Powder metallurgy technology has a series of advantages such as significant energy saving, material saving, excellent performance, high product precision and good stability, which is very suitable for mass production. In addition, some materials and complex parts that cannot be prepared by traditional casting methods and mechanical processing methods can also be manufactured with powder metallurgy technology, which has attracted the attention of the industry.

The powder metallurgy products industry in a broad sense includes iron and stone tools, cemented carbide, magnetic materials, and powder metallurgy products. The powder metallurgy products industry in the narrow sense only refers to powder metallurgy products, including powder metallurgy parts (mostly), oil-bearing bearings and metal injection molding products.

Preparation method

(1) Production of powder. The powder production process includes the steps of powder preparation and powder mixing. In order to improve the moldability and plasticity of the powder, plasticizers such as engine oil, rubber or paraffin are usually added.

(2) Press molding. The powder is pressed into the required shape under the pressure of 15-600MPa.

(3) Sintering. It is carried out in a high-temperature furnace or vacuum furnace with a protective atmosphere. Sintering is different from metal melting, at least one element is still in the solid state during sintering. During the sintering process, powder particles undergo a series of physical and chemical processes such as diffusion, recrystallization, fusion welding, compounding, and dissolution, and become metallurgical products with a certain degree of porosity.

(4) Post-processing. Under normal circumstances, the sintered parts can be used directly. But for some parts that require high precision, high hardness and wear resistance, post-sintering treatment is required. Post-processing includes precision pressing, rolling, extrusion, quenching, surface quenching, oil immersion, and infiltration, etc.