Production process of powder metallurgy

The basic process of powder metallurgy includes powder preparation, molding and sintering. Powder preparation methods include mechanical crushing method, reduction method, atomization method, electrolysis method, gas phase deposition method, liquid phase deposition method, reduction method and so on.

Compression molding (steel mould) is the most widely used method in powder metallurgy production. It is a semi - finished or finished product with a predetermined shape, size, density and strength. Sintering is a complicated process of material transfer between powder particles at high temperature, which results in the strengthening of the bonding between the powder particles and the densification of the powders.

(1) production of powder. Powder production process including the preparation of powder, powder mixing and other steps. In order to improve the formability and the plasticity of the powder, the addition of gasoline, rubber or wax, etc..

(2) pressing and forming. The powder is pressed into the desired shape under 500-600MPa pressure.

(3) sintering. In the protection of the atmosphere of the high temperature furnace or vacuum furnace. Sintering is different from metal melting, sintering at least one element is still in the solid state. Become metallurgical products with a certain porosity and sintering process of powder particles by diffusion, recrystallization, welding, the compound, the dissolution a series of physical and chemical processes.

(4) after treatment. In general, sintered parts can be used directly. But for some of the requirements of high precision and high hardness, wear resistance of the parts will be processed after sintering. Postprocessing including coining, rolling, extrusion, quenching, surface hardening, immersion and infiltration etc.