Influence of Fiber Laser Scribing on Magnetic Domains Structures and Magnetic Properties of NO Electrical Steel Sheets

In this paper, microsecond pulsed fiber laser was used to study its effects on the resulting changes in magnetic domains structures, coercivity, and thermal stresses values in the area of interaction of laser beam with surface of high silicon non-oriented electrical steel sheets.The laminations for the cores used in electrical applications like motors, generators, and ballasts are manufactured by punching, mechanical cutting, or cutting by laser of coils of non-oriented fully processed electrical steels.The magnetic material close to the cutting edge is essentially influenced by these processes.Depending on the parameter, the magnetic properties can vary substantially.The experimental parameters including laser power variation in the range of 0-100 W, constant frequency of 500 Hz, and 20 µs pulse duration were used to perform four various laser scribing treatments.The results showed that compared to the laser untreated material with magnetic coercivity of 22 A/m, significant improvements, i.e., coercivity reductions were obtained after the laser treatments within laser power range of 12-50 W. The major effects responsible for the observed core losses improvements are related to optimal refinement of magnetic domains structures by applied laser treatments.