Microstructural Properties and Hardening Mechanism of Explosion Hardening of Mn13Cr2 Steel Surface

Abstract

This article is aimed at the surface explosion hardening of Mn13Cr2 steel. The mechanical properties of Mn13Cr2 steel after explosion hardening were tested. The microstructure of Mn13Cr2 steel after explosion hardening was studied using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD). The experimental results showed that after an explosion hardening the surface hardness of Mn13Cr2 increased from 220 to 400 HB, and the impact toughness decreased from 60 to 15 J cm⁻², the depth of the hardened layer was about 35 mm. The tensile strength increased from 500 to 690 MPa, yield strength increased from 400 to 430 MPa, the elongation was 15%. After the second aryexplosion, the surface hardness of Mn13Cr2 increased from 400 to 420 HB, and the impact toughness decreased from 15 to 12 J cm⁻², the depth of the hardened layer was about 38 mm. Tensile strength increased from 690 to 750 MPa, yield strength increased from 430 to 460 MPa. A large number of slip bands appeared in Mn13Cr2 steel specimens after an explosion, and the deformation twins were not observed, and the martensite phase did not appear on Mn13Cr2 steel according to XRD analysis. But martensite phase appeared after the secondary explosion. Therefore, an explosion hardening mechanism of high manganese steel is mainly dislocation hardening, the secondary explosion hardening mechanism of high manganese steel is mainly martensite hardening and dislocation hardening.