The Effect Of Technics Parameter On The Microstructure, Property And Residual Stress Of 20CrMnTi Carburization Steel

The effect of quenching temperatures, tempering times, and grinding feed rates on the microstructure, surface hardness, and the percent of retained austenite, residual stress, the grinding surface morphology and the roughness of the surface on surface and the center of steel 20CrMnTi were investigated, By the observation of the microstructure, X-ray diffraction analysis etc.The results showed that:Regardless of quenching temperatures, its microstructures, from surface to the heart, were compose of quenching martensite,Carbide, retained austenite then quenching martensite, finally quenching martensite, ferrite. Hardness of the surface increased first then reduced, and finally keep stable with increment of distance from the surface. Both a low-temperature tempering and twice tempering treatment, by quenching temperature reduced, the residual austenite and residual compressive stress were increased. Peened before tempering, the residual compressive stress was increased and retained austenite was reduced. At the feed of 0.06 mm, cracks emerged on the surface. After grinding, the residual stress changes from compressive stress to residual tensile stress and by the feed of rate increase the residual stress and residual austenite percent were increased then decreased. Adding a low-temperature tempering treatment after grinding, residual stress and retained austenite remarkably reduced, was more uneven coMPared to those after grinding.