湿H2S环境下低合金钢焊接接头氢扩散数值模拟
Numerical simulation of hydrogen diffusion in low alloy steel welded joint under wet H2S environment
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摘要: 利用电化学渗透法测定了氢在16MnR低合金钢焊接接头处的焊缝金属、热影响区金属以及母材中的扩散系数。利用有限元软件ABAQUS,对16MnR钢焊接接头氢扩散进行数值模拟,考虑焊接残余应力、不同组织对氢扩散的影响,得到焊接接头扩散氢的浓度随时间的分布。结果表明,在焊缝和热影响区,氢的扩散系数和焊接残余应力较大,使氢在焊缝和热影响区聚集,降低材料的力学性能,使得焊接接头部位成为最薄弱环节,在湿H2S环境下很容易发生与氢有关的损伤和破坏。Abstract: Hydrogen diffusion coefficients in weld metal, heat affected zone (HAZ) and base metal of the 16MnR low alloy steel welded joint were measured by electrochemical permeation technique.Based on finite element code-ABAQUS, the hydrogen diffusion in welded joint was numerically simulated.The effects of welding residual stress and microstructure on the hydrogen diffusion were taken into account.The variation of hydrogen concentration with time was obtained.The results show that the hydrogen diffusion coefficients and welding residual stress were much larger in weld metal and HAZ where the hydrogen accumulates, which can decrease the material properties and cause the cracking and damage related to hydrogen under wet H2S environment.
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