X120管线钢焊接试验及分析

采用焊接热模拟方法研究了线能量对X120管线钢HAZ韧性的影响，并通过3种不同成分焊丝与焊剂的匹配试验，确定了X120管线钢的最佳焊材匹配方案。以确定的工艺参数对JCO成型的X120管线钢进行了焊接实践，并对焊后钢管的性能进行了分析。研究表明，当线能量为35kJ·cm-1时，X120管线钢HAZ具有最高的韧性值；目前现有的焊接材料较难实现X120管线钢的过匹配焊接，应重点开发X120管线钢专用焊材；与普通管线钢具有较佳的弯曲变形能力不同，X120钢管在8倍壁厚的弯轴直径下弯曲出现裂纹，这主要是因为X120钢管焊缝CGHAZ晶粒长大明显，组织中M/A数量多，呈长条状分布，导致了X120钢管焊缝CGHAZ的脆化。

Welding Test and Analysis of X120 Pipeline Steel

The influence of linear energy on HAZ toughness was studied by means of welding thermal simulation.The best matching scheme for welding materials was determined through matching tests of 3 kinds of different welding wire and welding flux.Using determinate parameter to carry out welding for X120 pipeline steel formed by JCO process,and analyzed steel pipe properties after welding.The results showed when the linear energy is 35 kJ·cm-1,HAZ has the highest toughness value;But the present welding materials hardly achieve over-matching welding.In future special X120 welding materials should be developed.The common pipeline steel has good bend deformation ability,while the crack occurred in X120 steel pipe under bend axis diameter with 8 times thickness.The reason was that CGHAZ grains in weld obviously growed big and existed large quantity M/A in structure which was distributed in long strip,it led to CGHAZ brittleness of X120 steel pipe.