고 Mn 오스테나이트계 스테인리스강의 기계적 성질에 미치는 역변태의 영향

Abstract

This study was carried out to investigate the effect of reverse transformation on the mechanical properties in high manganese austenitic stainless steel. Over 95% of the austenite was transformed to deformation-induced martensite by 70% cold rolling. Reverse transformation became rapid above an annealing temperature of 550°C, but there was no significant transformation above 700°C. In addition, with an increasing annealing time at 700°C, reverse transformation was induced rapidly, but the transformation was almost completed at 10 min. There was a rapid decrese in strength and hardness with annealing at temperature above 550°C, while elongation increased rapidly above 600°C. At 700°C, hardness and strength decreased rapidly, and elongation increased steeply with an increasing reverse treatment time up to 10 min, whereas there were no significant change with a treatment time after 10 min. The reverse-transformed austenite showed an ultra-fine grain size less than 0.2 μm, which made it possible to strengthen the high manganese austenitic stainless steel. (Received February 22, 2012)