Three-body abrasive wear of carbide-free bainite, martensite and bainite-martensite structure of similar hardness

The three-body abrasive wear behavior of three ferrous alloys with different microstructures but similar hardness has been investigated using a standard dry-sand rubber wheel test (ASTM G65-16). Although the hardness of the alloys was similar, the abrasion rates are radically different owing to differences in abrasion mechanisms in their microstructures. A carbide-free bainitic steel having fine bainitic laths exhibited better abrasion resistance owing to the strain- induced transformation of austenite into martensite. Nano-scaled martensitic laths that formed on the surface resisted plastic deformation during abrasion and thereby increased the abrasion resistance. The microstructure containing bainitic ferrite undergoes extensive plastic deformation associated with a large quantity of dislocations, which in turn accommodates the strain of abrasion. The steel with a blocky-martensitic microstructure had the least wear resistance. In that case, fragmentation and chipping comprised the prominent abrasion mechanism. The degeneration of a martensitic structure and its subsequent tempering radically reduces the hardness at the surface and makes it more susceptible to abrasion. Steel containing a mixture of bainite and martensite had intermediate abrasion resistance relative to the other two alloys. •The Specific Wear rate (SWR) of martensite is approximately two times higher than other microstructures.•The carbide free bainitic microstructure exhibits best abrasion resistance.•The transformation-induced-plasticity effect of retained austenite accounts for the improved wear resistance.•The heat of abrasion aids tempering of martensitic, results in softening, leading to more wear.