Springer Science and Business Media LLC

The hot rolling and cold rolling control models of silicon steel strip were examined. Shape control of silicon steel strip of hot rolling was a theoretical analysis model, and the shape control of cold rolling was a data-based prediction model. The mathematical model of the hot-rolled silicon steel section, including the crown genetic model, inter-stand crown recovery model, and hot-rolled strip section prediction model, is used to control the shape of hot-rolled strip. The cold rolling shape control is mainly based on Takagi-Sugeno fuzzy network, which is used to simulate and predict the transverse thickness difference of cold-rolled silicon steel strip. Finally, a predictive model for the transverse thickness difference of silicon steel strips is developed to provide a new quality control method of transverse thickness of combined hot and cold rolling to improve the strip profile quality and increase economic efficiency. The qualified rate of the non-oriented silicon steel strip is finally obtained by applying this model, and it has been steadily upgraded to meet the needs of product quality and flexible production.

Static recrystallization (SRX) behaviors and corresponding recrystallization mechanisms of 7Mo super-austenitic stainless steel were studied under different deformation conditions. The order of influence of deformation parameters on static recrystallization behaviors, from high to low, is followed by temperature, first-stage strain and strain rate. Meanwhile, the effect of holding time on static recrystallization behaviors is significantly controlled by temperature. In addition, with the increase in temperature from 1000 to 1200 °C, the static recrystallization mechanism evolves from discontinuous static recrystallization and continuous static recrystallization (cSRX) to metadynamic recrystallization and cSRX, and finally to cSRX. The cSRX exists at all temperatures. This is because high stacking fault energy (56 mJ m−2) promotes the movement of dislocations, making the deformation mechanism of this steel is dominated by planar slip of dislocation. Large undissolved sigma precipitates promote static recrystallization through particle-stimulated nucleation. However, small strain-induced precipitates at grain boundaries hinder the nucleation of conventional SRX and the growth of recrystallized grains, while the hindering effect decreases with the increase in temperature.

Using 3-D elastic-plastic FEM, the cold strip rolling process in a 4-high mill was simulated. The elastic deformation of rolls, the plastic deformation of the strip, and the pressure between the work roll and the backup roll were taken into account. The distribution of rolling pressure along the strip width was obtained. Based on the simulation results, the peak value of rolling pressure and the location of the peak were analyzed under different rolling conditions. The effects of the roll bending force and the strip width on the distribution of rolling pressure along the width direction were determined.

To avoid the volume expansion of basic oxygen furnace (BOF) slag for use in building materials, a hot slag modification process was proposed to reduce free CaO (f-CaO) in the molten slag. A transient 3D numerical model of BOF molten slag modification by SiO2 particles was established. The flow and heat transfer of molten slag, movement and dissolution of the modifier, and concentration distribution of f-CaO in slag during the modification of BOF were studied. The distribution of f-CaO concentration is inhomogeneous all over the molten slag. The mixing effect at the slag surface is weaker than that at the half-height plane of the slag. To consume the f-CaO below 2.0 wt.% in the slag, the optimum quantity of the SiO2 modifier is 10.0% of the mass of the slag. The fine SiO2 particles help attain a lower final mass fraction of f-CaO and a higher SiO2 utilization ratio.