Difference between cold-drawn steel pipe and hot-rolled steel pipe

Cold-drawn steel pipe is a kind of steel processed by a series of cold-drawing and cold-bending techniques at room temperature.

Compared with cold-drawn steel pipe, hot tube is a kind of steel processed above the recrystallization temperature.

Difference 1:

When making cold-drawn steel pipe, its cross section can have a certain degree of bending, and bending is beneficial to the bearing capacity of cold-drawn steel pipe. However, when making hot tube, its cross section should not have local bending, which will affect its service life.

Difference 2:

Because the manufacturing process of cold-drawn steel pipes is different from that of hot tube, their dimensional accuracy and surface smoothness are also different. Generally speaking, the precision of cold-drawn steel pipe is higher than that of hot tube, and the surface finish is much better.

Three differences:

The manufacturing process of cold-drawn steel pipe is different from that of hot tube. When cold-drawn steel pipes are made and formed, they need to go through pipe rafting, heating, piercing, hot rolling, heading, pickling, phosphating, cold drawing, annealing, straightening, pipe cutting, inspection of finished products and packaging. In hot tube, however, it is necessary to carry out pipe processing, heating treatment, piercing molding, pipe rolling treatment, sizing treatment, cooling bed treatment, straightening treatment, switching treatment, and final inspection and packaging. It can be seen from these introductions that there are certain differences in their technological procedures.

Difference 4:

The cross-section distribution of cold-drawn steel pipe is also different from that of hot tube, which is because the causes of residual stress are different when forming. This leads to some bending of the residual stress in the cross section of cold-drawn steel pipe, while the residual stress in hot tube belongs to film type.

Five differences:

Because the manufacturing process of hot tube and cold-drawn steel pipe is different, the hot tube sold in the market can be divided into hot-rolled seamless steel pipe and hot-rolled welded steel pipe. Cold-drawn steel pipes can be divided into cold-drawn seamless steel pipes and cold-drawn welded steel pipes, and cold-drawn seamless steel pipes can be divided into round pipes and special-shaped pipes.

Actually, there is not much difference between hot tube and cold-drawn steel pipe after forming, and their mechanical properties are similar.