| Starting from the modern ferromagnetic domain theory, the simplified analyses of laser processing have been conducted for lowering the core loss of grain-oriented 3% silicon steel sheets, so as to determine the main technical parameters of laser processing. In addition to these analyses, both the experimental results and the theoretical analyses of heat conduction and mechanics indicate that either the pulse laser or continuous-wave laser processing is able to lower the core loss of more than 5% without the damage of the coating or the bending of sheet. The investigation still indicates that the heating time being too short is the main cause of the damage of the coating for the pulse laser processing and the heating time being too long is the main cause of the bending of sheet for the continuous laser processing. As a result, the reasonable heating time should be about 10-6s and 10-3s in order to prevent the damage of the coating and the bending of sheet respectively.The theoretical analyses have been conducted for heat transfer and mechanics during laser processing of the steel sheets and analytical solutions have been obtained for two-layer sheets with an axial symmetric pulse laser heating or a moving continuous-wave laser heating and with one—dimonsional switch-Q laser heating. All these lead to the model of the thermal elastic stress, thermal elastoplastic stress and residual stress based on some simplications.The non-Fourier heat conduetion in pulse laser processing is also discussed and analysed. The results may explain the phenomena—the coating is easier to be molten and the depth of dislocation is larger, than that predicted by means of Fourier heat conduction analysis.
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