Cold working:

1. In metal technology, cold working refers to the process of plastic deformation of metal below recrystallization temperature, such as cold rolling, cold drawing, cold forging, stamping and cold extrusion. Cold working deformation resistance is great, and work hardening can be used to improve the hardness and strength of the workpiece and form metal at the same time.

2. In mechanical manufacturing technology, cold working usually refers to the cutting of metal.

Hot working:

Hot working is a processing method that makes metal materials produce plastic deformation and recrystallization at the same time under the condition of higher than recrystallization temperature. Hot working usually includes casting, forging, welding, heat treatment and other processes. Hot working can change the structure of metal parts or the established state of formed parts while forming, so as to improve the mechanical properties of parts.

Advantages of cold working method:

The required shape can be obtained while strengthening the metal;

Good dimensional tolerance and surface roughness can be obtained;

Cheap;

Some metals can only be cold-worked to a limited extent because they are brittle at room temperature;

Cold working will weaken ductility, electrical conductivity and corrosion resistance. However, the degree of conductivity reduction caused by cold working is less than that caused by other strengthening processes, so cold working is also used to strengthen conductive materials, such as copper wires.

Anisotropy and residual stress will also bring benefits if they are properly controlled. If it is not properly controlled, the material properties will be greatly weakened;

Because the effect of cold working will decrease or even disappear at high temperature, it is not suitable for those parts working in high temperature environment.

References:

Baidu encyclopedia-heat treatment

Baidu Encyclopedia-Cold Processing