Study On Microstructure And Texture Of High Silicon Steel Thin Sheets By Two-Stage Cold Rolling

High silicon steel(Fe-6.5wt.%Si)is an ideal core material with low core loss,high magnetic permeability and low noise,because of the characters of higher resistivity,lower magnetic anisotropy and near zero magnetostriction coefficient.The brittleness of high silicon steel in room temperature makes it difficult to manufacture by the traditional rolling methods.Therefore,the studies mainly focus on rolling forming,and which has achieved some breakthroughs.However,there are few reports on the texture control technology which plays a key role in soft magnetic properties of oriented high silicon steel.The increasing of silicon content hinders the dynamic recrystallization of hot rolling sheet and makes inhibitors coarse on the one hand;and inhibits the formation of deformation bands and increase the deformation of grain boundary by strengthening internal intensity and weakening boundary intensity on the other hand.So the weak Goss recrystallization texture makes secondary recrystallization difficult for high silicon steel.In addition,the traditional high-temperature annealing mode has shortcomings in the respects of large temperature gradient and long annealing period.Therefore,it is very important to develop a new high-temperature annealing mode.In this paper,the grain oriented high silicon steel sheets with strong ?<001>//RD)texture were manufactured by the traditional hot rolling,cold rolling,annealing processes and a composite inhibitor system.The effects of NbC on microstructure and texture were studied through X-ray diffraction and electron backscattering diffraction.What's more,a secondary recrystallization regularity of short-path high-temperature annealing was also investigated.The main conclusions are as follows:(1)NbC particles restrain the surface recrystallization during hot rolling,which retains more deformation structures and strengthens shear deformation texture,thus NbC particles increase the Goss texture of hot rolling plate and provide more seeds for secondary recrystallization;(2)NbC particles refinement the structure of hot rolling and intermediate annealing sheets and regulate the cold rolling microstructure effectively,which lead to the decrease of the primary recrystallization ? texture,the enhancement of y texture and promoting the secondary recrystallization;(3)NbC particles have significant inhibition to the primary recrystallization and high temperature annealing process,they can release their inhibition slowly,which realize the 100%strong ? texture of secondary recrystallization;(4)The primary recrystallized {210}<001>grains of high silicon steel have the advantages of nucleation,size and the surrounding high-frequency high energy grain boundaries,so they have more advantages to grow up abnormally than Goss grains;(5)In the rapid annealing mode,the nucleation rate of the secondary nuclei is large and the orientation is single.The final sample has higher magnetic induction and lower iron loss,so it is expected to replace the slow heating mode.