堆焊结构的氢浓度分布及其对剥离断裂的影响

EFFECTS OF DISTRIBUTION OF HYDROGEN CONCENTRATION ON DISBONDING FOR STAINLESS STEEL WELD OVERLAY

采用有限元分析方法计算堆焊结构中氢浓度的分布，并将电解充氢试验条件下试块中氢扩散行为的计算结果和高压釜试验条件的计算结果进行对比分析．计算结果表明，采用电解充氢方法，可以在熔合线附近获得与高压釜充氢数值相近的氢浓度峰值，而到达这一峰值的时间较短．通过解析模型比较了不同试样条件和电解充氢条件对试验结果的影响．结果显示，增大充氢电流密度，延长充氢时间，减薄母材厚度，均使氢浓度峰值升高，从而使堆焊层剥离倾向增大．

The finite element method was adopted to compute the distribution of hydrogen concentration inweld overlay structures. Comparison between the computed results for the hydrogen diffusion behaviour under electrolytic hydrogen charging and those under gaseous hydrogen charging in autoclave was carriedout. The results showed that in both cases the peak hydrogen concentrations near the fusion line aresimilar and can be reached in a shorter time under electrolytic hydrogen charging.The factors affecting hydrogen-induced disbonding were studied through a serieS of theoretical computation, and the influence of different specimen conditions and different test conditions were analyzed.The results showed that the increase of current density, the prolongation of charging time and/or thethinning of the base metal will inerease the peak hydrogen concentration and enhance the tendency ofdisbonding.