1Cr低合金管线钢焊接接头组织和性能研究

Research on Microstructure and Mechanical Properties of 1Cr Low Alloy Pipeline Steel Weld Joint

采用TIG焊对1Cr低合金管线钢进行了焊接,研究了焊接接头的显微组织、力学性能和耐蚀性,探讨了1Cr低合金钢的焊接性能。结果表明,以铁素体组织为主要特征的母材和热影响区具有较好的冲击韧性,冲击吸收功较高;以粒状贝氏体组织为主的焊缝区,韧性较母材和热影响区稍差。焊接接头的最高硬度为250HV,出现在熔合线附近,整体硬度适中。在管线钢中加入1%Cr未明显降低接头热影响区韧性或提高硬度,表明1Cr低合金管线钢具有较好的焊接性。

1Cr low alloy pipeline steel was welded by tungsten inert gas welding （TIG） technology. Then the microstructure, mechanical properties and corrosion resistance of the weld joint were studied, and weldability of 1Cr low alloy steel was discussed. The results showed that base metal and heat-affected zone（ HAZ） was with good toughness and higher impact absorbed energy,and fen＇ite was its main structure; the toughness of weld metal was lower than that of base metal and HAZ,and its main structure was gramdar bainite. The highest hardness value of the weld joint was 250HV,which locates in the fusion line; the overall hardness was moderate. Adding 1% Cr to the low alloy steel didn＇t increase the hardness or reduce the toughness of the HAZ,so the weldability of the pipeline steel was excellent.