Powder metallurgy is a process technology for manufacturing metal materials, composite materials, and various types of products by using metal powder (or a mixture of metal powder and non-metal powder) as raw materials, and through shaping and sintering. The broad powder metallurgy industry includes iron-based tooling, hard alloys, magnetic materials, and powder metallurgy products. The narrow powder metallurgy product industry refers only to powder metallurgy products, including powder metallurgy parts (which account for the majority), oil-bearing bearings, and metal injection molded products.

Process characteristics:

1. The density of the product can be controlled, such as porous materials and good density materials.

2. Fine grains, uniform microstructure, and no component segregation.

3. Near-net-shape forming, raw material utilization rate > 95%.

4. Minimal cutting, cutting processing only 40-50%.

5. Material composition can be controlled, which is conducive to preparing composite materials.

6. Difficult-to-dissolve metals, ceramic materials, and nuclear materials can be prepared.

Basic process flow:

1. Powder production: Powder production is the process of making raw materials into powder. Common powder production methods include oxide reduction and mechanical methods.

2. Mixing: Mixing is the process of mixing various powders needed according to a certain proportion and making them into uniform pellets. There are three types of dry, semi-dry, and wet methods, which are used for different requirements.

3. Forming: Forming is the process of loading the uniformly mixed mixture into a die and pressing it into a certain shape, size, and density. The forming method is basically divided into pressure forming and non-pressure forming. The most widely used in pressure forming is mold pressing.

4. Sintering: Sintering is a crucial process in powder metallurgy. The molded blanks are sintered to obtain the required final physical and mechanical properties. Sintering is divided into unimodal sintering and bimodal sintering. In addition to ordinary sintering, there are also special sintering processes such as loose sintering, melt immersion, and hot pressing.

5. Post-processing: After sintering, processing can be done 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, achieving ideal results.

Powder metallurgy products have a wide range of applications, from ordinary mechanical manufacturing to precision instruments, from hardware tools to large machinery, from the electronics industry to motor manufacturing, from civilian industry to military industry, and from general technology to aerospace high-tech fields, all of which can be seen the presence of the powder metallurgy process.

Typical applications

Application in the automotive industry include:

1. Engine components: In order to improve fuel economy and control emissions, the working conditions of automotive engines have become more stringent. By using powder metallurgy valve seats, valve guides, VCTs, and sprockets, high strength, high wear resistance, and excellent heat resistance can be achieved.

2. Transmission components: The world's hardest clutch hub has been made by combining near-net-shape synchronizer rings with dual friction materials and high-strength materials. In addition, high-strength components such as shift gears and shift forks have been manufactured by high-temperature sintering. Powder metallurgy transmission components in automobiles mainly include synchronizer wheel hubs, synchronizer rings, parking components, column shift components, and control rods.

3. Vibration damper components: In the vibration dampers of automobiles and motorcycles, piston rods and piston guide valves are important components. Considering the stable damping force of the vibration damper, the use of powder metallurgy parts with high-precision thin sheet surfaces can reduce friction, ensure stable operation, and improve riding comfort.