The effect of manganese on the strain-induced martensitic transformation and high temperature wear resistance of Fe–20Cr–1C–1Si hardfacing alloy

Sliding wear tests of Fe–20Cr–1C–1Si–xMn alloys with x varying from 0 to 25 wt% were performed in air at temperatures of 25–450°C under a contact stress of 103 MPa. During wear at 25°C, low-Mn alloys containing less than 5 wt% Mn and high-Mn alloys containing more than 10 wt% Mn exhibited the γ→α′ and γ→ε strain-induced martensitic transformations, respectively. As the test temperature increased, low-Mn alloys showed a wear transition from mild oxidative wear to galling at a temperature between 350°C and 400°C due to the absence of γ→α′ strain-induced martensitic transformation. In the case of high-Mn alloys, the mild oxidative wear was maintained until 450°C, which was the highest test temperature in this study, with the formation of strain-induced ε martensite. It was considered that the γ→ε strain-induced martensitic transformation could be more beneficial to the high temperature wear resistance of iron-base hardfacing alloy than the γ→α′ strain-induced martensitic transformation due to the higher Md temperature.