고질소 SD500 강의 미세조직 및 기계적 특성

Abstract

Steel makers are bubbling with argon to improve the quality of materials. However, in order to save manufacturing cost, low-cost nitrogen bubbles are being tried. This study investigated the effect of nitrogen bubbling on the microstructure and mechanical properties of SD500 steel with different nitrogen concentrations. As the residual nitrogen concentration increased, not only the amount of inclusions and pin-holes increased, but also the size increased. The amount of ferrite decreased, and the amount of pearlite increased. The ferrite and pearlite grain sizes were reduced. The hardness, strength and yield ratio increased, and the elongation decreased. Vickers hardness could be explained by a 2-parameter Weibull statistical analysis.