Study On Texture And Magnetic Properties Of 0.2mm-thick Thin Gauge Non-oriented Electrical Steel By Two-stage Cold Rolling

The thin-gauge non-oriented electrical steel have excellent characteristics with low loss,high permeability and low magnetic noise at the medium and high frequencies as the non-oriented electrical steel finished product thickness less than 0.3mm,it become the main material in the field of"high,fine and sharp"cores manufacturing in the electromagnetic conversion devices.In this paper,based on 1.85wt%Si-0.45wt%Al non-oriented electrical steel as the research object,by using XRD and EBSD technology,systematically investigated the effects of different normalizing processes,intermediate annealing processes,finished annealing processes and the microstructure and texture were studied.The formation mechanism of the strong?texture under the two processes were analyzed and the differences of the structures,textures and properties under different processes are investigated.The main research results are as follows:?1?The 0.2 mm thick thin-gauge non-oriented electrical steel were prepared by conventional process and the magnetic performances P_1.0/400=11.43 W/kg and B₅₀=1.836 T.In the experimental process,the optimized main process parameters are normalizing at 920-960?for 3 min,intermediate annealing at 980?for 4min and finally annealing 950?for 5 min,when the 0.2mm thick thin-gauge non-oriented electrical steel was prepared without normalizing annealing process,the optimal magnetic properties P_1.5/50=1.715 W/kg,P_1.0/400=11.48 W/kg,B₅₀=1.825 T of finally product was obtained by the intermediate annealing at 980?for 4min and finally annealing at 960?for 5 min.When the intermediate annealing temperature was higher than980?,the magnetic induction increase and the iron loss increased.?2?When the 0.2 mm thick thin-gauge non-oriented electrical steel was prepared by conventional process,the finished sheet is dominated by strong Cubic texture and Goss texture.Increasing the normalizing temperature can optimize texture,improve magnetic induction and reduce iron loss obviously.Firstly,with the increase of normalizing temperature,the Goss texture in the normalized plate is strengthened and?texture is gradually weakened,the copper texture was continuously enhanced,and components of the?and?texture in the finished plate are enhanced.At the same time,the proportion of harmful{111}texture components were gradually decreased.However,when the temperature is too high?1000??,the grain size of the finished plate is too large and the size of them are non-uniform,the abnormal eddy current loss increased in 0.2mm thick thin-gauge electrical steel sheet,which is not beneficial to the reduction of iron loss.Secondly,with the increasing of the intermediate annealing temperature,the components of the{111}texture in intermediate annealed plate continuously decreased and?texture were continuously enhanced.After the secondary cold rolling,the{001}<210>,texture is gradually weakened,while{111}texture gradually increased,after the finished product were annealed at960?,the grain size of the finished product plate increased.The favorable recrystallization?and?texture are enhanced while the unfavorable texture{111}were greatly weakened,which enhanced the magnetic of finished products.Thirdly,with the increasing of final annealing temperature,the grains of the finished plate grow up continuously and the Goss texture is enhanced continuously,the component of the unfavorable{111}<112>texture were weaked effectively,and the magnetic induction increased and the iron loss decreased.However,after the temperature exceed 950?,the grain size was too large to improve the eddy current loss.?3?In the non-normalizing process,firstly,with the increasing of intermediate annealing temperature,the grain size of the intermediate annealed sheet increased.In the process of temperature rise,the precipitated grain of original part was formed and the element was back-dissolved and the grain was raised in the initial stage of the final product annealing process.At the same time,due to the oversizedgrainsize of the intermediate annealing sheet formed a rich shear bands in the secondary cold rolling process,which promoted the increasing of the nucleation rate,which result in the grain size increased firstly and then decreased.One-step cold rolling sheet is fibrous microstructure of{100}<011>,{112}<110>and{111}texture.The intermediate annealing plate is strong{111}texture and inherited from the secondary cold rolling process.Abundant shear bands promote the formation of the strong?texture in the finished product.Secondly,with the final annealing temperature increasing,the?texture components increased gradually.The addition of the annealing temperature of the finished product is conducive to the grains growed with strong?orientation and the{111}orientation texture reduced.The strong?texture component Goss texture{110}<116>formed in the final finished sheet while the iron loss of the finished plate were reduced gradually.?4?The 0.2 mm non-oriented electrical steel sheets were prepared under the two process of the normal process and the non-normalization process both showed strong?texture.The difference is that the former is mainly composed of{320}<001>and Goss texture,while the latter at the peak of{210}<001>and has a stronger Goss{110}<116>texture.The?-oriented and Goss-oriented grains in the sample nucleate and grow in the shear bands during the initial recrystallization.The recrystallized grains gradually grew up by the nucleation of grain boundaries bulging swallowed the surrounding distortional matrix.The adjacent?-oriented grains formed a large-angle grain boundary in a way of the sub-grain combination,and obtained a strong?texture eventually.Under the normalizing process at 960?,the strong?texture and Goss texture formed finally.However,the?-oriented texture in the finished plate increased first and then decreased and the Goss texture gradually shifts toward{110}<116>under the non-normalizing process.