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Why Powder metallurgy parts after post-sintering step strength is not strong enough and break easily
Jun 07, 2018

In recent years, the use of powder metallurgy (PM) technology applied in automobile power system part of the manufacturing continues to increase, as a result of PM process manufacturing parts has many important unique advantages, it can be used to reduce costs, improve performance, reduce the weight of the parts, and to protect the environment.

Powder metallurgy parts performance and machining difficulties.

    Mechanical properties.

   The porous structure is one of the characteristics that Powder metallurgy parts are widely used.Most properties of PM components, including machinability, are related not only to the chemical composition of the alloy, but also to the porosity of the porous structure.

  The tensile strength, toughness and elongation rate of PM materials will increase with the increase of density. However, the machinability of PM materials is increased because the porosity of PM materials is reduced to harm the tip.Increase the porosity materials can improve the sound insulation performance of parts, standard parts in the prevalence of damped oscillation decrease in Powder metallurgy parts, the machine tools, air conditioning duct and pneumatic tool is very important.In addition, high porosity is necessary for self-lubricating gear.

  Machining difficulities.

Although only a small amount of Powder metallurgy parts processing, but is extremely difficult to machining the PM parts, this is mainly due to the porous structure of PM materials, porous structure to reduce the service life of the cutting tool.

Porosity leads to micro - fatigue of cutting edge.As the tool moves back and forth from the hole to the solid particles, the tip continues to be impacted.Continuous small impact will result in small cracks on the cutting edge. These fatigue cracks will gradually increase until the cutting edge collapses.This micro - collapse is usually very small and usually manifests as normal abrasive wear.

In order to improve the cutting performance of powder metallurgy parts, the powder metallurgy industry has adopted a unique treatment technology for materials.Surface porous structures are often sealed by infiltration, so free cutting is usually required.New technologies in powder metallurgy that have recently been in use can increase the cleanliness of powder and reduce the production of oxides and carbides during heat treatment.

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