| Summary: | 碩士 === 國立雲林科技大學 === 機械工程系碩士班 === 100 === This study investigated the effect of primary recrystallization temperature, from 725 to 800 °C, partial pressure ratio of water to hydrogen, ammonia flow rate, and secondary recrystallization temperature on the microstructure, size and volume of precipitates, thickness of the oxide layer, secondary recrystallization behavior, magnetic properties of two-stage hot band annealing grain-oriented electrical steel
During annealing at 750 °C, and dew point setting at 42 °C, the calculated effluent gas partial pressure ratio was 0.267. Then the carbon content could decrease to 45 (ppm). Moreover, the primary grain size was 18.5 μm and the thickness of the oxide layer is 1.45 μm. The injection nitrogen into steel sheet increased with increasing ammonia flows rate and nitriding time. The optimum conditions to obtain the best abnormal grain growth and magnetic properties for the two-stage hot band annealing grain oriented electrical steels was primary annealed at 750 °C for 5 minutes. Then nitriding was conducted at 750 °C for 30 seconds. Finally, secondary recrystallization was performed at 995 ° C for 12 hours. The flux density, B8, reached 1.926 Tesla and the iron loss, W15/50, was 1.04 watt / kg.
Keywords: grain-oriented electrical steel steel, iron loss, magnetic flux density.
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