热轧加热时间对1.8%Si无取向硅钢电磁性能和夹杂物的影响

Effect of hot rolling heating time on electromagnetic properties and inclusions of 1.8%Si non-oriented silicon steel

对比了1.8%Si无取向硅钢在不同加热时间下的电磁性能,分析了其显微组织和夹杂物的变化规律。结果表明:热轧加热炉加热时间长的试样铁损劣化0.43 W/kg,这主要是因为试样中存在大量尺寸小于1μm、形状不规则的AlN夹杂钉扎在晶界,导致晶粒无法正常长大,晶粒组织细小且不均匀;试样长时间处在1000~1120℃的加热炉中,促使大量AlN在板坯中均匀固溶,在轧制和冷却过程中,AlN以弥散细小态析出并遗传到冷卷中,在硅钢机组连续热处理过程中,温度达到950℃以上,AlN再次固溶后以弥散细小形态析出;对于正常加热时间的试样,即使在加热炉均热段温度较高的情况下,由于AlN未来得及均匀地固溶在板坯的各个位置,在轧制和冷却过程中AlN以簇拥态析出,夹杂物主要为尺寸相对较大的Al N、CaS-Al_(2)O_(3)、Al N-CaO-Al_(2)O_(3)复合夹杂,电磁性能良好。

The electromagnetic properties of 1.8%Si non-oriented silicon steel with different heating time were compared,the change rules of microstructure and inclusions were analyzed.The results show that the iron loss of the sample with long heating time in the hot rolling furnace was 0.43 W/kg,which was mainly because there were a large number of AlN inclusions with size less than 1μm and irregular shape pinned at the grain boundary,which led to the failure of grain growth and the fine and uneven grain structure.A large amount of AlN was uniformly dissolved in the slab by heating furnace at 1000~1120℃for a long time.In the process of rolling and cooling,AlN was precipitated in a dispersed and fine state and inherited into the cold coil.In the continuous heat treatment process of silicon steel unit,when the temperature reached above 950℃,AlN was precipitated in a dispersed and fine form after solid solution again.For the samples with normal heating time,even in the case of high temperature in the soaking section of the heating furnace,because AlN was not uniformly dissolved in each position of the slab,AlN was precipitated in a clustered state during rolling and cooling.The inclusions were mainly AlN,CaS-Al_(2)O_(3),AlN-CaO-Al_(2)O_(3) composite inclusions with relatively large size,and the electromagnetic properties were good.