Influence of Mn and Al additions to carbon steel on material transfer and coating damage mechanism in a sliding contact between steel and TiN coated HSS tool

A crossed cylinders sliding test, simulating the contact between the chip and the cutting tool, is used to evaluate material transfer, friction characteristics and coating damage of a TiN coated high speed steel against specifically designed model steels. These steels include one reference with C as the only alloy element (Base steel), and two alloyed also with 1 mass% Mn or Al. When sliding against the Base steel, an Fe-O layer forms on the coating and protects it from wear. Against the Mn alloyed steel, Fe-Mn-O forms, which has no protective effect. Against the Al alloyed steel, an almost pure Al-O layer forms. This leads to the highest friction, rapidly causing substrate softening and coating fracture.