Impurity-free and high-efficiency modification for 30CrMo steel

It is still difficult to simultaneously achieve surface polishing and purity-free modification of 30CrMo steel by conventional treatment technologies. Herein, the continuous circular scanning electron beam process (CCSEBP), a novel route, for direct surface modification of 30CrMo steel is proposed. The changes regularity in microstructure, surface roughness, microhardness and wear resistance after electron beam treatment was investigated. Results indicated that the modified layer was primarily composed of typical acicular and lath martensite. After polishing, the surface roughness was decreased from 2.2 μm to 0.9 μm and microhardness improved significantly, which is closely associated with martensitic transformation. Moreover, the wear amount of the 30CrMo steel after modification is reduced by 50% compared to the pristine specimen. Following appropriate treatment, 30CrMo steel exhibited an extraordinary combination of hardness and finish. This study shed light on the development of high-efficiency modification for electron beam scanning 30CrMo steel. [Display omitted] •Present a CCSEBP to modify 30CrMo steel, impurity-free and high-efficiency.•Finish, hardness and wear resistance were improved in a “one-step” process.•The highest hardness of the treated sample reaches 2.6 times that of the matrix.•Temperature of different depths had great effect on morphology of martensite.