Technology for the world's first production of 6.5% Si steel sheets has been commercially developed in coil-form. The DC and AC magnetostriction in 6.5% Si steel sheets and the noise of the transformer made of 6.5% Si steel sheets were investigated in comparison with that of conventional 3% Si steel sheets. 6.5% Si steel sheets showed extremely low magnetostriction and were recognized to be suitable for application to the low noise audio frequency transformer.
