MAGNETIC FLAW DETECTING SENSOR EXCELLENT IN PERFORMANCE OF DETECTION OF MINUTE FLAW

PROBLEM TO BE SOLVED: To provide a magnetic flaw detecting sensor which can detect a minute flaw without letting it pass through a gap between magnetism-sensitive elements conducting differential detection. SOLUTION: On the base of a detecting element holder to be brought into contact with the surface of a steel material, paired magnetism-sensitive element arrays (a1 , b1 )-(an , bn ) and paired magnetism-sensitive element arrays (x1 , y1 )-(xn , yn ) which conduct differential detection are arranged in parallel and in zigzag with prescribed spaces smaller than the longitudinal dimension of magnetism- sensitive elements provided, on the opposite sides of the center in the width direction of the detecting element holder. Thereby a pit flaw and a minute flaw of a small length are detected with excellent reproducibility and high efficiency.