Powder metallurgy is the process of making metal or using metal powder (or a mixture of metal powder and non-metal powder) as raw material, forming and sintering, manufacturing metal materials, composite materials and various types of products.In a broad sense, powder metallurgy products include iron tools, hard alloys, magnetic materials and powder metallurgy products.In the narrow sense, powder metallurgy products only refer to powder metallurgy products, including powder metallurgy parts (accounting for the majority), oil-bearing and metal injection molding products, etc.
Process characteristics
1. Controlled density of products, such as porous materials and good density materials;
2. Fine grain, uniform microstructure and no component segregation;
3. Near-form forming, raw material utilization > 95%;
4, little no cutting, cutting only 40~50%;
5. Controllable material components, conducive to the preparation of composite materials;
6. Preparation of insoluble metals, ceramics and nuclear materials.
Basic process flow
1, Pulverizing
Powder making is the process of making powder from raw materials. The commonly used methods of powder making include oxide reduction and mechanical method.
2, Mixing
Mixing is the process of mixing all kinds of required powders in a certain proportion and homogenizing them into billet powder.There are three types of separation-dry type, semi-dry type and wet type, respectively used for different requirements.
3, Forming
Forming is the process of forming a blank with a certain shape, size and density by mixing evenly mixed materials into a pressing pressure.Molding methods are basically divided into compression molding and non - compression molding.Compression molding is the most widely used die molding.
4, Sintering
Sintering is a key process in powder metallurgy process.The final physical and mechanical properties are obtained by sintering the formed billet.Sintering is divided into unit sintering and multi - sintering.In addition to ordinary sintering, there are also special sintering processes, such as loose sintering, melting and hot pressing.
5. Post-processing
The treatment after sintering can be done in various ways according to the different requirements of the products.Such as finishing, oil immersion, machining, heat treatment and electroplating.In addition, in recent years, some new technologies such as rolling and forging have also been applied to the processing of powder metallurgy materials after sintering, and better results have been obtained.
The main application
Powder metallurgy products have a wide range of applications, from ordinary machinery manufacturing to precision instruments;From hardware tools to large machinery;From electronics to motor manufacturing;From civil industry to military industry;Powder metallurgy technology can be seen from general technology to cutting-edge high technology.
Typical applications - Automotive industry
Powder metallurgy parts are widely used in automobiles
1. Engine components
To improve fuel economy and control emissions, the working conditions of car engines have become more stringent.With powder metallurgy seats, valve guides, VCT and sprockets, it offers high strength, high wear resistance and excellent heat resistance.
Inlet and exhaust valve seats
2. Transmission components
The nearly finished synchronizer ring is combined with dual friction material and high strength material to produce the world's first clutch hub.In addition, high strength components such as handle shift gears and shift forks have been manufactured by sintering at high temperatures.
The main parts of powder metallurgy transmission in automobile are: synchronizer wheel hub, synchronizer ring, parking parts, column shift parts and control rod.
Synchronizer cone ring
3. Shock absorber components
In shock absorbers of automobiles and motorcycles, piston rod and piston guide valve are important parts.Considering the stable damping force of the shock absorber, the use of powder metallurgy parts, with a high precision sheet surface, can reduce friction, ensure the stability of the operation, improve ride comfort.
Shock absorber parts
Typical applications - Aerospace industry
Powder metallurgy materials used in the aviation industry include special functional materials, such as friction materials, anti-wear materials, sealing materials, filtration materials, etc., mainly used in aircraft and engine auxiliaries, instruments and airborne equipment.The other is high temperature and high strength structural materials, which are mainly used for the important structural parts of the main engine of aircraft.
Air filter
Typical applications - Household appliances
Some materials and parts of household appliances can only be made by powder metallurgy, such as the porous self-lubricating bearings in refrigerators, compressors, washing machines, electric fans, etc.Some materials and parts for home appliances, such as the complex shaped gears and magnets used in home air conditioning fans and vacuum cleaners, are made of powder metallurgy to produce better quality and lower prices.
Typical applications - consumer electronics
Typical application - Power tools
Electric and electric tool part