S380高频焊管焊缝开裂分析

针对S380热轧板焊管开展压扁和扩孔试验时焊缝开裂问题，利用扫描电镜、金相显微镜和显微硬度检测手段对焊接接头进行组织观察和性能检验。试验结果表明，S380焊缝熔合线处出现魏氏组织和焊缝中心尺寸较大的熔融金属是导致焊管压扁试验产生开裂的主要原因，采取了加大焊接棍挤压力、加快焊缝金属冷却速度和使用了微合金化成分体系材料等针对性改进措施后开裂率明显降低。

Weld cracking analysis of S380 highfrequency welded-pip

Aiming at the weld-cracking problem in the process of using Tangsteel S380 to make welding-pipes,which happened in the tests of Flatten and Hole-expansion carried out on these pipes,microstructure-inspecting and property test were taken by the usage of SEM and microhardness tester.The results shown that Widmanstatten microstructures in the fusion-line and molten metal in the center of S380 weld are the main reasons causing the weld-cracking in the tests of Flatten.And then,some improving-measures were proposed for users and the rate of cracking had been greatly reduced.