What is the powder function of powder metallurgy?

Powder is the general term for all functions, including the geometric functions (particle size and shape, etc.), chemical functions, mechanical properties, and physical functions of powder. These functions cannot be achieved by traditional casting methods, and to a large extent, powder functions can often determine the functionality of powder metallurgy products in powder metallurgy bearings.

Granularity. It is the ultimate function of shortening during sintering and producing oil-free shaft sleeves, which can affect the processing and forming of powders. The functionality of some powder metallurgy products is directly related to particle size, for example, the filtration accuracy of filtered materials can be calculated by dividing the average particle size of the initial particles by 10.

The particle shape of the powder. It depends on the powder production method, such as the powder produced by electrolysis, and the oil-free self-lubricating particles of the bearing are in a dendritic shape; The iron powder particles obtained by the reduction method are sponge like. In addition, some powders are in the form of eggs, discs, needles, onion heads, etc. The shape of powder particles can affect the flowability and bulk density of the powder. Due to the mechanical meshing between particles, the strength of irregular powder compacts is also high, especially for dendritic powder, which limits the strength of the compacts to the maximum. But for porous materials, spherical powder is the best choice.

The mechanical function of powder refers to the technical function of powder, which is the main technical parameter in powder metallurgy forming skills. The loose density of powder is the basis for weighing by volumetric method when limiting; The flowability of the powder determines the filling speed of the mold and the production capacity of the press; The compressibility of the powder limits the difficulty of the process and the unevenness of the applied pressure; The formability of the powder determines the strength of the blank.

The chemical function mainly depends on the chemical purity of the raw materials and the method of powder production. A higher oxygen content will reduce the limiting function, green strength, and mechanical properties of sintered products, so most powder metallurgy skills have certain specifications for this.

Powder metallurgy has a unique chemical composition and mechanical and physical functions that cannot be achieved through traditional casting methods. The use of powder metallurgy skills can directly produce porous, semi fine or fully fine materials and finished products, such as oil containing bearings, gears, camshafts, guide rods, cutting tools, etc., which are a type of powder metallurgy product with low or no cutting requirements.