Based on the idea of uniform cooling in
secondary cooling zone of
concasting billet, the spraying cooling structure and jet
layout have been redesigned and optimized to increase a
secondary cooling section. The new secondary cooling model of spraying water for relation between each section water amount Qi (L/min) in secondary cooling zone with molten steel overheating temperature ΔT (℃) and csting speed V (m/min) is established: Qi = a+bv+cv2+d(ΔT-30)+F, where a, b, c, d and F are constant. The practice indicated that the maximum concasting speed of 150 mm×150 mm billet was up to 3.8～4.0 m/min by using optimized secondary cooling structure and model, the concasting billet quality of steel Q235 and steel HRB335 was obviously improved, the microstructure rating units of cast billet such as porosity, segregation and crack was no more than 2, rejection rate decreased by 0.23 percent point, the average month output of steel billet
increased to 94 000 t from 80 000 t and the productivity increased by about 17.5%.