Investigation of the influence of temperature-speed mode on the parameters of secondary cooling of continuously casted billet from free-cutting steel

Abstract

Practically the whole steel, including the free-cutting one, is casting by continuous casting machines (CCM). The technological parameters of the free-cutting steel continuous casting have their features, since the high content of Sulphur and phosphor in the free-cutting steel, necessary for its high machinability, increases the probability of fractures and emergency breach of metal. The purpose of the work was study of influence of temperature-speed mode of A12 free-cutting steel casting on cooling agent consumption in the secondary cooling zone of radial type billet CCM. The CCM mold was 900 long with supporting system on the mold frame of two rows of rollers. The secondary cooling (SC) zone comprised four zones of 340, 2360, 3460 and 3610 mm length. The cooling in the first zone is accomplished by water, in the others – by water-air mist. The study was carried out by application of mathematical simulation method to the process of billet secondary cooling, elaborated by V.N. Selivanov. The temperature of the free-cutting steel billet surface was calculated by zones of secondary cooling at various steel temperature in the tundish. The flow density and water consumption in various SC zones determined, necessary to reach the required variation of billet surface temperature. The dependence of total and specific water consumption for the billet cooling on the metal temperature in the CCM tundish determined.