Evaluation of Microstructure and Tribological Properties of GX120Mn13 and GX120MnCr18-2 Cast Steels

The results of microstructure examinations and hardness measurements carried out on two selected grades of high-manganese cast steel with an austenitic matrix, i.e. GX120Mn13 and GX120MnCr18-2, are presented. The examinations of the cast steel microstructure have revealed that the matrix of the GX120MnCr18-2 cast steel contains the precipitates of complex carbides enriched in Cr and Mn with two different morphologies. The presence of these precipitates leads to an increase in hardness by approx. 30 HB compared to the GX120Mn13 cast steel. Samples cut out from the tested materials were loaded (10 strokes) with an energy of 53 J, and then a ball-on-disc tribological test was performed. The test was carried out in reciprocating motion under technically dry friction conditions. While analyzing the obtained results of the microstructure, hardness, and abrasion tests, it was found that the presence of the hard carbide precipitates in the plastic matrix of the tested GX120MnCr18-2 cast steel promoted an increase in hardness, but also led to chipping of these particles from the alloy matrix, thus contributing to micro-cutting during friction.