What's the difference between hot rolled steel tube and cold rolled steel tube

The main differences between hot rolling and cold rolling are:
Cold -rolled formed steel allows local buckling of the section, so that the bearing capacity of the bar after buckling can be fully utilized; while hot -rolled steel does not allow local buckling of the section.

Hot -rolled steel and cold -rolled steel have different causes of residual stress, so the distribution on the cross section is also very different. The residual stress distribution on the section of cold -formed thin -walled steel is curved, while the distribution of residual stress on the section of hot -rolled or welded steel is thin -film.

There is not much difference between hot rolled steel tube and cold rolled steel tube in finished products. They are generally manufactured according to standards. There is no big difference in mechanical properties. Hot rolled steel tube and cold rolled steel tube are mainly different in processing technology and final accuracy. Generally speaking, cold rolled steel tube has higher dimensional accuracy and surface finish.

Hot rolled steel tube process: billet - heating - piercing - pipe rolling - sizing - cooling bed - straightening - pipe cutting - inspection - packing - delivery.

Cold rolled steel tube process: billet - heating - piercing - hot rolling (secondary threading), etc - heading - pickling - phosphating - cold drawing - annealing (can repeat heading to later process for many times) - straightening - pipe cutting - inspection - packing - delivery.