低温取向硅钢常化工艺和渗氮工艺对组织、织构和磁性能的影响

Effects of normalizing process and nitriding process on the microstructure, texture, and magnetic properties in low-temperature grain-oriented silicon steel

  • 摘要: 利用电子背散射衍射技术(EBSD)、扫描电镜(SEM)分析了低温取向硅钢常化工艺、渗氮工艺对常化组织、再结晶组织与抑制剂的影响, 对比研究了常化冷却速率、渗氮温度和渗氮量对再结晶组织、织构和磁性能的影响规律.结果表明, 常化冷却速率越快, 一次再结晶晶粒尺寸越小.常化冷却速率较慢时, 高温渗氮的样品一次再结晶晶粒尺寸偏大, 使二次再结晶驱动力降低, 二次再结晶温度提高, 且渗氮量低, 追加抑制剂不足, 最终二次再结晶不完善.高温渗氮与低温渗氮导致脱碳板中抑制剂尺寸不同, 高温渗氮表层抑制剂与次表层抑制剂尺寸基本无差异, 低温渗氮表层抑制剂尺寸比次表层抑制剂尺寸大.低温渗氮且渗氮量低的样品虽然二次再结晶较完善, 但由于其常化温度低、常化冷却速率快, 一次再结晶晶粒尺寸小, 二次再结晶开始温度稍早, 黄铜取向晶粒出现, 最终磁性差.渗氮量较高的高温渗氮和低温渗氮样品虽都能基本完成二次再结晶, 但磁性存在差异, 磁性差的原因是高温渗氮样品的最终退火板中出现较多的偏210 < 001>取向晶粒.

     

    Abstract: The influences of the normalization parameters and nitriding parameters on the microstructure of normalized samples, the primary recrystallization microstructure, and inhibitors were analyzed by electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM) techniques. The effects of normalizing cooling rates, nitriding temperatures and nitrogen content on the primary recrystallization and secondary recrystallization microstructure, textures, and properties were studied. The results show that grain sizes decrease with the increasing normalizing cooling rate; when the rate is slow, the grain size of high-temperature nitriding sample increases with the slow normalizing cooling rate, reducing the driving force for secondary recrystallization and increasing secondary recrystallization temperature. The acquired inhibitor is insufficient, which leads to unsuccessful secondary recrystallization. High-temperature nitriding and low-temperature nitriding lead to different sizes of inhibitors in the decarburized sheets; however, inhibitors in the surface and subsurface regions of high-temperature nitriding samples are primarily of the same size, while the inhibitors in the surface region of low-temperature nitriding samples are larger than those of the subsurface inhibitors. The lower-temperature nitriding sample with low nitrogen content exhibits a poor magnetic property. As the grain size remains small at a low normalizing temperature and high normalizing cooling rate, the second recrystallization starts at a slightly lower temperature and Brass-type oriented grains are present. The secondary recrystallization of high-temperature nitriding and low-temperature nitriding samples with high nitrogen content could be basically completed; however, the magnetic properties of samples are different, and more grains with deviated 210 < 001> orientation lead to a reduction in magnetic properties.

     

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