根据超声波反射的特点，设计曲率与被检工件曲率相同的专用试块，以保证探头与工件良好耦合，并在试块上加工入射点和折射角度标识，无需计算和专用测量工具，利用超声波声束在试块圆弧面和大平底面处的反射，就可实现准确、便捷地测量弧面斜探头的入射点和折射角。

Based on the characteristics of the reflected ultrasonic wave and through designing the block with the same curvature as the tested object, this paper aims to show the way how to ensure good coupling for the inspection. By fabricating an identifying mark for the incidence point and the refraction angle on the block, accurate and convenient measurement of incidence point and the angle of refraction can be realized by simply using the reflection of sound beam at the circular arc and large flat bottom without the need of calculation and the help of special calculation tools.