Mixing of raw materials for powder metallurgy parts and application of various components

The mixing of raw materials for powder metallurgy parts involves mixing two or more powders with different chemical compositions. The powder formed by mixing is called mixed powder. His quality will directly affect the internal quality of powder metallurgy parts. Therefore, powder mixing is not only the raw material preparation before the production of the pressing process, but also the first step in the production of powder metallurgy parts, and is a key process to ensure the material quality of the parts.

There are two basic requirements for mixing raw materials for powder metallurgy parts.

1. According to the material grade of the parts, the selected raw materials and auxiliary materials (additives) should meet the quality requirements of part production.

2. The mixed powder should achieve the best mixing uniformity, meeting the required loose density and formability during compression molding.

Requirements for raw materials for powder metallurgy parts: Generally, the raw materials are iron powder, copper powder, stainless steel powder, and copper powder.

1. Iron powder mainly includes two types: reduced iron powder and atomized iron powder. In addition, there are diffusion alloy powders, and alloy powders.

1. When selecting reduced iron powder and atomized iron powder for part production, different standards of iron powder are used based on the characteristics of the parts (such as bearings, gears, etc.). According to the material requirements of the parts, alloy element (copper, nickel, molybdenum, etc.) powders can be added and synthesized into mixed powders, which are generally used for low to medium strength structural parts.

   
   

2. When selecting pre alloyed powder for parts production, the pre alloyed powder is used to bond alloy elements (copper, nickel, molybdenum) powder particles to iron powder particles through sintering or adhesive bonding, which can greatly reduce the segregation of alloy powder. Its compression performance is good, the sintering size is stable, and it can eliminate the diffusion lag caused by the need to restore the oxide layer on the surface of the particles before sintering, and improve the hardenability. Graphite can be added Mixing of lubricants, etc. Generally used for high-density and high-precision structural parts.

   
   

3. When using diffusion alloying steel powder with copper, nickel, and molybdenum as the main alloying elements for parts production, graphite powder (C) or different amounts of pre alloying element powder (nickel, etc.) can be added to improve the toughness and impact performance of the parts, or heat treatment can be carried out. Generally used for high-strength and high-precision structural parts.

2. Copper powder mainly consists of atomized 663, 6% tin, 6% zinc, 3% lead (non environmentally friendly tin bronze), and other copper powder. Atomized 660, 6% tin, 6% zinc (environmentally friendly tin bronze), and other copper powder. Atomized 9010, 10% tin (environmentally friendly tin bronze), other copper powder.

3. Stainless steel powder, divided into two types: austenite and ferrite. Austenite has good rust resistance, including 316, 304, etc. Ferrite can be post heat treated, including 430, 434, 410, etc.