Effects of Laser-Cutting and Spark Erosion Techniques and Heat Treatment on the Magnetic Properties of Grain-Oriented Transformer Steels
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Spark erosion and laser-cutting processes were examined in terms of their effects on the magnetic properties of grain-oriented electrical steels at working frequencies. The maximum permeability value in each case was considered a reference to determine the quantitative effect of cutting and eroding methods as well as the effects of heat treatment. To minimize the deterioration that appears after the piercing process is implemented, the specimens were subjected to heat treatment at the most appropriate temperature. The influence of stress-relief annealing could be observed throughout the domain refinement on the surface by using magneto-optical Kerr microscopy. Additionally, it was clearly seen that the domain contrast at the cut edge of the spark-eroded sample was more uniform than that provided by laser cutting upon applying a high AC-field amplitude.
KeywordsCutting effect Spark eroding Laser cutting Magneto-optical Kerr effect Relative permeability Coercive field
The author would specially like to thank Prof. Rudolf Schäfer from the Leibniz Institute for Solid State and Materials Research Dresden IFW for technical and scientific contribution and acknowledge S. Pofahl from IFW Dresden for sample preparation.
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