海工用X100管线钢管的焊接工艺及接头质量分析

Analysis of welding process and joint quality of X100 pipeline steel pipe for marine engineering

采用海洋平台建造中符合AWS D1.1标准的6GR位置特定坡口形式,利用焊条电弧焊(SMAW)单面焊双面成形工艺焊接某国产X100管线钢管。通过拉伸、冲击、弯曲试验检测接头的力学性能,通过光学显微镜对比分析X100管线钢焊接接头坡口两侧熔合线显微组织。结果表明,该公司生产上所用的X100管线钢管在6GR位置通过合适的预热及焊接热输入可以得到满足结构使用性能要求的焊接接头,但接头未开坡口侧在-40℃冲击时,冲击吸收能量相对较低,原因是未开坡口侧(直边)熔合线晶粒粗化严重,大晶粒晶界有相互连接趋势。

Single-side welding by shielded metal arc welding with the inevitable 6GR position and specific groove form(comply with AWS D1.1)in the offshore platform construction was used to weld domestic X100 pipeline steel pipe.The mechanical properties of the welded joints were measured by tensile strength,impact toughenss,bending test and the microstructures of the fusing area on both sides of the X100 pipeline steel welded joint were analyzed by optical microscope.The results shown that the X100 pipeline steel pipe used in the production of the company could be welded and the weld joint could satisfy the structural performance requirement with appropriate preheating and welding heat input control in the 6GR position.But the impact absorbed energy was relatively low on the unbevel side of the welded joint in the-40℃impact test.The reason is that the grain size coarsened severely and the boundary of the large grains have a mutual connection trend in the fusion area of the unbevel side(square side).