Numerical Study on Solidification Behavior and Structure of Continuously Cast U71Mn Steel

Abstract

Abstract:The solidification behavior and structure of continuous casting high rail U71Mn bloom, under different secondary cooling conditions and superheat, were numerically investigated using the Cellular Automaton-Finite Element (CAFE) model implemented with ProCAST software. Nail shooting and macro etch experiments of the bloom samples under different cooling conditions were conducted to verify the model of macroscopic solidification and structure. The results showed that the simulated results of the solidified shell and solidification structure are basically consistent with experimental results. The secondary cooling condition has little effect on the grain size and distribution of the bloom, while both the bloom surface and corner temperatures are higher and the temperature rise at the beginning of the air-cooling zone is smaller under the super-slow cooling condition. The percentage of center-equiaxed grains decreases from 44.6% to 20.1% and the grain average radius increases from 1.025 to 1.128 mm when the superheat increases from 15 to 40 K, with little change in the grain size occurring between 15 and 20 K. Moreover, for a step increase in the superheat of 5 K, the solidification end is lengthened by about 0.19 m and the surface temperature is enhanced by 3 K. The super-slow secondary cooling condition with the superheat controlled within 20 K is suitable for big-bloom casting.

Laboratory Experimental Setup and Research on Heat Transfer Characteristics during Secondary Cooling in Continuous Casting

“…An optimized transition boiling can help to improve heat transfer for specific spray characteristics. The test model was for carbon steel, but the results equally apply to other materials [24]. However, deviations should be expected due to the surface characteristics of the spray-cooled surface [25].…”

Effect of Mold Electromagnetic Stirring and Final Electromagnetic Stirring on the Solidification Structure and Macrosegregation in Bloom Continuous Casting

“…There were four regions including the chilled zone, columnar zone, mixed zone, and the equiaxed zone. The view [9,15,20] that equiaxed crystals plays an important role in decreasing the center segregation and center porosity was accepted by many researchers. In the current work, the equiaxed crystal ratio is the area ratio between the equiaxed zone and the whole cross section.…”

Numerical and experimental investigation of solidification structure evolution and reduction of centre segregation in continuously cast GCr15 bloom

“…In order to calculate the coefficients for the investigated steel which is composed of various elements (as shown in Table 1), the Bobadilla, Lacaze and Lesoult approach was adopted [16]. Therefore, a 2 and a 3 were determined as 0 and 4.59 × 10 -6 using the ProCAST software, respectively.…”