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目前绝大多数蠕变超声检测研究都是使用常温且无应力的蠕变试样进行检测实验,在该条件下测得的超声检测参数值与实时(维持蠕变温度和蠕变应力)测得的蠕变参数值有一定的差异,影响对检测对象蠕变程度的准确判断。该文使用纯铅进行连续蠕变实验,并在实验过程中进行实时超声检测,获得了蠕变过程和松弛过程中的超声实时检测信号,对此信号进行处理,得到了衰减、声速、时间衰减等参数随蠕变程度的实时变化曲线。实验结果表明:实时条件下测得的蠕变超声检测参数相对于无应力条件下测得的参数具有更高的检测灵敏度;如果以无应力检测参数值作为评定标准,则需对实时检测参数值作出修正才能准确评价被检测目标的蠕变程度;时间衰减参数与衰减参数具有相同的蠕变变化趋势,但时间衰减参数不需要对被检测目标进行几何尺寸的测量,因此时间衰减参数更适用于实际检测,可以作为金属蠕变检测中衰减参数的替代参数。
At present, most of the studies on creep ultrasonic testing are performed using normal temperature and stress-free creep test specimens. The measured values of ultrasonic testing and real-time (maintaining creep temperature and creep stress) measured under these conditions Creep parameter values have certain differences, affecting the accuracy of the detection object creep judgment. In this paper, pure lead was used to conduct continuous creep experiments. During the experiment, real-time ultrasonic testing was carried out to obtain the real-time ultrasonic signals during creep process and relaxation process. The signal was processed and attenuation, velocity of sound and time attenuation Real-time curves of other parameters with the degree of creep. The experimental results show that the parameters of creep ultrasonic testing measured under real-time conditions have higher detection sensitivity than those measured under no-stress conditions. If no-stress detection parameter is used as evaluation standard, The time attenuation parameter and the attenuation parameter have the same trend of creep, but the time attenuation parameter does not need to measure the geometric size of the target to be detected, so the time attenuation parameter is more suitable for The actual test can be used as a substitute for the attenuation parameter in metal creep test.