X80级别管线钢热影响区组织与性能研究

Research on Microstructure and Mechanical Properties in Heat Affected Zone of X80 Grade Pipeline Steel

对X80级别管线钢进行不同热输入量焊接试验,利用冲击试验、硬度试验检测低温韧性和硬度的变化规律,通过光学显微镜(OM)、扫描电子显微镜(SEM)对X80级别管线钢焊接接头的组织进行研究。结果表明:X80级别管线钢焊接热影响区组织由粒状贝氏体、多边形铁素体和块状M-A岛组成;当焊接热输入量>45 kJ/cm时,-30℃热影响区粗晶区的冲击功达到100 J以上,焊接热影响区没有出现软化现象,焊接性能优良。

Welding test with different heat input is performed on X80 grade steel plate.Impact and hardness tests are carried out to determine the variation rule of low temperature toughness and hardness.Microstructure at weld joint is studied by means of OM and SEM analysis.The results show that the microstructure at heat affected zone of X80 grade pipeline steel is composed of granular bainite,polygonal ferrite and massive M/A island.When the welding heat input is over 45 kJ/cm,the impact energy of the coarse crystal zone in the heat affected zone is more than 100 J at-30 ℃,and no softening phenomenon occurs in the heat affected zone,showing excellent welding performance.