The role of microstructure in the wear of selected steels

This investigation is a continuation of impact wear studies which focus on the nature of subsurface microstructure. Both AISI 1045 and 2.25Cr-1Mo steels were selected for their capacity to form various phase morphologies at given compositional states. Heat treatment was then performed to produce the desired two-phase (duplex) structure in both materials. The mating counterface to each test material was a 17-4 PH stainless steel in the martensitic condition. Compound impact wear tests were performed at relative transverse sliding velocities of 1 and 10 m s −1 with peak nominal contact stress maintained at 69 MPa for various numbers of repetitive load cycles. The formation and characterization of subsurface zones were studied by scanning electron microscopy and energy-dispersive X-ray analysis. Wear debris was inspected by powder X-ray diffraction. The impact wear resistance of AISI 1045 and 2.25Cr-1Mo steels is dependent on transverse velocity. Variations in velocity lead to “trade offs” between specimen and counterface 17-4 PH stainless steel wear which is evidenced in weight loss data and correlates with microstructural observations (subsurface zone formation) for each two-phase system. Wear debris analysis confirms the presence of mechanochemical material interaction between specimen and counterface with increasing transformation and oxidation at the higher transverse sliding velocity.