针孔是铸造铝合金材料中最为常见的缺陷之一, 目前工业生产中通常采用随机抽样金相目视比较法检测铸铝中的针孔, 并评定缺陷等级。该方法具有费时费力、受人为主观因素影响较大等诸多不足之处。采用超声无损检测的方法, 通过采集不同针孔等级试样中的超声信号, 计算出纵波速度、横波速度及衰减系数等参量, 总结这些参量与针孔缺陷的联系及变化规律, 实现对针孔等级的评价。试验结果证明, 利用超声无损方法检测并评价铸造铝合金的针孔缺陷是可行的, 并且具有快速客观准确等优点。

Pinhole is one of the most common defects of cast aluminum alloys. The method of metallographic visual comparison of random sampling is used to evaluate the level of pinhole in modern industry. But it is time/labor consuming and affected by human factors. In this paper, the ultrasonic nondestructive testing method by collecting signals from the samples with different pinhole levels, calculating the ultrasonic longitudinal/transversal wave velocity and attenuation coefficient, summarizing the relation and variation between these parameters and pinhole defects, is used to evaluate the level of pinhole. Experiment results show that it is feasible that inspecting and evaluating the pinhole defect of cast aluminum alloys by ultrasonic nondestructive testing method. And this method is rapid, objective and accurate.