Effect Of Normalization On Deformation And Recrystallizaton Texture In High Silicon Steel Added With Boron

High silicon steel containing about 6.5wt.%Si has excellent magnetic properties:high permeability,high resistibity,near zero magnetostriction and low magnetocrystalline anisotropy.It has significantly low core loss and noise pollution compared with common silicon steel especially at high frequency.Therefore,it has usually been used as motor cores,high-frequency transformers and magnetic shielding devices.Meanwhile,it has been considered as ideal material for the realization of high speed and miniaturization of electrical and electronics equipment.In present study,high silicon steel thin sheet added with(Mn,Cu)2S and B element was successfully produced by conventional rolling method,including hot rolling,cold rolling and final annealing.Furthermore,texture evolution during deformation and recrystallization was analyzed by X-ray diffraction and electronic backscattered diffraction(EBSD).This research focuses on the effects of hot band normalization on deformation and recrystallization texture and the effect of grain boundary segregation B element on the development of secondary recrystallization.The main results are as follows.The increased hot band normalization temperature makes the grain of hot band grow up,weakens Goss texture produced by friction force in the subsurface layer and a fiber in the center layer,resulting the reduction of the entire sheets.Hot band normalization obviously influences first-stage cold rolling texture.High temperature normalization reduces the intensity of a fiber in the first-stage cold rolled sheet.? deformation texture with peaks at {111}<112>and{111}<110>and relatively strong a fiber with peaks at {223}<110>and{113}<110>are formed at 1/4 layer of the first-stage cold rolled sheet without normalization or with low temperature(900?)normalization hot bands.Strong ?fiber forms as well in the center layer of the first-stage cold rolled sheet without normalization or with low temperature(900?)normalization hot bands.However,strong and relative homogeneous distributed ? deformation texture and weak a deformation texture forms at 1/4 thickness layer and relative weak ? fiber at 1/2 thickness layer for the first-stage cold rolled sheet normalized at high temperature(?950?).The intensity of y deformation texture at 1/4 and 1/2 thickness layers for the first-stage cold rolled sheet without normalization and normalized at low temperature is lower than the first-stage cold rolling texture of hot band normalized at high temperature.Hot band normalization also obviously influences the intermediate-annealing texture.Strong ? fiber with peak at {210}<001>is formed at 1/4 thickness layer of intermediate-annealed sheet without normalization or with low temperature normalization hot bands.Relatively weak ? fiber with peak at {210}<001>is formed at 1/4 thickness layer of intermediate-annealed sheet with high temperature,but the intensity of ? fiber increases.All the intermediate-annealed sheet forms {114}<418>texture at center layer.Hot band normalization reduces the difference of ? fiber at 1/4 layer and 1/2 layer on decarburizing annealed sheet.? deformation texture with peak at{111}<112>dominates the secondary-stage cold rolling texture at both 1/4 and 1/2 layer for each hot band normalization,and the intensities have little difference.?fiber intensity at 1/4 layer is slighly higher than that at 1/2 layer on decarburizing annealed sheet without hot band normalization or with low temperature normalization,while ? fiber intensities at 1/4 layer and 1/2 layer on decarburizing annealed sheet with high temperature normalization are the same.The hot band of high silicon added with(Mn,Cu)2S and B was cold rolled with 70%reduction for the first stage,and intermediate annealed at 950?,and than secondary cold rolled with 55%reduction,followed by decarburizing annealed at 900? for 5 min.The obtained high silicon steel thin sheet was annealed from 830? to 1050? with a slow heating rate of 20?/h.During the annealing,? fiber with peaks at {110}<001>and {210}<001>cannot gain size advantage during incubation period of secondary recrystallization.Because of coarsening of(Mn,Cu)2S precipitation and reduced grain boundary segregation of B element with increasing annealing temperature,inhibition ability generally drops and grains normally grow while slowly annealing over 950?.