The Evolution Of Microstructure And Texture Of High Silicon Steel Thin Sheets On The Process Of Rapid Annealing

High silicon steel containing 6.5%Si has excellent magnetic properties:high permeability.higher resistivity,near zero magnetostrictive coefficient and lower magnetic anisotropy,which led to low noise and iron loss.Therefore,it is favorable to be used as motor cores.high-frequency transformers and magnetic shielding materials.Recrystallization texture is one of the key factors affecting the magnetic properties.The soft magnetic properties were improved drastically by strong recrystallization η fiber texture,which took place during the long time final box annealing.However,it is time-consuming and the final products have poor mechanical properties.As a kind of high efficient strong η texture preparation technology,high temperature rapid annealing has advantages of low cost,high efficiency and fine mechanical properties.At present,the researches on high temperature rapid annealing are still focused on ordinary silicon steel.Its application in high silicon steel sheets is expected to balance the mechanical and magnetic peculiarities.Therefore,the study on microstructure and texture evolution of high silicon steel thin sheets on the process of rapid annealing has a great value.In this study,primary recrystallization high silicon steel sheets with different microstructure and texture were annealed finally at more than 950℃ for 30min.Cu2S was selected as the inhibitor.The microstructure and texture evolution of the process was analyzed by metallographic observation,X-ray diffraction(XRD)and electron back scatter diffraction(EBSD).(1)The final annealing texture of different primary recrystallization high silicon steel sheets was composed of η fiber texture and y fiber texture,and the secondary recrystallization didn’t occurr.(2)After final annealing at 950℃、1050℃ and 1150℃.the primary recrystallization sheet η fiber texture became weak and y fiber texture became enhanced with the temperature increasing.And steel sheets η fiber texture was weaker than final annealing primary recrystallization,γ fiber texture was stronger than final annealing primary recrystallization after 950℃final annealing.(3)Under the process of high temperature nitriding,the matrix grain size increase with the increasing nitriding temperature.The number of abnormal grains reduce with the increasing nitriding temperature,these phenomenons show that the ability of acquired AIN inhibitors is enhanced with the increasing nitriding temperature.(4)The surface grains of high silicon steel sheet have a high coarsening rate,the microstructure and texture evolution in the process of rapid annealing was controlled by the process when surface grains swallowed up the internal grains.This paper explored the way to improve the production efficiency of high silicon steel sheet with strong recrystallization η fiber texture.The results show that the appropriate process route can enhance the η fiber texture,the key to enhance η fiber texture in the process of rapid annealing is inhibiting the growth of surface grains.