases the welding speed significantly. For combined welding with high-frequency preheating, the quality of welded steel pipe is equivalent to conventional argon arc welding and plasma welding. The welding operation is simple, and the entire welding system is easy to automate. This combination is easy to connect with existing high-frequency welding equipment. Low investment costs and good returns. 2.5 Bright heat treatment For the heat treatment of stainless steel pipes, a non-oxidation continuous heat treatment furnace with a protective gas is generally used in foreign countries for medium heat treatment and heat treatment of finished products. The conventional pickling process is eliminated because a bright surface that is free of oxidation is obtained. The use of this heat treatment process not only improves the quality of the steel pipe, but also overcomes the environmental pollution caused by pickling. According to the current trend of world development, bright continuous heat treatment furnaces are basically pided into three types: (1) Roller type bright heat treatment furnace. This type of furnace is suitable for heat treatment of large-size and large-volume steel pipes with an hourly output of 1. Ot above. The shielding gases that can be used are high purity hydrogen, ammonia decomposition and other shielding gases. A convection cooling system can be provided to cool the steel pipe faster. (2) Net belt type bright heat treatment furnace. This type of furnace is suitable for small The thin-walled precision steel pipe has an hourly output of about 0.3 to 1.0 t, and the treated steel pipe can be up to 40 m in length, and can also be processed into a coiled capillary. Equipped with a convection cooling system for fast cooling. Various gas can be used for gas fuel or electric heating. The steel pipe after heat treatment of this furnace type has no scratches and good brightness. (3) Muffle pipe type bright heat treatment furnace The steel pipe is installed on a continuous bracket and heated in the muffle pipe to process high-quality small-diameter thin-walled steel pipe at a low cost, and the hourly output is above 0.3t. The shielding gas can be used economically, and the heating source can be gas, oil or electricity. 2.6 Organic solvent degreasing The organic solvent degreasing technology has good degreasing effect and high degree of automation. In order to remove the oil stain on the surface of the steel pipe during cold rolling and cold drawing lubrication, the quality of the heat-treated steel pipe is improved and carburization is prevented, and the degreasing effect is good and the technical equipment is advanced. Organic solvent degreasing unit. Commonly used organic solvents are trichloroethylene, tetrachloroethylene, trichloroethane, chlorinated methane, and more commonly used is trichloroethylene. This solvent has good effect, easy recovery and low toxicity. Degreasing is carried out in a sealed chamber. The stainless steel pipe in the basket is taken off in the solvent tank. Grease, or further condense and degrease in solvent vapor. The entire degreasing process is done automatically by a computer in the sealed chamber. The trichloroethylene degreaser can be regenerated and reused. And monitor the solvent gas content in the use environment to avoid environmental pollution. 2.7 Finishing equipment modernization Equipped with modern finishing equipment and enhanced quality control is an important part of the production of contemporary stainless steel pipes. The stainless steel pipe finishing section is equipped with a non-destructive testing process, which is an indispensable quality inspection method. The advancement of non-destructive testing technology has enabled more manufacturers to adopt eddy current and ultrasonic combined flaw detection units, and equipped with laser caliper and ultrasonic thickness measuring device. Before the steel pipe leaves the factory, the quality is controlled from multiple links. This combined flaw detection unit has an advanced information processing system, and the measured signals are all digitized, processed and stored by computer, with high degree of automation and high production efficiency. High-precision straightening machine, cold pressing and rotary compression machine, multi-head (6-8 head) polishing machine, full-length marking device, etc., are all widely used stainless steel pipe finishing high-efficiency production equipment in the world. 2.8 Develop new technologies and processes Actively research and develop new technologies and processes to obtain high-quality, low-cost stainless steel pipe products. Many new processes and new technologies in the field of stainless steel pipe production have promoted the improvement of the quality of steel pipes and the reduction of production costs. 2.8.1 Welding + cold drawing production process The United States has developed a new process for the production of welded + cold drawn stainless steel pipes. That is, the stainless steel cold belt after slitting is formed into a welded pipe by argon arc welding, and then the finished product is obtained through a cold drawing and finishing process. Due to the high quality of argon arc welding, the performance of the weld is consistent with the substrate. Therefore, the stainless steel pipe produced by this process is 10% to 30% lower than the common process of hot extrusion + cold drawing (rolling). The production process is simplified and the cycle is shortened. 2.8.2 Warm rolling technology The warm rolling technology was invented by the former Soviet Union. It is obtained by heating the pipe material before cold rolling to 150 to 400 ° C by an induction heating device. This technology has the advantages of small rolling force and large amount of primary deformation. The OCrl8Ni9Ti steel pipe is subjected to two or three times of warm rolling without intermediate annealing, and the total deformation amount can reach 98%. 2.8.3 Ultrasonic vibration cold drawing process The ultrasonic vibration of the die during cold drawing can increase the reduction rate of each drawing pass, reduce the vibration phenomenon and surface pit of the steel pipe, and improve the surface quality of the steel pipe. This is because the ultrasonic frequency causes the device to vibrate, reducing the friction during drawing. The steel pipe is subjected to the extrusion of the drawing die and the mandrel to reduce the adverse effects of tensile stress. Source: China Stainless Steel Pipes Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Various types of stainless steel are increasingly being used extensively and successfully in a variety of different marine environments. It must be pointed out that the long-term corrosion protection of stainless steel in seawater requires complex anti-corrosion engineering techniques and substantial investment. Austenitic and martensitic stainless steels have long been used for superheater pipes and turbine blades on marine power plants. It is not easy to maintain a low chloride content in these devices because the application technology of the marine power plant does not differ from the basic principle of a general power generation device. Stainless steel is also being used in large-capacity chemical containers on ocean-going merchant ships, and its use is in some respects different from that used in land-based chemical plants. Most stainless steel grades have satisfactory results in marine applications, but different grades are sensitive to stress corrosion cracking. Martensite steel, represented by Type 410, and ferritic steel, represented by Type 430, will rust within a few months under ocean conditions. This uniform rust can be removed by mechanical grinding. The more popular stainless steel is austenitic stainless steel because of its high resistance to rust (except for stress corrosion cracking). Austenitic stainless steels also black out over time. This blackening can also be removed by sanding for aesthetic or other reasons. Stainless steel rarely produces a uniform rust candle in seawater, so you don’t have to worry about it in actual use. Propellers Tugboats on the ocean and propellers on other vessels can be made of cast stainless steel CF-8 (equivalent dry type 304 stainless steel). When the vessel is not sailing, a conductive metal loop is formed from the propeller shaft through the bearing to the hull. Casting propellers, which are equivalent to type 410 stainless steel, are also often used, and are widely used in other applications such as icebreakers. In the development of modern stainless steel technology, multiphase austenitic-ferritic stainless steel 20Cr-8Ni-3.5Mo has been used to cast large propellers (up to 3000kg) on ocean-going giant wheels. Ships that often work in ports are particularly susceptible to encountering logs or other floating bodies on the surface of the sea to accelerate the damage of the propeller. Therefore, the use of austenitic stainless steel to make the propeller can be repaired by straightening or welding, which is a problem worthy of attention in the selection of materials. Pumps It has long been observed that centrifugal pumps operate under seawater conditions, such as stainless steel components, which show a certain degree of reliability. In the seawater that keeps flowing, the CF-8M cast stainless steel impeller (which is equivalent to 316 stainless steel) and the 316 stainless steel as the main shaft can be used without any problem. Crevice corrosion and pitting corrosion are likely to become serious problems when the pump stops working. However, if a pump box with a relatively large wall thickness is made from a relatively lively and rust-resistant cast iron, the cast iron can provide cathodic protection during downtime. When the pump is working, the cathodic protection of the cast iron box must be able to polarize the lower rust steel, but the flowing water maintains the cathodic protection. In addition, long-term working pumps may be used interchangeably, sometimes with the replacement of seawater into fresh water for protection. Bulk containers Stainless steel has been used as a bulk container in freight to carry LNG, chemicals, beverages, etc. The container for LNG in freight is customary to use 304L stainless steel, the purpose of which is not to resist corrosion but to consider the mechanical properties at low temperatures. For containers of marine chemicals, the purpose of using stainless steel is mainly to take into account its corrosion resistance, which is different from the storage and transportation of terrestrial chemicals. If the vessel is a general irregular ship, the container carrying the chemical can also transport any item, from acetic acid, slurry to xylene. 316L stainless steel is generally used as the valve, freight pump, tube, heating coil and the container itself. The container may be composed of integral stainless steel or a layer of 0.06-0.08 in (1.5-2.0 mm) stainless steel plate coated with carbon steel. Before use, it is necessary to carry out a detailed inspection of the board for defects and thorough cleaning and passivation treatment. Experiments have shown that the chemical-filled passenger device allows flushing with seawater, but then it is annoying to rinse quickly with fresh water. For any stainless steel heating device in the container, do not start to prevent stress corrosion cracking before the chloride is completely flushed out. When designing a chemical container, it should not be considered for the purpose of holding seawater because it would lead to crevice corrosion. If the design stipulates that non-water supply is not acceptable, then a cathodic protection system must be considered to control the development of crevice corrosion. In this case, stainless steel containers may produce limestone deposits that are difficult to remove, which is a problem worthy of attention. Heat exchangers Austenitic stainless steel pipes have been widely used in the forced water circulation system coolers and power station steam condensers. The latter inlets are not suitable for copper alloy materials due to high pollution. A more popular material is 316 stainless steel. In the coastal and harbor areas, a large amount of foreign agglomerates and silt enter the condenser pipeline, which is particularly prone to serious obstacles, and measures must be taken to eliminate them. A reasonable measure is to use a rubber ball to circulate through the pipe, and the pipe wall is cleaned because the rubber ball can be squeezed. When the flow rate of seawater is about 1 m/s, it is possible to prevent marine organic impurities from being sucked in, thereby protecting the condenser pipe from pitting corrosion. Unlike other non-ferrous alloys, pipes made of stainless steel as a condenser are not limited by large flow rates, but are related to the economics of the entire pump unit. O-rings Series electrical connectors and O-ring locating devices are widely manufactured in Type 304 and Type 316 stainless steel, particularly marine and military engineering. With the above materials, satisfactory results can be obtained. The O-seal can be cathodically protected by hull, aluminum frame or other factors. Without cathodic protection, the O-ring seals quickly (some within a few weeks) produce crevices that cause severe failure. Source: China Stainless Steel Pipes Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

1. Tooling design and manufacture The large flange is made up of two clamping base plates of 900, two flanged plates and two vertical plates and four reinforcing ribs. In order to ensure the rigidity of the tooling, the welded joints of the connected plates shall be welded through the groove, and the welding angle is 20-30 mm. A corresponding bolt hole is drilled in the flange plate to ensure that the flange can be accurately connected with the flange bracket, and a gap between the back end of the small end flange and the pallet can be placed in the small manual jack, and simultaneously A notch is formed in the flange plate in the direction of the vertical plate, so that the elbow can be loaded into the tooling, and the tooling with the groove structure can be made by the thick steel plate, which can meet the rigidity requirement during cutting. 2. Tooling performance requirements The two flange faces of the large flange are perpendicular to each other, and the table of the vertical lathe is horizontally rotated, so the main function of the tool is to connect the tooling to the flange by bolt holes on the large end flange. . When the tooling is clamped on the workbench, ensure that the flange plane to be processed is concentric and parallel with the vertical lathe workbench. To reduce the number of tooling, the tooling should be able to change the clamping position to ensure that the bending can be processed on one tooling. Head 2 end size flange. At the same time, the tooling must have sufficient rigidity, otherwise it will seriously affect the processing quality of the flange sealing ring groove, so the height of the tooling should be reduced as much as possible under the use condition, which can improve the rigidity and facilitate the operation. The turning radius of the tooling and the large flange should not exceed the working radius of the vertical car, and the clamping can be easily adjusted to facilitate the cutting. 3. Tooling stiffness check When the cantilever beam of the trough structure is subjected to bending and torsion under the force of turning, the deflection and the rotation angle should be verified. Through the above check, the maximum deflection of 7.27×lO-7m and the maximum angle of 8.969×10-5 are extremely small deformations, and the ribs are added in the relevant parts. The stiffness is far beyond the calculated value, and the stiffness can fully satisfy the cutting force. The requirement is that the maximum turning diameter of the tooling and the elbow flange is 2.42 m<3.50 m (two-column vertical turning diameter), so this tooling is theoretically feasible. 4. Turning processing When processing large flanges, the bottom plate is adjusted downwardly and clamped on the vertical workbench. The elbow flange is installed in the manual assembly. The large end flange is fixed with the bolts to ensure the flange working surface and the vertical working. The table is concentric and parallel to cut. When processing the small end flange, the tooling bottom plate is downwardly mounted on the vertical working table. With 6 manual small jacks, the small end flange is bolted to the small end flange and the small end plate is tightened. The small flange can be cut with the small pallet, and the verticality of the size flange should be ensured when cutting and aligning the clamp. The large-scale flange tooling structure is simple and reasonable, easy to manufacture, good in rigidity, easy to adjust and operate during processing, and fully meets the needs of the three sets of elbow flanges that are processed by the large elbow flange on the vertical car. Qualified, in the future without a face machining machine, the use of vertical lathe processing of similar components has opened up a new way. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The flange is connected to the part between the pipe and pipe, connecting pipe used for end flange in between; also useful equipment import and export of, for the connection between the two devices, such as the reducer flange. Flange connection or flange connection, is defined by the flange, gasket and bolt three are connected as a group of combined sealing structure of the detachable connection. Pipe flange refers to the pipeline installation of piping flange, used in equipment refers to equipment import and export flange. There are holes on the flange, bolt the two flange connect. The flange gasket seal. Sub threaded flange connection (threaded connection) flange, welding flange and clamp flange. Flanges are used in pairs, low-pressure pipeline can use the wire connected flange, four kg more than the use of pressure welding flange. Between the two flange with a sealing gasket, and then tighten the bolts. The different pressure of different thickness of flange, bolt they use are different. Pump and valve, connection and pipe, these equipment locally, also made the corresponding flange shape, also known as the flange connection. In general the two plane surrounding the use of bolted connection parts and closed, generally referred to as “flange”, such as ventilation pipeline connection, the parts can be called “flange type parts”. But this connection is only a partial one device, such as a connecting flange and a water pump, water pump is not good to call “flange type parts”. Relatively small such as valves and so on, can be called “flange type parts”. Butt welding flanges are often used in environments where media conditions are relatively mild, such as low pressure non-purified compressed air and low pressure circulating water. The advantage is that the price is relatively cheap. The sealing surface of the welding flange can be pided into three types: smooth, concave and convex and grooved. Smooth butt weld flanges are used in a wide range of applications, and the other two types of butt weld flanges are also used in many applications. Butt Welding has a reasonable structure, high strength and rigidity, and can withstand various harsh environments such as high temperature and high pressure, repeated bending and temperature fluctuation, and does not reduce the sealing performance. 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. It is widely used at present because Butt Welding is not easy to be deformed, sealed, and has a wide range of uses, and has corresponding rigidity and elasticity requirements and a reasonable butt welding thinning transition. At the same time, because the distance between the welding joint and the joint surface is large, the joint surface can be protected from the welding temperature deformation, and a relatively complicated structure is adopted, which is suitable for pipelines with high pressure or temperature fluctuation or high temperature, high pressure and low temperature pipelines. It is generally used for the connection of pipes and valves with PN greater than 2.5 MPa; it is also used to transport expensive, flammable and explosive media. In the production process, the welding flange is strictly controlled in the production and welding to ensure that it can fully play its role and value in production and use. Butt welding flange refers to a flange with a neck and a round tube transition and is butt welded to the pipe. It is not easy to be deformed, has good sealing, is widely used, has corresponding rigidity and elasticity requirements, and has a reasonable butt welding thinning transition. . The relevant information on the welding flange is as follows: (1) The center circle diameter of the bolt hole of the butt flange is 50mm—-2130mm (2) The bolt hole diameter of the butt flange is 11mm-30mm (3) Thickness of butt welding flange: 12mm-58mm (4) Pipe outer diameter: A (17. 2-2032MM) B (14-2020MM) (5) Flange inner diameter: A (18-2036MM) B (15-2024MM) (6) Flange theoretical weight: 0.36kg–234.6kg (DN1800) Butt weld flanges are especially suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines. They are generally used for the connection of pipes and valves with PN greater than 2.5 MPa, and also for expensive, flammable and explosive transportation. On the tubing of the media. The butt weld flange is the same as the pipe to be welded at the interface end, and is welded like two pipes. The production and use characteristics of Butt Welding are easy to use and can withstand relatively large pressures. For welded flanges, materials are produced according to different grades of pressure. From low-pressure asbestos pads, high-pressure asbestos pads to metal mats. The welding flange is produced and produced in different ways and processes in actual production and development. According to the method and principle of the process, it can produce important value and effect on different aspects, and add certain in actual production. The elements that increase the characteristics and value of the carbon steel flanges, perform well in terms of use characteristics and value. In industrial pipes, the use of Chengdu welded flange connections is very extensive. In the home, the pipe diameter is small and low pressure, and the connection to the weld flange is not visible. If you are in a boiler room or production site, there are flanged pipes and equipment products everywhere. In the actual production process, the welding flange adopts certain technical parameters and requirements for production and application to ensure correct use and promotion according to certain methods and principles. Colleagues use certain process methods and principles for production and welding. To ensure the reliable quality of Butt Welding in use. The product grade and technical requirements for the butt weld flange are to comply with the relevant requirements in JB4726-4728. Carbon steel or austenitic stainless steel forgings with a nominal pressure of 0.25MP-1.0MPa are permitted, allowing them to be manufactured with Class I forgings. Forgings with a nominal pressure between 1.6 MPa and 6.3 MPa shall meet the requirements of Class II or Class II forgings. For forgings for flanges with a nominal pressure of not less than 10.0 MPa, chrome-molybdenum steel forgings with a nominal pressure of more than 4.0 MPa, ferritic steel forgings with a nominal pressure of more than 1.6 MPa and an operating temperature not exceeding -20 ° C, such flat welding Flange forgings must comply with the relevant requirements for Class III forgings. Normally, the butt weld flanges are manufactured using forging or forging techniques. If it is to be made of steel or steel, it must meet these requirements. The butt welding flange factory must pass the ultrasonic flaw detection test, and there should be no delamination defects after inspection. It is to be cut into strips along the rolling direction of the steel, and it is butt-welded into a ring shape by a bending process, and at the same time, the surface of the steel is formed into a ring cylinder surface, and it is not possible to machine the steel sheet material into a neck. Butt welding flange. For the butt weld of the ring, it is necessary to adopt the form of full penetration weld. The butt weld of the ring must be heat treated after welding, and the test of 100% radiation or ultrasonic flaw detection should be carried out, and the results of the radiographic inspection should be consistent. For the Class II requirements in JB4730, the results of ultrasonic flaw detection of Butt Welding must meet the Class I standard requirements of JB4730. Butt weld flanges are necked, while flat weld flanges are not. If it is for safety reasons, it is best to use butt welding. If it is normal medium, the pressure is not high, and the leakage will not cause danger. Source:China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fittings and flange production enterprises should take into account the production cost of pipe fittings, but also the factors of preventing corrosion and improving product quality. Therefore, it is necessary to adopt solid solution process in the production process of stainless steel flange to enhance the safety of pipe fittings. Heat treatment process plays a vital role in the quality and safety of pipe fittings. It is known that in order to save cost in pipe fittings production, a few enterprises did not take solid solution treatment, only used polishing and sandblasting methods to deal with the defects and shortcomings of pipe fittings, which will bring permanent hidden dangers to the use of pipe fittings. Effect of heat treatment on stainless steel pipe fittings The molecule structure, magnetic properties and physical properties of stainless steel pipe fittings have changed after forming and welding. The corrosion resistance of the stainless steel can be restored by the solution process under atmosphere protection. At the same time, the required hardness of the stainless steel can be obtained to ensure the best service performance of the stainless steel. The stainless steel pipe fittings after solution treatment have good improvement effect. 1. Eliminate the modification of stainless steel pipe fittings in the process of processing, reduce the hardness of stainless steel to less than 220HV, improve the plasticity and toughness of stainless steel, and make the pipes more convenient and safe in installation. 2. Restore the stress and intergranular change in the production process of stainless steel pipe fittings, reduce the intergranular corrosion and stress corrosion of stainless steel, and enhance the anti-corrosion ability. 3. Remove the magnetism of stainless steel and stabilize the structure. 4. Natural brightness of reduced stainless steel (different from polished brightness). Solid solution characteristics of stainless steel pipe fittings Stainless steel is a special kind of steel. Because of the existence of alloying elements such as nickel and chromium, its heat treatment has different characteristics from that of ordinary steel. 1. The thermal conductivity of stainless steel is low, which is only 27% of that of carbon steel at room temperature. With the increase of heating temperature, the thermal conductivity of stainless steel decreases gradually. Therefore, when stainless steel is heated at low temperature, the heating process should be carried out slowly. 2. Stainless steel can inhibit carbide formation by solution heating to about 1100 ℃, then rapidly cool to room temperature, so that carbon reaches supersaturation state, which can greatly improve the corrosion resistance of stainless steel. 3. Gas protection (hydrogen) is used in the solid solution process to avoid the formation of viscous iron oxide on the surface of stainless steel, reduce the brightness of the surface of stainless steel, and improve the appearance of the reputation. Three elements of solid solution for stainless steel pipe fittings The solid solution process of stainless steel pipe fitting has a great influence on the corrosion resistance and appearance brightness of stainless steel, and plays a decisive role in the processing performance of stainless steel. Therefore, the heat treatment process of stainless steel is very important in the production of stainless steel pipe fittings. 1. Solution temperature. According to the characteristics of the chemical composition of stainless steel, the solution temperature of stainless steel should be 950 – 1150 degrees Celsius to achieve the softening effect, so that the hardness of stainless steel can be reduced to less than 220HV, to meet the quality requirements of pipe installation and clamping. If the temperature control is unreasonable, it is easy to produce various quality defects. 2. Solution time. During the heating process of stainless steel, the residual ferrite content in the steel decreases with the prolongation of heating time. Therefore, the solution treatment of stainless steel pipe fittings should be controlled at about 1050 ℃ to saturate carbon and improve corrosion resistance. Then it is cooled rapidly in the air to achieve solid solution effect. 3. Solution speed and heat preservation. The thermal conductivity of stainless steel is low, which is only 27% of that of carbon steel at room temperature. Therefore, the heating process of stainless steel at low temperature should be carried out slowly. If the heating speed is too fast, it is easy to produce deformation. In solid solution, the heating speed of stainless steel should be controlled, and the holding time should be paid attention to. If 316L steel is kept at about 1100 ℃ for a long time, the content of residual ferrite will decrease continuously. In solid solution production, the solid solution of stainless steel pipe fitting needs to be heated, insulated and time cooled, and the whole process takes about 40 minutes.

Butt welding flange, also known as high neck flange or large tail flange, is a type of pipe fitting. It refers to a flange with a neck and a transition of a round pipe and is welded to the pipe. The butt welding flange is not easily deformed. It is well sealed and widely used. It is suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines. The advantage is that the price is cheap, the nominal pressure does not exceed 2.5MPa; it is also used for transportation expensive, flammable and explosive. On the pipeline of the medium, the nominal pressure is around PN16MPa. Use an accurate installation sequence for the welded flange: 1. Firstly, the inner and outer sides of the connected stainless steel pipe fittings should be finished before connecting the butt welding flange. 2. Install the flanges with grooved rings on the pipe to be connected. 3. The port of the pipe needs 90 degree flanging process. After processing, the port plane requirements of the pipe are polished. After grinding, it should be vertical and flat, and there are no doubts about burrs, bumps and deformations, and the nozzle needs to be rounded with special tools. . 4. Another simple method is to use the finished product to make a short pipe and then weld it to the pipe. 5. Insert the O-shaped rubber sealing ring stainless steel sealing ring installed on both sides in the flange with grooved ring. The inner diameter of the seal ring is the same as the inner diameter of the pipe. 6. Then connect the flange holes with bolts, and the bolt assemblies should be tightened symmetrically. 7. When tightening the Shandong butt welding flange, it is necessary to pay attention to the tightness of each joint, and it is necessary to reach the required specifications. 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. The welding flange is not easy to be deformed, sealed, and widely used. It is suitable for pipelines with high pressure or temperature fluctuations or high temperature, high pressure and low temperature pipelines. The strength is cheaper, the nominal pressure does not exceed 2.5MPa; also used for conveying quotes. On the pipeline of expensive, flammable and explosive medium, the nominal pressure is around PN16MPa. There are two techniques for making welded flanges: The first type is die forging, which is to heat the steel material in a heating furnace to 1200 C, and then put it into a mold of the corresponding specification for forging. The second type is free forging. The material is heated to 1200 C in a heating furnace, and then the square material is forged into the shape of a round cake. The material is punched and the special material is used to ream the punched material to the required size. Technical requirements for welding flanges: The welding flange connection is easy to use and can withstand relatively large pressures. For welded flanges, materials are produced according to different grades of pressure. From low-pressure asbestos pads, high-pressure asbestos pads to metal mats. The welding flange is produced and produced in different ways and processes in actual production and development. According to the method and principle of the process, it can produce important value and effect on different aspects, and add certain in actual production. The elements that increase the characteristics and value of the carbon steel flanges, perform well in terms of use characteristics and value. In industrial piping, the use of butt flange connections is very broad. In the home, the pipe diameter is small and low pressure, and the connection to the weld flange is not visible. If you are in a boiler room or production site, there are flanged pipes and equipment products everywhere. In the actual production process, the welding flange adopts certain technical parameters and requirements for production and application to ensure correct use and promotion according to certain methods and principles. Colleagues use certain process methods and principles for production and welding. To ensure the reliable quality of the welded flange in use. The product grade and technical requirements for the butt weld flange are to comply with the relevant requirements in JB4726-4728. Carbon steel or austenitic stainless steel forgings with a nominal pressure of 0.25MP-1.0MPA are permitted, allowing them to be manufactured with Class I forgings. Forgings with a nominal pressure between 1.6MPA and 6.3MPA shall meet the requirements of Class II or Class II forgings. For forgings for flanges with a nominal pressure of not less than 10.0MPA, chrome-molybdenum steel forgings with a nominal pressure of more than 4.0MPA, ferritic steel forgings with a nominal pressure of more than 1.6MPA and an operating temperature not exceeding -20 degrees Celsius, such flat welding Flange forgings must comply with the relevant requirements for Class III forgings. Normally, the butt weld flanges are manufactured using forging or forging techniques. If it is to be made of steel or steel, it must meet these requirements. The butt weld flange must be subjected to ultrasonic flaw detection, and there should be no delamination defects after inspection. It is to be cut into strips along the rolling direction of the steel, and it is butt-welded into a ring shape by a bending process, and at the same time, the surface of the steel is formed into a ring cylinder surface, and it is not possible to machine the steel sheet material into a neck. Butt welding flange. For the butt weld of the ring, it is necessary to adopt the form of full penetration weld. The butt weld of the ring must be heat treated after welding, and the test of 100% radiation or ultrasonic flaw detection should be carried out, and the results of the radiographic inspection should be consistent. For the Class II requirements in JB4730, the results of ultrasonic flaw detection of the welded flange must meet the Class I standard requirements of JB4730. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Types of flanges As already described before, the most used flange types ASME B16.5 are: Welding Neck, Slip On, Socket Weld, Lap Joint, Threaded and Blind flange. First, the different diameter flange Product Name: Reducing flange Technical parameters: implemented in accordance with national standards Quality standards: manufacturing in strict accordance with relevant standards established by the state Product specifications: DN15-DN2000 Product packaging: wooden box or other Product color: metallic color Features: anti-corrosion, acid and alkali resistance, long service life, reasonable price calculation, smooth surface, acid and alkali resistance, high temperature, beautiful appearance, strong texture Production process: professional overall forging, forging manufacturing, medium plate cutting, medium plate rolling, etc. Processing methods: high-precision CNC lathe turning, general lathe finishing, argon arc welding, etc. Nominal pressure sch5s, sch10s, sch20s, sch30s, sch40s, etc. Manufacturing standards: national standard, American standard, Russian standard, Japanese standard, etc. Material: 201,304.316.316L.0Cr18Ni9.321.202, etc. Uses: Widely used in water conservancy, electric power, power stations, pipe fittings, industrial, pressure vessels, etc. Connection method: flange nut, bolt connection. Second, stainless steel flange Name: Stainless steel flange Specifications: 1/2″ ~ 240″ (10-6000) Pressure rating: 0.6Mpa ~ 32Mpa, 150Lb ~ 2500Lb, PN0.25-PN42.0 Material: 304, 304L, 321, 316, 316L, 310S and other materials Ministry of Chemical Industry Standards: HG5010-52~HG5028-58, HGJ44-91~HGJ65-91, HG20592-2009 (PN Series), HG20615-2009 (Calss Series) Applications: Boiler and pressure vessels, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, food and other industries. Third, the pressure vessel flange Product Name: Pressure Vessel Flange Specifications: DN300~3000 Product Remarks: Pressure Vessel Flange Application Industry: HVAC Power Building Water Supply Pressure Vessel Accessories, Pressure Pipe Fittings. Product category: Flange series Application industry: HVAC Power Building water supply Pressure vessel fittings, pressure piping fittings. Application technical parameters: Seal Nominal pressure PN, MPa(bar) 0.6 1.0 1.6 2.5 4.0 6.4 Concave surface (MFM) DN1300~3000 DN300~3000 DN400~2000 DN300~800 (TG) DN1300~3000 DN300~3000 DN300~3000 DN300~800 Full plane (FF) DN300~3000 DN300~3000 DN300~3000 DN300~800 Fourth, flat welding flange Flat welding flanges include plate flat welded flanges and neck flat welded flanges. (1) Plate type flat welding flange (PL) Plate type flat welding flange structure diagram 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 type. Smooth type flat welding The flange is the largest application. It is mostly used in the case of moderate media conditions, such as low pressure non-purified compressed air and low pressure circulating water. (2) Sketch with neck flat welding flange with neck flat welding flange (SO) The neck flat welded flange has a low neck height and 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, repeated bending and temperature fluctuation cannot be withstood, but the on-site installation is convenient, and the process of welding seam bruises can be omitted, which is more popular. Five, welding Neck Flanges (WN) Welding Neck Flanges: Neck flange welds are often referred to as “high-hull” flanges. The purpose is to transfer the pressure of the pipe, thereby reducing the high stress concentration in the flange base. Neck flange welding is the best design for brazing those flanges that provide structural value due to their existence. However, the price is relatively high because the production process of the product is complicated. Sixth, threaded flange The threaded flange is connected by a thread. However, the center of the product has a thread size corresponding to the tube. The main advantage is that it can be assembled without welding. Seven, Sliding flange The sliding flange has a lower hinge because the pipe enters the single flange before welding. This is the internal and external weld that provides sufficient strength to prevent leakage. The sliding flanges are all matching of the boring slightly larger outer diameter pipe. They are superior to neck flanges because of the low initial cost and many users, but the final installation cost is probably not as low as the increased weld neck flange is less. Eight, lap flange The lap flange is actually the same sliding flange unless it has a radius between the hole and the flange race. It is necessary that the radius has a flange to accommodate the end of the lap stub. Typically, the lap flange and the lap joint will be mated together at the end of the month. The socket weld flange is a similar sliding flange unless it has a hole and reverse hole size. The counter hole is matched to the pipe so that the pipe is inserted into a similar sliding flange of the flange. The diameter of the smaller holes is the same as the matching of the same ID pipe. The limit is a built-in hole that acts as a sleeve for the pipe to stay at the bottom. This eliminates any flow restrictions on the use of socket weld flanges. Nine, socket welding flange (SW) Socket weld flange sealing surface form: raised surface (RF), concave and convex surface (MFM), grooved surface (TG), ring joint surface (RJ) Material: Carbon Steel: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65 , F70; Alloy Steel: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo, 12Cr1MoV, 15CrMo, 12Cr2Mo1, A335P22, St45.8/III, 35CrMoV, 45CrMo, etc. Manufacturing standards: ANSI B16.5, GB/T9117.1-2000-GB/T9117.4-200, etc. Ten, threaded flange (TH) Threaded flange nominal diameter: DN8 ~ DN100 Working pressure: 1.0 ~ 2.5 (MPa) Plate thread flange material: stainless steel, carbon steel, alloy steel. Thread flange use: Suitable for fire-fighting, gas, hot and cold water, air conditioning, air pressure pipe, oil pipe, instrument, hydraulic pipe and other industrial and civil pipe thread lock and seal. Eleven, flange cover (BL) The flange cover, also known as the blind flange, is a flange without a hole in the middle for sealing the pipe plug. There are many types of sealing surfaces, such as planes, convex surfaces, concave and convex surfaces, grooved surfaces, and ring joint surfaces. Sealing surface: plane (FF), protruding surface (RF), concave and convex surface (MFM), grooved surface (TG), ring joint surface (RJ) Production materials: Carbon Steel: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70 ; Stainless Steel: ASTM A182 F304, 304L, F316, 316L, 1Cr18Ni9Ti, 0Cr18Ni9Ti, 321, 18-8; Alloy Steel: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo, 12Cr1MoV, 15CrMo, 12Cr2Mo1, A335P22, St45.8/III. Twelve, loose flange (1) with neck butt weld ring loose flange Loose flanges, butt welds, loose sleeves, neck flanges, butt welds, loose sleeves, flat flanges, welded rings, loose sleeves, flanged plates, overturned loose flanges. In addition, in order to meet the needs of the rear locking of the device, there are rods. Holes, these holes can make the bolts not loose when they are vibrated. Some flange bolts have no threaded rods to be thin, called thin rod flange bolts. This kind of flange bolts are beneficial for the coupling of variable forces. There are special high-strength bolts on the structure. The head will be larger. The size is also changed. The hot-dip galvanized round steel reacts the molten metal with the iron matrix to produce an alloy layer. (2) Flat welding ring loose flange (PJ/SE) 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. (3) Flat welding ring loose flange: 1. Cost savings. When the material of the pipe is special and expensive, the flange of the same material is costly. 2. It is not convenient to weld or inconvenient to process or requires high strength. Such as plastic pipes, glass steel pipes and the like. 3. Easy to construct. If the flange bolt hole is connected during the connection, it is not easy to find or prevent the flange bolt hole of the equipment to be replaced in the future. Disadvantages of the flat welding ring loose flange: 1. Understand low pressure. 2. The strength of the weld ring is low (especially when the thickness is less than 3mm) Flat welding ring loose flange production standards: National standard: GB/T9112-2000 (GB9113•1-2000~GB9123?4-2000) American Standard: ANSI B16.5 Class150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW) Japanese standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL, WN, TH, SW) German standard: DIN2573, 2572, 2631, 2576, 2632, 2633, 2543, 2634, 2545 (PL, SO, WN, BL, TH) Ministry of Chemical Industry Standards: HG5010-52~HG5028-58, HGJ44-91~HGJ65-91 Flange standard: HG20592-2009 (PN series)\HG20615-2009 (Calss series) Ministry of Machinery Standard: JB81-59~JB86-59, JB/T74-1994, JB/T79-94~JB/T86-94 Pressure vessel standard: NB/T47020-2012~NB/T47027-2012, JB1157-82~JB1160-82 B16.47A/B B16.39 B16.48 (4) Ring groove flange and flange cover Large diameter flat flange Large diameter high neck flange Eight-word blind board Butt ring loose flange Thirteen, rotating flange Anchor flange Surfacing/welding flange Marine lap welded steel flange standard number: This standard applies to marine products and marine engineering products. The main materials are: carbon steel, alloy steel, low temperature steel, stainless steel. Fourteen, forged flange Forging flange connection is to put two pipes, pipe fittings or equipment, and forging flange connection is an important connection method for pipeline construction. The forged flange connection is easy to use and can withstand large pressures. In industrial pipes, forged flange connections are widely used. In the home, the pipe diameter is small and low pressure, and the connection of the flange punching elbow is not visible. If you are in a boiler room or production site, there are flanged pipes and equipment everywhere. Chromium content 0.1% to 0.5% (forged flanges generally do not contain chromium), carbon content below 1.0% and forged flanges are made of high temperature forging, some forged flange surface hardness (HRC) although It can reach ≥56 or above (the quenching layer is only about 15mm). Because of the poor hardenability of the forged flange material, the hardness of the core is generally only 30 degrees. Under normal circumstances, the water is quenched when forging the flange. Fifteen, flange protection cover (flange protection joint) Flange protection covers are mainly used for flange connection corrosion protection in all industries. Flange Cover The flange protection head of this product is used to protect the flange face (convex or ring joint). Double-ended studs and gaskets are protected from corrosion. The product is available in 316 ss stainless steel and non-metal (plastic) and is manufactured in sizes from ½” to 144″ ANSI, API and AWWA flanged diameters. The flange head system in combination with flange packing protects against harsh applications. The structure of the flange seal: 316 stainless steel belt or non-metallic belt 316 ss casting 316 ss worm gear clamp Closed tank neoprene layer (temperature. – 34.4°C to 82°C) ECH rubber gasket (temperature. – 34.4°C to 149°C) safety relief valve releases 5 psi Advantages of Mestec flange seals: Easy to install No special tools required Easy to detect Durable connection (not easily damaged) UV stabilized non-metallic materials Reusable Sixteen. Flange packing system Suitable for temperatures of 80 ° C. Flange packing is a unique solution to long-term corrosion problems. The flange filler is a coating based on a composite polar polymer. The paste form allows it to be used without pretreatment. The viscoelastic formulation allows this material to flow into the gaps and voids, creating an excellent seal that is corrosion resistant. Flange packing system flange packing saves time and money because it is easy to use. Provide long-term protection. Performance: Excellent adhesion to steel, FBE (fused epoxy powder), polyurethane, polyethylene advanced resistance weathering / salt resistance temperature range from -51 ° C to 80 ° C filling the entire gap removable / reusable flange surface Manual or pneumatic guns with flexible nozzles are used for gentle injection without excessive pre-treatment. This ensures that the annular gap is completely filled before sealing with the CZ wrap tape. E-2400/E2000 high temperature flange packing – suitable for temperatures up to 149 °C. E-2400/E2000 high temperature anti-corrosion flange filler is designed to protect flanges from corrosion at temperatures up to 149 °C. E-2400/E2000 is a non-electrolytic corrosion protection of steel flanges, bolts, pipes and structures with a gel. The nut and bolt assembly was tested for 2000 hours using the ASTM-B1117 salt spray test. The area protected by the E2000/2400 can still be rotated by hand. Proper use of the E2000/2400 helps protect flange connections from corrosion. Seventeen, high temperature flange seal Parts of high-temperature flanges often require a flat high-temperature seal. If there is no good sealant in the separate pressure zone, it will be affected by the pressure, which will cause production inaccuracy or deformation, that is, pressure in the separate pressure zone. Leakage occurs underneath, requiring an unscheduled repair. The best application in the field of high temperature flat seals is the Bocos high temperature sealant, which is specially formulated to remain inert in standard applications for steam and gas turbines and high temperature flanges, thus withstanding hot air, steam, water, light fuel Oil and lubricants are resistant to crude oil and natural gas. It is a one-component, paste-like sealant for industrial applications and high-quality sealing compounds. It is suitable for applications where the temperature and pressure of smooth, flat sealing surfaces (butt joints) are high. Spread on a dry surface using a plaster trowel or a rubber spatula. Since the sealed product will not cure, its consistency will change slightly, maintaining flexibility and flexibility, so there is no time requirement in use, and it can be put into operation immediately after construction, without waiting. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

This problem about flat welding flanges has always been a topic of concern. It is related to the production costs or economic benefits of companies and enterprises. Therefore, the sealing principle of flat welding flanges is constantly improving and perfecting. However, 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. No product can be free from defects, just try to control the product to the least, so the company should try to improve the performance of the product when producing flat welding flange, so that it can play its biggest role. Features of flat welding flange: Flat welding flange not only saves space, reduces weight, but more importantly ensures that joints will not leak 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. Secondly, the flange gasket has been replaced by a sealing 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 to 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%. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The selection standard of materials used for non-standard flange refers to metal materials with fire resistance not lower than 1587 ℃. It should be adopted according to the product design requirements and should comply with the current national material standards. Non-standard flanges are subjected to various physical and mechanical movements in the high temperature environment, which may cause refractory materials to be damaged by melting, softening, cracking and abrasion. The non-standard flange materials mainly have the following strict requirements: (1) Stainless steel and fuses have high temperatures and do not change and melt at operating temperatures; (2) It can withstand the stress generated during high temperature operation, without losing structural strength, without deformation or breaking; (3) The volume is stable at high temperatures, and the masonry is not deformed or cracked due to expansion and contraction; (4) Non-standard flanges shall not rupture and peel off when the temperature changes or the heat is uneven; (5) It should have a certain ability to resist chemical attack; (6) It should have sufficient strength and wear resistance to withstand the scouring and impact of high temperature and high speed flame, soot and slag; Large-diameter flanges should have good working performance, meet the requirements of pipe joint quality, and comply with the relevant product protection, safety protection regulations and technical specifications. Connect the bulk density. The ratio of the non-standard flange product nozzle to its total volume, the true density refers to the various pore volume openings that do not include other tube ends. The connection tightness is closed with one end of the nozzle, and the other end is connected to the outside, which can be safe. The ability of a gas to pass through a nozzle at normal temperature and pressure is usually measured by the gas permeability coefficient. Raw materials for non-standard flange large-diameter flanges are made of refractory materials, high-temperature resistant materials, good sealing performance, and some ordinary steel materials and heat-resistant metals. Reasonable material selection plays an important role in ensuring the quality, safe and economic operation of large-diameter flange products and increasing their service life. Source:China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Definition and Classification of Steel Pipe Pickling 1. Definition of Pipe Pickling: According to a certain concentration, temperature and speed, acid is chemically removed from the surface of the steel pipe, called pickling. 2. Pickling classification of steel pipes: According to the types of acids: sulfuric acid pickling, hydrochloric acid pickling, nitric acid pickling, hydrofluoric acid pickling. Pickling must select different media according to the material of steel, such as pickling carbon steel with sulfuric acid and hydrochloric acid, pickling stainless steel with nitric acid hydrofluoric acid and so on. According to the shape of steel: wire pickling, forging pickling, steel plate pickling, strip pickling and so on. According to the type of pickling equipment, it can be pided into trough pickling, semi-continuous pickling, full continuous pickling and tower pickling. Removal of oxide scale on steel pipe surface Removal methods of oxide scale on steel pipe surface: mechanical method, chemical method and electrochemical method Mechanical methods: polishing, rolling, high pressure water washing, brushing, shot blasting, sand blasting, scaling, etc. Chemical method: The iron oxide scale is removed by chemical reaction of acid, alkali and other chemical substances with iron oxide scale on steel surface. Electrochemical method: When pickling, direct current is applied to both sides of steels immersed in acid solution through electrodes to accelerate the removal of iron oxide scale. Main Forms of Pickling At present, there are three main pickling methods for steel steels in the world: single steel pickling method (steel plate pickling method, Single Coil pickling method, single bundle wire pickling method), continuous pickling method and semi-continuous pickling method. Single-piece pickling is the most original and simplest pickling method. It is characterized by pickling the whole coil of wire or loosened coil without uncoiling, and then hanging in the pool for washing. Due to the poor quality of pickling, low production efficiency, especially the great environmental pollution, it has been vigorously eliminated. Continuous pickling is a high-yield, high-quality and fast-developing pickling method. It ensures the continuous operation of the unit by installing welding machine and looper device on the unit. However, the unit is long, the equipment is complex and the investment is high. There are two main forms of continuous pickling line: continuous horizontal pickling line and continuous tower pickling line. Semi-continuous pickling is relative to single-piece pickling and continuous pickling. Because it does not need to install welding machines (or simple welding machines such as sewing machines) and large capacity loopers, it is necessary to shut down when changing coils. This method is most suitable for production with output of 20-900,000 t/a. With the improvement of people’s living standards and the increasing demand for the environment, new technologies and production lines for iron oxide scale removal with high efficiency, pollution-free and good quality are emerging. The new technology of EPS treatment eliminates the pickling of steel coil, eliminates the generation of waste, recycles all the media, makes the surface of steel coil cleaner and has better corrosion resistance. EPS patented technology is developed on the basis of SCS technology. Its basic principle is that EPS treatment is carried out in a sealed space with special equipment. That is, the upper and lower surfaces of plate and silk steel plate are sprayed by EPS working medium, i.e. mixture of steel sand and water. Under the action of certain spraying force, the oxide or iron oxide scales on the surface of plate are removed without any residual oxides. It can make the surface of steel plate smooth and clean, which is called green surface. Principle of pickling Pickling is the process of removing oxide scales on the surface of steel pipes by chemical methods, so it is also called chemical pickling. Iron oxide scales (Fe203, Fe304, Fe0) formed on the surface of strip steel are alkaline oxides insoluble in water. When they are immersed in acid or sprayed with acid on the surface of strip steel, a series of chemical changes can take place between these alkaline oxides and acid. Because the oxide scales on the surface of carbon structural steel or low alloy steel have the properties of looseness, pore and crack, and the oxide scales are straightened, stretched and rectified together with the strip steel in the pickling machine, so that these pore cracks are further increased and enlarged. Therefore, while the acid solution reacts with the oxide scales chemically, it also passes through cracks and pores. It reacts with the matrix iron of steel. That is to say, three kinds of chemical reactions between iron oxide scale and metal iron and acid solution were carried out at the beginning of acid pickling. (1) The oxide scale on the surface of the steel tube reacts with acid and is dissolved (dissolved). (2) Metallic iron reacts with acid to produce hydrogen and mechanically peels off the scale of iron oxide (mechanical peeling). (3) Atomic hydrogen produced reduces iron oxides to ferrous oxides which are easy to react with acids, and then is removed by reacting with acids. Comparison of hydrochloric acid pickling and sulfuric acid pickling The most widely used pickling media are hydrochloric acid and sulphuric acid, but the use of hydrochloric acid pickling occupies a larger proportion in actual production. In terms of the characteristics of the two media, hydrochloric acid can dissolve all iron oxide scales without producing pickling residues. And hydrochloric acid basically does not corrode the base metal, so after pickling, the surface of the plate is smooth and bright. Therefore, the hydrochloric acid pickling method has the advantages of good product quality, high production capacity, less loss of metals and acids, low cost and so on. In addition, the iron loss of hydrochloric acid pickling is 20% lower than that of sulfuric acid pickling. The iron loss of hydrochloric acid pickling is 0.4%~0.5% of that of acid pickling strip steel and 0.6%~0.7% of that of sulfuric acid pickling strip steel. The pickling rate of hydrochloric acid is 2 times higher than that of sulfuric acid. In recent years, due to the development of recovery and treatment technology of hydrochloric acid waste acid (that is, the development of acid regeneration technology), hydrochloric acid pickling method has been widely used. Source: China Stainless Steel Pipes Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Flat welded flange is a kind of flange connected with fillet weld of container or pipeline. It belongs to arbitrary flange. According to the integrality degree of the connection between the flange ring and the straight cylinder section, the integral flange or the loose flange are checked separately in the design. There are two kinds of flange rings with neck and without neck. Compared with the butt-welded flange with neck, the flat-welded flange has simple structure and less material consumption, but its rigidity and sealing are not as good as the butt-welded flange with neck. Flat welded flanges are widely used in connection of medium and low pressure vessels and pipes. Flat welded flange is often used in the case of medium temperature and pressure are not high and medium corrosion is strong. When the corrosive medium is strong. Rare integral flanges are flat welded flanges and butt welded flanges. Flanged fittings refer to fittings with flanges (flanges or joints). It can be cast. Flat welded flanges are mainly parts that connect pipes to pipes. According to the structure type. It can also be made up of threaded connection or welding. Flange connection refers to a pair of flanges, a gasket and a number of bolts and nuts. The main design disadvantage of flat welded flange is that it can not guarantee no leakage. This is the shortcoming of its design: the connection is dynamic, and the movement between flange surfaces will be caused by thermal expansion and fluctuating periodic loads, which will affect the function of flange, thus impairing the integrity of flange and eventually leading to leakage. Any product can not be without defects, but try to control the insufficiency of the product to the minimum, so the company in the production of flat welding flange as far as possible to improve the performance of the product, so that it can play a maximum role. Flat-welded flange features: Flat-welded flange not only saves space and reduces weight, but also ensures that the joint does not leak, and has good sealing performance. The reason why the size of compact flange decreases is that the diameter of the seal is reduced, which will reduce the cross section of the sealing surface. Secondly, the flange gasket has been replaced by the sealing ring to ensure that the sealing face matches the sealing face. In this way, only a small amount of pressure is needed to press the cover tightly. As the required pressure decreases, the size and quantity of bolts can be reduced accordingly, so a new product with small size and light weight (70%-80% less than the weight of traditional flange) is finally designed. Therefore, flat welding flange is a relatively high quality flange product, which reduces the quality and space, and plays an important role in industrial applications. Sealing Principle of Flat Welded Flange: The two sealing faces of bolts extrude each other flange gasket and form a seal, but at the same time, it also leads to the destruction of the seal. In order to keep the seal, it is necessary to maintain a huge bolt force, for this reason, the bolt has to be made bigger. Larger bolts match larger nuts, which means larger diameter bolts are needed to create conditions for tightening nuts. However, the larger the diameter of the bolt, the more flexible the flange will be. The only way is to increase the wall thickness of the flange. The whole device will require a great deal of size and weight, which becomes a special problem in the offshore environment, because in this case, weight is always the main problem that people must pay attention to. Moreover, in essence, flat welded flange is an ineffective seal, which requires 50% of the bolt load to be used to extrude gaskets, while only 50% of the load to maintain pressure is left. Flat Welded Flange Processing Technology Cutting Flange with Steel Plate Generally, the steel plate produced by the regular enterprise, the raw material is more regular, the small aperture is more easily processed, the tread is relatively flat, the cost is lower, and the quality is also able to. Large caliber flange Generally, it is made by cutting and heating the steel plate, and the raw material is not good. Only the center will have an interface to be welded. Although no weld can be seen in the future, it is still not advocated to be used in high-pressure pipelines. Forging flange Good raw materials, high density, high price and good quality. Flat welded flange has certain technical requirements and parameters in production and use. 1. The butt weld of the ring should be heat treated after welding and 100% X-ray or ultrasonic flaw detection. The X-ray flaw detection meets the grade II requirements of JB4730 and the ultrasonic flaw detection meets the grade I requirements of JB4730. The welding flange is manufactured and processed by certain welding standards and technologies, which meets the corresponding national production standards and requirements. 2. The steel plate for flat-welded flange shall be inspected by ultrasonic wave without delamination defect to ensure good quality and performance. It shall be produced and inspected in accordance with certain quality requirements to ensure that the steel plate for production and use has no quality problems. 3. The steel should be cut into strips along the rolling direction and welded into circular rings by bending and butt welding, and the surface of the steel should be made into a circular cylinder. In the production of Harbin flange, the steel plate can not be directly machined into necked flange, and a certain process is used to make and process it. Source: China Stainless Steel Flanges Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

There are many kinds of gaskets, which can be pided into three categories: non-metal, semi-metal and metal gaskets. (1) Non-metallic gaskets. Non-metallic gaskets are soft, corrosion-resistant and cheap, but have poor temperature and pressure resistance. It is mostly used for flange sealing of medium and low pressure vessels or pipes at room temperature and medium temperature. Non-metallic gaskets include rubber pads, asbestos pads, asbestos rubber pads, flexible graphite pads and polytetrafluoroethylene pads. ① Rubber board. The main materials for making rubber plate gaskets are natural rubber, nitrile rubber, chloroprene rubber, etc. In addition, special rubber such as fluorine rubber has also begun to be used. Rubber is widely used in the sealing of containers and pipelines because of its compact structure, soft texture, good resilience, easy shearing into various shapes, low cost and easy to buy. However, it is not resistant to high pressure, easy to dissolve and expand in mineral oil and not corrode, and easy to aging and losing resilience at high temperature. ② Asbestos. Asbestos materials are wet asbestos and blue asbestos. Wet asbestos has good heat resistance, alkali resistance, high tensile strength and poor acid resistance. Most asbestos rubber boards are made from it. Blue asbestos is not only good in heat resistance, but also good in acid resistance, so it is mostly used to make acid-resistant asbestos rubber boards. The normal service temperature of asbestos board is below 550 degrees. Large diameter low pressure vessels can use asbestos tape or asbestos rope. When asbestos rope is used, water glass is usually impregnated. Such gaskets can also be used in medium such as acid and alkali solvents. ③ Asbestos rubber sheet. Asbestos rubber sheet is made by pressing asbestos, rubber and fillers. General asbestos fibers account for 60% – 85%. According to its mixing technology, performance and use, there are mainly high-pressure asbestos rubber sheet, medium and low-pressure asbestos rubber sheet and oil-resistant asbestos rubber sheet. Asbestos rubber sheet has suitable strength, elasticity, flexibility and other properties. It is convenient and cheap to make gaskets with asbestos rubber sheet. Therefore, it has been rapidly promoted and applied in chemical enterprises. ④ Flexible graphite. Flexible graphite is a novel sealing material with good resilience, softness and temperature resistance, which has been rapidly promoted and applied in chemical enterprises. ⑤ Polytetrafluoroethylene (PTFE). Polytetrafluoroethylene (PTFE) is known as the “king of plastics” because of its superiority in chemical resistance, heat resistance, cold resistance and oil resistance. It is not easy to aging, does not burn, and absorbs almost zero water. Its compact structure, non-polar molecular structure, as a gasket, the contact surface can be smooth, non-stick to the metal flange. In addition to being eroded by molten alkali metals and fluorine-containing gases, it can resist the corrosion of various acid, alkali, salt and grease solution media. Polytetrafluoroethylene gaskets include pure polytetrafluoroethylene, filled polytetrafluoroethylene or expanded polytetrafluoroethylene. (2) Semi-metallic gaskets (also known as metal composite gaskets). Nonmetallic materials have many advantages, such as good flexibility, compressibility and low bolt loading capacity. But its main determination is that the strength is not high, the resilience is poor, and it is not suitable for high pressure and high temperature occasions. So the bonded metal material has high strength and good resilience. Characteristic of withstanding high temperature. A gasket which combines the two structures is formed. It is a semi-metallic gasket. (3) Metallic gaskets. Octagonal Ring Joint Gaskets > Ring Joint Gaskets are for oilfield and process industry duties. > Octagonal shape gasket is belong to API 6A R series > These gaskets are used in pressures up to 10,000 PSI, more than Oval ring joint. > The oval type is the only gasket that will fit a bottom radiused groove. > Gaskets and not re-used after torque. Octagonal Ring Joint Gasket was initially developed for high pressure and temperature applications found in the petroleum industry and is primarily used in the oil field on drilling and completion equipments. However, today this product range can also be found on valves and pipework assemblies, along with some high integrity pressure vessel joints. Oval Ring Joint Gaskets > Ring Joint Gaskets are for oilfield and process industry duties. > Oval shape gasket is belong to API 6A R series > These gaskets are used in pressures up to 10,000 PSI. > The oval type is the only gasket that will fit a bottom radiused groove. > Gaskets and not re-used after torque. Oval Ring Joint Gasket was initially developed for high pressure and temperature applications found in the petroleum industry and is primarily used in the oil field on drilling and completion equipments. However, today this product range can also be found on valves and pipework assemblies, along with some high integrity pressure vessel joints. Spiral Wound Gaskets Spiral Wound Gasket can be made from a large selection of alloys and filler materials in a variety of shapes and sizes. wilsonpipeline also provide non-round spiral wound gaskets, manhole and handhole spiral wound, and just inner & outer rings for SWG. The Spiral Wound Gaskets is suitable for flange, valve, pump, heat exchange etc. Corrugated/Serrated Gaskets Corrugated/Serrated Gaskets, for ASME standard corrugated gasket. The CMG gaskets is punched by moulds, the tolerance is strictly control. Corrugated Metal Gasket are known as Graphonic Gaskets. Corrugated metal gasket is widely used for pipe flange, pump, valve joint. We supply the complete corrugated gaskets, and metal core only. What is the role of gaskets? 1. Prevent the use of spring pads in the process of screw disassembly from causing damage to the object. In the process of using, we can first make the flat cushion and the object closely connected, and then use the spring cushion outside, so that we can prevent the damage caused by the spring cushion to the object, also can play the effect of the spring cushion, and also can make the stress area more balanced. When used in this way, the spring pad can also prevent damage to the connected objects. 2. It can increase the contact area. Generally, the contact area between the screw and the object is relatively small, so the force acting on the screw will be relatively small and easy to loosen. In order to make the screw more firmly lock the object, gaskets will be used to increase the contact area between the screw and the connected object. 3. It can be used in some special cases. For example, if there are no threads, then we can use gaskets, and when our screw is too long, if we want to be beautiful, then we use gaskets, which can make the screw look more beautiful. 4. Increase friction. In the process of using high-strength bolts, they are fixed by friction. In order to increase the friction between high-strength bolts and objects, the use of gaskets can effectively solve this problem. Source: China Stainless Steel Gaskets Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)