焊接接头氢扩散数值模拟(I)

Numerical Simulation of Hydrogen Diffusion in Welded Joint

采用ABAQUS有限元分析软件对氢在不均质焊接接头的扩散进行了模拟计算 ,结果表明 ,对 2 0MnNiMo钢焊接接头 ,随时间延续 ,焊缝金属中的氢浓度逐渐降低 ,而熔合区以外区域氢的浓度经历了一个峰值变化过程。由于焊接接头不同部位氢的扩散系数和溶解度不同 ,一定时间以后热影响区中的氢浓度超过焊缝金属和母材 ;预热使焊缝金属中的氢浓度快速降低 ,并缩短热影响区出现峰值浓度的时间 ;后热可加速氢从焊接接头的逸出 ,降低热影响区氢浓度峰值并缩短其出现时间。

In this study,finite element analyses were performed to simulate hydrogen diffusion behavior in heterogeneous welded joints.The results indicated that:(1)for 20MnNiMo welded joint,the hydrogen concentration within weld metal decreases in a monotonic manner as time elapses,in contrast,hydrogen concentration outside the fusion zone goes through a local maximum.Because of different diffusivity and solubility in different region of welded joint,the hydrogen concentration within heat affected zone(HAZ)will exceed that within weld metal and base metal some time later;(2)preheating decreases hydrogen concentration within weld metal rapidly and shortens the time to reach a peak hydrogen concentration within HAZ;(3)postheating may accelerate hydrogen removal from welded joint and reduse the peak hydrogen concentration within HAZ and shorter time of reaching the pear value.