由于铸铁材料的特殊性，普通测厚仪无法准确测量铸铁烘缸的厚度。利用带A扫信号的超声波检测仪在铸铁阶梯试块上进行试验，得出在一定压力和温度范围内，铸铁的声速、硬度和金相基本保持不变的结果，因此可以利用烘缸凸缘部位进行声速校准。通过对不同超声波探头的对比试验，得出不同频率、不同晶片尺寸探头的优缺点，有助于提高铸铁烘缸超声测厚的精确度。

Ordinary thickness tester cannot accurately measure the thickness of cast iron because of the particularity of cast iron materials. From the experiment on cast iron step block used by ultrasonic detector with a A-scanning signal. It is known that the sound velocity, hardness and metallographic structure of cast iron remain unchanged in a certain range of pressure and temperature. Accordingly, we can calibrate the speed of ultrasonic wave in cast irons by flange parts, and understand the advantages and disadvantages of the probes with different frequencies and crystal sizes through comparison experiments of different ultrasonic probes, which is helpful to improve the accuracy of measuring thickness of cast iron dryer.