金属蠕变的实时超声检测实验研究

发布时间：2019-06-26 20:39

【摘要】：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。
[Abstract]:At present, most of the creep ultrasonic testing studies are carried out using normal temperature and stress-free creep specimens. The ultrasonic testing parameters measured under this condition are different from those measured in real time (maintaining creep temperature and creep stress), which affects the accurate judgment of the creep degree of the tested object. In this paper, pure lead is used to carry out continuous creep experiment, and real-time ultrasonic detection is carried out in the experimental process. The ultrasonic real-time detection signals in creep process and relaxation process are obtained. The signals are processed, and the real-time variation curves of attenuation, sound velocity, time attenuation and other parameters with creep degree are obtained. The experimental results show that the creep ultrasonic detection parameters measured under real-time conditions have higher detection sensitivity than those measured without stress, and if the stress-free detection parameters are used as the evaluation standard, the real-time detection parameters need to be modified in order to accurately evaluate the creep degree of the tested targets. The time attenuation parameter and the attenuation parameter have the same creep change trend, but the time attenuation parameter does not need to measure the geometric size of the tested target, so the time attenuation parameter is more suitable for practical detection and can be used as an alternative parameter of attenuation parameter in metal creep detection.
【作者单位】：清华大学机械工程系先进成形制造教育部重点实验室;
【分类号】：TG115.285

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