열연 DP 강의 오스테나이트 내 탄소 재분배를 고려한 MS 예측

Abstract

During the production of dual phase(DP) steels, intermediate phases such as acicular ferrite or upper bainite were frequently observed, which were very detrimental to the mechanical property of DP steels. The existence of undesirable phases could be adjusted by the enrichment and the redistribution of carbon in retained austenite after formation of polygonal ferrite during inter-critical annealing. In this study, the enrichment and the redistribution of carbon, which was a major strengthening factor, were measured by nano-hardness by changing holding time during inter-critical annealing. Indentation was conducted from center to near boundary of 2nd phases. The diffusion behavior of carbon during inter-critical annealing between DP steel and plain carbon steel was compared in order to understand the effect of Si on behavior of carbon and phase transformation.