利用热模拟技术对X100管线钢热影响区粗晶区的组织和冲击韧性的研究

Study on Microstructure and Properties of CGHAZ of X100 Pipeline Steel Using Thermal Simulation Technique

摘要: 采用热模拟技术研究了X100管线钢粗晶热影响区(CGHAZ)在不同冷却时间下的组织和冲击韧性。结果表明：当t8/5冷却时间在5～21 s范围内，粗晶区晶粒尺寸较小，晶粒内部的贝氏体铁素体板条使粗晶区具有较高的冲击韧性。当t8/5冷却时间在32～130 s范围内，晶粒尺寸显著增大，晶粒内部出现了准多边形铁素体和大尺寸的M-A岛等非典型组织，使粗晶区的冲击韧性明显下降。

Abstract: The microstructure and impact toughness of coarse-grained heat affected zone（CGHAZ） in X100 pipeline steel were studied by thermal simulation technique.The results indicate that when the cooling time t8/5is 5-21 s, the CGHAZ has small grain size, and bainitic ferrite lathes in the grains ensure that the CGHAZ has good impact toughness. When the cooling time t8/5is 32-130 s, the grain size increases and quasi-polygonal ferrite and large size M-A islands appear in the grains, therefore the impact toughness of CGHAZ decreases sharply.