Inhanced machinability and oxidation resistance of P/M steels using modified MnS additions

摘要

The usefulness of manganese sulfide as amachinability-enhancing additive, especially for powder metalparts, is well known. The residual pore structure generallycauses limited tool life and restricts the use of liquid coolants.Here, the results of a study on improved machinability of steelvia additives based on manganese sulfide with controlledadditions of iron are presented. The shortcomings of the pureadditive are reviewed, including an explanation of physical andchemical aspects. For the new additive, the role of oxygencontent, particle size distribution and the iron are analyzed.Results are presented which show that the modified additiveprovides enhanced machinability and improved oxidationresistance compared to pure MnS.