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Classification of straight seam steel pipes and uses of welded steel pipes

Views: 6     Author: Site Editor     Publish Time: 2023-10-19      Origin: Site

Straight seam steel pipe refers to a welded steel pipe with one longitudinal weld seam in the pipe body. GB/9711.1 stipulates that when the diameter is greater than 914.4, the straight seam steel pipe can have two straight welds, and the angle between the welds is 180 degrees. The welding seam requires the same technical parameters as the straight seam steel pipe for the same welding seam. According to the production process, it is divided into: ERW high-frequency straight seam steel pipe, JCOE straight seam steel pipe, and rolled straight seam steel pipe. Straight seam steel pipe is a general term for production process products such as high-frequency straight seam, submerged arc straight seam, electric welding straight seam, and pipeline straight seam.

High-frequency straight seam steel pipe uses the skin effect of high-frequency current to generate high temperature at both ends of the steel plate in a short time and squeeze and fuse them with external force. It is a true base metal butt without a welding rod. ERW high-frequency straight seam steel pipes use hot-rolled coils as raw materials, and the wall thickness can be uniformly controlled at about ±0.2mm. Both ends of the steel pipe are trimmed according to APl standards or GB/T9711.1 standards, the ends are beveled and the length is fixed. Goods and other advantages. In recent years, various gas pipeline network projects and gas companies have widely adopted ERW steel pipes as the main steel pipes in urban pipeline networks. At present, ERW high-frequency straight seam steel pipes account for 60% of the world's steel pipe usage.

Straight seam steel pipe often refers to the double-sided submerged arc straight seam steel pipe produced by JCOE. It adopts the JCOE cold-forming process. The welding seam uses welding wire and granular flux is used to submerge the arc at the same time, so it is called submerged arc straight seam steel pipe. Submerged arc welded straight seam steel pipes mainly have flexible production processes and can produce any specifications and wall thicknesses between 325mm and 1420mm, which meet the steel pipe size standards used in various countries around the world. High-frequency straight seam steel pipes are usually produced in commonly used specifications.

A guide to the use of welded steel pipes: divided into the following categories: general welded pipes, galvanized welded pipes, oxygen blown welded pipes, wire casings, metric welded pipes, idler pipes, deep well pump pipes, automotive pipes, transformer pipes, and electric welded thin pipes Wall pipe, electric welded special-shaped pipe and spiral welded pipe.

1. General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steels that are easily weldable. Steel pipes are subject to hydraulic pressure, bending, flattening, and other experiments, and there are requirements for the surface. The delivery length is usually 4-10m and delivery of fixed length (or multiple lengths) is often required. The specifications of welded pipes are expressed in nominal diameter (millimeters or inches). The nominal diameter is different from the actual. According to the specified wall thickness, there are two kinds of welded pipes: ordinary steel pipes and thickened steel pipes.

2. Galvanized steel pipe: To improve the performance of steel pipes, general steel pipes (black pipes) are galvanized. Galvanized steel pipes are divided into two types: hot-dip galvanizing and electric steel zinc. Hot-dip galvanizing has a thick zinc layer and electro-galvanizing has a low cost.

3. Oxygen-blowing welded pipe: used as oxygen-blowing pipe for steelmaking. Generally, small diameter welded steel pipe is used, with eight specifications ranging from 3/8 inch to 2 inch. Made of 08, 10, 15, 20, or Q195-Q235 steel strip. To prevent corrosion, some are aluminized.

4. Wire casing: It is also an ordinary carbon steel electric welded steel pipe. It is used in concrete and various structural power distribution projects. The commonly used nominal diameter is from 13-76mm. The wire sleeve has a thin wall and is mostly used after being coated or galvanized, requiring a cold bending test.

5. Metric welded pipe: The specification is in the form of seamless pipe, and the welded steel pipe is expressed in millimeters of outer diameter and wall thickness. It is welded with tropical or cold zones of ordinary carbon steel, carbon steel, or general low alloy steel, or after hot zone welding It is then made by cold drawing method. Metric welded pipes are divided into general-purpose and thin-walled pipes. They are generally used as structural parts, such as transmission shafts, or to transport fluids. Thin-walled pipes are used to produce furniture, lamps, etc. The strength and bending test of the steel pipe must be ensured.

6. Idler tube: Electrically welded steel pipe used for belt conveyor idlers, generally made of Q215, Q235A, B steel, and 20 steel, with a diameter of 63.5-219.0mm. There are requirements for the curvature of the pipe, the end face to be perpendicular to the center line, and the ovality. Generally, water pressure and flattening tests are conducted.

7. Transformer tube: used to manufacture transformer heat pipes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending, and hydraulic testing. Steel pipes are delivered in fixed lengths or multiple lengths, and there are requirements for the bending of the steel pipes.

8. Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, hollow rubber steel pipes for doors and windows welded from ordinary carbon structural steel and 16Mn and other steel strips. They are mainly used as agricultural machinery components, steel windows and doors, etc.

9. Electrically welded thin-walled tubes: mainly used to make furniture, toys, lamps, etc. At present, thin-walled tubes made of stainless steel strips are widely used in furniture, decoration, fences, etc.

10. Spiral welded pipe: It is made by rolling low-carbon carbon structural steel or low-alloy structural steel strips into a pipe blank according to the angle of the spiral (called the forming angle), and then welding the pipe seams. It can be made of narrow The strip steel produces large diameter steel pipes. Spiral welded pipes are mainly used for oil and gas transportation pipelines, and their specifications are expressed by the outer diameter and wall thickness. Spiral welded pipes are either single-sided or double-sided. Welded pipes should ensure that the hydraulic pressure test, tensile strength, and cold bending performance of the weld meet the regulations.

Hunan Great Steel Pipe Co.,Ltd
Hunan Great Steel Pipe Co.,Ltd is a world-class production and service provider of submerged arc straight seam welded pipe as the first subsidiary of Shinestar Group. Hunan Great Steel Pipe Co.,Ltd pays more attention to in the pipeline engineering research areas as a pioneer of China Petroleum Pipeline & Gas Pipeline Science Research Institute.



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