Powder metallurgy is a new type of net near-molding technology, which uses melting, heating, injection and pressing of metal powder to carry out the required mold molding. For some special materials such as refractory metals, refractory metals, high alloy and so on. So what factors affect the quality of powder metallurgy pressing forming of automobile parts?

Ⅰ： Influence of pressing forming die

It is self-evident that the die is important for the pressing forming technology. It is recommended to use the female die or mandrel made of cemented carbide, powder high-speed steel and other materials. When the die (such as the inner cavity of the female die and the outer diameter of the mandrel) is working, the smaller the surface roughness is, the better it is to reduce the friction factor between the powder particles and the die wall.

If it is a relatively large or complex blank, long-term pressing will cause the female mold to heat and deform, water cooling device can be used to reduce the temperature of the female mold and reduce the friction factor.

In addition, in the design of the female mold, we should focus on strength and rigidity, which can reduce the degree of heat deformation of the female mold, reduce the pressure loss, and prevent cracks in the process of pressing automobile parts.

Ⅱ： Effect of mould and lubricant

In the process of powder metallurgy pressing and forming of automobile parts, due to the pressure loss caused by the friction between the mixed powder and the mold wall, the density distribution of the compacts is uneven. Minxin Powder recommends to use a high hardness mold or a better lubricant.

Ⅲ： Effect of lubricants

Adding lubricant to the metal mixed powder can effectively reduce the friction between the powder and the mold wall, and make the density distribution of the compact more uniform. The commonly used lubricant is zinc stearate. Although it can improve the pressing and forming conditions, it is easy to produce segregation after mixing due to the low loose density, and the sintered parts are prone to pitting and other problems.

Using a good lubricant can effectively improve the friction between the powder and the mold wall, and greatly reduce the density error of the compact. In the aspect of powder mixing, attention should also be paid to the powder mixing method, which can also reduce friction.

Ⅳ： Influence of pressing parameters

1: Pressurizing speed

If the pressing speed is too fast, it will affect the uniformity of the density of the compact, and will also produce cracks. It is better to use the hydraulic powder forming machine for production.

2: Pressure holding time

The density of compact formed by powder metallurgy pressing of automobile parts can be significantly increased under relatively large pressing pressure and with proper holding time.

3: Structure of powder feeding boots

If the general powder feeding shoe is used for powder loading, it will cause uneven powder filling at the top and bottom of the mold cavity or at the front and back, which will affect the quality of the blank. Improving or redesigning the powder feeding shoe can improve the problem of powder loading uniformity.