PM parts performance summary

Although one of the original intention of the P/M industry is to eliminate all of the processing, but this goal has not been reached. Most of the parts are "close to the final shape", it must be some kind of finishing. However, the removal of a small amount of material from the P/M component is typically very wear-resistant compared to castings and forgings.

Porous structure is one of the characteristics of P/M parts, which are widely used, but the tool life was damaged by porous structure. Porous structure can be oil storage and noise, but also produce intermittent cutting on the micro. When from the hole to solid particles moving to and fro nose continuously by the impact, which can lead to very small fatigue deformation and fracture along the cutting edge of the tiny chip. What is worse, usually hard particles.

Even if the macro hardness detected between Rockwell 20~35 degrees, but part of the particle's 60 degrees high of talok. These hard particles lead to severe and rapid wear of the blade. Many P/M parts are heat treated, and they are much harder and stronger after heat treatment. Finally, due to sintering and heat treatment technology and the use of gas, the surface will be hard and wear resistant oxide and / or carbide.

The bulk properties of P/M parts, including machinability, are not only related to the chemical composition of the alloy but also to the level of the porous structure. Many structural parts with hole rate up to 15~20%. The hole rate of the part used as a filter device may be as high as 50%. At the other end of the series, or HIP (forging die casting parts with hole thermionic) rate of 1% or less. This is especially important in the automotive and aircraft applications, because they can get a higher level of strength.

The tensile strength, toughness and ductility of P/M alloy will increase with the increase of the density, and it may also improve the workability. This is because the porous harmful effect on the nose. The increase of the hole rate and the sound insulation performance of the parts. Standard parts generally damped oscillations in the P/M parts to reduce. This is very important for machine tools, air conditioning duct and pneumatic tools. The high porosity of self lubricating gear is also necessary.