As is known to all, hot rolling and cold rolling are both procedures of forming section steel or plate, which have great influence on the microstructure and properties of steel. Hot rolling is the main rolling method for steel, while cold rolling is only used to produce small sections and sheets. Now, it will introduce the difference between cold pressed steel and hot rolled steel.
Hot rolled steel is directly processed on the die in the steel furnace in the steel factory. When it comes out of the furnace, it is hot (hence called "hot rolled"), and the finished product can be used after cooling.
On the other hand, cold pressed steel is what cold process hot rolled steel, such as steel cold drawing at normal temperature.
Hot rolled steel has low yield strength and good plasticity. cold pressed steel has high yield strength and poor plasticity. The ultimate tensile and compressive strength of both are the same.
Local buckling is allowed in the section of cold-pressed steel, which can make full use of the bearing capacity of the bar after buckling; However, local section buckling is not allowed in hot rolled steel.
The causes of residual stress in hot rolled steel and cold pressed steel are different, 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 bending type while that on hot-rolled steel or welded steel is thin film type.
The free torsional stiffness of hot-rolled steel is higher than that of cold-pressed steel, so the torsional resistance of hot-rolled steel is better than that of cold-pressed steel.