What is the Powder Metallurgy (PM)?
Powder metallurgy is the process whereby metal parts in large quantities can be made by compressing and sintering various powdered metals such as brass, bronze, stainless steel, and iron. Self-lubricating sintered metal bearings are produced by powder metallurgical methods.
Powder metals are fed into a die and axially compacted. The resulting "green parts" are sintered in a protective gas atmosphere at temperatures below the melting point. Through diffusion, a bonding results at the points of contact of the powder particles. This bonding defines the strength of components. Through subsequent calibration, the specified tolerances primarily in the bore are met without blocking up the pores.
Vacuum impregnation with a suitable lubricant is the final stage of the process. And supplementary heat treatments may be employed.
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Why PM?
The demand for P/M components is growing. Why? Because of the many advantages powder metallurgy as a metal-forming process offers. Extremely enormous design flexibility, P/M can meet specific strength, tailored properties, design characteristics and, quite often, operational advantages with a high degree of accuracy.
In addition, P/M is efficient on a mass production basis. Products with extremely close tolerances can be net-shape manufactured with virtually no waste and without extensive (if any) secondary machining.
Finally, P/M enables the manufacture of parts or combinations of parts that otherwise may be impossible or too costly to produce using more conventional metal forming techniques or machining processes. |
