| The electromagnetic stirring technology can apply the electromagnetic force generated by the stirring roller to the liquid steel in the slab.It can agitate the liquid steel,and finally achieve the purpose of controlling the convective heat and mass transfer of the liquid steel and the distribution of the solidified shell.With the improvement of computers' computing power,numerical simulation technology can greatly save manpower,material resources and time,and achieve high-value goals at low cost.At present,numerical simulation technology has become an important method to study the influence of electromagnetic stirring on metallurgical continuous casting process.Electromagnetic stirring modes can change the magnetic field distribution in the molten steel and the flow pattern of the molten steel in the continuous casting process,so it can affecting the distribution of the solidified shell.In this paper,the effect of electromagnetic stirring mode and continuous casting parameters on the magnetic field,flow field and solidified shell distribution in the slab were analyzed by numerical simulation method for the ultra-wide slab electromagnetic stirring with segment roller in secondary cooling zone.The conclusions can be summed up as follows:(1)The intensity of induced magnetic in slab increased with the increase of current intensity.For every 20A increase of current intensity,the magnetic field strength increases 12.5mT.The intensity of induced magnetic decreased with the increase of current frequency.The intensity of induced magnetic decreased 6mT when the current frequency increases 2Hz.(2)The electromagnetic force in slab increased with the increase of current intensity.For every 20A increase of current intensity,the electromagnetic force increases 6000N/m3;The electromagnetic force increases first and then decreases as the frequency increases,the maximum electromagnetic force is reached when the frequency is 11 Hz.(3)The electromagnetic stirring mode has a significant effect on the liquid steel flow field.In the reverse electromagnetic stirring mode,a counterclockwise flow field is formed between the two pairs of electromagnetic stirring rollers,and there are four circulating currents;In the same direction electromagnetic stirring mode,two eight-shaped flow fields are formed between the two pairs of electromagnetic stirring rollers;In the single-flow symmetrical electromagnetic stirring mode,two half-circular flow fields are formed symmetrically between the two pairs of electromagnetic stirring rollers;In the double-flow symmetrical electromagnetic stirring mode,two"back-to-back" semi-circular flow fields are formed between the two pairs of electromagnetic stirring rollers;In the single-roller electromagnetic stirring mode,four annular flow fields are formed on the electromagnetic stirring roller.(4)At the horizontal section of the upper electromagnetic stirring roller,the maximum flow rate of liquid steel in the reverse electromagnetic stirring mode is 0.482m/s;The maximum flow rate of liquid steel in the same-direction electromagnetic stirring mode is 0.534m/s;The maximum flow rate of liquid steel in the single-flow symmetrical electromagnetic stirring mode is 0.327m/s;The maximum flow rate of liquid steel in the dual-flow symmetrical electromagnetic stirring mode is 0.314m/s.In the single-roller electromagnetic stirring mode,the maximum flow rate of the molten steel at the horizontal section of the electromagnetic stirring roller is 0.248m/s.(5)The effect of electromagnetic stirring mode on the thickness of the shell is significant.The thickness of the left narrow shell at the exit of the calculation domain is different under different electromagnetic stirring modes.The thickness of the shell is 188.7mm in the reverse electromagnetic stirring mode;The thickness of the shell is 138.7mm in the same direction electromagnetic stirring mode;The thickness of the shell in the single-flow symmetrical electromagnetic stirring mode is 191.1mm;The thickness of the shell in the dual-flow symmetrical electromagnetic stirring mode is 155.1mm;The thickness of the shell in the singleroller electromagnetic stirring mode is 133mm.(6)The casting speed has a significant effect on the thickness of the thickness of the shell,and the superheat has little effect on the thickness of the shell.When the casting speed is increased from 1m/min to 1.2m/min,the thickness of the shell at the exit of the mold is reduced from 20.1mm to 16.8mm.When the superheat is increased from 10K to 30K,the thickness of the shell at the exit of the mold is reduced from 18.8mm to 18.5mm. |
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