On-line hardness assessment of cold-rolled motor lamination steels

It is important to be aware of variations in the mechanical hardness of strip emerging from the strand anneal lines, which are used to anneal continuous steel strip during production. Lamination stamping, punching, and handling characteristics can depend on the hardness of the materials. A novel technique for the nondestructive determination of the hardness of nonoriented electrical steels has been developed. This technique exploits the measurements of structure-sensitive magnetic parameters, which are measured continuously on-line in real time. The magnetic data being produced are then processed through appropriate algorithms to provide an evaluation of material mechanical hardness. Variation of hardness along the length of coils then can be readily examined.