GRAIN BOUNDARY CHARACTER DISTRIBUTION AND MECHANICAL PROPERTY OF THE AS COLD ROLLED HIGH NITROGEN AUSTENITIC STAINLESS STEEL

Grain boundary character distribution and mechanical property of a cold rolled stainless steel with high nitrogen content of 0.66% in weight were studied. The employed cold rolling reductions are 0%, 10% and 20%, respectively. It is shown that both yield strength and ultimate tensile strength were almost linearly increasing with increase of the cold rolling reduction, but uniform elongation was decreased. The high nitrogen steel is found to possess the plastic instability stress (PIS), which is independent of cold working condition. The microstructure deformed by cold rolling was studied by transition electron microscopy (TEM). Electron back scattered diffraction (EBSD) was used to further evaluate the evolution of the grain boundary character distribution, which was caused by the planar slipping of dislocations. The combination of the above two characteristics produced a deeper understanding of the relationship between the deformed microstructure and the mechanical properties.