Abrasive Wear Behavior Of Ultrafine-grained Medium Carbon Low Alloy Steel

In this work, a ultrafine-grained low alloy steel with high hardness and high ductility was produced by multi-directional forging (MF) and annealing treatment. The aim of this work is mainly to investigate effect and mechanism of the microstructure, hardness, ductility, work hardening, MF and heat treatment on abrasive wear behavior in ultrafine-grained materials. Microstructures were characterized by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). And mechanical properties were studied in hardness test and tensile test. To investigate the variation of wear mass loss and relative wear resistance, two-body and three-body abrasive wear tests were respectively carried out at varying loads and impact energy. This paper researched the relationship between the microstructure, hardness, ductility, work hardening, multi-directional forging and heat treatment on abrasive wear behavior in ultrafine-grained materials.The results showed that though strength and hardness in steels can be greatly enhanced by MF, the poor ductility and fracture toughness make abrasive wear resistance deteriorated in hard abrasive wear condition. It has been shown that the ductility and fracture toughness in MF sample can be distinctly improved after annealing with strength and hardness reduced slightly. It makes a significant improvement of two-body abrasive wear resistance under a light load, compared with the conventional treatments. Moreover, after annealing the MF sample has a good work-hardening capability in the three-body abrasive wear test, resulted in a change of wear mechanism from chisel-cutting wear to fatigue wear with the increase of impact energy. Therefore, under a medium impact energy condition, the wear resistance can be greatly improved by MF and annealing treatment.