Research And Development Of High-grade Thin-gauge Non-oriented Silicon Steel

In this paper,the high-grade and thin-gauge non-oriented silicon steel is firstly trial-produced,and the microstructure,inclusions and texture characteristics of the through process are systematically studied.On this basis,the effect of the cold rolling reduction rate and annealing process on the microstructure,texture and properties are investigated.Finally,the nucleation and growth process of{114}<481>texture are analyzed and discussed.The main findings are as follows:The 30mm slab microstructure of the trial-produced non-oriented silicon steel is equiaxed grains,and the slab texture is mainly deviated Goss texture.The inclusions in each process section are Al N or composite Al N and Mn S,which reach?m scale.The hot-rolled texture has obvious stratification.The surface layer is deviated brass and copper texture.The 1/4 layer is mainly Goss texture with weak?fiber texture located at{100}<011>.The 1/2 layer is similar to the 1/4 layer,but the intensity of?fiber texture and?fiber texture at the 1/2 layer is obviously enhanced.The surface texture of the normalized sheet located at copper texture,and 1/4 layer texture is?*fiber texture with the{114}<221>and{114}<371>as core.The 1/2 layer texture is?*fiber texture with the peak at{114}<481>and weak?fiber texture.The cold rolled texture is?fiber texture and?fiber texture,while the texture of the annealed plate located at?*fiber texture with{114}<481>as core.The trial-produced non-oriented silicon steel final sheet has excellent magnetic properties with the magnetic induction B₅₀=1.791T and the iron loss P_10/400=15.09W/kg.With the cold rolling reduction rate increased,the fibrillation of the cold-rolled sheet microstructure was more obvious,and the deep-etched{111}orientation area increased;the texture volume of cold-rolled?fiber increased,and the?fiber reduced;the grain size of the annealing plate at 1030?×3min reduced,and the annealing texture transformed from{111}<112>to{114}<481>;the annealed sheet P_10/400decreased,and the proportion of eddy current loss decreased.With annealing temperature increased for 3min,the texture of annealed sheets rotated from strong{111}<112>texture to{111}<112>coexisting with{114}<481>strong texture,and finally the strength of{111}<112>texture weakens while single{114}<481>texture strengthens;iron loss P_10/400decreased,which confirmed that increasing the annealing temperature benefits to reduce the iron loss.The annealing time increased at955?,all texture located at?*fiber texture with the peak at{114}<481>,while the texture volume of{114}<481>almost unchanged;P_10/400increased,and B₅₀decreased,which confirmed that increasing the annealing times is not conducive to the magnetic properties.Therefore,the high temperature and short time annealing process is more suitable for ultra-thin non-oriented silicon steel.Annealing at 1030?,1s annealed sheet is not completely recrystallized and the{114}<481>grains are mainly nucleated at the grain boundary area of{111}<112>,{111}<110>and{001}<001>grains,{114}<110>inner deformed band and{114}<481>substructure.2s annealed sheet has been completely recrystallized,while compared to{114}<481>,the{111}<112>grains will nucleate and grow preferentially;in the 10s stage,both{111}<112>and{114}<481>grains will continually grow,but the growth rate of{111}<112>grains slows down;at the final 180s annealing stage,the growth of{111}<112>grain is further suppressed,while due to the high mobility grain boundaries,size advantages and texture content advantages,{114}<481>grains become the main texture component.