Effects of stress on the magnetostriction of 2% Mn pipeline steel

The effects of varying the order of the application of stress and a demagnetization procedure on the magnetostrictive behavior of a 2% Mn pipeline steel sample are studied and compared to the predictions of recent theory. Plots of magnetostriction versus both magnetic field and magnetization are given. Significant differences were found in the behavior of the magnetostrictive initial curve when the sample was both demagnetized and the measurements made under a constant stress as compared to the results when the sample was demagnetized and then stressed. Tension was also found to decrease the range and the hysteresis of the sample´s saturation major magnetostrictive loops, while compression had the opposite effect. This behavior appeared to be independent of whether the stress was applied before or after the demagnetization process, and was found to be due to changes in magnetostriction at low magnetization values. Comparison of the sample´s magnetostrictive behavior to theory showed that only some of the features seen experimentally were correctly predicted by theory