【摘要】 常化是高磁感取向硅钢生产中的重要环节，通常认为通过控制常化工序中900℃开始的缓冷阶段，可实现γ→α相变来促进抑制剂的弥散析出进而改善磁性能，而本工作在系统研究了高磁感取向硅钢常化工艺中的升温速率、固溶温度、相变等温温度与时间、相变后冷却速率等参数对常化组织和抑制剂的影响后，对此有不同的发现。常化前的初始组织由以珠光体为主的富C片层和片层之间大量分布的铁素体所组成，在常化的加热与固溶过程中，只有碳化物片层区发生奥氏体相变，且提高固溶温度、延长固溶时间可形成更多奥氏体，但在1120℃固溶3 min依然无法完全溶解碳化物且不同区域内所形成奥氏体C浓度不均匀，奥氏体水冷后转变为马氏体和残余奥氏体。组织观察、原位膨胀实验结果与热力学计算结果均表明，在1120℃固溶后冷却至900～950℃相变温度保温时继续发生奥氏体化，而非普遍认为的γ→α相变，因此此时并不能通过该相变促进抑制剂析出。取向硅钢中细小抑制剂有2种来源：一是在铁素体区域由于降温导致抑制剂形成元素的固溶度下降而析出；二是900℃以下空冷时发生珠光体相变时析出。另外，提高加热速率和固溶温度均可溶解更多已形成的抑制剂，从而可在冷却时再析出更多的细小抑制剂。常化后抑制剂的类型主要为AlN、AlN与MnS的复合析出物及TiN。更多还原

【Abstract】 Normalizing is an important process that is widely employed in the industrial production of highly permeable grain-oriented silicon steel(GOSS). This is because it yields a proper microstructure,which is subsequently subjected to cold rolling, primary recrystallization, and secondary recrystallizationannealing. As a result, the sharpness Goss texture can be developed and GOSS posseses excellent magnetic properties. In this study, the influence of normalizing process parameters, including the heating rate, solution temperature, second-stage isothermal holding temperature and period for transformation,and cooling rate, on the resultant microstructures and inhibitors in the normalized GOSS were systematically investigated. Two types of distinct regions exist in the hot-rolled GOSS before normalization: the lamellar carbon-riched region elongated along the rolling direction, which is mainly composed of pearlite,and large ferrite region between the former regions. These two regions are alternately distributed from the subsurface to the center of the steel sheet. During heating and the solution processes, austenitization occurs only in the lamellar carbon-riched regions accompanying carbide dissolution, while no transformation occurs in the ferrite regions. An increase in either the solution temperature to up to 1200oC or its period to up to 3 min leads to the formation of more austenite. And the widely adopted solution condition of 1120oC for 3 min cannot dissolve all the formed lamellar carbides in the hot-rolled GOSS, leading to the nonuniform carbon concentration of the formed austenite in different regions. Consequently, some austenite can be retained after most of them transformed into martensite during water quenching. Moreover, all the results on microstructural characterization, in situ dilation experiment, and thermodynamic calculation show that austenitization continues to occur at the second-stage phase transformation temperature(900～950oC), instead of the commonly believed γ→α phase transformation. Therfore, inhibitor precipitation cannot be promoted by this phase transition. Furthermore, the fine nanosized inhibitors can precipitate in the ferrite region because the inhibitor ’ s solubility is greatly reduced with decreasing temperature and in the pearlite regions accompany with the austenitic-to-pearlite transformation during air cooling below 900oC.An increase in the heating rate and solution temperature cause additional inhibitors in the hot-rolled GOSS to dissolve during the solution stage and reprecipitate to a fine size during the subsequent cooling. After normalization, the main types of inhibitors are AlN, the composite precipitates of AlN and MnS, and TiN.更多还原