What Is Heat Treatment Process

 

Heat treatment process is an important technology in the field of metal processing. It mainly changes the internal structure of the material by controlling the heating, insulation, and cooling processes of the material, thereby achieving the purpose of improving material performance, improving material processing performance, or solving internal defects of the material.

 

Heat treatment process classification

Overall heat treatment

This is the most common form of heat treatment, in which the entire workpiece is heated to a certain temperature, held at this temperature for some time, and then cooled at a predetermined cooling rate. This type of processing can affect the organization and performance of the entire workpiece.

Surface heat treatment

Only the surface of the workpiece is heated to change its surface structure and properties. This method is often used when the surface hardness, wear resistance, or corrosion resistance of the workpiece needs to be improved.

Local heat treatment

Only specific areas of the workpiece are heated. This method is often used to repair local defects of the workpiece or change its local properties.

Chemical heat treatment

While heating, the workpiece is placed in a specific chemical medium to allow certain chemical elements to penetrate the surface of the workpiece, thereby changing the chemical composition and structure of its surface and improving its performance.

 

Basic process of heat treatment process

Heating

The workpiece is heated to a predetermined temperature, which is usually determined based on the type of material and the required structural properties.

Insulation

Keep it at a predetermined temperature for some time to make the internal temperature of the workpiece uniform and the structural transformation fully proceed.

Cooling

Cooling is performed according to a predetermined cooling rate. The cooling method can be natural cooling or rapid cooling methods such as water quenching and oil quenching. Different cooling methods lead to different organizational structures and properties.

 

The four basic processes of heat treatment

Annealing

It is mainly used to eliminate the internal stress of materials and improve the processing performance and structure of materials.

Normalizing

The structure and properties of the material are adjusted by heating above a critical temperature and cooling in air.

Quenching

Heating the material above a critical temperature and then cooling it rapidly gives the material high hardness and strength.

Tempering

It is carried out after quenching to eliminate the quenching stress and improve the plasticity and toughness of the material.

Through different heat treatment processes and parameter combinations, materials with different structures and properties can be obtained to meet the needs of various engineering applications.