焊接材料对X70直缝埋弧焊管焊缝组织性能的影响

Effect by Welding Material on Microstructure Properties of X70 SAWL Pipe

针对因钢板原料的化学成分发生较大变化,使得原焊材与母材出现焊接不匹配,造成X70钢级管线钢直缝埋弧焊管焊缝的低温冲击韧性不合格的现象,采取两种焊丝进行焊接试验,通过观察和检测焊缝显微组织、力学性能,研究焊接材料对X70钢级直缝埋弧焊管焊缝组织性能的影响。试验结果表明:在采用相同的焊接工艺参数焊接同批次同规格钢管时,选用Mn、Si、Cr、Ti含量较高的焊丝进行焊接,焊管焊缝中先共析铁素体和针状铁素体晶粒更为细小,低温冲击数值较高,韧性较好。

The welding tests with two types of welding wires are conducted addressing the problem that owing to the remarkable change of the chemical composition of the blank steel plate which causes the mismatching between the primary welding material and the base metal,and in turn causes the nonconformance of the weld seam low-temperature impact toughness of the SAWL pipe.Based on observation and testing of the microstructure and mechanical properties of the weld seam,the effect by the welding material on the weld seam microstructure properties of the X70 SAWL pipe is analyzed.The test results show that when using the welding wire containing rather high contents of Mn,Si,Cr and Ti to weld the steel pipes of the same batch and the same size with the same welding process parameters,the pro-eutectoid ferrite and the acicular ferrite grains in the weld seam are much thinner,the low-temperature impact toughness value is higher,and the toughness is better.