回火温度对DP600钢氢扩散及氢脆敏感性的影响

Effect of tempering temperature on hydrogen diffusion and hydrogen embrittlement susceptibility of DP600 steel

利用慢应变速率拉伸和双电解池氢渗透试验,结合SEM、TEM、EBSD表征手段研究了不同回火温度下DP600钢中显微组织变化对其氢扩散及氢脆敏感性的影响。结果表明,DP600钢的氢脆敏感性和有效氢扩散系数均随回火温度的升高呈下降趋势,这主要与钢中位错、小角度晶界等可逆氢陷阱浓度降低以及碳化物/基体界面、大角度晶界等不可逆氢陷阱浓度增加有关。其中弥散分布的碳化物使碳化物/基体界面捕获的氢原子分布均匀,导致试验钢的氢脆敏感指数由44.6%(270℃)下降至1.8%(350℃)。综合考虑回火温度对试验钢强度和氢脆敏感性的影响,DP600钢的最佳回火温度为330℃。

Effect of tempering temperature on the hydrogen embrittlement susceptibility and hydrogen diffusion behavior of DP600 steel was explored by slow strain-rate tensile test and double cell hydrogen permeation test,and combined with SEM,TEM and EBSD techniques.The results show that the hydrogen embrittlement susceptibility and the effective hydrogen diffusion coefficient of the DP600 steel decrease with the increase of tempering temperature,which is mainly related to the decrease of concentrations of reversible hydrogen traps such as dislocation and small angle grain boundary,and the increase of concentrations of irreversible hydrogen traps such as carbide/matrix interface and large angle grain boundary.Among them,the dispersed carbides make the captured hydrogen atoms distribute evenly,which results in the decrease of hydrogen embrittlement susceptibility index from 44.6%(270℃)to 1.8%(350℃).Considering the influence of tempering temperature on the strength and hydrogen embrittlement susceptibility,the optimum tempering temperature of the DP600 steel is 330℃.