| Grain oriented silicon steel with the main inhibitors of Cu2 S and MnS has warm-rolled at 50300 ℃.And then,all warm-rolled sheets are subjected to primary and secondary recrystallization annealing.The evolution rule of microstructure,texture and precipitate along the whole processing routes has been investigated by means of optical microscope（OM）,electron back-scattered diffraction（EBSD）,X-ray diffraction（XRD）and transmission electron microscope（TEM）.The magnetic properties of the steel strip after the secondary recrystallization annealing of four kinds of rolling temperature were detected by magnetic property tester.According to the low iron loss and high magnetic induction performance requirements of silicon steel to optimize a reasonable temperature of the rolling process parameters,For the development of high-performance electrical steel strip put forward new methods and ways to achieve green,low cost,high performance oriented silicon steel development.Main conclusions are expressed as follows:（1）The microstructure along the thickness direction of the hot-rolled plate is not uniform.The surface layer is composed of equiaxed grains with an average size of 30 μm,while the 1/4 layer and center layer contain the elongated grains with size of 15.8 μm and some banded carbides.After warm-rolled,surface layer and center layer are composed of lots of fiber grains.The microstructure of primary recrystallization annealing contains mainly the fine equiaxed grain,and the grain size in the surface layer is smaller than that of grains in the center.After secondary recrystallization annealing,the abnormal growth phenomenon occurs in all warm-rolled sheets,and the average grain size of the product rolled at 50 ℃,100 ℃,200 ℃ and 300 ℃ is about 3.5 mm,2.3 mm,4.5 mm and 3.8mm,respectively.（2）With the increase of warm-rolled temperature,the core loss of the final annealed sheets increases gradually,and the magnetic induction value goes up firstly and then lows down,which exhibits a maximum value at the 200 ℃ warm-rolled sample.The B8 of products warm-rolled at 50 ℃ and 200 ℃ is 1.711 T and 1.780 T,and P1.7/50 is 2.975W/kg and 3.229 W/kg,respectively.（3）The texture of warm-rolled sheets contains mainly the α-fiber（<110>//RD）texture with a maximum value of intensity at {001}<110>,and also the strong γ-fiber（<111>//ND）texture.Moreover,the intensity of γ-fiber at the surface layer is higher than that at the center layer.After primary recrystallization annealing,the α-fiber weakens significantly,and the strong γ-fiber texture and the weak Goss（{110}<001>）texture dominant.Furthermore,the α-fiber texture and the γ-fiber texture in primary-recrystallized sheets warm-rolled at 50 ℃ and 200 ℃ are stronger than that in other samples.（4）The amount proportion of low angle grain boundary with large angle grain boundary is about 3:2 in the hot-rolled sheet.However,the proportion changes into about3: 1 in the warm-rolled sheet,and the amount of the Σ3Σ11 grain boundary occupies a high proportion.（5）For hot-rolled sheet,the MnS particle precipitates firstly and the Cu2 S particle precipitates subsequently when the hot-rolled temperature decreases.In hot-rolled sheets,the Cu2S-MnS particle is mainly formed by the complex precipitation form,which has average size of 43nm and number density of 1.5×109/cm2.The Cu2S-MnS particle formed by the complex precipitation form also exists in the warm-rolled sheet,and some AlN particles are also observed.After primary recrystallization annealing,the fine and dispersed Cu2 S and MnS particles with average size of 52.9 nm and number density of2.5×1010/cm2 dominant.Compared to the hot-rolled sheet,the precipitate size in the primary-recrystallized sheet is larger and more uniform,which shows a greater role of the particle pinning grain boundary. |
