Hysteresis Scaling Behavior in a Remanent Magnetization State

Scaling laws of minor hysteresis loops have been examined in cold rolled low carbon steels with varying initial magnetic states, field sweep rate, and temperature. Minor B-H loops, obtained in a remanent initial state are non-symmetrical in shape and their center largely deviates from the origin of the B-H space, which is in contrast to symmetrical loops obtained in a demagnetized initial state. However, it was found that a relation between maximum flux density and hysteresis loss of both the symmetrical and non-symmetrical loops exhibits the same curves in the wide field region and has a power law with the same exponent of 1.59 ± 0.02, irrespective of initial magnetic state, rolling reduction ratio, and temperature. The coefficient of the power law, which is sensitive indicators of internal stress, increases with rolling reduction or decreasing temperature and was obtained with a standard deviation of 2%. These observations demonstrate that the scaling analysis of minor B-H loops is advantageous for on-site evaluation of materials degradation in ferromagnetic structural steels where a demagnetized initial state is difficult to obtain.