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In the actual operation of the pickling process of stainless steel plate, will inevitably encounter some problems, such as stainless steel plate surface defects caused by pickling, if you do not know the cause of these defects and solutions that will make the same mistake next time. Here is to introduce these defects and causes. Pickling bubble The bubble is because acid and acid exposed stainless steel board reacts to generate hydrogen, with the formation mechanism refers to the stainless steel plate and acid to produce chemical reaction, generate some hydrogen atoms, it penetrates into the crystal lattice of stainless steel, and the deformation, deformation after the hydrogen diffusion in metal to more among them, a part of hydrogen atoms and molecules through the stainless steel plate, escaping from the acid liquid, part of the hydrogen atom molecule in the lattice distortion of “micro hole” on the boundary of inclusions and pores or stainless steel, pressure of hydrogen in air holes can reach a large value (tens of MPA), the stainless steel plate produced in the internal stress caused by hydrogen embrittlement. This will make the stainless steel plate cracking occurred in the cold rolling process of the explosion, the appearance feature is a strip drum bubble, after the breakdown performance of fine black cracks. After rolling, the bubble cracks on the surface of the plate extend and expand, thus reducing the mechanical properties of the products (impact toughness). The method to avoid pickling bubbles is to adjust the concentration of acid solution, control the temperature of pickling solution and the flat state of strip steel. Over pickling If the stainless steel plate to stay too long in the acid solution, the acid solution under the action of the surface of the stainless steel plate is slowly becoming rough pits phenomenon over pickling. The elongation of pickling strip is greatly reduced, and it is easy to break and break in the rolling process, and cause the sticking roll. Even if the strip is rolled, it can not be used as a finished product because its mechanical properties are greatly reduced. The cause of acid pickling is the continuous operation interruption of the unit, which leads to the loss of continuity of the pickling or the long treatment time due to strip breaking. Prevention method must be close to the whole unit operation coordination, to ensure normal production. Acid washing After pickling, the stainless steel strip is called pickling due to its residual surface which does not wash out the oxide scale. In stainless steel strip pickling, the light will face a dark or shaped in the rolling surface; severe iron oxide can be pressed into a black plate. In addition, the extension of the oxide scale is poor, so uneven extension after rolling will make stainless steel appear wave shape or ladle bending defects. Sometimes the iron oxide sheet is firmly attached to the roll surface, which directly results in the increase of rolling waste. Produced under pickling is generally because of the uneven thickness of the oxide scale, thick scale part of the longer the pickling time and at the same time Fe0 is decomposed into a difficult dissolved Fe2O3 (Fe3O4); also some stainless steel wave degree and camber is large, in the pickling process, fire bending part or not soaking in acid pickling by leakage. In actual production, under pickling occurs mainly at the end and end of the strip and on both sides of the strip. Rust The phenomenon of rust on stainless steel plate after pickling is called corrosion. The reason for this defect is that the surface of the stainless steel strip is acid free after pickling, or the stainless steel surface is rusted again after the strip cleaning has not been completely dried. The surface of stainless steel plate corrosion performance in the dark after rolling, the product will lead to corrosion again in place, thereby reducing the surface quality of finished products, even the stainless steel board scrap. The way to avoid corrosion is to strictly carry out pickling and cleaning procedures, and should be stored in a dry place. Inclusion The stainless steel strip is sometimes covered with deeply dotted black spots on the surface after pickling. It is called inclusion. It is because the iron oxide sheet is pressed into the hot rolling. Such defects can not be taken to remove acid washing. When it is cold rolled, black spots expand and extend into black strip, which seriously affects the impact properties of finished stainless steel plate. Scratch The stainless steel strip in a new unit operation in the process of scratching, because foreign body hard surface drive roller, a guide roller, or stainless steel strip shaped and folding edge and guide into the line contact, or strip in unwinding process on the folding scraper, which makes the surface draw new scars. In addition, part of the scar appeared in the process of cooling and coiling after hot rolling. The scratch of stainless steel strip can be pided into upper surface scratch and lower surface scratch. The cold rolled stainless steel plate will form wide and long black strip on the surface of finished stainless steel strip after cold rolling. Stainless steel strip scratch depth exceeds the allowable tolerance of stainless steel strip half, even after rolling can not be eliminated. The way to avoid scratching is to check the rolling parts and guide plates of the unit regularly and maintain the equipment well. Indentation Indentation refers to the indentation of stainless steel strip on the surface of the concave. The reason is in the indentation forming and roll welding without blowing clean welding slag, steel strip is to bottom roller, which pressed on the strip surface marks; hearth roll caused by roll sticking in sliding surface of the strip. The strip surface indentation; hot rolling pressure failure, sudden pressure stop, then lift the pressure under rolling etc.. When the indentation depth exceeds half of the allowable thickness of the strip, the indentation can not be eliminated after cold rolling. Generally speaking, the defects on the surface of stainless steel plate can be avoided and reduced as long as careful operation, strict implementation of the pickling process system and operation procedures, timely inspection and maintenance of the equipment. Source: China Stainless Steel Plate Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

317LXN, 317LX and 317L are austenitic stainless steels containing alloying element molybdenum, which have better corrosion resistance than common chromium nickel austenitic stainless steel. In addition, the creep resistance and stress cracking resistance of 317XN, 317LX and 317L stainless steel at high temperature are better than that of 304 stainless steel. The comprehensive performance of the three alloy is significantly higher than that of type 317 stainless steel, so the low carbon level (“L”) stainless steel will exhibit better resistance to intergranular corrosion in welding or other thermal processing, “X” and “N” meaning respectively containing high molybdenum and nitrogen components. The combined action of Mo and N can significantly improve the pitting corrosion resistance and crevice corrosion resistance of stainless steel in acidic, CI – and sulfide containing high temperature water vapor. Nitrogen also increases the strength of the steel itself. The above three kinds of stainless steel can be used in more stringent corrosion environment, such as flue gas desulfurization system. 317LXN, 317LX and 317L stainless steel in moderately corrosive medium corrosion resistance of 304 stainless steel is more excellent than conventional, but generally on type 18-8 stainless steel corrosion environment, the formation of corrosion of the stainless steel containing molybdenum is not the same, but the strong oxidizing acid such as nitric acid exception. In sulfuric acid solution, 317LXN, 317LX and 317L are more corrosion resistant than type 304 stainless steel, and the corrosion resistance will increase with the increase of alloying element molybdenum content. The three kinds of stainless steel can be corroded with 49 and 5% sulfuric acid. When the temperature is below 38, the three kinds of stainless steel will show excellent corrosion resistance in the higher concentration of sulfuric acid. The carbon content of the three kinds of stainless steel is less than 0.03%, and the low carbon content can significantly enhance the intergranular corrosion resistance in the process of welding or forging. They also contain more chromium, so they have better resistance to intergranular corrosion. However, it is clear that when they are exposed to the temperature range of 417-816 degrees Celsius for a long time, because of the precipitation of the delta phase, they will greatly weaken the anti crystal corrosion ability of these alloys, and will likely become brittle. 317LXN, 317LX, 317L stainless steel in acidic solution containing CI or other halogen ions in resistance to pitting corrosion and crevice corrosion ability is stronger than the 316 or 304 stainless steel, so they are often used in flue gas desulfurization system. When welding 317L stainless steel, the welding material should contain at least 6% molybdenum; when welding 317LX and 317LXN stainless steel, the welding material should have at least 8% of molybdenum, such as using 625 alloy as welding material. In actual welding operation, if the high matching welding material can not be adopted, the post weld heat treatment and pickling can not be taken into consideration, the welding parts of the self fusion welding should be carefully considered to meet the requirements of the process conditions. The best corrosion resistance can be obtained after heat treatment and acid washing of 317LXN, 317LX and 317L self fusion welding parts. Source: China Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

310S stainless steel angle bar is widely used as engineering structures of various buildings, such as beams, bridges, towers, hoisting and conveying machinery, ships, industrial furnace, reaction tower, container or even warehouse shelves. From the angle of the name can be seen made of 310S stainless steel, 0Cr25Ni20 stainless steel grades for GB, this is also called the 2520 stainless steel is a kind of austenitic chromium nickel stainless steel, has excellent oxidation resistance and corrosion resistance, and also because of the high proportion of chromium and nickel content, 310S stainless steel has excellent creep strength and, good high temperature performance, can continuously work under high temperature. Due to the high nickel and high chromium content in 310S stainless steel, so its resistance to oxidation, corrosion resistance, acid and alkali resistance, high temperature performance is very good, so for 310S stainless steel as raw material, high temperature resistant steel can be made into the electrothermal furnace tube and other products, increasing the carbon content in austenitic stainless steel, can enhance its solid solution strengthening effect and increase strength, chemical composition characteristics of austenitic stainless steel is chrome, nickel based addition of molybdenum and tungsten, niobium and titanium elements, also because of its organization is face centered cubic structure, so the strength and good creep strength at high temperature. 310 stainless steel is now widely used, including petroleum, electronics, chemical, pharmaceutical, textile, food, machinery, construction, nuclear power, aerospace, military and other industries. So what is stainless steel angle bar? An angle bar is a long strip of steel with angles perpendicular to each other. There are two kinds of shape, namely equilateral stainless steel angle bar and scalene stainless steel angle. The two side widths of equilateral stainless steel angles are basically equal, and their specifications are expressed by the width of the edge, the width of the side, the width of the side and the thickness of the edge. In addition, scalene stainless steel angles can be pided into two kinds: unequal thickness, unequal thickness and unequal thickness. The specifications of stainless steel angles can be expressed by the length of the side and the thickness of the edges. Domestic stainless steel angle specifications for 2 – 20 cm, to length number number, the same number of stainless steel angle bar is often 2 – 7 different edge thickness. Import stainless steel angles mark the actual size and edge thickness of both sides, and indicate the relevant standards. The stainless steel angle is usually larger than 12.5cm, and the angle between 12.5cm and 5cm is medium stainless steel angle. The stainless steel angle is smaller than 5cm. The import and export of stainless steel angle bar in China has a certain quantity, generally imported from Japan and Western Europe, and exports mainly to Hong Kong and Macao, Southeast Asia, Latin America and Arabia countries. The export enterprises are mainly steel mills (rolling mills) in Jiangsu, Liaoning, Hebei, Beijing, Shanghai, Tianjin and other provinces and municipalities. Imported stainless steel angle bar varieties are large, small stainless steel angle bar and special shape of stainless steel angle bar, export varieties are medium stainless steel angle, such as 6, 7, etc.. The surface quality of stainless steel angle bar has certain standard stipulation. It is usually required that there is no disadvantage which is unfavorable to application, such as delamination, scab, crack, etc.. The allowable range of the geometric deviation of stainless steel angle bar is also stipulated by the standard, usually including bending, edge width, edge thickness, vertex angle, theoretical weight and so on, and the stainless steel angle shall not have significant torsion. Source: China Angle Bar Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

In the process of processing of stainless steel pipe, the more common one is heat treatment. As a process with certain technical content, the heat treatment of each type of stainless steel pipe can be slightly different. Solid solution treatment Precipitation hardening stainless steel tube after solid solution treatment (1000 ~ 1050 ℃, 1 h, air cooling), the microstructure is austenite can be obtained with a small amount of ferrite, and then in 500 ~ 800 ℃ to adjust processing, austenite and ferrite alloy element chromium content is higher in the organization, and the carbide (Cr23C6) easily along the alpha (delta) and r phase interface precipitation, also reduce the austenite content of carbon and other alloying elements in the organization, and thus increase the Ms point of this kind of steel, make it get more martensite microstructure. Alpha (delta) ferritic quantity cannot be too much, otherwise it will have negative effect on heat processing, and will not participate in martensite transformation, thus reducing the strength of stainless steel tube. Adjust the handle The intermediate treatment, which is carried out after the stainless steel tube solid solution treatment process, is usually also called adjustment treatment, to obtain a certain amount of martensitic tissue to strengthen the stainless steel tube. There are three kinds of commonly used method, the first is in the middle as statutes) (hereinafter referred to as T treatment after solid solution treatment and then heated to 760 + 15 ℃, the heat preservation, 90 min, by Cr23C6 carbide precipitation from austenite, reduce the content of carbon and alloy elements in the austenite, the Ms point rise to 70 ℃, then cooled to room temperature will get martensite + + alpha ferrite residual austenite, the residual austenite in 510 ℃ ageing followed up. Followed by high temperature adjustment and cryogenic treatment method after processing method (R) solid solution, first heated to 950 ℃ warm after 90 minutes. Because it increases Ms point, cools to room temperature, can obtain a small amount of martensite; And then after – 70 ℃ cold treatment, 8 hours heat preservation, can get a certain amount of martensite. The third method is the cold deformation on the stainless steel tube method (C treatment) after solid solution treatment, cold deformation at room temperature, the amount of cold deformation martensite formed when related to the deformation and the composition of stainless steel tube. Generally, the amount of martensite can be obtained by 15% ~ 20%, and the excessive deformation will harden the martensite and make the plasticity drop significantly. Aging treatment (H treatment) The stainless steel tube needs to be treated after adjustment. This aging treatment process is another way for such stainless steel tubes to be strengthened. When processing the aging temperature higher than 400 ℃, precipitation from martensite structure intermetallic compounds (such as Ni3Ti, etc.), a highly dispersed distribution of precipitation hardening effect. Usually at about 500 ℃ for aging treatment, can get satisfactory hardness and high strength. Source: China Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

As a kind of Molybdenum Stainless steel pipe, the 316 stainless steel tube corresponds to the national brand 0Cr17Ni12Mo2, while the 316L stainless steel tube corresponds to 00Cr17Ni14Mo2. The overall performance of the 316 stainless steel tube is better than that of 310 and 304 stainless steel tubes. Its maximum carbon content is 0.03%, which can be used in the fields where the welding cannot be annealed and the maximum corrosion resistance is required. Because the 316 stainless steel pipe has excellent resistance to chloride erosion, it is often used in the marine environment. In addition, under high temperature conditions, if the concentration of sulfuric acid medium is less than 15% or greater than 85%, the role of 316 stainless steel tube is more prominent. Corrosion resistance The corrosion resistance of 316/316L stainless steel pipe is better than that of 304 stainless steel pipe, especially in the production of pulp and paper, its good corrosion resistance can reflect the advantage. Among them, 316 stainless steel pipe can withstand the erosion of marine and corrosive industrial atmosphere. The oxidation resistance of the 316 stainless steel tube is very good when it is used in the environment below 1600 degrees and used continuously in the environment below 1700 degrees centigrade. In the range of 800-1575 degrees, as far as possible to avoid the continuous use of 316 stainless steel pipe material equipment, and in this temperature range outside the continuous use of 316 stainless steel tube, the stainless steel tube heat resistance performance is better. In addition to the same temperature range, the 316L stainless steel tube has better resistance to carbide precipitation than that of the 316 stainless steel tube. Heat treatment They can be annealed at a temperature range of 1850-2050 degrees, and then cooled rapidly. 316 stainless steel tubes can not be hardened by heat treatment. Welding performance 316 stainless steel pipe welding performance is good, can use all the standard welding method for welding. Welding process can be used according to the use of 316Cb, 316L or 309Cb stainless steel pipe filler rod or electrode to weld. In addition, in order to obtain the highest corrosion resistance, the 316 stainless steel pipe welding section is best after welding annealing treatment. And if the material is 316L stainless steel tube, there is no need to do the post weld annealing treatment of the material. It should be noted that the carbon content of the 316L stainless steel pipe is low, so the carbon is not easy to react with chromium, which can reduce the corrosion of the welding parts. Typical uses of both 316 stainless steel pipe because of adding molybdenum element, so its corrosion resistance, atmospheric corrosion resistance and high temperature strength are very excellent, can be used in harsh environment, has excellent work hardening characteristics. 316L stainless steel tube as low carbon steel version 316, in addition to the characteristics and 316 stainless steel pipe is the same as the outside, its resistance to intergranular corrosion performance better, can be used to produce resistance to grain boundary corrosion products with special requirements. Source: China Stainless Steel Tube Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Steel pipe in the use and transportation, the inevitable use of the environment and the impact of the transmission medium, prone to chemical or electrochemical reaction and then corrosion, so the use of anti-corrosion coating steel pipe can effectively prevent corrosion of steel. Analysis of Corrosion Protection Technology of Steel Pipe At present, domestic and foreign commonly used welded pipe, oil casing and other seamless steel pipe factory automatic painting process mainly has the following four: Steel pipe anti-corrosion coating process one: the use of leaching coating, coating before and after the middle roller conveyor line to form a coating. And then fork and fork transfer, hook-like chain rolling conveyor, steel pipe into the steam oven, heating and drying; Steel pipe anti-corrosion coating process two: the use of electrostatic coating method, before and after the application of the application of inclined roller roller conveyor to form a coating. And then lift the elevator lift to the shelf cooler, the natural drying; Steel pipe anti-corrosion coating process three: steel pipe transport, the use of UV coating system, vacuum coating method, coupled with the air erosion to form a coating. Immediately after coating UV radiation curing coating. Is characterized by the formation and curing of the coating are completed between the two rollers; Steel pipe anti-corrosion coating process four: coating by heating no air spray method, the application of roller conveyor before application, after application of sub-synchronous V-shaped tooth chain conveyor to form a coating. After coating the steel pipe from the stepper into the horizontal V-shaped chain conveyor into the steam drying box, heating and drying. Comparison of various coating processes Steel pipe anti-corrosion coating process one: As a result of the use of leaching coating, coating hanging serious. And because the roller and chain design is unreasonable, the coating there are two longitudinal and multiple ring scratches. This process is being eliminated. The only merit of this process is that it is heated and dried after coating; Steel pipe anti-corrosion coating process two: the existence of hanging film coating, the whole body spiral scratches and whitening quality defects. In particular, the thickness of the coating at the screw abrasion is only one-fifth of the specified thickness and the appearance is poorly felt. At the same time the process of electrostatic ignition process of fire hazards, in recent years has occurred several fire accidents, posing a threat to safe production. No drying process is also an important flaw in the process. Because of this process there are many difficult to overcome and mutually restrictive contradictions, making it increasingly obsolete, has been unable to adapt to the requirements of modern factory automatic painting, will gradually withdraw from the field of steel coating; Steel pipe anti-corrosion coating process three: is a technologically advanced but not very mature technology. In the two rollers between the moment to complete the spraying and curing, the advantages of self-evident. But there are also difficult to overcome the weaknesses, such as: steel pipe surface pretreatment requirements are extremely strict, slightly inadvertently, adhesion decreased significantly; UV coatings and equipment expensive, technical management requirements; coating crisp, Bump, easy to fall off, and difficult to make up. Due to the existence of such a number of problems so that the promotion of this process is subject to constraints; Steel pipe anti-corrosion coating process four: is a technology developed in recent years more advanced and relatively mature technology. It overcomes the other process of the existence of a serious sagging film, abrasions, whitening, fragile and other ills. The resulting coating adhesion strong, flexible, rust-proof effect is very good, very few sagging, beautiful and complete. The process also has a simple, complete, technical management requirements of low and safe features. As a result of technical improvement called steel pipe heating without gas spraying complete sets of technology. Treatment technology of airless spray of steel pipe Process one to the process of three embodies the traditional process of the prevalence of painting defects, that is, serious sagging film, abrasions, whitening and so on. The latest technology four to solve this series of problems, and formed a perfect steel pipe heating airless spray sets of technology. The technology has the following technical advantages. 1. Avoid strip or spiral abrasions In the late 1990s, Chinese experts analyzed the abrasion of steel pipe coating. At that time the abrasions mainly for the steel surface width of 40 mm two longitudinal full-length abrasions. For the introduction of foreign steel pipe coating production line before and after the use of painting before and after the roller conveyor, and the middle of the shower box is also installed roller design, the two sides put forward the front of the front roller conveyor belt conveyor transmission mode for airless spray Of the technical program. This program in the early 21st century, by the Beijing Polonus Painting Equipment Co., Ltd. in Daqing General Machinery Plant tubing plant to achieve and put into production applications. It is proved that this process can effectively prevent the longitudinal abrasion of the steel pipe. After the coating, there are only two small dotted teeth with a spacing of 600 mm, and the self-healing property of the coating itself is adopted. Reflected well. The process of further improvement (taking the process of segmented conveyor belt before and after spraying), so that the steel pipe is always in contact with the V-shaped teeth of the chain, and the front and rear chain synchronous movement, to ensure that the spray between the surface and the fulcrum The minimum contact, to avoid the roller conveyor strip scratches the ills, beautiful and complete coating. At present, the technical level both in the international and domestic in the current is more advanced. The technology is not only advanced and mature, has been in the domestic 13 automatic oil line to be verified. As for the spiral band abrasions to prevent very simple, remove the screw conveyor to this method can be. 2. To overcome the problem of sagging Hanging can be pided into five types: specific gravity, too thick, low viscosity type, special shape type, contact type. Steel pipe anti-rust coating is relatively small proportion of the impact of the sag can be ignored. The main types of steel pipe sag are too thick and low viscosity type, the secondary type is special shape and contact type. As the steel pipe section is round, close to the streamline, so the paint is more easy to flow, easy to hang, it is inevitable, but can overcome. Only by spraying the original viscosity of the higher viscosity but after the viscosity reduction of the coating, with the temperature to reduce the higher viscosity of the way to reduce the flow of paint on the surface of the pipe to overcome the sagging. The contact type sagging is due to the contact surface of the steel pipe after contact with the steel pipe surface, forming a contact surface near the surface of the steel pipe, guiding the coating to leave the coating film to form a sagging. This is inevitable. But can be reduced by film thickness control. Fortunately, the number and size is very small, the appearance of little impact. As for the thick type of sagging due to the formation of a lot of reasons, it is necessary to pay attention to the problem is a lot of this is the need to control the key, must ensure that the following: steel pipe anti-corrosion coating steel pipe must ensure a certain speed, and can in a certain range Within the adjustment. Steel pipe corrosion coating steel pipe transport must be uniform motion; Corrosion-resistant coating of steel pipe with no gas heating spray method, the working pressure of the paint can be adjusted, while the pressure must be stable. The heating temperature of the coating can be adjusted; Steel pipe anti-corrosion coating nozzle model through the correct selection of the experiment, including the flow, spray width and other parameters; Steel pipe anti-corrosion coating airless automatic gun for the steel pipe circular cross-section of the uniform distribution of the angle for the steel pipe surface and the steel pipe surface distance can be adjusted; Steel pipe anti-corrosion coating must ensure that the center of the gun group and steel pipe center; Steel pipe anti-corrosion coating exhaust air volume wind speed and spray state must match; The corrosion resistance of the pipe is good. If for each type of steel pipe are carefully adjusted above points, too thick sag is completely overcome. The problem is to establish a complete coating process management system to ensure that the variety of replacement, the technical adjustment work in an orderly manner. 3. To prevent the coating whitening The formation mechanism of the whitening defects in the coating film is the result of the condensation of the moisture into the coating to produce a translucent white film. There are many reasons for its production, such as the air humidity of the construction environment, excessive dispersion of the coating, the temperature of the dispersion process, the local temperature of the coating surface, the water content in the coating, the surface temperature of the workpiece is too low, the boiling point of the solvent or the ratio is improper, Wait. For steel pipe coating, the first three are the main reason. These manifestations are a forming process under certain conditions. As an electrostatic coating, the main reason for the formation of whitening of the coating can be described as follows: After the air humidity in the environment is relatively large and the temperature is relatively low, the coating is dispersed from the slotted electrostatic atomizer and then dispersed Steel pipe surface. In this process, due to the excessive dispersion of the coating into an extremely large quantity and extremely fine coating droplets, the specific surface area of the coating is large, the area of the contact with the wet air is large, and the water molecules can be attracted to the surface of the water and mixed with the coating liquid The stream eventually enters the interior of the coating, resulting in a whitening defect in the coating. As can be seen from the above discussion, the ambient air humidity is only the conditions, the real reason is the excessive dispersion of paint. In order to prevent the appearance of the coating whitening defects can be in the ambient air humidity under the same conditions, through the control of excessive dispersion approach to achieve. The use of heated airless spray method is considered to be the best way to control the above two reasons. The so-called heating airless spray, as the name suggests, heating is the coating heated to a temperature after spraying. The general temperature is between 40 and 80 ° C. Airless spray means that the air is not compressed when the paint is atomized. The atomization principle is: the liquid coating with a pressurized pump to a certain pressure, through the pipeline into the spray gun, sprayed through the nozzle after the formation of high-speed liquid film; high-speed liquid film and air friction after the dispersion is small Droplets and atomization. Its atomization effect is moderate, will not occur excessive dispersion, suitable for pipeline coating. Airless spray can reduce the amount of solvent, spray coating high viscosity, spray paint than air-saving, slightly larger than the amount of electrostatic spraying paint. But through the recovery device can make up for this weakness. As the heating airless spray with temperature and atomization advantages, as the best choice for steel coating. And this choice process effect is obvious, a number of manufacturers and a number of coating lines to use the results, always found no white phenomenon. Even far from the ocean coating can also ensure good anti-rust effect. In addition, the effect of heating and drying after the heating of the airless coating to prevent the occurrence of whitening defects can not be ignored. Through the above description, anti-corrosion coating steel pipe can effectively avoid corrosion problems such as steel pipe, making the use of steel pipe can play a greater role. Source: China Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Generally, the diameter of stainless steel tubes is classified into outer diameter, inner diameter and nominal diameter. The seamless steel pipe diameter using the letter D to that in diameter attached to the size and thickness, such as diameter is 108 seamless steel pipe, wall thickness of 6MM, is expressed as D108 * 6, another plastic tube with outer diameter is also said, such as De63, such as reinforced concrete pipe, cast iron pipe and galvanized steel pipe also is to use DN to represent, in the design drawings are usually used to represent the nominal diameter, nominal diameter is a standard in order to design and manufacture and maintenance convenient set artificially, also called nominal diameter, such as stainless steel pipe fittings is most specification name. DN is nominal diameter, nominal diameter, also known as nominal diameter, that is, all kinds of pipe fittings and pipe accessories of the general caliber. The same nominal diameter of the pipe and piping accessories can be connected with each other, with interchangeability. It is not a real sense of pipe diameter or diameter, although its value is closer with the pipe diameter or equivalent; in order to make the tube, pipe connection size uniform, with nominal diameter (or nominal diameter, nominal diameter). For example, welded steel pipe can be pided into thin walled steel pipe, ordinary steel pipe and thickened steel pipe according to the thickness. Its nominal diameter is not an outer diameter, nor an inner diameter, but a nominal size similar to the diameter of ordinary steel pipe. Each nominal diameter corresponds to an outer diameter, and its inner diameter varies with the thickness. Nominal diameter can be expressed in metric mm, and can also be expressed in Imperial in. With nominal diameter pipeline accessories, which means the same and seamed tube. Such as stainless steel pipe fittings nominal diameter and the inner diameter and the outer diameter are not equal, such as the nominal diameter is 100mm seamless steel pipe is 1025, 1085 and 108 of them are several, the outer diameter of pipes, 5 stainless steel tube wall thickness, so the pipe diameter is (108 * 5-5) = 98mm, but this result is not completely equal to two times the wall thickness difference, reducing the pipe diameter in other words, just close to the nominal diameter of a stainless steel inner diameter, but not exactly the same to the diameter of pipe diameter specification name, so the need for nominal diameter on the design drawings, the purpose is to determine according to the nominal diameter of the pipe and pipe fittings valve, flange, gasket structure dimensions and connection dimensions, nominal diameter is represented by the symbol DN, if the diameter is used to represent the design drawings, also need to give the size of pipe The nominal diameter and wall thickness of a pipe are indicated by a comparison table. The design and construction of a series of standard pressure pipes for stainless steel pipes, the first step is to consider the selection of the standard series of pressure piping and its components. In this regard, although the application of standard systems in many countries, but can be pided into two categories. Nominal steel tube diameter, also known as the average diameter of steel pipe. The nominal diameter is followed by a number to represent the letter. Because the tube is thinner, the outer diameter of the pipe is almost the same as the inner diameter of the pipe, so the diameter of the steel pipe can be used as the average value of the inner diameter of the pipe. Source: China Stainless Steel Tube Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe is a kind of hollow strip steel, mainly two kinds of seamless steel pipe and welded steel pipe, often used as a pipeline for conveying fluid, such as oil, natural gas, water, gas, steam, etc. When the bending strength is the same, the weight of the stainless steel tube is relatively light, so it is widely used to produce mechanical parts and engineering components. It is also used to make all kinds of conventional weapons, barrels, shells and so on. The Classification of stainless steel pipe According to the production method of stainless steel pipe, seamless steel pipe can be pided into cold drawn tube, extruded pipe, cold rolling pipe. stainless steel seamless pipe manufacturing process in the order of smelting, ingot, rolling, sawing, peeling, perforation, annealing, pickling, ash, cold drawing, cutting head, pickling, storage. Stainless steel pipe can also be classified according to cross-section shape, pided into circular steel pipe, rectangular tube. And by wall thickness classification of thin-walled steel pipe, thick-walled steel pipe. The use of steel pipe to pide, can be pided into civilian pipe: sub-tube, rectangular tube, flower tube, generally used for decoration, construction, structure, etc.; industrial pipe: industrial pipe with pipe, general pipe with pipe (drinking water pipe ), Mechanical structure / fluid delivery pipe, boiler heat exchange tubes, food hygiene pipes and so on. Usually used in various fields such as: petrochemical, paper, nuclear, food, beverage, pharmaceutical and other industries on the fluid medium requires a higher pipeline. The characteristics of seamless steel pipe From the above process can know a few points, the first stainless steel seamless pipe wall thickness thicker, the more economical and practical, and the thinner wall thickness, the processing cost will be greatly improved; followed by stainless steel processing technology It is usually limited, usually the accuracy of seamless steel pipe will be low, uneven wall thickness, tube inside and outside the table brightness is low, the length of the high cost, and the inside and outside the table is also easy to pitting, black spots, not very good to remove; Three stainless steel seamless pipe inspection and shaping must be off-line treatment. So in the high-pressure, high strength, mechanical structure of the material reflects the superiority of seamless steel pipe. Stainless steel welded pipe Again, stainless steel welded pipe, welded steel pipe referred to as welded pipe, steel plate or strip through the unit and mold curling after forming the steel pipe. According to the stainless steel processing technology to pide, there are gas protection welded pipe, arc welded pipe, resistance welded pipe (high frequency, low frequency), and according to the weld to points, there are straight seam welded pipe, spiral welded pipe. Welded steel pipe manufacturing process and process sequence is the steel plate, sub-section, forming, dissolved, induction light heat treatment, inside and outside the weld processing, shaping, sizing, eddy current testing, laser caliper, pickling, storage. Welded steel pipe is characterized by the first continuous production on-line, the thicker the wall, the greater the unit and the investment in welding equipment, welded steel pipe is not more economical and practical. And the thickness of the thinner, the input and output ratio will be a corresponding decline; another welding pipe technology to determine its advantages and disadvantages, usually welded steel pipe with high precision, uniform wall thickness, the inside and outside the table brightness is high (steel plate surface grade steel pipe surface Brightness), can be any length. So the welding pipe in the high-precision, low pressure fluid applications reflects its economic and aesthetic. Source: China Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

At present, there are many kinds of polishing processes for stainless steel pipe fittings. This paper introduces some common polishing processes, including mechanical polishing, chemical polishing, electropolishing, ultrasonic polishing, fluid polishing, etc.. Mechanical polishing Mechanical polishing on cutting and plastic deformation of plate surface is convex removed after polishing to obtain a smooth surface polishing method, usually use oilstone, wool wheel, sand paper, these are mainly manual operation, including special parts such as rotary surface, can be used to machine tool, if higher requirements on the surface quality, you can use the method of ultra precision polishing. Ultra precision polishing is the use of special abrasive tools, in the grinding fluid containing abrasives, tightly pressed on the surface of the pipe to be processed, for high-speed rotation movement. Using this technique, the surface roughness of Ra0.008 micron M can be reached, which is the highest in various polishing methods. Chemical polishing Chemical polishing is to dissolve the micro protruding part of the stainless steel tube surface in chemical medium to obtain smooth surface. The main advantage of this method is that the complex shape of the pipe can be polished without complex equipment, and many pipes can be polished at the same time, and the efficiency is very high. The key of chemical polishing is the preparation of polishing fluid. The surface roughness obtained by chemical polishing is generally 10 m. Electro polishing The basic principle of electropolishing is the same as chemical polishing, which relies on selective dissolution of tiny bulges on the surface of stainless steel to obtain smooth surfaces. Compared with chemical polishing, the effect of cathodic reaction can be eliminated, and the effect is better. Ultrasonic polishing The stainless steel pipe is placed in the abrasive suspension and placed in the ultrasonic field together, and the surface of the pipe is polished by the oscillating action of the ultrasonic wave. Ultrasonic machining has small macro force and can not cause deformation of pipe fittings, but it is difficult to make and install tooling. Ultrasonic machining can be combined with chemical or electrochemical methods. Based on the solution of corrosion, electrolysis, and ultrasonic vibration is applied to dissolving the mixing solution, the surface of the pipe from near the surface of the product, corrosion or electrolyte evenly; ultrasonic cavitation in the liquid can also inhibit the corrosion process for surface light lighting. Fluid polishing Fluid polishing is based on high speed flow of liquid and its abrasive particles to scour the pipe surface to achieve polishing purposes. Commonly used methods are: abrasive jet machining, liquid jet machining, fluid dynamic grinding, etc.. Fluid dynamic grinding is driven by hydraulic pressure, which allows the liquid medium carrying abrasive particles to flow through the pipe surface at high speed. The medium is mainly made of special compound (polymer material) which is flowing through the lower pressure and mixed with abrasive. The silicon carbide powder can be used in the abrasive. Source: China Stainless Steel Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

304 stainless steel pipe has excellent hygienic performance. It is corrosion resistant, beautiful and grade, and its service life is more than 70 years. It is one of the pipelines with better comprehensive performance. 304 stainless steel water supply pipe is characterized by no rust, stable chemical performance, no two pollution, is a very good green environmental protection material. Many high-rise buildings in the world use 304 stainless steel pipe as the main pipeline of water supply. For example, the Kuala Lumpur Malaysia communications tower, is the use of 304 stainless steel pipe, its high pressure joints can be up to 421 meters of water supply, the main stainless steel pipe diameter of 318 meters. 304 stainless steel pipe in the air or chemical corrosive medium is a highly corrosion resistant alloy steel. From the angle of metallographic metal, because of containing chromium chemical composition of 304 stainless steel, so on the surface to form a thin protective film of chrome but dense, this film from stainless steel immersed in oxygen continue to penetrate the steel body, which plays the role of corrosion resistance. In order to maintain the corrosion resistance of stainless steel, the chromium content must be higher than 12%. 304 thin wall stainless steel pipe is a versatile stainless steel, and it is also used in a large number of equipment and parts that require good comprehensive performance (corrosion resistance and formability). The corrosion resistance of the 304 stainless steel pipe is better than that of the 200 stainless steel tube, and the heat resistance is better, and it can withstand the high temperature of 1000-1200 degrees. 304 stainless steel has excellent stainless steel corrosion resistance and better intergranular corrosion resistance. The corrosion resistance of 304 stainless steel tubes in boiling nitric acid with concentration lower than 65% is very strong. It can also resist alkali solution and corrosion of most organic and inorganic acids. A high alloy resistant to corrosion in air or in a chemically corrosive medium. Source: China Stainless Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

At present, steel extrusion units in the world, in addition to a small number of extrusion processing profiles, most of the extrusion units are used to produce steel pipe, of which the main variety is stainless steel seamless pipe. Compared with the production methods such as rolling (longitudinal rolling and cross rolling), the extrusion process is characterized by the three direction compressive stress in the process of metal deformation. Under the optimum stress state, the stainless steel seamless pipe with large variety and large deformation resistance can get better deformation, internal and external surface quality and metallographic structure. Seamless stainless steel pipe With the improvement of vertical hydraulic piercing equipment, the wall thickness deviation of the extruded seamless stainless steel pipe can reach 5%~7%. In addition, extrusion mould is simple, manufacture and easy replacement, suitable for small batch and various specifications of stainless steel seamless pipe production. The extrusion unit can also pipe production specifications wide, 1 sets of 50MN (5000t) of the extruder unit can produce specifications is 25~245mm diameter stainless steel seamless pipe, needs to adapt to the market and meet is much higher than the other mill. With the biggest advantage of extrusion production of stainless steel seamless pipe is able to direct the use of continuous casting as raw materials, so as to ensure the stability of product quality, variety replacement and flexible, can be directly produced by hot extrusion pipe, also can produce a variety of special-shaped stainless steel seamless pipe. However, the stainless steel seamless pipe produced by extrusion process has an obvious drawback, that is, low yield. In order to improve the yield, foreign manufacturers have improved the production process. For the high demand varieties, the production process of pre drilling, hydraulic punch reaming and extrusion pipe forming is usually adopted. For the cold processing of raw materials for common requirements for pipe according to use different production processes specific circumstances, such as small size stainless steel seamless pipe billet directly in the vertical hydraulic punch punch and extruded pipe; medium size stainless steel seamless pipe with blank as far as possible pre drilled holes, vertical hydraulic reaming and extrusion punch into large size stainless steel pipe; the seamless pipe blank pre drilling larger holes, directly into the extrusion pipe. It can be clearly seen that the production of finished pipes by extrusion and the provision of steel pipes for cold processing are a more economical and practical production process for stainless steel seamless pipes which are now widely used in foreign countries. Source: China Stainless Steel Pipes Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The surface of stainless steel plate is relatively smooth, the plasticity, toughness and mechanical strength are higher, to a certain extent, acid and alkaline gas solution or other corrosive media, is a kind of alloy steel is not easy to rust. Stainless steel plate has been widely used in chemical, food, pharmaceutical, papermaking, petroleum, atomic energy and other industrial fields, as well as civil fields such as building, kitchenware, vehicle, electrical appliance parts and so on. Stainless steel plate Generally speaking, stainless steel plate can withstand the corrosion of oxalic acid, sulfuric acid, ferric sulfate, nitric acid, nitric acid hydrofluoric acid, sulfuric acid copper sulfate, phosphoric acid, formic acid, acetic acid and other acids. The corrosion resistance of stainless steel mainly depends on its chemical composition (chromium, nickel, titanium, silicon, aluminum, etc.) and the metallographic structure of steel body, the main role is chromium. Chromium has a high chemical stability, can form passive film on the steel surface, so that the metal is isolated from the outside world, protect the steel plate is not oxidized, increase the corrosion resistance of steel plate. When the passivation film is destroyed, the corrosion resistance will decrease. The thickness of the stainless steel plate is greater than 1.2mm, and Rockwell hardness tester is used to test the hardness of HRB and HRC. Stainless steel plate with thickness of 0.2 ~ 1.2mm is tested with surface Rockwell hardness tester HRT and HRN hardness. A stainless steel plate with a thickness ratio of 0.2mm is used to test the hardness of HR30Tm by using a diamond anvil cell with a Rockwell hardness tester. Stainless steel plate determination method can use stainless steel plate determination liquid. Stainless steel plate determination, can quickly distinguish between 200, 201, 202, 301, 304, 316, 316L, 309, 310, 321, stainless steel is a kind of medicine, able to recognize and distinguish types of stainless steel material, identification, testing, identification, testing etc.. It is based on analytical chemistry, can make the battery power make the reaction surface, generating colored complex control technology through appropriate measuring elements and the reagent, realizing rapid determination of metal elements in stainless steel. The technology is a global leader, which plays an irreplaceable role in the field rapid determination of stainless steel materials, sorting, recycling and reuse of stainless steel scrap. Stainless steel plate liquid products have the following characteristics: 1. The product is suitable for the determination of nickel, molybdenum, titanium and other elements in stainless steel, the accuracy is more than 95%, the cost is only 0.05 yuan per time. 2, the use of no equipment, easy to carry, anytime, anywhere can be detected. It is especially suitable for metallurgical furnace analysis and material recycling industry. 3 simple operation, as long as the liquid drops on the stainless steel, with 9V battery power reaction for 1-8 seconds. Look at the color to determine the approximate ingredients. 4, rapid reaction, only within a few seconds to know the general composition of stainless steel. Rapid determination of Ni stainless steel plate liquid qualitative, low Ni (200), Ni2 (201), Ni4 (202), Ni6 (301), Ni8 (304), Ni14 (309, 316L), Ni20 (310), Ni40, Ni60, Mo2 (316), stainless steel, steel and other liquid identification. As long as the drop point on stainless steel, liquid and stainless steel chemical reaction immediately, through the reaction of different colors, can clearly determine the type of stainless steel. Especially, the discrimination of 202, 301, 304 and 316 is the most obvious. Each cell must be equipped with a battery, used for electrolytic water, accelerated reaction, is that you analyze the stainless steel plate of the liquid material. Source: China Stainless Steel Plate Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)