对铅合金铸件声学特征参数测试发现，铅合金的纵波声速较低，衰减系数较大，为超声的强衰减材料。对不同孔径的平底孔试样检测结果表明，目前采用超声水浸和直接接触法，均可较好地检出10 mm厚板材内的 1 mm人工缺陷。因此采用超声方法检测中等厚度的铅合金铸件是可行的，重点是选取恰当的检测方法，以实现最佳的检测灵敏度。

The acoustic parameters of Pb alloy cast were tested. The results showed that the longitudinal wave velocity in the cast was relatively low and its attenuation coefficient was high, so it belonged to strong attenuation material for ultrasonic testing. The testing results of the flat-bottomed hole equivalent blocks with different diameter were analyzed, and it showed that  1 mm defect in the plate with 10 mm thickness could be detected by immersion testing or direct contact method. Thus ultrasonic testing could be used to test Pb alloy cast of moderate thickness. However, the selection of appropriate testing method to achieve best sensitivity was a key problem.