The Difference Between Hot Rolled Pipe and Cold Drawn Pipe
When making cold-rolled pipes, its cross-section can be bent to a certain degree, and bending is beneficial to the endurance of cold-rolled pipes. However, when making a hot-rolled tube, its cross-section must not be partially bent, which will affect its service life.
Due to the different manufacturing processes of cold-rolled tubes and hot-rolled tubes, the dimensional accuracy, precision and surface finish of their surfaces are also different. Generally speaking, cold-rolled tubes have higher precision than hot-rolled tubes, and the surface finish is much better.
The manufacturing process of cold rolled pipe is different from that of hot rolled pipe. When the cold-rolled pipe is made and formed, it needs to go through the pipe process, heating treatment, piercing technology, hot rolling process, heading treatment, pickling process, phosphating treatment, cold drawing process, annealing treatment, straightening treatment, pipe cutting process, And inspect the finished product, pack it up. The hot-rolled tube requires tube processing, heating treatment, piercing forming, tube 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 process procedures.
The cross-sectional distribution of cold-rolled pipes and hot-rolled pipes are also different. This is because the causes of residual stress are different when they are formed. This leads to some bending of the residual stress in the cross-section of the cold-rolled tube, while the residual stress of the hot-rolled tube is of film type.
Because the manufacturing process of hot-rolled pipes and cold-rolled pipes is different, the hot-rolled pipes sold on the market are divided into hot-rolled seamless steel pipes and hot-rolled welded steel pipes; while cold-rolled pipes can be divided into cold-rolled seamless steel pipes and Cold-rolled welded steel pipes and cold-rolled seamless steel pipes can be divided into two types: round pipes and special-shaped pipes.