Ultrasonic Inspection of Surface Defects on Cold Rolled Steel Strip

Abstract

Utilizing of ultrasonic method was studied for inspecting of surface defects on cold rolled steel strip.When the ultrasonic wave is projected in the water against surface of steel strip keeping proper projecting angle, the total reflection occures on the surface.But there occurs irregular reflection on parts where there are any defects or flaws and detecting of such defects is possible through receiving the reflection.Specimens with artificial flaws were used for the test concerning the correlation between the shape of probe, projecting condition and flaws. Furthermore, the test was also made for defecting of some natural flaws.All fine defects visually inspected could be detected and it was confirmed that the method was capable enough of practical use.