HIGH MANGANESE STEEL ALLOYING PROCESS AND ITS INFLUENCE ON MICROSTRUCTURE AND PROPERTIES OF THE STEEL

The influence of two kinds of alloying processes, adding Nb (or Ti) and N-Mn alloy as well as adding Nb (or Ti) and spraying Nz, on microstructures and properties of a high manganese steel has been studied. It has been found that adding Nb(or Ti), accompanying with N-Mn alloy, is unfavourable to microstructure compactness of the high manganese steel, but adding Nb (or Ti) and spraying N-2 into the melt is good for refining austenitic grain, forming a lot of hard particles and improving microstructure compactness. The mechanical properties of the high manganese steel have relation to the content of elements Nb or Ti. Its fracture mode will turn ductile fracture into brittle cleavage fracture gradually By X-ray and TEM analysis, it is proved that the austenite can be transformed to deformation-induced cr martensite after adding a certain amount of element Nb (or Ti). The microstructure transformation of alloying high manganese steels through deformation is one of methods for strengthening austenite matrix acid increasing the work-hardening rate as well as improving antiwear property.