The CS-4 test block is designed according to NB47013 standard for ultrasonic testing of carbon steel and low alloy steel forgings used in pressure equipment. It is suitable for measuring the sound energy loss caused by different curvature when the curvature radius of the workpiece detection surface is less than or equal to 250mm.

Test method: This type of test block is suitable for measuring the sound energy loss caused by the curvature of the workpiece detection surface when the radius of curvature is less than or equal to 250mm. The probe is placed on the test block surface and the 85mm thickness direction detection surface, and the dB difference between the two measurements is the sound energy loss.