残余奥氏体对40CrNiMoA钢应力腐蚀和腐蚀疲劳裂缝扩展速率的影响

The Influence of Retained Austenite on Crack Growth Rates of Stress Corrosion and Corrosion Fatigue of 40CrNiMoA Steel

影响高强度钢在水介质中的应力腐蚀和腐蚀疲劳裂缝萌生和扩展特性的因素甚多。本文研究了残余奥氏体含量对40CrNiMoA 钢在蒸馏水中的应力腐蚀和腐蚀疲劳裂缝扩展速率的影响,采用1200℃奥氏体化和870℃奥氏体化以及冰冷处理以获得不同的残余奥氏体含量。实验结果表明在同样的载荷、环境、材质和奥氏体化温度条件下,残余奥氏体是影响40CrNiMoA 钢的应力腐蚀和腐蚀疲劳裂缝扩展速率的重要因素,残余奥氏体的存在将使裂纹扩展减慢。

There are some factors which influence the characteristics of initiation and propagation of stress corrosion cracking and corrosion fatigue cracking in high-strength steel in a watery environment.The influence of the amount of retained austenite on the crack growth rates of both stress corrosion and corrosion fatigue of 40CrNiMoA steel in distilled water was investigated.Various amounts of retained austenite were obtained by austenization at 1200℃ and 870℃ and by using sub-zero treatment.The experimental results showed that the retained austenite played an important part in influencing the crack growth rates of stress corrosion and corrosion fatigue under similar conditions of load,environment,metallurgical quality of material and austenitizing temperature.The existence of retained austenite resists the crack propagation of stress corrosion and corrosion fatigue.