Machinability Studies with Sintered Ferrous Alloys

The use of additives to improve the machinability of powder metal parts is discussed. It is concluded that no single additive has yet been identified satisfying all requirements in relation to cost, toxicity, effectiveness, and influence on sintered strength.

The significant influence of mix composition (copper and graphite levels) on machinability is illustrated by drilling force measurements. Elemental manganese additions were found to be beneficial provided graphite content did not exceed 0.6%.