Surface Evolution and Performance of 45CrNiMoV Steel Modified by Electron Beam Irradiation

Enhancing the surface mechanical properties and extending the service life of 45CrNiMoV mold steel are critical goals in mold development. To achieve these objectives, electron beam (EB) irradiation was employed to treat the 45CrNiMoV mold steel. This high-energy physical process enables precise modification of the surface microstructure. By meticulously controlling EB parameters, including energy, dose, and scanning mode, significant structural alterations occur in the surface layer. Consequently, the surface microhardness more than doubles, reaching 812.7 HV. This enhancement is attributed to grain refinement, increased dislocation density, and potential formation of new phases induced by EB irradiation. Beyond hardness improvement, the wear resistance of the treated specimen increases by 2.5-fold. Under standardized testing conditions, wear loss decreases markedly from 0.28 mg to 0.11 mg. This reduction in wear loss not only extends the mold’s operational lifespan but also minimizes maintenance and replacement requirements, thereby reducing production downtime and associated costs. This study transcends mere presentation of experimental data by comprehensively elucidating the intricate relationship between surface microstructure and the overall mechanical properties of 45CrNiMoV mold steel. Advanced characterization techniques, including scanning electron microscopy (SEM) and X-ray diffraction (XRD), were utilized to uncover the underlying mechanisms. The refined microstructure, characterized by fine grains and elevated dislocation density, impedes dislocation movement and crack propagation, thereby enhancing both hardness and wear resistance.