Development of Automatic Fluorescent Magnetic Particle Testing of Square Steel Billets by Image Processing Technology

The fluorescent magnetic particle testing is used mostly to detect the surface defects of square billets. The conventional method relies on naked eyes and so it lacks consistency and efficiency. This paper refers the development of an automatic system for this testing by the CCD camera and the image processing technology. Several experimental testing by the system proposed in this paper shows the following results: (1) seam defects deeper than 0.3mm were mostly detected and over-detection rate is nearly equal to 0%, (2) high detection speed as 40m/min is realized. These results assure that the proposed automatic testing system is an effective one to detect the surface defects of square billets and can be employed for practical use.