Difference between hot and cold rolled working processes

Welded steel pipe is one common type of steel pipe in the current steel pipe market, which has been widely used in various applications in the modern times. Technically speaking, welded steel pipe can be divided into two major categories based on working process in a mill. Are you still confused about how to distinguish hot rolled and cold rolled working processes in a mill? DongPengBoDa Steel Pipe Group is a famous steel pipe manufacturer in China. Here we would like to help you learn more about your welded steel pipe used in applications.

First of all, hot rolling metal is fed to the rolls after being heated above the recrytallization temperature. And cold rolling metal is fed to the rolls when it is below the recrystallization temperature. In general, hot rolling is used un ferrous as well as non ferrous metals such as industries for steel , aluminum, copper , brass, bronze , alloy to change ingot into slabs, while cold rolling is equally applicable to both plain and alloys steels and non ferrous metals and their alloys. In general hot rolled metal does not show work hardening performance while cold rolled metal shows the working hardening performance after being cold rolled in a mill. In addition, mechanical properties are improved by breaking cast structure are refining grain sizes below holes and others, similar deformation in ingot (get welded) and or removed the strength and the toughness of the job should increases. Take cold rolled steel pipe for an example. Hotness increased excessive cold working greatness crackers ductility of metal reduction. Cold rolling increased the tensile strength and yield strength of the steel. Meanwhile, hot rolls radius is generally larger in size while cold rolls radius is smaller. Hot rolling is the father of the cold rolling. And Cold rolling follows the hot rolling.

In the recent years, structural steel pipe is very popular in construction industry. In many projects, cold rolled steel pipe have many competitive advantages compared with hot rolled steel pipe in the current steel pipe market. For one thing, cold rolling thin sections are obtained while hot rolling thin sections are not obtained. For the other thing, the cold rolled surface is smooth and oxide free while hot rolled surface has metal oxide on steel products which causes surface finish look not so good in applications. Furthermore, cold rolled steel pipe has competitive lower stock compared with hot rolled steel pipe in the market.