环境载荷下42CrMo合金钢蠕变特性研究

Study on creep characteristics of 42CrMo alloy steel under environmental load

开展了不同温度、应力状态及水平等环境载荷条件下俯仰轴用42CrMo合金钢的蠕变实验和力学性能测试。结果表明:42CrMo合金钢在环境载荷下发生了典型的双阶段蠕变(初始蠕变阶段和稳态蠕变阶段),随应力水平和温度的增加,总蠕变量和稳态蠕变速率均增大。然而,拉压应力状态对其蠕变行为影响不显著。通过计算得到环境温度40~60℃范围内42CrMo合金钢的蠕变应力指数n≈5,表明蠕变机制以位错滑移机制为主,且其表观激活能随应力增加而降低。此外,在环境载荷条件下,合金钢蠕变前后的抗拉强度和屈服强度变化不显著,而随温度和应力水平的增加,合金钢蠕变后的伸长率有降低的趋势。

The creep experiments and mechanical performance tests of 42 CrMo alloy steel for pitch axis under different environmental load conditions such as temperature,stress state and stress level were carried out.The results show that a typical two-stage creep(initial creep stage and steady-state creep stage)occurs in 42 CrMo alloy steel under environmental load.As the stress level and temperature increase,the total creep variable and steady-state creep rate increase.However,the tension and compression stress state has no significant effect on the creep behavior.Through calculation,the creep stress index n of 42 CrMo alloy steel is approximately equal to 5 in the ambient temperature range of 40-60℃,which indicates that the creep mechanism is dominated by the dislocation slip mechanism,and its apparent activation energy decreases with the increase of stress.In addition,the change of tensile strength and yield strength of alloy steel before and after creep under environmental load conditions is not significant,but with the increase of temperature and stress level,the elongation of alloy steel after creep tends to decrease.