Laser nitriding process for reducing core loss of grain oriented silicon steel and improving its thermal stability

A laser nitriding process (LN) for reducing the core loss of grain oriented silicon steel has been developed by the use of cw-co(2) laser irradiation with hot nitrogen flow (LHN) or nitrogen plasma (LPN). Nitrodation of the surface layer of the bold silicon steel by the CHN or the LPN induced new grain boundaries or restricted magnetization lines and a stress, which resulted in a refinement of 180 degrees domain wall spacing. This phenomenon not only reduced the core loss of the steel but also the refining domain wall spacing had higher thermal stability. It was found that the laser nitriding technique was more effective in a specimen with a higher magnetic induction and the core loss reduced by more than 10% under proper conditions. Since the process is not a rather simple technique, it is easily applicable to the production line of the silicon steel.