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利用激光冲击波对X70管线钢焊接接头进行了表面改性处理,通过SSRT分析了激光冲击处理对试样在NACE饱和H2S溶液中应力腐蚀的影响。采用扫描电镜观察了激光冲击处理前后试样表面腐蚀产物形貌、断口形貌和应力腐蚀裂纹形貌等,并用能谱分析仪分析了腐蚀产物化学成分组成,探讨了激光冲击处理对试样SCC的影响机理。结果表明:激光冲击处理后焊接接头抗拉强度、伸长率和断面收缩率分别提高了5.1%、4.5%和28.7%,内积功的SCC敏感性指数Iscc从50.94%下降至45.10%,降低了11.64%,断口形式由脆性断裂转变为韧性断裂。激光冲击处理改善了焊接接头表面应力状态和材料组织结构,减缓了裂纹的萌生和扩展,增强了其抗SCC的性能,但不能消除明显的应力腐蚀倾向;激光冲击处理降低了氢致开裂的倾向,有利于提高焊接接头抗H2S应力腐蚀的性能。
The laser shock wave was used to modify the welded joint of X70 pipeline steel, and the influence of laser shock treatment on the stress corrosion of the sample in NACE saturated H2S solution was analyzed by SSRT. Scanning electron microscopy (SEM) was used to observe the surface morphology, fracture morphology and stress corrosion cracking morphology of the sample before and after laser shock treatment. The chemical composition of the corrosion products was analyzed by energy spectrum analyzer. The effects of laser shock treatment on the surface of sample SCC The mechanism of influence. The results show that the tensile strength, elongation and reduction of area of the welded joint after laser shock treatment are increased by 5.1%, 4.5% and 28.7% respectively. The SCC sensitivity index Iscc decreased from 50.94% to 45.10% 11.64%, the fracture form changes from brittle fracture to ductile fracture. Laser shock treatment improved the surface stress state and material structure of welded joints, slowed the initiation and propagation of cracks, enhanced their resistance to SCC, but did not eliminate the obvious stress corrosion tendency. Laser shock treatment reduced the tendency of hydrogen induced cracking , Is conducive to improving the performance of resistance to H2S stress corrosion of welded joints.