Effect Of Annealing Process On Microstructure And Texture Of High Strength Non-Oriented Silicon Steel

The three major components of electric vehicles are battery,motor and electronic control.Non-oriented silicon steel is an indispensable key material for driving the motor rotor,and its speed reaches tens of thousands of revolutions per minute.At this time,traditional non-oriented silicon steel can no longer meet the high centrifugal force generated by high-speed operation.In this paper,niobium-containing non-oriented silicon steel was smelted in the laboratory.It was rolled to 2.5 mm by a two-roll reversing rolling mill,and the cold-rolled plate of 0.5 mm was cold-rolled at one time.5 min annealing at 850℃,900℃,950℃and annealing at 850℃annealing temperature for 3 min,5 min,7 min and 9 min respectively,to study the effect of annealing temperature on the microstructure,precipitation phase and texture of the experimental steel,and to study the recrystallization shape during the annealing process.Nucleation mechanism,recrystallized grain growth behavior and second phase precipitation behavior.The annealed metallographic structure was observed by Zeiss metallographic microscope,the macroscopic texture was observed by X-ray diffractometer,the microscopic grain was observed by EBSD,and the precipitate phase was observed by SEM and TEM electron microscope,and the following research results were obtained:（1）After annealing by different annealing processes,the recrystallized texture is mainly{111}<112>orientation,in which theα-orientation line texture and theη-orientation line texture are weak,and theγ-orientation line texture is stronger.When the annealing time is fixed,the sample has been completely recrystallized at 950℃,and the grains begin to grow.Under the annealing temperature of 850℃,the intensity of{111}<112>orientation texture in the surface layer of the sample increases gradually,and the{100}<001>orientation texture increases slightly;the{111}orientation texture in the central layer of the sample increases The strength of the<112>orientation texture is gradually increasing,and the texture strength of other orientations is gradually weakening.（2）During the annealing process,the precipitation phase of the high-strength non-oriented silicon steel annealed sheet is mainly the LAVES phase of Fe₁₆Nb₆Si₇.The solid solution temperature of this phase is 880℃.During the annealing process at 850℃,with the extension of the annealing time,the Laves phase The average diameter of the precipitates is increasing,and the volume fraction is decreasing.With the increase of the annealing temperature,the average size of the precipitates increases gradually,and the volume fraction gradually decreases,and the Fe₁₆Nb₆Si₇precipitates undergo Ostwald ripening.（3）The deformed bands of Nb-containing high-strength non-oriented silicon steel samples after cold rolling are mainly{100}<011>,{112}<110>,{111}<112>and{111}<110>orientations.In the initial stage of recrystallization of non-oriented silicon steel,the nucleation length of{111}<112>oriented recrystallized grains is longer than that of{111}<110>oriented deformation grains in the internal shear zone;{111}<110>oriented recrystallized grains Grain nucleation length is longer than{111}<112>orientation deformed grains;with the progress of recrystallization,{111}<110>orientation grains preferentially nucleate,{111}<112>orientation Grains grow preferentially,and the proportion of{111}oriented grains increases gradually.