薄带铸轧流程制备含钇3% Si取向硅钢的组织和织构研究

通过50 kg真空感应炉冶炼，用常规流程和薄带铸轧两种工艺分别在实验室制备了含稀土钇的3%Si取向硅钢。薄带铸轧浇注温度1530℃,轧制速率0.3 m/s,铸带厚度2.5 mm。常规流程为80 mm铸坯加热温度1150℃,热轧板厚度2.4 mm,终轧温度935℃。采用扫描电镜(SEM)和电子探针(EPMA)研究了钢中夹杂物成分、形貌、数量、尺寸和分布；利用光学显微镜(OM)和电子背散射衍射(EBSD)分析了硅钢铸带、热轧板、0.3 mm冷轧板、870℃ 7 min和1100℃ 10 min再结晶退火板组织和织构。实验结果表明：与常规流程相比，薄带铸轧硅钢一次再结晶后晶粒较细小，且γ织构强度达到17,但是二次再结晶后晶粒尺寸不均匀，平均晶粒尺寸为61μm,部分Goss取向晶粒尺寸达到1 mm以上。原因为细小的含钇夹杂物数量过多，且分布不均匀，夹杂物聚集的区域晶粒长大受到明显抑制。常规流程生产的含钇硅钢二次再结晶热处理后晶粒均匀长大，平均晶粒尺寸为102μm,没有形成明显的Goss织构。

Microstructure and Texture of Yttrium Bearing 3% Si Oriented Silicon Steel Fabricated by Thin Strip Casting Rolling Process

The 3% Si oriented silicon steel containing yttrium is prepared by 50 kg vacuum induction furnace with conventional production process and thin strip casting rolling process, respectively. The casting temperature of thin strip is 1 530 °C with rolling rate 0.3 m/s to 2.5 mm cast strip thickness. The conventional process silicon steel 80 mm cast billet heating temperature is 1 150 °C,hot rolled thickness to 2.4 mm with end rolling temperature 935 ℃.The composition, morphology, quantity, size and distribution of inclusions in steel are studied by scanning-type electron microscope (SEM) and electro-probe microanalyser (EPMA). The microstructure and texture of silicon steel strip, hot rolled plate, 0. 3 mm cold rolled sheet and 870 °C 7 min and 1 100 °C 10 min recrystallzing annealed sheet are analyzed by optical microscope (OM) and electron back-scattering diffraction (EBSD). The experimental results show that, compared with the conventional process, the grains of the thin strip cast rolled silicon steel after the first recrystallization are finer and the strength of 7 texture is 17 ； but the grain size is nonuniform after secondary recrystallization heal treatment, the average grain size is 61 μm, and the partial grain size of Goss orientation bigger than 1 mm. The reason is that the amount of fine yttrium inclusions is too large and the distribution is uneven, and the grain growth in the area where the inclusions gather is obviously inhibited. After secondary recrystallization heat treatment process, the grain size of the silicon steel of yttrium bearing produced by conventional process is uniformly and the average grain size is 102 μm, but the Goss texture is not formed.