Microstructure And Texture Evolution Behavior Of Fe-3%Si-Cu Grain-oriented Silicon Steel And Inhibition Mechanism Of Cu Particles

Oriented silicon steel with{110}<001>texture（Goss texture）as the main feature is pursued for its high magnetic induction and low iron loss.However,its production process is complex,involving a long flow,high energy consumption,and high cost.Presently,although the control of the microstructure and texture has been achieved through complex composition and process design,inhibitor control is still a problem that plagues the conventional production technology of oriented silicon steel,particularly the high-temperature heating of the cast slab and the high-temperature and long-time purification annealing,which cause enormous production losses.Therefore,in order to break through the limitations of traditional processes for the control of the microstructure,texture,and inhibitors of oriented silicon steel,this paper innovatively proposes the preparation of Fe-3%Si-Cu oriented silicon steel using copper particles as single inhibitor.The evolution of microstructure and texture throughout the entire process and the mechanism of the Cu particle inhibitor were studied in depth.The main research contents and the conclusion is as follows:The interactive laws between precipitation and recrystallization in Fe-3%Si-Cu alloy was investigated,and the recrystallization kinetics curve of Fe-3%Si-Cu alloy and the precipitation kinetics curve of Cu particles were obtained.After aging treatment,a large amount of Cu-rich nanoparticles were uniformly and dispersedly precipitated in the alloy.The best aging hardening effect was achieved at an aging temperature of 500℃and an aging time of 10^4.5s.The precipitation of Cu particles increased the activation energy of recrystallization in cold-rolled Fe-3%Si-Cu alloy,significantly delaying the recrystalli-zation process.The delaying effect of precipitated Cu particles on the recrystallization behavior of cold-rolled Fe-3%Si-Cu alloy was more significant than that of Cu in the solid solution state.The preparation process of Fe-3%Si-Cu oriented silicon steel with copper particles as single inhibitor was studied.The content of Cu element in the composition system is controlled as 1.0 to 1.2wt.%.In order to form the inhibitor of Cu particles,the content of Mn,S,N,Al and other elements is strictly limited.The cast billet was heated at 1180℃.After hot rolling,normalization,cold rolling and decarbonization annealing,the carbon content was reduced to less than 0.004wt.%.The aging treatment at 500℃was added to the high temperature annealing,and the high temperature purification process of 1200℃for a long time is eliminated.The large area of secondary recrystallization grains are formed after high temperature annealing.The magnetic induction B₈₀₀of 0.3 mm thick Fe-3%Si-Cu-oriented silicon steel sheet is 1.76 T,the iron loss P_17/50is 1.5 W/kg,and the magnetic properties preliminarily meet the national standard.It is an energy saving and environmental friendly production method for oriented silicon steel.The evolution behavior of microstructure and texture in the whole process of Fe-3%Si-Cu grain-oriented silicon steel was studied.The distribution of hot rolled microstructure and texture is uneven along the thickness direction of the plate.The Goss texture originates from the surface and the sub-surface of the hot rolled plate,and the normal texture inherits the non-uniformity of the hot rolled texture.α-fiber texture andγ-fiber texture were formed after cold rolling.A small number of Goss grains in the surface layer and the sub-layer of the decarburized annealing plate occurs secondary recrystallizationare near 900℃of the high-temperature annealing heating period.After the secondary recrystallization,large area of Goss grains are obtained,and the volume ratio of the secondary recrystallized grains reaches more than 90%.The mechanism of Cu particle inhibitor in Fe-3%Si-Cu oriented silicon steel was investigated.After hot rolling,a large number of Cu particles with sizes ranging from 10 to40 nm precipitated in the matrix.The surface distribution density of the particles increased after annealing,but decreased after decarburization annealing due to the dissolution of Cu particles.After high-temperature aging treatment at 500℃for 2-6 hours during high-temperature annealing,the surface distribution density of Cu particles could be increased to6.95-8.04×10⁹particles/cm².The heating rate during high-temperature annealing affected the precipitation,coarsening,and dissolution processes of Cu particles.The precipitation peak of the 40°C/h heating rate is 700°C,while the peak at a heating rate of 100℃/h occurred at 850℃.In the process of heating up,the coarsening rate of Cu particles at a heating rate of 100℃/h was slower than that at 40℃/h.When the temperature was increased to above 900℃,Cu particles underwent obvious coarsening and dissolution,which released the pinning effect and resulted in secondary recrystallization.These results indicate that Cu particles are an effective inhibitor in Fe-3%Si-Cu oriented silicon steel.