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The pickling process of stainless steel lap joint stub end is an important process step of stainless steel pipe fittings, and that a lot of people ask, stainless steel flange itself will not rust, why pickling for it? Actually the process of pickling of stainless steel flange, a is to go out to bend in the machining process produced by high temperature oxide skin, let the edge of stainless steel products is bright and clean, beautiful; 2 it is to make the surface of the stainless steel to generate a compact oxidation film, thus further protection in the later use process, prevent them from rusting again. The pickling of stainless steel lap joint stub end is often linked with passivation, generally need must be passivation pickling of stainless steel, because of no formation on the surface passivation film after pickling or form passivation film thickness is very thin, not going to work, must increase subsequent passivation process, the formation and improvement of passivation film on stainless steel surface. Source: China Pipe Fitting Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

There are many kinds of processing methods for pipe fittings, many of which are in the category of mechanical processing, and the most used are punching method, forging method, rolling method, rolling method, bulging method, stretching method, bending method and combined processing method. Pipe fitting processing is an organic combination of machining and metal pressure processing. Examples are as follows: Forging method: the end of the pipe or part of the forging machine to red stretch, so that the outer diameter reduction, commonly used forging machine with rotary, connecting rod, roller type. Stamping: Extend the pipe end to the desired size and shape on a punch with a tapered core. Roller method: Place the core in the tube, the outer circle with a roller to push, for the round edge processing. Rolling method: generally do not have mandrel, suitable for thick-walled tube inside the circle. Bending method: There are three methods are more commonly used, a method called stretching method, another method called the stamping method, the third is more familiar with the roller method, with 3-4 rollers, two fixed roller, an adjustment Roller, adjust the fixed roller from the finished pipe is curved. This method is widely used, if the production of spiral, the curvature can also increase. Bubble method: one is placed in the tube rubber, the top with the punch compression, so that the tube protruding forming; Another method is the hydraulic bulging forming, filled in the middle of the tube liquid, the use of liquid pressure tube drum into the desired shape , As we commonly used in the production of bellows most of this method is used. Source: China Pipe Fitting Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Inspection and installation of flange 1. Open the product package to check whether the main part of the list or the contract in line with the product, inventory the number of products. 2. Check whether the product surface pits, scratches, rust fragments and oil, flange surface roughness of not more than 6.3μm, if the roughness does not match, then trim the flange surface, check the flange, bolt holes, etc., and cleaning method Blue face 3. Flange sealing surface should be smooth and smooth, no burr and radial groove; thread flange part of the thread should be complete, no damage; concave and convex sealing surface of the sealing surface should be able to naturally fit, the height of the convex surface shall not be lower than the concave Groove depth. 4. Check and clean bolts, nuts, apply insulating grease to all bolts and nut threads 5. Align the flanges to keep them coaxial, parallel, and carefully install the gasket, prohibit the use of lubricants, grease, and adhesives on the gasket and flange surfaces to prevent damage to the seals on the gasket. 6. Align the bolt holes and insert them into the fixed flange (especially for large flanges) with 30 perforated nails at least 120 degrees. 7. Insert bolts, nuts and washers. Lubricants with grease should first be fitted with stainless steel washers, preloaded bolts until the flange and gasket are in contact with each other 8. Use a micrometer, flashlight and other tools to check the gap between the flange and the gasket, if the gap exists, indicating that the flange assembly is not parallel. 9. If there is a gap, unscrew the nut a little bit and then retighten until the two flanges are in contact with the gasket. This method is necessary to prevent the flange from contacting the gasket. If the method is not correct Will also cause the flange and gasket contact with the bolt when the load is too large to damage the gasket seal. 10. Tighten the loose nuts again by following the recommended bolt tightening torque (10-15% bolt torque), remove the piercing studs, apply bolts, nuts, washers, and tighten with the same torque. 11. Continue to tighten the bolt and raise the preload to 50% of the bolt torque; continue to tighten the bolt until the final torque. 12. This is an operating procedure for effective tightening of bolts, especially for large diameter piping systems. 13. All of the above operations should use a torque wrench (mechanical or hydraulic) or use a bolt pretensioner. Source: China Flange Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fitting is not easy to rust and the composition of stainless steel has a great relationship. Stainless steel in addition to the composition of iron, there are chromium, nickel, aluminum, silicon and so on. General stainless steel chromium content is generally not less than 12%, high or even up to 18%. Steel added chromium and other elements, you can change the performance of steel, such as steel, such as the molecular structure is more uniform in the steel surface is more likely to generate a layer of dense oxide protective film, etc., thereby greatly improving the ability of stainless steel corrosion resistance. So stainless steel can resist fire, water, acid, alkali and a variety of solutions to its corrosion, no rust. Scientists have found that the more uniform the internal structure of steel, the more closely connected components, the more difficult the corrosive invasion, coupled with the surface and attached a layer of oxide protective film, like steel to wear armor, natural It is not easy to rust. The Requirements of Stainless Steel Pipe Fittings in Bridge Construction 1) durability requirements. Bridge in the marine environment, the design life of 120 years, the higher the durability requirements. 2) Save maintenance costs. The use of stainless steel pipe in the course of the use of the bridge without the need for regular maintenance, saving a lot of maintenance costs. 3) security requirements. Wind tunnel tests show that the lighter pylon is susceptible to vortex-induced vibration, which can also cause large-amplitude cable vibration. Therefore, in order to improve the aerodynamic performance of the pylon, the pylon is filled with concrete in the stainless steel pipe Stainless steel tube concrete structure. 4) looks beautiful. Source: China Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fitting is a kind of pipe fittings, stainless steel material is it made so called stainless steel pipe fittings, it includes: stainless steel elbow, stainless steel tee, cross stainless steel, stainless steel reducer, stainless steel pipe cap, etc., according to join method can be pided into the socket type stainless steel pipe fittings, flanges threaded stainless steel pipe fittings, stainless steel pipes and welded stainless steel pipe fittings four classes. Stainless steel elbow is used for fitting the turning places; Flange is used to make the pipe with pipe connecting parts, connection pipe, stainless steel tee to the meeting-place of three pipe; Stainless steel cross pipe used in the meeting-place of four pipe; Stainless steel reducer used for different pipe diameter of two pipes are connected. Main material: stainless steel 304 l, 304 l, 304, 304, 310, 321, etc. Processing and the related knowledge of transportation: 1. Stainless steel pipe fittings of multi-channel multi-layer welding arc used to welding, arc should fill arc crater. Banned in pipes and pipe fittings of the surface of the parent metal arc or the arc. By playing the arc or the arc found defects such as blowholes, cracks should be clean. 2. When the tack welding seam inside should be filled argon protection. 3. Stainless steel pipe fittings cutting cannot use the ordinary grinding wheel cutting, should use the special grinding wheel piece or plasma cutting. 4. After welding for pipe fittings for pickling and passivation. 5. In material handling, can’t direct contact with other metals, should be padded non-metallic materials such as wood or rubber sheet. Source: China Pipe Fitting Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fittings are widely used in tap water engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction, is China’s development of one of the 20 key products. For liquid delivery with: water supply, drainage. For gas transmission with: gas, steam, liquefied petroleum gas. For the structure with: for piling pipe, for the bridge; terminal, road, building structure and so on. (1) stainless steel pipe manufacturing process can be pided into: hot rolling (extrusion), cold rolling (pull), thermal expansion of the basic categories of these. (2) welded pipe in accordance with the manufacturing process can be pided into: straight seam welded steel pipe, submerged arc welded steel pipe, coil butt welded steel pipe, welded pipe thermal expansion pipe. The following are the same as the “ (3) According to the shape of the pipe can be pided into square tube, rectangular tube, octagonal, hexagonal, D-shaped, pentagonal and other special-shaped steel pipe. Complex cross-section steel pipe, double concave steel pipe, five plum-shaped steel pipe, conical steel pipe, corrugated steel pipe, melon-shaped steel pipe, double convex steel pipe (4) Classification by use – Steel pipes for pipes, pipes for thermal equipment, Steel for mechanical industry, Steel for oil, Geological drilling, Containers, Pipe for chemical industry, Special purpose pipes, etc… Source: China Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fittings are widely used in both industrial and civilian applications. The choice of stainless steel pipe fittings when the quality of their own materials will affect its application, and some special industries such as petrochemical, nuclear, medical and other industries on the quality requirements of stainless steel pipe fittings higher. First, the gas protection welding in the welding of the gas under the protection of stainless steel surface of chromium and nickel will not be oxidized, retain the original characteristics of stainless steel and corrosion resistance; Second, pickling passivation: can make the water pipe and pipe wall to produce a thin and dense, hard passivation film, is to prevent the root causes of corrosion; Third, the bright solidification: stainless steel pipe after forming, welding process, must be 1050 degrees of solid solution to eliminate the stainless steel tube due to deformation caused by internal stress, reduce stress corrosion, recovery pipe welding process of intergranular changes, Carbide dissolved in austenite, to prevent adverse effects; Fourth, the sealing material: sealing material is the key point of the life of stainless steel pipe, sealing material life determines the life of stainless steel pipe fitting. Source: China Pipe Fittings Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Six methods of processing stainless steel pipe fittings: 1. roller method: put the core in the tube, the periphery with the roller push, for the edge processing. ​ 2. method: use type forging press machine will be at the end of the pipe or part shall be rushed out, the diameter reduced, commonly used swaging machine have rotary, connecting rod type, roller type. 3. bending method: there are three kinds of commonly used methods, a method called stretch method, another method called stamping method, third roller method, 3-4 roller, two fixed roller, a roller adjustment, adjust the fixed roller distance, the finished product is bent pipe. 4. rolling method: generally without mandrel, suitable for thick wall pipe inside round edge. 5. Method: one is placed in the rubber tube, with compression punch above the tube bulge forming; another method is hydraulic bulging in the middle pipe, filling liquid, liquid pressure into the pipe drum to the shape of corrugated pipe production with the most is this method. 6. stamping method: in the punch with the taper of the tube will be extended to the required size and shape. Six types of stainless steel pipe fittings processing conversion: Form one, with flange of pipe fitting, the former refers to the pipe end to the medial or lateral convex, which is a swell in the circumferential direction of the tube or groove pipe fittings; Form 2, thin-walled stainless steel elbow processed into thick wall stainless steel elbow, along the length direction pipe wall thickness changes; Form 3, stainless steel elbow, we contact more, is the straight pipe into different curvature radius of bend, such as the elbow, bend, and so on; Forms four, stainless steel elbow into diameter of pipe fittings, refers to one part of the tube or pipe diameter decreased; Form five, with edge and bottom sealing fitting, increase the pipe’s overall strength to pipe the inner or outer edge or the pipe end seal pipe fittings; Form processing pipe section, square, oval, circular section into a polygon. Source: China Pipe Fitting Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Three calculation methods of stainless steel pipe: (1): cold drawn seamless rectangular steel pipe calculation method: W (kg/m) = *4* thickness *0.00785 (2): the density of steel is 1.85kg/dm2, the formula for calculating the weight per meter is W (kg/m) =0.02466* wall thickness * (outer diameter wall thickness) (3): stainless steel pipe per meter weight formula: W (kg/m) =0.02491* wall thickness * (outer diameter – wall thickness) Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel pipe fitting is a kind of pipe fittings, stainless steel material is it made so called stainless steel pipe fittings, which include: stainless steel elbow, stainless steel tee, stainless steel cross, stainless steel reducer, stainless steel pipe cap, etc., according to join method can be pided into the socket type stainless steel pipe fittings, flanges threaded stainless steel pipe fittings, stainless steel pipes and welded stainless steel pipe fittings four classes. Stainless steel pipe fittings used as pipes conveying fluid in great quantities, such as oil, natural gas, water, gas, steam, etc., in addition, doing bending and torsional strength phase at the same time, the weight is lighter, it is widely used in the manufacture of machinery parts and engineering structures. Stainless steel elbow is used for fitting the turning places; Flange is used to make the pipe with pipe connecting parts, connection in the pipe; Stainless steel tee for three pipes of the place; Stainless steel cross for four pipe collection place; The stainless steel reducer is used for the connection of two pipes of different diameters. Source: China Pipe Fitting Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

In today’s industrial automation is becoming more common now, in production, to be without a well-made sight glasses.Stainless steel sight glass is installed on the piping or equipment can at any time to check the material within the monitoring work of a product. Stainless steel sight glass is made from 304/316 304/316 / l etc give priority to material produced by sight glasses. It has high corrosion resistance, and easy processing, beautiful appearance. Sight glasses at the same time use tempered borosilicate glass, polyethylene ptfe gasket. The stainless steel sight glass is suitable for most of the poor working environment. And a longer service life. Stainless steel sight glass due to compact structure, its installation is simple, easy to use, and easy cleaning and maintenance, is the most commonly used an optical lens. Which view mirror stainless steel equipment used in pressure vessel, chemical tower and other cylindrical device, and stainless steel pipe lens is suitable for chemical, oil, electric power line, etc. Source: China Sight Glass Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The classification of steel pipe 1, according to the production method of classification (1) seamless pipe, hot rolled, cold rolled tube, cold drawn tube, extrusion tube, pipe jacking welded pipe (2) (a) according to the technological points – arc welding pipe, electric resistance welding (high frequency and low frequency) and gas welding tube, furnace welding pipe. (b) according to the weld points – straight seam welded pipe, spiral welded pipe. 2, according to the cross section shape classification (1) simple section steel tube, round steel pipes, square steel tube, oval tube, triangular steel, hexagonal steel tube, the diamond steel pipe, octagon steel pipes, semicircle round steel, the other (2) complex cross section steel tube – not equilateral hexagon steel tube, five disc plum blossom shaped steel tube, double convex tube and double concave steel tube, melon seeds shaped steel tube, conical steel pipe, corrugated pipe, casing pipe and other 3, according to the classification of wall thickness, thin-walled steel tube ⒑ 4, according to use classification – pipe with steel tube, thermal technology equipment in steel, and machinery industry with a steel tube, petroleum, geological drilling in steel, container steel pipes, and chemical industry with a steel pipe, steel pipe, and other special purposes Second, the seamless steel tube. Is a hollow section, no seams around the strip steel. Steel pipe has a hollow section, a large number of used for conveying fluid pipe, such as oil, natural gas, coal gas, water and some solid materials, such as pipelines. Compared to the steel pipe and round steel solid steel bending torsional strength phase at the same time, the weight is lighter, is a kind of economic cross section steel, widely used in the manufacture of structural and mechanical parts, such as petroleum drill pipe, auto transmission shaft, bicycle frame and construction of steel scaffolding is used. With steel pipe manufacturing annular parts, can improve material utilization, simplifying the manufacturing process, material saving and processing time, such as rolling bearing ring, jack sets, at present has been widely made from steel pipe. Steel pipe or all kinds of conventional weapons indispensable materials, gun, gun barrel to steel pipe manufacturing. Steel pipe according to the cross-sectional area in the shape of different can be pided into circular tube and special pipe. Due to the equal conditions, the circumference circle area is the largest, with circular tube can deliver more fluid. In addition, the circle cross section under radial pressure, the internal or external stress is relatively uniform, therefore, the vast majority of steel tube is round tube. But, pipe also has some limitations, such as in the plane bending condition, the pipe is not square, rectangular tube bending strength is big, some agricultural machinery and skeleton, rectangular tube, steel wood furniture is commonly used. According to the different USES also needs to have other cross section shape of profiled steel pipe. 1. The structure with seamless steel tube (gb/t8162-1999) is used for general structure and the mechanical structure of seamless steel tube. 2. Fluid with seamless steel tube transmission (gb/t8163-1999) is used for conveying water, oil, gas and other fluid general seamless steel tube. 3. Low medium pressure boiler seamless steel tube (gb3087-1999) is used in the manufacture of various structural low intermediate pressure boiler superheated steam pipe, water pipe and locomotive boiler superheated steam pipe, pipes, small pipe and arch brick works of high quality carbon structural steel hot rolling and cold drawing (rolling) seamless steel tube. 4. High pressure boiler seamless steel tube (gb5310-1995) is used in the manufacture of high pressure and over pressure water tube boiler heating surface quality carbon steel, alloy steel and heat resistant stainless steel seamless steel tube. 5. Fertilizer equipment with high-pressure seamless steel tube (gb6479-86) is applicable to the working temperature for – 40 ~ 400 ℃, the working pressure of 10 ~ 30 ma chemical equipment and pipeline of high quality carbon structural steel and alloy steel seamless steel tube. 6. Seamless steel tube used in oil cracking (gb9948-88) is suitable for oil refinery furnace tube, heat exchangers and pipe seamless steel pipe. 7. Geological drilling with steel tube (yb235-70) is for the use of geological departments the core drilling of steel pipe, according to the purpose can be pided into the drill pipe, drill collar, core pipe, casing and precipitation, etc. 8. Diamond core drilling with seamless steel tube (gb3423-82) is used for diamond core drill pipe, core rod, casing of seamless steel tube. 9. The oil drill pipe (yb528-65) is used in oil drilling at both ends of seamless steel tube with thick or external upset. Pole points two car and car silk, silk work joint connection, no car work butt welding method and the tool joint connection. 10. Ship with carbon steel seamless steel tube (gb5213-85) is the manufacturing of ship class I pressure piping, ii grade pressure piping and boilers and overheating for carbon steel seamless steel tube. Carbon steel seamless steel tube wall temperature does not exceed 450 ℃, the alloy steel seamless steel tube wall temperature over 450 ℃. 11. Automobile axle works seamless steel tube (gb3088-82) is the manufacturing automotive axle tube and shell shaft drive axle bridge works of high quality carbon structural steel and alloy structural steel hot-rolled seamless steel tube. 12. The diesel engine with high-pressure tubing (gb3093-86) is a manufacturer of diesel injection system high pressure work cold drawn seamless steel tube. 13. The hydraulic and pneumatic cylinder with precision inner diameter seamless steel tube (gb8713-88) is used in manufacture of hydraulic and pneumatic cylinder is precision cold drawn or cold rolled precision seamless steel tube diameter. 14. Cold drawn or cold rolled precision seamless steel tube (gb3639-83) is used in the mechanical structure, hydraulic equipment of high dimensional accuracy and surface finish good cold drawn or cold rolled precision seamless steel tube. Choose precision seamless steel tube manufacturing mechanical structure or hydraulic equipment, etc., can greatly save the machining time, improve material utilization, at the same time to improve the quality of the product. 15. Structure with stainless steel seamless steel tube (gb/t14975-1994) is widely used in chemical industry, petroleum, textile, medical, food, machinery and other industrial corrosion of pipeline and components and parts are made of stainless steel hot rolling (crowded, expanding) and cold drawing (rolling) seamless steel tube. 16. The fluid conveying stainless steel seamless steel tube (gb/t14976-1994) is used for conveying fluid made of stainless steel hot rolling (crowded, expanding) and cold drawing (rolling) seamless steel tube. 17. Heterotypic seamless steel tube is in addition to the outside of the pipe cross section shape of the floorboard of the seamless steel tube. According to the size of steel pipe cross section shape is different and can be pided into such as wall thickness seamless steel tube (code-named d), ranging from wall thickness seamless steel tube (code-named bd), variable diameter seamless steel tube (code-named bj). Alien seamless steel tube is widely used in all kinds of parts, tools and machinery parts. Compared with those of circular tube section tube usually have large moment of inertia and section modulus, have bigger bending torsional capacity, can greatly reduce the structure weight, save steel. Third, welded steel pipe Welded steel pipe and welded pipe, is to use steel plate or steel strip after crimp molding made of welded steel pipe. Welded steel pipe production technology is simple, high production efficiency, varieties, specifications, less equipment investment, but the general strength is lower than the seamless steel tube. Since the 1930 s, with the rapid development of high quality strip steel rolling production and the progress of welding and inspection technology, constantly improve the weld quality, increasing varieties of welded steel pipe specifications, and in the field of more and more instead of seamless steel tube. In the form of welded steel pipe according to the weld seam welded pipe and spiral welded pipe. Straight seam welded pipe production technology is simple, high production efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than straight seam welded pipe, use a narrow billet production of larger diameter welded pipe, you can also use the same width of billet in the production of different pipe diameter welded pipe. But compared with the same length of straight seam pipe, weld length by 30 ~ 100%, and the production speed is low. As a result, a small diameter welded pipe are mostly with straight seam welding, large diameter welded pipe for the most part adopts spiral welded. 1. The low pressure fluid conveying in welded steel pipe (gb/t3092-1993), also known as general welded pipe, commonly known as the clarinet. Is used to transport oil, gas, air, water and heating steam and other general low pressure fluid and other purposes of welded steel pipe. Steel tube wall thickness is pided into ordinary steel pipe and increasing pipe; To take over the side form is pided into without thread steel pipe (light pipe) and take rebar. Of the specifications of the steel tube with a nominal diameter (mm), nominal diameter is the inner diameter of approximation. Traditionally used in said, such as 1 1/2. Low pressure fluid conveying in welded steel pipe in addition to directly used for conveying fluid, also used as a low voltage large amounts of fluid conveying with galvanized welded steel pipe. 2. Low pressure fluid conveying with galvanized welded steel pipe (gb/t3091-1993), also known as galvanized welded steel pipe, commonly known as the white tube. Is used to transport oil, gas, air, water and heating steam, warm water generally low pressure fluid or other purposes such as hot dip galvanized welded butt weld or welding steel pipe. Steel tube wall thickness is pided into ordinary galvanized steel pipe and thickening of galvanized steel pipe; To take over the side form is pided into without thread galvanized steel pipe and galvanized steel pipe with screws. Of the specifications of the steel tube with a nominal diameter (mm), nominal diameter is the inner diameter of approximation. Traditionally used in said, such as 1 1/2. 3. The ordinary carbon steel wire casing (gb3640-88) is an industrial and civil construction and installation of machinery and equipment, such as electrical installation of the steel tube is used to protect the wire. 4. The straight seam welded steel pipe (yb242-63) is the weld and the steel tube parallel to the longitudinal steel pipe. Usually pided into metric welded steel pipe, welded thin-wall tube, transformer cooling pipe and so on. 5. Confined fluid conveying with spiral seam submerged arc welding steel pipe (sy5036-83) is a hot rolled steel coil tube billet, often spiral shape, with double-sided submerged arc welding method, welding, spiral seam steel pipe used for pressurized fluid conveying. Steel tube confined ability, good welding performance, through strict scientific inspection and testing, the use of safe and reliable. Steel pipe diameter is big, high transmission efficiency, and can save laying pipelines. Mainly used for conveying oil, natural gas pipeline. 6. Confined fluid conveying with high frequency welding steel pipe spiral seam (sy5038-83) is a hot rolled steel coil tube billet, often spiral forming temperature, using high-frequency welded lap welding method, used in pressurized fluid conveying spiral seam high frequency welding steel pipe. Steel tube confined ability, good plasticity, easy to welding and processing molding; After all kinds of strict and scientific inspection and testing, the use of safe and reliable steel pipe diameter is big, high transmission efficiency, and laying pipelines of investment can be saved. It is mainly used for laying of pipeline transport oil, gas, etc. 7. General low-pressure fluid conveying spiral seam submerged arc welding steel pipe (sy5037-83) is a hot rolled steel coil tube billet, often temperature spiral forming, the double automatic submerged arc welding or one side welding into legal system for water, gas, air and steam general low-pressure fluid conveying with submerged arc welding steel pipe. 8. General low-pressure fluid conveying spiral seam high frequency welded steel pipe (sy5039-83) is a hot rolled steel coil tube billet, often spiral forming temperature, using high-frequency lap welding welding for general low-pressure fluid conveying spiral seam high frequency welding steel pipe. 9. The pile with spiral weld pipe (sy5040-83) is a hot rolled steel coil tube billet, often spiral shape, made of double-sided submerged arc welding or high frequency welding, used in civil construction structure, port, bridge foundation pile with steel pipe. Source: China Steel Pipe Manufacturer – wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)