traight hair can be divided into hot rolled coil and finishing roll (sub-volume, volume leveling and slitting volumes).

Their material properties can be divided into: ordinary carbon structural steel, low alloy steel, alloy steel.

According to their different uses can be divided into: cold forming steel, structural steel, automotive steel, corrosion-resistant structural steel, mechanical structural steel, welding gas cylinders and pressure vessel steel, pipeline steel and the like.