X100热煨弯管用管线钢的CCT曲线研究  

Research on CCT Curves of Linepipe Steel Used for X100 Grade Hot Bent Pipe

作　　者：胡平[1] 郑磊[1] 章传国[1] 

机构地区：[1]宝山钢铁股份有限公司研究院,上海201900

出　　处：《热加工工艺》2015年第18期67-70,共4页Hot Working Technology

摘　　要：针对热煨弯管的热处理工艺特点,采用Gleeble 3800进行了X100管线钢的连续冷却相变规律研究。利用热膨胀法,结合金相和硬度分析,绘制了X100管线钢的CCT曲线。研究了不同冷却速率对相变温度、组织和硬度的影响。结果表明:随冷却速率的不断提高,组织逐渐从多边形铁素体向准多边形铁素体、粒状贝氏体、贝氏体铁素体转变。冷速为0.1℃/s时,组织为多边形铁素体+少量珠光体;冷速达到50℃/s时,组织为贝氏体铁素体。晶粒尺寸和板条亚结构的细化、切变型组织比例的增加,是硬度随冷速提高而增加的主要原因。Based on the heat treatment process of hot bent pipe, the phase transformation behavior of X100 linepipe steel under continuous cooling condition was investigated using Gleeble 3800. CCT curve for X100 linepipe steel was obtained by adopting therm-dilatometer as well as the assistance of metallography and hardness analysis. The influences of cooling rate on the transformation temperature point, microstructure and hardness were studied. The results indicate that the microstructure tends to change gradually from polygonal ferrite to quasi-polygonal ferrite, granular bainite, bainite ferrite in sequence with the cooling rate accelerating. When the cooling rate is 0.1℃ /s, the microstructure mainly consists of polygonal ferrite and little pearlite; as the cooling rate enhancing to 50℃/s, the bainite ferrite becomes the dominated microstructure. Finer grain and lath sub-structure as well as increasing the volume fraction of shear-type transforming microstructure are considered as the main reason that the hardness increases when the cooling rate rises.

关 键 词：热煨弯管 X100 管线钢 CCT 曲线 贝氏体铁素体 

分 类 号：TG113.2[金属学及工艺—物理冶金]