摘要
油气管道往往服役于恶劣环境,其焊接接头面临着严重的腐蚀问题,存在较大安全隐患。激光-电弧复合焊焊接效率高、变形小,已成为管道施工焊接领域具有良好应用前景的焊接方法。针对不同激光功率下X80管线钢激光-MIG复合焊焊缝的耐腐蚀性进行研究。分析焊接接头各区域显微组织分布,研究母材和不同激光功率下激光-MIG复合焊焊缝的极化曲线、交流阻抗谱和SEM表面腐蚀形貌,得到了激光功率对激光-MIG复合焊焊缝电化学腐蚀行为的影响规律。结果表明,激光-MIG复合焊焊缝的显微组织由针状铁素体、粒状贝氏体和先共析铁素体构成;随着激光功率的增加,粒状贝氏体数量减少,针状铁素体和先共析铁素体含量增加。母材和激光-MIG复合焊焊缝的极化曲线均无显著的钝化区,母材的腐蚀电流密度大于激光-MIG复合焊焊缝,电荷转移电阻小于激光-MIG复合焊焊缝。随着激光功率的增加,激光-MIG复合焊焊缝的耐腐蚀性先上升再下降,激光功率为3.0 k W时焊缝的耐腐蚀性最好。
Oil and gas pipelines are often used in harsh environments, and their welded joints are facing serious corrosion problems and great potential safety hazards. Laser-arc hybrid welding has become a promising welding method in the field of pipeline construction welding due to its high welding efficiency and small deformation. Hence, corrosion resistance of hybrid laser-MIG welded metal of X80 pipeline steel under different laser powers was investigated. Microstructure distribution in different zones in the welded joints was analyzed. Polarization curves, electrochemical impedance spectroscopy and SEM corrosion morphology of base metal and weld metal with different laser powers were also investigated. Influence of laser power on electrochemical corrosion properties was obtained. The results show that microstructures in hybrid laser-MIG welded metal are mainly composed of acicular ferrite, granular bainite and proeutectoid ferrite. Less granular bainite and more acicular ferrite/proeutectoid ferrite formed in the hybrid laser-MIG welded metal with increasing laser power. The polarization curves of both base metal and hybrid laser-MIG welded metal show no obvious passivation region. The base metal exhibits a higher corrosion current density and a lower charge transfer resistance compared with that of the hybrid laser-MIG welded metal. With increasing laser power, the corrosion resistance increases first and then decreases. The hybrid laser-MIG welded metal with a laser power of 3.0 kW shows the best corrosion resistance.
作者
姜心怡
严春妍
周倩雯
李琛
张可召
包晔峰
JIANG Xinyi;YAN Chunyan;ZHOU Qianwen;LI Chen;ZHANG Kezhao;BAO Yefeng(College of Mechanical and Electrical Engineering,Hohai University,Changzhou 213022,China)
出处
《电焊机》
2022年第4期51-57,共7页
Electric Welding Machine
基金
国家自然科学基金资助项目(51804097)
中央高校基本业务费基金(B200203154)。
关键词
激光电弧复合焊
X80管线钢
激光功率
显微组织
耐腐蚀性
hybrid laser arc welding
X80 pipeline steel
laser power
microstructure
corrosion resistance
