Powder metallurgy gears are commonly used in various automotive engines. Although they are very economical and practical in large quantities, there are other areas that need improvement. Let's take a look at the advantages of powder metallurgy gears.
advantage:
1. There are few manufacturing processes for powder metallurgy gears.
2. When manufacturing gears by powder metallurgy, the material utilization rate can reach more than 95%
3. The repeatability of powder metallurgy gear is very good. Because powder metallurgy gears are pressed and formed by a mold, under normal use conditions, a pair of molds can press tens to hundreds of thousands of gear compacts.
4.Powder metallurgy can integrate several parts
5. The material density of powder metallurgy gear is controllable.
6. In powder metallurgy production, in order to facilitate the removal of the compact from the mold after forming, the roughness of the working surface of the mold is very good.
What is powder metallurgy
It is a process technology for preparing metal or using metal powder (or a mixture of metal powder and non-metal powder) as raw materials, forming and sintering, and manufacturing metal materials, composite materials and various types of products. In the broad sense, the powder metallurgy industry includes iron tools, cemented carbide, magnetic materials, and powder metallurgy products. The powder metallurgy products industry in the narrow sense only refers to powder metallurgy products, including powder metallurgy parts (accounting for the vast majority), oil-containing bearings and metal injection molded products.
Process characteristics
1. Controllable product density, such as porous materials, good density materials, etc .;
2. Fine grains, uniform microstructure, no component segregation;
3. Proximity forming, raw material utilization rate> 95%;
4, less no cutting, cutting processing is only 40 ~ 50%;
5. Controllable material components are conducive to the preparation of composite materials;
6. Preparation of insoluble metals, ceramic materials and nuclear materials.
Basic process
1.Milling
Milling is the process of making raw materials into powder. Common milling methods include oxide reduction and mechanical methods.
2.Mixing
Mixing is the process of mixing various required powders in a certain proportion and homogenizing them into a green powder. There are three types: dry, semi-dry and wet, which are used for different requirements.
3.Shaping
Forming is a process of mixing a uniformly mixed material into a stamper and pressing it into a parison having a certain shape, size and density. The molding method is basically divided into pressure molding and non-pressure molding. The most commonly used in compression molding is compression molding.
4.Sintering
Sintering is a key process in powder metallurgy. The compacted green compact is sintered to obtain the required final physical and mechanical properties. Sintering is divided into unit-based sintering and multi-component sintering. In addition to ordinary sintering, there are special sintering processes such as loose sintering, melt immersion and hot pressing.
5. Post-processing
The treatment after sintering can take a variety of ways according to different product requirements. Such as finishing, oil immersion, machining, heat treatment and electroplating. In addition, in recent years, some new processes such as rolling and forging have also been applied to the processing of powder metallurgy materials after sintering, and have achieved relatively satisfactory results.