Application and Study on Heat Transfer Model for Continuous 82B Billet Casting
The centerline segregation in the 82B steel billet reduces seriously the final product quality; it is closely related to the unreasonable secondary cooling water system. This paper has established a two-dimensional non-steady-state heat transfer model for the continuous 82B billet casting process, and optimized the existing secondary cooling water scheme, The results show that: the strand surface temperature falling rate is lower than the center temperature falling rate in the original cooling water scheme; it is necessary to add an additional cooling subzone after the fourth subzone for decreasing centerline segregation; the optimal cooling water scheme is that cooling intensity of the fifth subzone is increased by 150% compared with the original fourth subzone.
Study on Influences of Physical Property Parameters on Model Calculation Results of Heat Transfer in the Continuous Casting Mold
This research had developed a two-dimensional non-steady state heat transfer mode with the actual condition of a billet continuous caster.The influences of thermal conductivity coefficient,specific heat and density on the calculation results of the heat transfer model were studied.The calculation results showed that the billet surface center temperature increased with increasing of the thermal conductivity coefficient,while the billet center temperature decreased;the billet temperature increased with increasing of the specific heat and density,these were related to the influences of the thermal conductivity coefficient,specific heat and density on the accumulation and release of heat in the billet.In consideration of influence level of the thermal conductivity,density,specific heat on the model calculation results,the influence of thermal conductivity coefficient was the largest;the specific heat the second,the density relatively small.
Finite element analysis of electromagnetically driven flow in sub-mold stirring of steel billets and slabs
This paper describes a new method for solving coupled three-dimensional electromagnetic and fluid flow equations in induction systems and its application to electromagnetic stirring in continuous casting of steel. This method is based on the differential-integral potential formulation of the electromagnetic field, and is capable of computing the field for any given stirrer configuration without solving the magnetic field in free space. The turbulent flow in the melt is represented by time averaged Navier–Stokes equation together with k-e turbulent model. The finite element formulation of the governing equations is also presented. Computed results were presented for the electromagnetic force distribution, velocity and turbulent parameters in rotary stirring of billets and linear stirring of slabs during continuous casting of steel. For rotary stirring, it was found that the electromagnetic forces are confined to the region surrounded by the stirrer, and the effective flow region is about twice the length of the stirrer and the flow exhibits weak axial velocity component. It was also found that the flow is turbulent with a maximum intensity of about 15% of the mean velocity, and decays rapidly above the edges of the inductor. For linear stirring of slabs, the spatial variation of the force field along and across the slab was found to generate a more complex flow pattern than predicted by two-dimensional analysis. The turbulent intensity was found to increase monotonically in the direction of the traveling force field.