Factors Affecting The Heat Treatment Of Powder Metallurgical Gear

1,Effect of Alloy Content and Type on Heat Treatment of Powder Metallurgy
Copper and nickel are common in alloy elements, and their content and type have an impact on the heat treatment effect. The heat treatment hardening depth decreases with the increase of copper content and carbon content. The stiffness of nickel alloys is greater than that of copper alloys, but the heterogeneity of nickel content leads to uneven austenite tissue.
2, the influence of high temperature sintering
Although high temperature sintering can obtain the best alloying effect and promote densification, different sintering temperatures, especially when the temperature is low, can lead to a decrease in the sensitivity of heat treatment(less alloys in solid solution) and mechanical properties. Decline. Therefore, using high temperature sintering, assisted by sufficient reducing atmosphere, can obtain a good heat treatment effect.
Effect of porosity on surface hardening depth during heat treatment
The heat treatment effect of powder metallurgical materials is related to the density of the material, the permeability of the infiltration(quenching), the thermal conductivity, and the resistivity. The porosity is the biggest cause of these factors. When the porosity exceeds 8 %, the gas will rapidly penetrate through the voids. In the case of carburizing hardening, increasing the carburizing depth will reduce the effect of surface hardening. Moreover, if the rate of carburizing gas infiltration is too fast, soft points will be produced during quenching, reducing surface hardness, and making the material brittle and deformed.
4, the impact of pores on the heat treatment process
During heat treatment, powder metallurgical materials are converted into other tissues by rapid cooling to inhibit austenite diffusion, thus obtaining martensite, and the presence of pores has a greater influence on the heat dissipation of the material. Through the heat conductivity formula:
Thermal conductivity = metal theoretical thermal conductivity ×(1-2 × porosity) / 100
It can be seen that the hardenability decreases with the increase of porosity. On the other hand, porosity also affects the density of the material, and the effect on the surface hardness and quenching depth after heat treatment of the material is related to the effect of density, which reduces the surface hardness of the material. Moreover, because of the presence of pores, salt water can not be used as a medium during quenching to avoid corrosion caused by salt residue. Therefore, heat treatment is generally carried out in vacuum or gas media.
The above is about the thermal treatment of powder metallurgical materials to introduce the factors, if you want to know more about powder metallurgical gear products, welcome to consult our online customer service, we will sincerely serve you!