Simply put, the process of heating the steel pipe and controlling it to be above the recrystallization temperature for rolling is called hot rolling. The process of rolling below the recrystallization temperature, including normal temperature, is called cold rolling.
Hot-rolled steel pipe has good plasticity and is easy to form. After forming, the steel pipe has no internal stress, which is convenient for processing in the following processes. For example, steel bars for construction, steel plates for stamping, and steel pipes for machining and heat treatment are all hot-rolled steel pipes.
Cold rolling of steel pipes has the characteristics of cold work hardening. Because cold rolling has better mechanical properties, many directly used steel pipes use cold rolled steel pipes. Such as cold-rolled steel bars, cold-rolled twisted steel bars, cold-rolled steel wires, cold-rolled steel plates, etc.