【摘要】 本文定性研究了不同强度级别5Ni-16Cr-Mo钢的缺口拉伸强度与氢含量之间的关系。利用慢应变速率拉伸试验,对缺口半径为0.15 mm的圆棒状试样进行了充氢后缺口拉伸强度的测定。同时,利用升温脱氢分析试验,研究了不同强度级别试验钢的氢扩散行为。慢应变速率拉伸试验结果表明,相比T520钢,T460钢具有较高的氢脆敏感性。试验钢的氢逸出激活能和微观组织表明,位错和板条马氏体间隙为5Ni-16Cr-Mo钢的氢陷阱。此外,利用慢应变速率拉伸试验测定了试样的氢致内应力,结果表明,空气中充氢试样在加载条件下其弹性极限大于未加载时未充氢试样的流变应力。试验钢中氢致内应力与氢含量呈线性关系,可表示为σ*=-0.622+2.015C₀。利用有限元分析模拟了试验钢缺口根部的应力分布,其最大主应力随着缺口半径的减小而增大。更多还原

【Abstract】 The qualitative relationship between hydrogen concentration and notch tensile strength has been investigated for 5 Ni-16 Cr-Mo steel with different strength. The notch tensile strength was determined by means of slow strain rate test（SSRT） on circumferentially notched round bar specimens with the notch root radius of 0.15 mm after hydrogen charging. Meanwhile, the hydrogen diffusion behaviors of various strength steel were studied by thermal desorption spectroscopy（TDS） analysis. The SSRT results show that the T460 steel has higher susceptibility of hydrogen embrittlement in contrast with T520 steel. The activation energies and microstructure indicate that the dislocations and interfaces of martensitic laths are hydrogen traps in 5 Ni-16 Cr-Mo steel. By SSRT, the elastic limit of charged specimen loaded in air is higher than the flow stress without hydrogen charging before unloading, while the difference is defined as hydrogen-induced stress. The value of hydrogen-induced stress σ* increases linearly with hydrogen concentration: σ*=-0.622+2.015 C₀. The finite element analysis results of stress distributions near the notch tip have shown that the maximum principal stress increases with the notch root radius decreasing.更多还原