Enhanced impact and wear properties of gear steel by supersonic fine particle bombardment modification technology

Abstract

In this work, the wear resistance and impact toughness of the carburized layer were improved by rare earth (RE) doped supersonic fine particle bombardment (SFPB) pretreatment assisted vacuum carburizing. On the surface of 17CrNiMo6 steel, vacuum carburizing (VC), SFPB vacuum carburizing (SC), and CeO2 doped SFPB vacuum carburizing (CSC) layers were formed, respectively. The effect of SFPB and CeO2 doping SFPB pretreatment on microstructure, impact toughness and wear resistance of carburized layers were investigated in detail. Results show that the microstructure of the CSC layer changes obviously, and equiaxed martensite and nano carbide are formed on the surface. The surface impact toughness and wear resistance of the SC layer and the CSC layer are significantly improved, compared with that of the VC layer. In particular, the impact absorbed energy of CeO2 doping SFPB carburized (CSC) (60.8 J) was 30.8% higher than that of the VC (46.5 J), which is attributed to the refinement of martensite and austenite by pretreatment. Among the carburized layers, the modified carburized layer doped with CeO2 (CSC) had the minimum wear rate (9.45 × 10−15m3N−1 m−1), indicating the strongest resistance to wear. Meanwhile, the wear rate of the CSC layer was increased by 11% compared to that of the VC layer. Moreover, the main wear mechanism of various carburizing layers was abrasive wear.