Machining performance of PM material containing MnX additives

A new free-machining additive, MnX, has been reported to improve the machin ing performance of ferrous powder metallurgy (PM) materials. This work inve stigated this claim by comparing the performance of three otherwise identic al PM materials containing: no additive, conventional manganese sulphide (M nS) additions find size new MnX additive. A turning operation and cutting s peeds of 100-250 m/min were used during which cutting forces, tool wear and surface finish were measured. The MnX material was found to exhibit superi or performance. However, this was most noticeable at higher cutting speeds and at the lower cutting speeds, differences in performance were substantia lly reduced. [S0094-4289(00)02004-1].