Evaluating Wear Properties of AISI 420 Martensitic Stainless Steel after Laser Transformation Hardening

As the turbine industries need to manufacture turbine blades made of martensitic stainless steel AISI 420 with high toughness and wear resistance, local laser hardening has become more and more important. In this research, surface of the samples was initially hardened by high-power pulsed laser beam; then, optimum parameters of hardening were calculated and wear resistance of surface hardened samples were compared with the similar parameter in the surface raw samples. Scanning Electron Microscope (SEM) was used to determine microstructure and surface phases. Reciprocating wear test was also performed for surveying wear resistance of the samples. The results showed that laser surface treatment led to producing a martensitic-austenitic microstructure and dissolution and/or redistribution of carbides. Hardness of surface of hardened samples was obtained about 700 Hv after laser hardening. Wear mechanism was transformed from laminate to abrasive during the testing.