焊接热输入对X90管线钢CGHAZ组织和冲击性能的影响

Influence of Welding Heat Input on CGHAZ Structure and Impact Property of X90 Pipeline Steel

采用焊接热模拟技术、显微组织分析和冲击试验的方法,研究焊接线能量对X90管线钢粗晶热影响区组织和力学性能的影响规律。结果表明,不同线能量下试验钢的组织均为板条贝氏体(LBF)和粒状贝氏体(GBF),线能量为25 kJ/cm时,试验钢的组织主要为LBF,冲击功较高;随着焊接线能量的增加,GBF增加,晶粒粗化,韧性显著下降。

The influential regularity of welding heat input on the microstructure and mechanical propertiesof coarse grain heat affected zone （CGHAZ） in X90 pipeline steel was studied by means of welding thermalsimulation technology, microstructure analysis and impact test. The results showed that the microstructure oftested steel with different heat input consisted of lath bainite and granular bainite. When the heat input was25kJ/cm, the microstructure was mainly lath bainite with high absorbed-in-fracture energy; with the increaseof heat input, there was a tendency of granular bainite increase with grain coarsened and toughness obviouslyreduced.