Friction and wear behaviour of AlCrN and TiN coated H13 tool steel

The wear characteristics of coated H13 tool steel and as-casted H13 tool steel in dry sliding conditions were investigated through a pin-on-disc tribometer, where the H13 steel is used as a pin and EN31 steel is used as disc material. The study was focused on evaluating the tribological behaviour by examining the friction characteristics, surface morphology and wear performance. Initially, to improve the hardness of the untreated (as-casted) H13 steel, the tempering process where carried out on the samples, which helped elevate the hardness from 38 to 55 HRC. The worn surface of the samples was analysed using atomic force microscopy (AFM). Among the four samples (as-casted, heat-treated, AlCrN coated and TiN coated) the as-casted samples were affected by oxidation and adhesive wear. The material loss measured for as-casted, heat-treated, AlCrN and TiN samples was 30.34, 7.85, 0.78 and 0.14 mg, respectively. The measured coefficient of friction was 0.541 for as-casted, 0.492 for the heat-treated, 0.48 for the AlCrN and 0.147 for the TiN sample. From the study, the major conclusion was that the TiN coating offers major wear protection and lower friction.