A study of the kinetics of magnetic aging in steels

Magnetic aging characteristics have been studied by resistivity and coercive force measurements in two grades of low carbon steel one containing the usual amount (0.03 wt.%) and the other containing 0.17% phosphorous.The higher P grade displayed less magnetic aging and the peak was also attained much later, presumably due to the P delaying the transition from ε-carbide to cementite, as well as in restricting the growth rate of the latter thus resulting in limited interaction with domain walls. The grade containing the usual amount of P showed higher coercive force when it was air cooled rather than water quenched from the solution treatment temperature. During aging, however, the coercive force changes for the two conditions varied depending upon the time and temperature of aging.