Study on the role of chromium addition on sliding wear and corrosion resistance of high-manganese steel coating fabricated by wire arc additive manufacturing

Guide shoe made of steel is an important component of coalcutter and rail transport to sustain forward direction. However, the guide shoe suffers from wear failure due to the heavy load and fatigue. Preparing wear-resistance coating on the worn surface is a practical and economic technology to elongate longevity. High manganese steel is a candidate material with excellent wear resistance. In this study, high-manganese (HiMn) and high-manganese medium-chromium (HiMnMeCr) coatings are fabricated by using wire arc additive manufacturing (WAAM) to investigate the role of Cr addition on the microstructure and resistance to wear and corrosion by analyzing the microstructure morphology, wear rate, coefficient of friction, surface and cross-sectional morphology of the wear track, and electrochemical behavior by using sliding wear test and electrochemical experiment. The experimental results obtained by using the counterface material of ZrO2 showed that Cr addition changed the microstructure constitutes of WAAMed HiMn coating from biphasic austenite + martensite to single austenite. The addition of Cr elongated the running-in period of the wear process and weakened the wear resistance of the WAAMed HiMnMeCr coating due to the work-hardening effect induced by the severe plastic deformation of austenite. At loads of 50 and 100 N, the primary wear mechanism for the HiMn coating was a complex mode of abrasive and adhesive wear. The wear mechanism transformed into a single adhesive wear at a load of 120 N. However, the primary wear mechanism of the HiMnMeCr coatings was abrasive wear at all tested loads. The electrochemical experiment (pote ntiodynamic curves and EIS analysis) shows that the corrosion resistance of HiMnMeCr coating was better than that of HiMn coating, indicating that the addition of Cr enhanced the corrosion resistance of the WAAMed HiMn steel by the passivation effect of Cr. This study will provide a fundamental theory for the fabrication of wear-resistance coating by using WAAM.