Corrosion Resistance and Fracture Toughness of Cryogenic-Treated X153CrMoV12 Tool Steel

Abstract Cryogenic treatment can be employed as an additional heat treatment step for martensitic steels, particularly high-carbon and high-alloy tool steels, to improve their mechanical properties and wear resistance. This enhancement results from a transformation of retained austenite and precipitation of finely distributed secondary carbides. The present study examines the impact of a shallow cryogenic treatment, performed between the quenching and tempering processes, on the corrosion resistance and fracture toughness of cold work tool steel X153CrMoV12. The influence of the shallow cryogenic treatment was evaluated using potentiodynamic polarization test, salt spray tests and three-point bending tests in various hydrogen charging conditions. In addition, the microstructure and phase transformation of the tool steel were investigated using high-resolution scanning electron microscopy, X-ray diffraction and dilatometer tests. The results suggest that the shallow cryogenic treatment followed by a single tempering cycle can slightly enhance the corrosion resistance of the steel. More importantly, the shallow cryogenic treatment positively affects fracture toughness and reduces hydrogen susceptibility. It is discussed how these improvements in the properties of the X153CrMoV12 steel are linked to the microstructural changes induced by the shallow cryogenic treatment.