The effects of boriding process on tribological properties and corrosive behavior of a novel high manganese steel

Abstract

In this study, wear and corrosion behavior of a novel borided high manganese steel (HMS) produced by the researchers was investigated. After the sheets were cold-rolled, they were annealed. HMS was borided at 850, 900, and 950 °C for 2, 4, and 6 h through the pack-boriding process. Borided HMS uncommonly exhibited a saw-tooth morphology like low alloy steels due to similar crystal structures of MnB and FeB. XRD analysis showed the existence of SiC, FeB, MnB and Fe2B phases. The present study indicated a silicon-rich zone by EDX mapping. The formation mechanism of silicon-rich zones was explained and expressed with the term “compact transfer of silicones”. The boriding time and temperature increased the thickness of the boride layer from 26.13 μm to 109.04 μm. The highest hardness value was observed in sample 5 (1757 HV0.05). The activation energy of borided HMS was quite low compared to several high alloy steels in the literature. Daimler-Benz Rockwell-C adhesion test showed that adhesions of borided HMS surfaces were sufficient. The “egg-shell effect” that emerge due to the high silicon rate did not occur. In the wear tests applied under 5, 10, and 15 N loads, the borided HMSs exhibited a better wear resistance compared to the base metal (BM). However, the wear test was applied under 5 N load and BM had a better performance than several borided HMSs because of the phase transformations. In general, the borided samples had lower corrosion rates compared to the unborided ones.