Molding method of metal powder

As the powder metallurgy method can be pressed into the final-size compacts without the need of subsequent machining, it can greatly save metal and reduce product cost. When manufacturing products in pressing method with metal nickel powder, metal loss is only 1-5%. In general casting production, the metal loss may reach 80%. Because the powder metallurgy process will not molt materials down in material production, so it is not afraid to mix impurities from the crucible and deoxidation agent. And sintering is generally carried out in vacuum and reducing atmosphere, there is no oxidation. It will no produce any pollution, so it is great possible foe making high purity materials.

The powder metallurgy method can guarantee the correctness of the material composition ratio and uniformity. Suitable for the production of the same shape and number of powder metallurgy products, gear and other products with high processing costs, manufacturing powder metallurgy method can greatly reduce production costs.

Modern and commonly used mechanical crushing, atomization, physical and chemical preparation of the powder. Preparation of the silicon powder after sieving and mixing, mixing well and add the appropriate plasticizers, and then press forming, powder between the atoms through the solid phase diffusion and mechanical interlocking effect, so that the parts combine to have a certain strength of the overall . The greater the pressure the greater the workpiece density and a corresponding increase in strength. Sometimes parts together to decrease the pressure increase density, but also can be used hot isostatic molding method. Will suppress the forming of the workpiece is placed in a closed furnace with reducing atmosphere sintering, the sintering temperature is about 2/3 to 3/4 times of the base metal melting point.

Due to the proliferation of different types of atoms at high temperatures, the powder surface oxides have been restored and deformed powder crystallization. It makes the powder particles combined with each other and improves the strength of powder metallurgy products of metal powder exporter. The organization is similarity to alloy. Through the sintered parts, there are still some tiny pores which belong to porous materials. Under normal circumstances, the sintered parts can achieve the required performance and be used directly. But sometimes it needs to make the necessary post-processing. Fine pressure treatment can improve the density, size and shape accuracy of the parts. Hardening and surface hardening treatment of iron-based powder metallurgy parts can improve their mechanical properties. To achieve the purpose of lubrication or corrosion, oil immersion or dipping liquid lubricant can be used. Penetrating the low melting point metal melt infiltration processing parts pores can increase the strength, hardness, plasticity and impact toughness of the parts.Source:http://www.mhcmp.com