What is the technological process of powder metallurgy?

What is the technological process of powder metallurgy?

In recent decades, China's powder metallurgy technology has been in a stage of rapid development. It not only adds some densification processes after the sintering process of the traditional powder metallurgy method, such as re pressing, re sintering, forging, drawing, extrusion, hot isostatic pressing, injection molding and mechanical alloying, but also overcomes the technical obstacles in the use of traditional powder metallurgy products due to low compactness, So that powder metallurgy technology can be widely used. What is the technological process of powder metallurgy? Here is a brief introduction of the Zhongwei Precision Editor:

powder metallurgy

The process of powder metallurgy technology is as follows:

1. Powder preparation and pressing

The powder is usually prepared by mechanical pulverization, atomization and physical and chemical methods. After sieving and mixing, the powder is evenly mixed and added with appropriate plasticizer, and then pressed into shape. The atoms between the powder particles are combined into a whole with a certain strength through solid phase diffusion and mechanical occlusion. The greater the pressure is, the greater the density of the part is, and the strength increases accordingly. Sometimes, in order to reduce the pressure and increase the product density, hot isostatic pressing can also be used.

2. Sintering

The pressed parts are sintered in a closed furnace with reducing atmosphere, and the sintering temperature is about 2/3~3/4 times of the melting point of the base metal. Due to the diffusion of different kinds of atoms at high temperatures, the reduction of oxides on the powder surface and the recrystallization of deformed powders, the powder particles combine with each other, improving the strength of powder metallurgy products, and obtaining a structure similar to that of general alloys. After sintering, there are still some tiny pores in the parts, which belong to porous materials.

3. Post processing

Generally, the sintered parts can achieve the required performance and can be used directly. But sometimes necessary post-processing is required. For example, precision pressing can improve the density, size and shape accuracy of parts; The mechanical properties of iron base powder metallurgy parts can be improved by quenching and surface quenching; Immerse oil or other liquid lubricants for lubrication or corrosion resistance; The penetration treatment of low melting point metal into the pores of the workpiece can improve the strength, hardness, plasticity or impact toughness of the workpiece.

The content introduced above is the process of powder metallurgy technology. Powder metallurgy technology is not only a manufacturing process for parts with high strength, high density, complex shape, no cutting and less cutting, but also a processing method for producing new materials. Up to now, it has become the key to solve the problem of new materials and plays an important role in the development of new materials.