초 고탄소강의 미세조직과 기계적성질에 미치는 열간 단조비의 영향

Abstract

This study was carried out to investigate the effect of the hot forging ratio on the microstructure and mechanical properties of ultra high carbon steel. The results obtained from this study are as follow : The microstructure of ultra high carbon steel with 1.5% w.t. C consisted of a proeutectoid cementite network and acicular microstructure in pearlite matrix. With increasing hot forging ratio, the volume and thickness of the network and acicular proeutectoid cementite decreased, and than were broken up into particle shapes . Lamella spacing and the thickness of eutectoid cementite decreased with increasing hot forging ratio, and were broken up into particle shapes, which then became spheroidized. When the forging ratio was over 65%, the network and acicular shape of the as-cast state disappeared. With increasing hot forging ratio, hardness, tensile strength, elongation and impact value were not changed up 50%, and then rapidly increased with the icrease of the forging ratio.