【摘要】 通过一种微合金高强管线钢未变形及热变形条件下连续冷却相变行为的研究,建立了相应的奥氏体连续冷却相变曲线,结合光学显微镜及扫描电镜的微观组织观察,研究了冷却速度及热变形对该钢相变及组织的影响;试验结果表明,试验钢在试验冷速范围内组织由多边形铁素体+珠光体,针状铁素体,贝氏体铁素体构成;变形将针状铁素体的相变温度提高100℃以上,形成针状铁素体的冷速范围由未变形的0.5~15℃/s扩大到变形后的3~50℃/s以上,促进了针状铁素体转变;随变形后冷却速度及变形量的增加,基体组织变细,基体中M/A小岛变得更加细小、弥散。更多还原

【Abstract】 The transformation behavior of a high strength microalloyed pipeline steel during continuous cooling under deformation and without deformation was investigated and CCT curves of undeformed and deformed austenite were constructed through observation of microstructure and dilatometric analysis.The effect of cooling rate and hot deformation on transformation and microstructure of the steel was studied.The results show that the microstructure of the steel consists of PF+P,AF,and BF,the deformation increases the transferring temperature of acicular ferrite about 100℃.The range of cooling rate for formation of AF increases from 0.5～15℃/s to 3～50℃/s for the steel without and with deformation and deformation accelerates the transformation of AF.With increasing of cooling rate and reduction,microstructure of the steel is refined and M/A islands become more fine and dispersive.更多还原