Abstract
The possibility of correction the application place of soft reduction by adjusting the depth of liquid metal sump in pipe steel slabs by changing the cooling intensity in the secondary cooling zone of the CCM is studied in the work. The research method consists in multivariate calculations according to the algorithm used in the automated system of industrial CCM. Mild steel of strength class K60 was selected for the study (slabs with a cross section of 350 × 2600 mm). The draw speed of casted slab is equaled to 0.75 m per min with three values of metal overheating in the tundish above the liquidus temperature of 14, 19 and 24°C. Relative water consumption have increased from 2 to 33% (rel.) in comparison to the initial meaning. 21 calculations were performed. Linear decreasing dependences of the length of sump in slabs on the relative water consumption for secondary cooling at various overheating of the metal were established. Linear decreasing dependences of the length of sump in slabs on the relative water consumption for secondary cooling at various overheating of the metal were established. The increasing linear dependences of the steel solidification coefficient on the intensity of the secondary cooling for different overheating of the metal are revealed. It should be noted that in the course of 350 mm slabs casting at a speed of 0.75 m / min, it is possible to adjust the location of soft reduction application by correction the length of molten metal sump. For getting the sump length within the zone of the last 15th segment, when the metal overheats is equaled to 19°C, it is necessary to supply water consumption for secondary cooling not less than 25% higher than initial one, for conditions when overheating of metal is 14-15°C% (rel.). The more uniform distribution of water over the width of the casted billet is also recommended.
Keywords
Continuous casting, pipe steel, soft reduction, slab, depth of sump, regulation, secondary cooling.