电化学充氢下2.25Cr1Mo0.25V钢氢脆敏感性研究
Research on the Hydrogen Embrittlement Sensitivity of 2.25Cr1Mo0.25V in Electrochemical Hydrogen Charging

针对制造加氢反应器的主要材料2.25Cr1Mo0.25V钢易发生氢脆的问题,重点研究了材料氢脆发生机制,以了解该材料的氢脆敏感性。利用电化学氢渗透测试技术,通过施加阴极恒电流,使氢原子渗透进入钢中,揭示了不同环境中的氢扩散特性,同时通过结合氢渗透技术和慢速率拉伸试验方法研究了钢材的氢脆敏感性。渗氢试验结果表明:随着电化学充氢电流密度的增大以及试样厚度的减小,氢扩散系数均逐渐增大;充氢温度的倒数1/T和氢扩散系数的自然对数之间存在线性关系。慢速率拉伸试验的结果表明:随着充氢电流密度的增大,钢的断裂强度、延伸率和断面收缩减小而氢脆指数增大。当充氢电流密度超过2.5×10－3 A/cm2时,钢材表现出明显的氢脆。该试验结果可为加氢反应器材料性能评价提供理论依据。
The alloy steel 2？？25Cr1Mo0？？25V is mainly used to make hydrogenation reactors, which is easily subject to failure of hydrogen embrittlement. This paper aims to study the mechanism of hydrogen embrittlement and understand the hydrogen embrittlement sensitivity of the material. With the electrochemical hydrogen permeability technique and applying constant cathode current to let the hydrogen permeate into the steel, the characteristics of hydrogen diffusion under different test conditions were revealed. Meanwhile, the hydrogen embrittlement sensitivity was investigated by combining the hydrogen permeability technique with the slow？？rate tensile test. The test results showed that the hydrogen diffusion coefficients were increased with the growth of the electrochemical hydrogen charging current density as well as the reduction of sample thickness. There is a linear relationship between the reciprocal of charging temperature (1/T) and the natural logarithm of hydrogen diffusion coefficient. Results of slow？？rate tensile tests showed that with the growth of the charging current density, the fracture strength, the elongation rate and the area reduction of the steel decreased, while the hydrogen embrittlement indexes increased. When the hydrogen charging current density exceeds 2.5×10－3 A/cm2, the steel showed obvious hydrogen embrittlement. The test results will help the performance evaluation of materials used to make hydrogenation reactors