A New Micro-Magnetic Method for Monitoring and Analyzing the Tensile Stress Damage State of Brass

Brass (e.g., H80 brass) is widely used in different industrial sectors. To ensure its quality and reliability, the stress damage state of brass has to be monitored and analyzed in practice. This article introduces a new micro-magnetic method for monitoring and analyzing the tensile stress damage state of brass. Specifically, the stress-magnetic flux density model of H80 brass in the micro-magnetic environment was developed based on the stress-magnetic coupling effect. The magnetic flux density value was then used as an indicator of the different stages of tensile damage, and a new model of the spontaneous magnetic signal and structural deformation of H80 brass in the tensile process was established. The tensile test results show that the strain of H80 brass in the elastic deformation stage is 0%-5%, there is a small amount of dislocation, and the magnetic flux density does not change significantly; the strain increases to 5%-48% in the work-hardening stage, the dislocation density increases, a dislocation wall is formed at the internal lattice, and the magnetic flux density decreases with increasing tensile stress; the strain continues to increase to 48%-52% in the necking fracture stage and the internal lattice. When the strain at the necking fracture stage continues to increase to 48%-52%, the dislocation density of the internal lattice gradually stabilizes, accompanied by the appearance of sub-slip bands, and the number and density of slip bands increase; the magnetic flux density drops abruptly when fracturing occurs. These results show that the developed micro-magnetic method is accurate and reliable for monitoring and analyzing the tensile stress damage state of brass.