| At present,due to the strong development momentum of new energy vehicles,China has increased support for new energy vehicles and clarified the strategic emerging industry status of new energy vehicles.According to the rapid growth of new energy vehicles,experts predict that by 2025,the market for new energy vehicles will reach 20 billion yuan.The high strength non-oriented electrical steel is the core material for making new energy motor core,so it is a hot topic to produce high magnetic induces,low iron loss and high strength non-oriented electrical steel.However,there are few studies on the influence of different rolling deformation distribution systems on the final microstructure,texture and precipitation of high-strength non-oriented silicon steel.Based on double roll thin strip casting process,in this paper,the volume of hot rolled and cold rolling of the high-strength non-oriented silicon steel are distributed and the evolvement rules of tissue,texture and precipitation are studied under different rolling deformation distribution systems.The contents and results of this study are as follows:(1)The structure,texture and precipitate characteristics of the casting belt are studied.The experimental results show that the cast structure is a large cylindrical grain and these grains are characterized by a strong ? fiber orientation.Furthermore,the texture density of the texture is near the spin cube texture.AlN and MnS precipitate out of the matrix,and the precipitation phase is about 100nm,at the same time Cu precipitate out.(2)Study the microstructure,texture and precipitation phase evolution of hot rolled plate under different hot rolling pressure.With the increase of hot rolling reduction,columnar crystals become equiaxed grains along the rolling direction,and the grains rotate.The texture gradually transforms from {001}<100>texture to{001}<110>texture,and a small number of components of gamma texture begin to appear.The precipitation of AlN and MnS increases to about 200nm,and the pinning effect on grain boundary is obviously weakened,and there is a small amount of Cu in the position of dislocation denser.(3)Study the microstructure and texture evolution of cold rolled plate under different cold rolling pressure.With the cold rolling reduction increases,shear zone increased gradually thicker,and the rolling direction angle decreases,the main form of the {001}<110>rotation cube texture,{112}<110>texture and a small amount of{111}<110>,{111}<112>texture,deflect along the a line to the direction of ?increase.(4)The effects of aging treatment on the evolution of tissue,texture and precipitation in different distribution systems were studied.With the increase of the amount of cold rolling,the recrystallization rate accelerates,the recrystallization grain becomes small and a texture is gradually weakened.The size of the second phase particles of AlN and MnS continues to increase,the size is concentrated in the 200?300nm,and the magnetic domain wall pinning is lost,and the Cu element is fully dissolved into the matrix.(5)The evolution of microstructure,texture and precipitation phase is studied by aging treatment.The grain size did not change significantly with the increase of aging time.The 4 process schemes all retained a high {100} texture.There were Goss textures and {111} textures of a certain component in the different processes,showing excellent magnetic properties.The second phase size of AlN and MnS increases slowly,and the Cu is evenly dispersed and precipitated,the precipitation size is between 5-15nm and the precipitation strengthening effect is obvious.(6)Compare the magnetic properties and mechanical properties of different process flow,and determine the optimum technological process for the experimental steel.The C process(44%hot rolling+75%cold rolling+860? solid solution for 120s+550? aging for 60min)is the best process.Under the premise of good magnetic performance,it has higher yield strength Rp0.2=679MPa and tensile strength Rm=765MPa. |
PDF Full Text Request