Deformation Behaviour Study of Micro-alloyed Steel by Magnetic Hysteresis Techniques

The magnetic properties of heat-treated, Cu containing, high strength low alloy (HSLA-100) steel and the variations of the magnetic properties during tensile deformation were studied. For samples aged at temperatures below 775 K, precipitation of nanosized coherent Cu particles occurred, causing an increase in hardness but a decrease in coercivity. For higher aging temperatures, the Cu precipitates coarsened and then were able to pin domain walls. As a result magnetic coercivity increased. During tensile deformation of selected heat treated samples, interaction of dislocations with the coherent and incoherent Cu precipitates influenced the magnetic properties. Systematic variation of coercivity with plastic strain was found for brittle and ductile types of fracture of the materials.