货油舱用耐蚀钢连续冷却的转变规律

摘要 在MMS-300热模拟试验机上测得货油舱用耐蚀钢在不同冷速下的连续冷却膨胀曲线，结合金相-硬度法， 研究了该耐蚀钢变形和未变形过冷奥氏体冷却过程中的组织演变，建立了连续冷却转变(CCT)曲线.结果表明，动态CCT曲线较静态CCT曲线明显向左上方移动，提高了奥氏体转变的开始温度；随着冷却速度的增大，显微组织由多边形铁素体、珠光体和少量贝氏体逐渐过渡到针状铁素体、粒状贝氏体，最后为板条贝氏体和马氏体.
Abstract：The continuous cooling transformation (CCT) curve of cargo oil tank (COT) steel was obtained by using dilatometric method combined with metallographic analysis-hardness measurement， and the austenites before and after the compress deformation were analyzed， which were tested on MMS-300 thermal mechanical simulation under different cooling rates. The results showed that the dynamic CCT curve compared to static CCT curve obviously moves to the left and up direction， and the starting temperature of austenite increases. With increasing the cooling rate， the microstructures gradually change from polygonal ferrite， pearlite and a little bainite to a small amount of acicular ferrite and granular bainite， finally transform into bainite and martensite.