Inner defect detection for a thin steel strip

Two detection methods, magnetic and ultrasonic method, were compared to detect a defect that is located in and on the steel strip. The main composition of that defect is non-metallic oxides. We can select a proper method of detection according to the purpose of detector installation, the strip thickness, and the line speed. Magnetic flux leakage method is one of the promising methods for a very thin steel strip. On the other hand, the guided ultrasonic wave is very useful on for the thin steel strip such as the strip in pickling line.