Surface Hardening on Wheel Steel Using Electrolytic Plasma

Abstract

Transmission electron microscopy (TEM) investigations of the structure and phase composition of ferritic-pearlitic wheel steel mark two surface after electrolyte-plasma surface hardening are presented. Initially the morphology of the steel matrix consists of lamellar perlite and non-fragmented and fragmented ferrite. Electrolytic plasma quenching of the steel surface results in the martensite transformation, steel self-tempering, and the formation of cementite particles in all martensite crystals. This treatment also leads to the diffusion transformation of gamma to alpha phases, the release of residual austenite along the low-temperature martensite laths and lamellas and in all crystals of lamellar martensite, the formation of М23С6 special carbides and, finally, to the enhancement of all parameters of the steel fine structure.