Primary Recrystallization of Grain Oriented Silicon Steel Strip Rolled by CSR and Annealed in Magnetic Field

The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling （CSR） of different mismatched speed ratio （MSR） and annealed in magnetic field under hydrogen were presented.Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.

Effect of Nitrogen Content on Primary Recrystallization Behavior and Magnetic Property of Hi-B Steel

The effect of nitrogen content on primary recrystallization microstructure,texture and magnetic property of Hi-B steel was studied by means of optical microscopy（OM）,scanning electron microscopy（SEM）,and electron backscatter diffraction（EBSD）.When nitrogen content increased gradually from 0.005 5% to 0.031 0%,the primary grain size and variation coefficient of nitrided sheet reduced from 26.85μm,0.590 to 18.87μm,0.525-0.565,respectively.Meanwhile,the primary recrystallization texture style of nitrided sheet was nearly identical to the texture style of decarburized sheet before nitriding treatment,but exhibiting a certain change on texture intensity.The variation of average magnetic induction value（B8）and core loss value（P17/50）were manifested to be Mshaped and W-shaped curves,respectively.When nitrogen content reached 0.016 0%,the best value of the average magnetic property of the final product was obtained as follows：the B8 and P17/50 were 1.921 Tand 0.968W/kg,respectively.Meanwhile,the best performance,B8 and P17/50,of single sheet was 1.964 Tand 0.854 W/kg.

New process for production of ultra-thin grain oriented silicon steel

The Hi-B silicon steels were cold rolled by cross shear rolling (CSR) with different mismatch speed ratio(MSR)s and conventional rolling(CR) respectively, followed by primary recrystallization annealing. The effects of MSR and annealing temperature on magnetic properties of ultra-thin grain oriented silicon steel were analyzed. Experimental results show that, with the increase of MSR, the magnetic properties can be remarkably improved. The higher the annealing temperature is, the higher the magnetic induction and the lower the iron loss in ultra-thin silicon steel is.

Mesoscopic Analysis of Deformation Heterogeneity and Recrystallization Microstructures of a Dual-Phase Steel Using a Coupled Simulation Approach

Microstructure-based numerical modeling of the deformation heterogeneity and ferrite recrystallization in a cold-rolled dual-phase(DP)steel has been performed by using the crystal plasticity finite element method(CPFEM)coupled with a mesoscale cellular automaton(CA)model.The microstructural response of subsequent primary recrystallization with the deformation heterogeneity in two-phase microstructures is studied.The simulations demonstrate that the deformation of multi-phase structures leads to highly strained shear bands formed in the soft ferrite matrix,which produces grain clusters in subsequent primary recrystallization.The early impingement of recrystallization fronts among the clustered grains causes mode conversions in the recrystallization kinetics.Reliable predictions regarding the grain size,microstructure morphology and kinetics can be made by comparison with the experimental results.The influence of initial strains on the recrystallization is also obtained by the simulation approach.

Characterizing microstructure and texture after recrystallization annealing of Hi-B steel with simutaneous decarburization and nitriding

How to manufacture the high magnetic induction grain-oriented silicon steel（Hi-B steel）by the process featured with the primary recrystallization annealing was demonstrated,during which nitriding and decarburizing were simultaneously realized in laboratory.By the techniques of optical microscope,scanning electronic microscope and electron backscattered diffraction,both the microstructure and the texture in the samples were characterized.The samples had been subjected to nitriding to different nitrogen contents at two specified temperatures using the two defined microstructural parameters：the grain size inhomogeneity factorσ＊and the texture factor AR.The former is the ratio of the mean value to standard deviation of grain sizes;the latter is the ratio of the total volume fraction of the harmful textures to that of beneficial textures including {110}〈001〉.When the N content increased from 0.0055%to 0.0330%after the annealing at both 835 and 875°C,the resultant recrystallized grain size decreased butσ＊changed little;whilst the rise of annealing temperature from 835 to 875°C resulted in the increase in both grain size andσ＊.Moreover,either the injected N content or temperature had insignificant influence on the components of primary recrystallization texture developed during annealing.However,the increase of temperature led to the decreases in both intensity and volume fraction of{001}〈120〉and{110}〈001〉textures but increases in the{114}〈481〉andγfiber textures and the resultant decrease of AR.