Patent ID: 6666929
Filing Date: 2003-12-23
Classification: C21D

Abstract:
A process to improve by laser treatment at least one of the magnetic characteristics of grain oriented electrical steel strip, chosen between magnetostriction, induction and core losses, wherein an oriented grain silicon steel strip having already undergone the secondary recrystallisation annealing and provided with final coatings, is treated with a continuous emission laser having a 10.46 &mgr;m wave length, by continuously scanning the strip in motion in a transversal direction with respect to the motion direction of the same strip, thus producing on the strip surface a plurality of traces according to the scanning path, characterized in that the following previously chosen process parameters: specific radiation energy, dwell time and distance between two consecutive traces of the laser beam on the steel strip are contemporarily and continuously adjusted respectively within the following ranges 0.1 to 25 mJ/mm2, 1Ã—10âˆ’6 and 1Ã—10âˆ’2 s, 2 and 12 mm, while measuring the value of the above magnetic characteristics before and after the laser beam treatment, the variation in value of such characteristics being utilized to adjust the value of the process parameters.