Effects of Quenching Temperature on Microstructure and Corrosion Resistance of Die Steel 30Cr13

Quenching was applied to die steel 30Cr13 at different temperatures. The microstructure, characteristics of undissolved carbides, corrosion resistance and corrosion mechanism of 30Cr13 die steel were analyzed by X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical testing. The results show that the annealed steel was mainly composed of ferrite, and the quenched die steel was mainly composed of martensite. With the increase of quenching temperature, the number of large undissolved M₂₃C₆ carbide particles in the die steel decreased, and the carbide particles basically dissolved in the matrix when the quenching temperature reached 1 130℃. The passive film was thicker on the surface of die steel 30Cr13 in quenched state than in annealed state, and its protection to the matrix was better than that to the matrix of the annealed die steel. And the corrosion resistance of the die steel gradually increased with the increase of quenching temperature. The decrease of carbide content in die steel 30Cr13 during the quenching process was helpful to improve the corrosion resistance of the die steel.