WET MAGNETIC PARTICLE EXAMINATION METHOD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To enable the upper and lower surfaces of steel to be subjected simultaneously to wet magnetic particle examination by surely excluding an extra magnetic particle solution throughout the periphery of the steel. SOLUTION: A wet magnetic particle examination method comprises arranging air ejection nozzles 25 around steel A, setting the circumferential intervals among positions where jets from the nozzle holes collide against the surface of the steel to be smaller than the diameter of a liquid exclusion area 47 formed by the jets ejected from the nozzle holes, and forming the liquid exclusion area 47 which is continuous throughout the periphery of the surface of the steel A, to exclude an extra magnetic particle solution throughout the periphery. Then magnetic particles retained in a defective part are detected.