Nb-V-Ti微合金化高强度钢08MnCr连续冷却转变曲线和组织

利用ThermecMaster-Z热模拟实验机测定了一种Nb-V-Ti微合金化高强度钢08MnCr(S2)在910～1 200℃不变形(静态)和变形(动态)奥氏体0.05～30℃/s冷速下连续冷却转变(CCT)曲线,并分析和观察了对应的相变及组织。实验结果表明,提高轧后的冷却速度使Ar₃降低,导致钢的晶粒进一步细化;冷却速度大于10℃/s开始出现贝氏体转变。提高加热温度时相变温度降低,变形奥氏体相变温度较不变形奥氏体相变温度高。冷速较低时,铁素体晶粒呈多边形;冷速高时,铁素体晶粒多呈尖角形。

Continuous Cooling Transformation Curves and Structure of Nb-V-Ti Microalloying 08MnCr High Strength Steel

Continuous cooling transformation (CCT) curves of non-deformed (static) and deformed (dynamic) austenite of Nb-V-Ti microalloying 08MnCr high strengh steel (S2) at 910~1200 ℃ with cooling rate0.05～30℃/s were measured by using Thermec Master-Z thermal simulator,and corresponding transformation and  structure were analyzed and observed. Test results showed that with increasing cooling rate after rolling,the Ar3 transformation point decreased led to further fine the grain of steel; with cooling rate more than 10 ℃/s,the bainite transformation occurred. With increasing heating temperature the transformation temperature decreased,and the transformation temperature for deformed austenite was higher than that for non-deformed austenite. With lower cooling rate the ferrite grain was polygon,and with higher cooling rate the ferrite grain presented pointed shape.