1.the difference between hot-rolled steel pipe and cold-rolled steel pipe
1) Cold-rolled seamless steel pipes are often of small diameter, and hot-rolled seamless steel pipes are often of large diameter.
2) The accuracy of cold-rolled seamless steel pipe is higher than that of hot-rolled seamless steel pipe, and the price is higher than that of hot-rolled seamless steel pipe.
3) Hot rolled seamless pipe is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, geological steel pipe and other steel pipes.
4) Cold rolled (dial) seamless steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes and alloy thin-walled steel pipes. Steel pipe, stainless thin-walled steel pipe, special-shaped steel pipe.
5) Cold rolled (dial) seamless steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes and alloy thin-walled steel pipes. Steel pipe, stainless thin-walled steel pipe, special-shaped steel pipe.
2. Is the residual stress generated by hot-rolled steel pipe tensile or compressive?
Hot-rolled steel only generates a force when it is cooled. If the water is used to cool the rolled steel, the hardness will increase. If it is a chemical problem, the surface of the rolled steel will have small cracks, which is more prominent in some areas. The air-cooled surface There are no specific changes, but only a return force, a tensile force between the crystals, will be generated, so the residual force is tensile stress.
Hot-rolled steel is a steel that is softened at a temperature higher than the recrystallization temperature of the alloy, and is pressed into a sheet or billet cross section with a roller to deform the material, but the physical properties of the material remain unchanged.
3. the difference between hot-rolled steel pipe and welded steel pipe
1) . In appearance, the difference between the seamless steel pipe and the welded steel pipe is that there are welding ribs on the inner wall of the welded pipe, but there is no seamless.
2) . The pressure of the seamless pipe is higher. Generally, the welded pipe is about 10 MPa. Now the welded pipe is seamlessly processed.
3) . Seamless steel tubes are formed at one time during rolling. Welded steel pipes need to be welded after being rolled, and generally have spiral welding and direct welding. The performance of the seamless pipe is better, and of course the price is higher. Steel pipe is a kind of hollow long steel. It is widely used as a pipeline for transporting fluids, such as petroleum, natural gas, water, gas, and steam. In addition, when the bending and torsional strength is the same, the weight is light, so it is also widely used. Used for manufacturing mechanical parts and engineering structures. It is also often used in the production of various conventional weapons, barrels, and shells. Hot-rolled steel pipe belongs to a category of seamless steel pipes. Compared with cold-rolled (dial) seamless steel pipes, its mechanical properties are better, and it is suitable for the needs of certain special fields, and it can also play a good effect. . Considering the actual life or purchasing choices, everyone may confuse different products, so today the editors mainly introduce the differences between hot-rolled steel pipes, cold-rolled steel pipes, and welded steel pipes. They can help us identify our needs. .