Difference Between Hot-Rolled Steel Pipe And Cold-Rolled Steel Pipe And Welded Steel Pipe

Although hot-rolled steel pipes are also a type of steel pipes, they still have many advantages that are difficult to replace compared with ordinary products. For example, it can refine the grain of the steel by destroying the casting structure of the ingot, and can eliminate the defects of the microstructure, so that the steel can have good mechanical properties. Specifications also help meet different needs of consumers, allowing everyone to have a high level of product service.

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 precision of cold-rolled seamless steel pipe is higher than that of hot-rolled seamless steel pipe, and the price is also higher than that of hot-rolled seamless steel pipe.

③ Hot-rolled seamless pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, oil cracking pipes, geological steel pipes and other steel pipes.

④ In addition to 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, cold-rolled (dial) seamless steel pipes also include carbon thin-walled steel pipes and alloy thin-walled steel pipes. , Stainless thin-walled steel pipe, special-shaped steel pipe.

⑤ In addition to 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, cold-rolled (dial) seamless steel pipes also include carbon thin-walled steel pipes and alloy thin-walled steel pipes. , Stainless thin-walled steel pipe, special-shaped steel pipe.

2. Hot rolled steel pipe produces residual stress

Hot-rolled steel will only generate a force when it is cooled. If the hardness of the rolled piece is cooled with water, the hardness will increase. If it is a chemical problem, then the surface of the rolled piece will have small cracks, especially in local areas. There is no specific change, but there will be a pull back force, the tensile force between the crystals, so the residual force is tensile stress.

Hot-rolled steel, hot-rolled steel is a steel that is softened at a temperature higher than the recrystallization temperature of the alloy and then pressed into a thin sheet or a cross section of a billet with a pressure wheel to deform the material, but the physical properties of the material do not change.

3. Difference between hot rolled steel pipe and welded steel pipe

① In appearance, the difference between seamless steel pipe and welded steel pipe is that there are welding ribs on the inner wall of the welded pipe, while the seamless one does not.

② The pressure of the seamless pipe is higher, the welded pipe is generally about 10 MPa, and the welded pipe is now seamless.

③ The seamless steel pipe is formed at one time during rolling. Welded steel pipes need to be rolled and welded, generally spiral welding and straight welding. The performance of the seamless tube is better, and of course the price is higher.

Steel pipe is a kind of hollow long steel, which is widely used as a pipeline for transporting fluids, such as oil, natural gas, water, gas, steam, etc. In addition, when the bending and torsional strength are the same, the weight is lighter, so it is also widely used. For the manufacture of mechanical parts and engineering structures. It is also commonly used to produce various conventional weapons, barrels, shells, etc.

Hot-rolled steel pipe belongs to a category of seamless steel pipe. Compared with cold-rolled (dial) seamless steel pipe, its mechanical properties are better, and it is suitable for the needs of some special fields, and can also play a good role in use.