Metal powder metallurgy process

Powder metallurgy is the combination of metal metallurgy and ceramic sintering process, it is usually go through the following process:

First, powder preparation and moulding commonly use mechanical crushing, atomization, physical and chemical prepare powder. Preparation of powder after sieving and mixing, uniform mixing and adding plasticizer, then pressing, atoms in powder through solid phase diffusion and mechanical lock effect make the parts are combined into a certain strength of the whole. The pressure is greater, the density is also greater, strength increasing accordingly. Sometimes in order to reduce the pressure and increase parts density, also can use hot isostatic pressing method.

Second, sintering, the pressing part is placed in the reductive atmosphere closed furnace for sintering, sintering temperature around the melting point is 2/3 ^3/4 times of the matrix metal. Due to different kinds of atomic diffusion under the high temperature, oxide powder surface by reduction and recrystallization of deformation of powder, the powder particles are combined with each other, improve the strength of powder metallurgy products, and get similar organizations with the general alloy. The parts after being sintered, there are still some tiny pores, which belongs to the porous material.

Third, after treatment, in general, sintering the good parts can reach the required properties, can be used directly. But sometimes it also need necessary post processing. Such as pressure processing, improving the work density and size shape accuracy; the iron-based powder metallurgy parts quenching, surface hardening treatment can improve its mechanical properties; in order to reach lubrication or corrosion resistance for purposes of oil or other liquid lubricant impregnated; low melting point metal infiltration pore in parts to infiltration processing, can be improving the work strength, hardness, plasticity and impact toughness.

The advantages of powder metallurgy technology, 1, the vast majority of refractory metals and their compounds, pseudo alloy, porous materials can only be manufactured by powder metallurgy method. 2, the powder metallurgy method can be pressed into the final size of the blank, but need not or rarely required subsequent machining, so it can greatly save metal, reduce the cost of product. Use powder metallurgy manufacturing methods, metal loss is only 1-5%, while using the general method of production, casting, metal loss can reach 80%. 3, the powder metallurgy technology in material production process is not melting materials, and is not afraid of mixing with the crucible and the impurities deoxy agent, and sintering is generally in a vacuum and restore atmosphere, is not afraid of being oxidized, and will not bring any pollution to material, so it is possible to produce high purity materials. 4, powder metallurgy method can ensure the accuracy and uniformity of materials. 5, powder metallurgy is suitable for producing the same shape and a large number of products, particularly the high cost of processing gear and other products, powder metallurgy manufacturers can greatly reduce production cost.

Powder metallurgy is a technology used for producing metal powder, forming and sintering metal powder ( or metal powder and metal powder mixtures) made of materials and products. In addition, in powder metallurgy materials usually use manganese powder as the main material or additive, it can help to improve the properties of materials and the development of new materials.

Source:http://www.mhcmp.com