Experimental and theoretical analysis of metal magnetic memory signals in the stress concentration area of 45# steel under tensile testing

Abstract

Tension tests were conducted on 45# steel to investigate metal magnetic memory in stress concentration areas. The normal and tangential components of metal magnetic memory signals at seven test points in each specimen were simultaneously measured with probe lift-off values of 1 mm, 3 mm, and 5 mm. Axial tensile load was applied until visible necking occurred, and magnetic flux density was compared with the fracture location predicted according to Doubov's theory. Experimental results showed that the final fracture locations were inconsistent with the locations predicted by metal magnetic memory testing theory. A theoretical analysis of the determination criterion in Doubov's theory also revealed that no perfect correlation between the two areas existed.