氢蚀程度对钢疲劳断裂性能的影响

研究了国产钢经不同温度和时间氢暴露后的力学性能、疲劳性能和断裂韧性，用扫描电镜证实了氢蚀后断裂机制发生了变化。研究表明：随氢蚀程度增加，２０Ｇ钢抗拉强度和塑性降低明显，ＣｒＭｏ钢抗拉强度略有降低，塑性变化不大。氢蚀使２０Ｇ钢的门槛值有一个最小值，而断裂韧性随氢蚀程度升高而降低，在氢蚀程度较低时，断裂韧性下降程度大；在氢蚀程度较高时，断裂韧性下降程度变缓。碳钢的疲劳性能变化是由于材料损伤作用和氢蚀造

Effect of Hydrogen Attack on Fatigue and Fracture Behaviour of Steels

The effect of hydrogen attack caused by exposure to hydrogen atmosphere at differenttemperatures and time on mechanical properties,fatigue crack growth behavior and fracture mechanism for Chinese made steels 20G,15CrMo and 2.25Cr-IMO were studied.The microstructure afterhydrogen attack and the propagation path of fatigue crack have been observed by optical and electrical microscopy.The tensile tests showed that tensile strength and ductility decreased considerablywith increasing of hydrogen attack.The COD testing indicated that fracture toughness material.The2.25Cr-IMc steel showed a lower susceptibility to hydrogen attack due to the action of element Crand Mo,not resulting in a significant change in fatigue crack behaviour.It is suggested that theincrease in the threshold K value could be attributed to the crack closure effect caused by the tortuous cracking path.