Welded pipes are made of steel plates or steel strips that are bent and then welded. According to the welding seam form, it is divided into straight seam welded pipe and spiral welded pipe.
According to the purpose, they are divided into generally welded pipes, galvanized welded pipes, oxygen-blown welded pipes, wire casings, metric welded pipes, roller pipes, deep well pump pipes, automotive pipes, transformer pipes, electric welded thin-walled pipes, electric welded special-shaped pipes and spiral welded pipes.
General welded pipe: General welded pipe is used to transport low-pressure fluids. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steels that are easily weldable. Steel pipes need to undergo experiments such as hydraulic pressure, bending, and flattening, and have certain requirements for surface quality. Usually, the delivery length is 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. The following is a brief introduction to the applications of several tough pipes:
1. Generally welded pipes are used for the transportation of general lower-pressure fluids such as water, gas, air, oil, and heating steam.
2. Ordinary carbon steel wire sleeves (GB3640-88) are steel pipes used to protect wires during electrical installations such as industrial and civil buildings and the installation of machinery and equipment.
3. Straight seam electric welded pipe (YB242-63) is a steel pipe in which the weld seam is parallel to the longitudinal direction of the steel pipe. Usually divided into metric electric welded pipes, electric welded thin-walled pipes, transformer cooling oil pipes, etc.
4. A spiral submerged arc welded pipe for pressure fluid transportation (SY5036-83) is a spiral submerged arc welded pipe for pressure fluid transportation. It is made of hot-rolled steel strip coils and spirally formed at constant temperature. It is welded by double-sided submerged arc welding. It is a spiral submerged arc welded pipe for pressure fluid transportation Sewing steel pipe. Steel pipes have strong pressure-bearing capacity and good welding performance. They have undergone various rigorous scientific inspections and tests and are safe and reliable to use. The steel pipe has a large diameter, high transportation efficiency, and can save investment in laying pipelines. Mainly used for pipelines transporting oil and natural gas.
5. Spiral seam high-frequency welded pipe (SY5038-83) for pressure-bearing fluid transportation is made of hot-rolled steel strip coils as pipe blanks, spirally formed at a constant temperature, and welded by high-frequency lap welding method. It is used for pressure-bearing fluid transportation. Spiral seam high-frequency welded steel pipe. Steel pipes have strong pressure-bearing capacity, and good plasticity, and are easy to weld and process. After various strict and scientific inspections and tests, they are safe and reliable to use. The steel pipes have large diameters, high transportation efficiency, and can save investment in laying pipelines. Mainly used for laying pipelines transporting oil, natural gas, etc.
6. Spiral submerged arc welded steel pipe (SY5037-83) for general low-pressure fluid transportation is made of hot-rolled steel strip coils as pipe blanks and is spirally formed at constant temperature; it is made by double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes are used for transporting general low-pressure fluids such as water, gas, air, and steam.
Welded pipes can use three hardness test methods.