Evolution Of Microstructure And Texture And Magnetic Properties In 4.5%Si Grain-oriented Silicon Steel Thin Sheets

Oriented silicon steel is known as the "the crown jewel" in steel industry,the core material for the preparation of directional transformer,and it is high value-added,high barrier products.Si guarantees high electrical resistivity in steel,resulting in low iron loss,but excessive Si content severely degrades the steel's machinability.Thinning the thickness of the steel sheets can reduce the iron loss effectively.At present,industrial production is below 3.5%Si,thickness specifications are 0.23 mm,0.27 mm,0.30 mm.4.5%Si oriented silicon steel has excellent formability and good magnetic properties,so it has good prospects for development.Iron loss is reduced by increasing the Si content and reducing the thickness.0.10?0.25 mm 4.5%Si oriented high silicon thin sheets were finally fabricated through the one-stage and two-stage cold rolling process.Study of microstructure and magnetic properties of nitriding temperature and the start temperature of high temperature annealing of one-stage cold rolling,intermediate annealing grain size,nitriding temperature and roling reduction of two-stage cold rolling.Conclusion as follows:(1)The 4.5%Si oriented silicon steel thin sheets of 0.25 mm and 0.10?0.15 mm were successfully prepared by one-stage and two-stage cold rolling process,and the highest magnetic induction B8 is 1.79 T.The high magnetic properties can be attributed to the preferential anomalies of the ? grains with small misorientation angles;(2)Appropriate nitriding temperature and start temperature of high temperature annealing can obviously promote the recrystallization of ? grains with orientation deviation angle less than 3° in 4.5%Si oriented silicon steel thin sheets.The temperature difference along the width of the hot rolled steel has a significant influence on the magnetic properties.It is difficult to control the inhibitor in the hot rolled sheets near the edges,and the grains other than the ? orientation tend to grow abnormally preferentially;(3)Controlling the primary recrystallization texture,the magnetic properties of 0.10?0.15 mm 4.5%Si oriented silicon steel thin sheets by two-stage cold rolling are effectively improved.Reducing the size of the intermediate annealed grains from 45?m to 35 ?m weakens the unfavorable {001} component in the primary recrystallization texture.The reduction of the second cold rolling reduction from 89%to 84%enhanced the favorable {111}<112>component of the primary recrystallization texture.