Investigation On Recrystallization Texture And Preparation Process Optimization Of Twin-Roll Strip Casting 4.5wt.%Si Steel

Twin-roll strip casting technology is an advanced technology for iron and steel production.It is the rapid solidification and rolling process simultaneously,the direct production of less than 6mm of the cast strip.In recent years,twin-roll strip casting has been applied to the manufacture of non-oriented silicon steel.This new technology can shorten the preparation process by more than 30%and reduce energy consumption and harmful gas emissions by more than 25%.It is the focus of research by steel companies and scientific researchers in various countries.In this paper,the goal is to prepare non-oriented silicon steel with high magnetic permeability and low iron loss.Design and strip casting of 4.5wt.%Si non-oriented silicon steel thin strip.Using optical microscope?OM?,X-ray diffractometer?XRD?and the backscattered electron diffraction?EBSD?technique examined and analyzed the evolution of the metallographic structure,micro-texture and macro-texture during the cold rolling process.And explored its recrystallization behavior and nucleation theory.The research findings of the paper include:?1?One-step rolling and two-step rolling treatments were studied.And the effects of different rolling processes on the structure and texture evolution of 4.5wt.%Si non-oriented silicon steel on mechanical properties and magnetic properties were discussed.Typical microstructural characteristics of non-oriented silicon steel with one-step cold rolling were obtained.The maximum texture intensity was located at the Goss component,while unfavorable components had a high proportion.Two-step cold rolling extremely changed the evolution of texture and microstructure.After the second cold rolling with 7.9%reduction,the annealed microstructure was composed of coarse grains,and the recrystallization texture exhibited strong{100}<001>and near Goss components.For one-step cold rolling process,the tensile strength can reach 719.53MPa after recrystallization annealing,while the magnetic properties were not as good as the two-step cold rolled specimen.The magnetic induction(B₅₀)of1.612 T and core loss(P_15/50,P_10/400 and P_5/1000)of 3.061 W/kg,21.43 W/kg and 25.07W/kg can be obtained by second cold rolling of 7.9%reduction.?2?The effect of different initial grain size on the microstructure,texture evolution and ultimate magnetic properties of the non-oriented silicon steel containing4.5wt.%Si was discussed.The twin-roll strip casting technology was used to prepare the cast strip with equiaxed crystal structure.Process optimization through alloy composition and initial grain size.The 4.5wt.%Si cast strip was cold rolled and recrystallized and annealed to obtain a strong?recrystallized texture.As the initial grain size increases,the{100}texture of the final annealed plate increases,and the magnetic properties are further improved.?3?Optimization of the initial structure and rolling process were adopted.The test equipment was used to successfully prepare the 0.15mm⁰.2mm thick 4.5wt.%Si thin strip.It is studied that annealing treatment can suppress the existence of unfavorable texture and increase the proportion of favorable{100}and{110}texture.The annealed sheet after 90.5%cold rolling reduction,the new nucleation without distortion occurs simultaneously at the shear zone and at the grain boundary.The advantage of the?texture nuclei was reduced.After recrystallization,the??<100>//ND?texture with a peak at{100}<140>orientation and{100}<160>orientation were existed.But the strong points were concentrated in the{112}<111>orientation.The??<100>//ND?texture decreases with the increase of the cold rolling reduction rate.The texture of{115}<120>orientation,{112}<111>orientation and{110}<223>orientation were found in the anneal sheet,and the component of{112}<111>was further enhanced.?4?The effects of one-step cold rolling process and two-step cold rolling process on structure and texture were studied.In the final annealing sheet of one-step cold rolling,the recrystallized grain size is smaller and the average grain size was 27.24?m.The recrystallized texture is mainly composed of??<110>//RD?texture and??<111>//ND?texture,and the texture intensity peak was at{111}<112>component.Compared with the one-step cold rolling method,the two-step cold rolling method is beneficial to release part of the deformation stored energy and suppress the?fiber texture.Increase grain sizes and favorable texture components.The recrystallized texture was a strong{113}<251>orientation and a weak{112}<111>orientation,which significantly improves its magnetic properties.