高温高压条件下早期氢腐蚀的超声波检测

摘要

In order to evaluate the degree of hydrogen corrosion on the pressure equipment at high temperature and high hydrogen pressure, the possibility of diagnosing hydrogen corrosion at early stage by ultrasonic method has been studied.Specimens made of 20 steel and Q345R steel were exposed to hydrogen gas at 450 C with a hydrogen partial pressure 18 MPa for 18 hours,and then its corrosion situations were measured by the velocity ratio, thickness measurement and TOFD methods.The results suggested that it was not easy to detect the hydrogen corrosion by the velocity ratio in this situation if the specimens were corroded lightly, but thickness measurement and TOFD could effectively diagnose the hydrogen corrosion at early stage.%为了对高温高压临氢承压设备的氢腐蚀程度进行评价,探讨了超声波法诊断早期氢腐蚀的可行性.试验将Q345R和20号钢的试块置于450 ℃、18 MPa氢分压的环境中腐蚀18 h,采用波速比法、测厚法、TOFD等超声检测方法进行检测.结果表明,氢蚀后Q345R和20号钢在宏观和微观上均发生了轻微变化,腐蚀程度轻,该条件下的试块仍处于氢腐蚀的孕育期.波速比法难以对该腐蚀条件下的试块进行检测,而测厚法和TOFD法可以对早期氢腐蚀进行有效诊断.