Study On Deformation And Recrystallisation Texture In High Silicon Steel Sheet Under Different Cold Rolling Reduction

Compared with conventional silicon steel,6.5wt.%Si-Fe alloy have excellent magnetic properties:high permeability, higher resistibity, near zero magnetostriction and lower magnetic anisotropy, result in low noise, low core lose, especially at high frequencies. Therefore, it has been widely used as motor cores, high-frequency transformers and magnetic shelding materials, meanwhile, it is considered as ideal material makes the electric machine faster and smaller. However, as the silicon concentration increased, the brittleness at room temperature is greatly elevated so that it is difficult to fabricate 6.5wt.%Si-Fe sheet with conventional rolling method and therefore its commercial application is seriously hindered.In this text,1.1mm hot band was normalized and then cold rolled to thickness of 0.5 mm, 0.39 mm and 0.2mm through conventional rolling method, the cold reduction is 55%,63% and 82%, respectively. Then the cold rolling texture was analysed. Afterwards, annealing treatment was implemented in two ways, continious annealing and two-step annealing, respectively, and the annealing texture under different cold rolling reduction was analysed.The hot band texture are mainly consisted of α, λ fibers and Goss. The intensties of α,λ fibers increased while the Goss decreased from the surface to the center layer of the band. The type of normalization texture are similar to that of hot band and have the same trend as that in hot band, but the intensities of normalized texture is lower.The cold rolling reduction has obvious effects on both components and intensties of cold rolling texture. γ,α fibers and texture components slightly deviated away from{111}<112> are main components at lower reduction, and the intensties of near{111}<112> components is higher than that of other orientations. At higher reduction, the main texture components are consisted of y and a fibers, the intensties of y, a fiber increased with the increasing reduction. As the reduction increased, the intensties of a fibers espercially{112}<110>-{111}<110> constant increased,{111}<110> increased while{111}<112> first increased then lowered at higher reduction.The texture of fully recrystallised sheet of various cold reduction is mainly consisted of η (RD//<001>), y (ND//<111>),λ (ND//<001>) fibers and texture components slightly diviated from {111}<112>. As the cold reduction increased, recrystallised η fiber first strengthened then lowered at higher reduction. After grain grew to some extent, there are some obvious differences in annealing texture of the thin sheet with various reduction:strong η and γ fibers and weak X fibers formed under 55% reduction; With the reduction increased, the intensties of η fibers is higher than that of y and X fibers under 63% reduction; strong X and y fibers and weak η fibers formed under 82% reductionhigh cold rolling reduction band treated with two-step annealing can improve the beneficial λ fibers, whereas small cold rolling reduction band shows similar characteristics after treated with either continuous annealing or two-step annealing.