直缝埋弧焊管焊缝内部横向裂纹产生原因分析

为了解决直缝埋弧焊管焊缝内部产生横向裂纹的问题，通过对焊缝拉伸性能的检测、焊缝化学成分以及焊缝形貌的分析，找出了引起焊缝内部横向裂纹的主要原因是焊缝中Nb含量偏高、焊缝延伸率低、屈强比大和焊缝宽深比小。提出了改进措施:当焊缝中Nb的含量偏高时，可通过减少母材熔合比进行调整；当焊缝金属延伸率偏低、屈强比偏高时，可换用合金含量较少的焊丝进行调整；适当调整焊接参数，加大焊缝宽深比。

Causes Analysis of Transverse Crack inside Weld in Longitudinal Submerged Arc Welded Pipe

In order to solve the problem of transverse crack inside weld in longitudinal submerged arc welded pipe, the main causes of transverse crack inside weld are found out by testing tensile properties of weld, analyzing chemical composition and weld morphology. It is found that high Nb content, low elongation rate, high yield strength ratio and small width depth ratio of weld are the main causes of transverse crack. Improvement measures are proposed. When Nb content in the weld is too high, it can be adjusted by reducing the base metal fusion ratio. When the elongation of weld metal is low and the yield strength ratio is high, the welding wire with less alloy content can be used for adjustment. Adjust welding parameters properly and increase the width to depth ratio of welding seam.