碳钢焊接接头腐蚀的有限元模拟

由于焊接接头各区域之间耐蚀性和力学性能的差异，在接头处容易发生局部腐蚀，严重威胁着管线的安全运行，需要对接头腐蚀行为进行预测. 基于电偶腐蚀原理建立了碳钢焊接接头腐蚀的有限元模型，结合COMSOL软件，对三种温度下的接头腐蚀形貌进行了预测. 并利用该模型研究了焊缝余高、焊缝与母材的面积比以及焊缝缺陷对焊缝金属腐蚀速率的影响规律. 结果表明，该有限元模型不但能进行焊接接头腐蚀行为预测，而且可为输油气管道的焊接接头设计提供理论依据.

Finite element simulation of carbon steel welded joint corrosion

Due to welded joint corrosion resistance and mechanical properties difference among various regions, the local corrosion is likely to appear in the welded joint. It seriously threatens the safety of pipeline operation, and it is need to predict the corrosion behaviour of welded joint. The finite element model of carbon steel welded joint is established based on the galvanic corrosion principle, combing the COMSOL software, the welded joint corrosion morphology under three kinds of temperature is predicted. Then the effect of weld reinforcement, the area ratio of weld metal and base metal, and weld metal defects on the weld metal corrosion rate were investigated with the model. The result showed that the finite element model not only can predict the corrosion behaviour of welded joint, and can provide the theory basis for the welded joint design of oil and gas pipeline.