Quantitative evaluation study on metal magnetic memory of welding cracks

Aimed at the question of metal magnetic memory (MMM), one of new development nondestructive testing method, which can not evaluate the welding cracks quantitative at present. This paper analyzed the derivative MMM signal of pre-welding cracks, extracted the location feature of welding cracks and founded the quantitative relation between derivative MMM signal and parameters of welding cracks. Spot inspection indicates that the welding cracks can be evaluated quantitative by the feature of derivative MMM signal.