THE WORK-HARDENING BEHAVIOR OF MEDIUM MANGANESE STEEL UNDER IMPACT ABRASIVE WEAR CONDITION

The work-hardening behaviour and the microstructure change of medium m anganese steel and Hadfield steel were studied by impact abrasive wear tests, TEM and Mossbauer spectrometer. The results showed that the we ar resistance of 6Mn-2Cr steel is about 1.5 times as high as that of H adfield steel under low impact energy condition. It was dropping as th e energy increased. The TEM and the Mossbauer results indicated that t here were two kinds of austenites in 6Mn-2Cr steel before wearing test s. Correspondingly, two kinds of strain-induced martensites were produ ced while impact wearing. In addition, the weight fraction of carbon ( C) and metallic alloying elements (Me)free martensites did not change with the increasing of impact energy, but that of C and metallic eleme nts (Me) containing martensite did. The high work-hardening rate in 6M n-2Cr steel was caused by the transformation of strain-induced martens ite, the additional pressure stress caused by this transformation, the obstruction of C-Me-C-Me lattice in movement of dislocation and the d ynamic strain aging.