超声表面波能有效检测出轧辊的表面裂纹，但由于其裂纹很浅且目前的超声波仪器无法对裂纹深度进行直接读数，因此轧辊表面裂纹深度的判定一直是困扰检测工作者的难题。通过计算得出了表面波检测中裂纹深度当量d与回波分贝差Δ的关系曲线，并将其应用于马钢各种型号的在役轧辊检测中，取得了良好效果。同时比对d-Δ关系曲线并通过实践证明得出，GB/T 23904—2009标准中的检测灵敏度调整方法不造用于磨削量最小为0.2 mm的在役工作辊的表面波检测。该d-Δ关系曲线使轧辊表面裂纹深度的判定更加简单准确，对在役工作辊的表面波检测具有一定的指导意义。

Ultrasonic surface wave can detect the surface crack of roll effectively，but the problem of how to determine the depth of the roll surface crack has been a major problem faced by test workers because surface crack is usually very shallow, meanwhile the current ultrasonic instrument can not precisely determine surface crack. This paper obtained the relation curves between the depth of crack equivalent d and echo db difference Δ in surface wave detection by calculation, which was applied to various types of Ma Steel roll in service testing, and achieved good results. Meanwhile through contrasting the d-Δ relation curves and practicing test, it proved that the detection sensitivity adjustment method in GB/T 23904—2009 standard should not be used for the surface wave detection in service work roll with minimum grinding of 0.2 mm each time. The d-Δ relation curve made the judgment of the roll surface crack depth more simple and accurate, and also it had some guiding significance for the surface wave detection of the work roll in service.