The Evolution Of The Microstructure Of The Shear Bands And The Orientation Of The Nucleation At Shear Bands In Fe-3%Si-0.02%C

Silicon steel is an important soft magnetic material in the electronic and electrical industries,which is commonly used in electrical power transformers and electric motors.Recrystallization texture is critical for magnetic properties of grain-oriented silicon steel,and recrystallization nucleation takes place preferentially inthe cold rolling shear bands.It is the key process to control the accuracy of recrystallized Goss texture that shear bands provide the nucleation sites for Goss nuclei in annealing process.The effect of cold rolling parameter on the evolution of shear bands is a hot topicin domestic and overseas.But there is still lack of mathematical statistics of shear bands.Research on the evolution of shear bands is important to the secondary recrystallization texture control technologyin view of the contribution of shear band to recrystallization.The starting materials were Fe-3%Si-0.02%C in the present study.The grain-oriented silicon steel ample with shear bands were prepared through hot rolling,cold rolling and partial recrystallization.And the evolution of shear bands was analyzed by metallographic and the electron backscattering diffraction(EBSD)technique.The effect of cold rolling reduction on the evolution of the shear bands in sub-surface were studied in order to explore the influence rule of shear bands on the orientation of partial recrystallized nucleation.The main conclusion are as follows:(1)The distribution of angle between nucleated shear bands and RD(20°-30°)become more concentrated and smaller than that in cold rolling processwhen the reduction rate are 42%,50%,60%;while the angle of shear bands in cold rolling process and part recrystallization process is smallwhen the reduction rate are 71%,80%,85%.And it indicates that the shear bands with small angle has an advantage of nucleation.(2)The proportion of grains with shear bands are high in the grains which are more than 90μm thickness,and the proportion of grains with shear bands at 71%reduction rateis larger than that at other reduction.(3)With the increasing of reduction rate,the average distance between shear bands increases first,and goes down and then increases.Which is affected by the distribution and the number of shear bands.(4)When the orientation of deformed matrix are same,the orientation is different in the shear bands with different angle,which means that the orientation may be inherited in same angle of shear bands between cold rolling process and part recrystallization process in the matrix with same orientation.