Methods of increasing the density of stainless steel powder metallurgy

Methods of increasing the density of stainless steel powder metallurgy

In recent years, powder metallurgy stainless steel has been favored by all people. Many products need to use stainless steel materials, with smooth and tough surface, and product performance is also related to strength. However, in the production process of stainless steel powder metallurgy, the material is fragile and easy to produce pores, and will also be scraped off during the pressing process, which seriously affects the use of stainless steel powder metallurgy, reducing its mechanical properties, corrosion resistance and corrosion resistance. It also severely limits its application in stainless steel powder metallurgy. Therefore, in the development of stainless steel powder metallurgy, the density of stainless steel must be improved. So, what are the methods to increase the density of stainless steel powder metallurgy? ABCDprecision powder:

1、 Super solid sintering

1. Traditional stainless steel sintering usually uses solid phase sintering, but the solid phase sintering will be carried out in stainless steel. Produce a large number of residual pores. The liquid phase of stainless steel prealloyed powder is formed in the process of super solid liquid phase sintering. The liquid phase fills the pores through the flow to increase the density and performance of the sintered body.

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2. The density, hardness, wear resistance and corrosion resistance of stainless steel sintered at 400 ℃ in super solid liquid phase are higher than 1200 ℃. For solid phase sintering, attention should be paid to avoid crystallization due to too high sintering temperature, and the particles grow full and burn.

2、 Use appropriate additives

1. Some low melting point alloy elements are added to the powder to reduce the porosity through the liquid phase formed in the sintering process, so that the stainless steel can meet higher performance requirements. For example, add 2% - 8% copper base alloy to the commonly used 304 stainless steel. Due to the low melting point of copper, the liquid phase can be formed at 960 ° C, and all liquid phases can be formed at 1000 ° C. When the temperature is higher than the melting point of copper, the liquid phase flow will lead to the continuous grinding and shrinkage of surface pores due to copper wetting, which has good performance and can be evenly distributed. The sintered body is manufactured on a stainless steel substrate. The microhardness increases with the decrease of pores.

2. In order to improve the performance of stainless steel powder metallurgy, appropriate strengthening phases can be added, especially the mechanical properties. Take 316L stainless steel as an example, add 1.5% - 3% silicon carbide to stainless steel. Due to the interaction between silicon carbide and stainless steel, a low melting point phase is formed, which increases the density of the sinter, and improves the hardness and wear resistance of the sinter.

The above is about the method of increasing the density of stainless steel powder metallurgy. The above two methods have been used for the longest time in stainless steel powder metallurgy production. Compared with the traditional smelting process, stainless steel powder metallurgy has the characteristics of near net shape, high dimensional accuracy, high material utilization and uniform structure. If the density problem of stainless steel powder metallurgy is solved, it will be widely used in production and life.