Grain oriented electrical steel is sensitive to mechanical stress which can have a significant negative impact on the magnetic performance of the material.
Mechanical stress can be imparted into the material in a variety of ways. External forces can impart stress through excessive or uneven compression upon the laminations. Internal stress is generated along the cut edges during slitting or cutting operations or as a result of bending the sheet or subjecting it to tension beyond the yield point.
Careful processing and the use of correctly adjusted sharp tungsten carbide tools and blades are necessary to minimize the introduction of residual stresses, which can cause a marked deterioration in the specific total loss. These stresses of processing, which are sometimes unavoidable, can be completely eliminated through stress relief annealing of the material.