Heat treatment of metal materials

In order to alter the mechanics, physical and chemical properties of metal workpieces, heat treating is an inseparable process, in addition to the rational selection of materials and various forming processes.

Heat treatment of metal materials is a process of heating, keeping warm and cooling solid metals or alloys in an appropriate manner to change the internal structure of the material and thus improve the performance of the material. This is called heat treatment.

Heat treatment generally does not change the shape and overall chemical composition of a workpiece, but rather changes the internal microstructure of the workpiece or the chemical composition of the workpiece surface to impart or improve the performance of the workpiece. Its characteristic is to improve the intrinsic quality of the workpiece, which is generally not visible to the naked eye. The role of heat treatment is to improve the mechanical properties of the material, eliminate residual stress and improve the machinability of the metal.

Types of heat treatment

Annealing

Stress relief, improved cutting, reduced hardness (cooled in furnace)

Annealing Machine is a device used for heat treatment of metal or other materials. By controlling the heating, heat preservation and cooling process, the internal structure of the material changes to achieve the following purposes:

• Reduce hardness and improve plasticity;

• Eliminate internal stress;

• Improve cutting performance;

• Stabilize size and organizational structure;

• Improve electrical or magnetic properties (such as annealing of copper wire and silicon steel sheet).

Common annealing machine types:

Annealing machine application industry

• Metal wire processing (such as copper wire, aluminum wire)
• Stainless steel tube/strip production
• Mold heat treatment
• Magnetic material annealing
• Semiconductor and electronic component manufacturing

Normalizing

Fast cooling speed (cooled in the open air）

Quenching

Increase hardness, toughness, and deteriorate plasticity. (Cooled in water or oil), must be used with tempering.

Tempering

Improve toughness

Tempering is divided into low temperature tempering, medium temperature tempering and high temperature tempering.

Low temperature: reduce internal stress and brittleness

Medium temperature: improve elasticity and strength

High temperature: improve comprehensive performance.

Tempering = quenching + high temperature tempering.

Classification of heat treatment furnaces