铌-钛微合金化高强钢连续冷却的相变规律

Phase Transformation Rule of a Nb-Ti Microalloyed High Strength Steel During Continuous Cooling

利用Gleeble 3500热模拟试验机研究了铌-钛微合金化试验钢在变形与未变形条件下的连续冷却相变规律。研究结果表明：试验钢在2-50℃/s的较大冷速范围内均可获得贝氏体组织,且随着冷却速度的增加,组织中粒状贝氏体的量下降,板条贝氏体的量增加;同时变形促进相变,有利于奥氏体中新相的形成。用热膨胀法建立了试验钢静态与动态条件下的连续冷却转变（CCT）曲线。

Phase transformation rule of a Nb-Ti microalloyed high strength steel with or without deformation during continuous cooling was studied by means of Gleeble 3500thermal-mechanical simulator.The results show that bainite can be obtained during a wide cooling rate range from 2to 50 ℃/s.The amount of granular bainite decreases,while the amount of lath bainite increases with the increase of cooling rate.Deformation promotes new phase transformation in austenite.Thermal expansion method was adopted to obtain the continuous cooling transformation curves under deformation and no-deformation conditions.