Numerical Simulation Of Continuous Casting Billet During Solidification And Heat-transfer Process

With the development of continuous casting technique, improving output and quality of products becomes an important problem in continuous casting research. By reason of these advantages, such as low manufacturing cast, operational efficiency, flexible operation, and high quality and so on, continuous casting develops speedily in the field of steel all over the world. Nowadays, high efficiency continuous casting developed as a major trend. In the heat-transfer process of billet solidification, temperature is concerned terribly; it has relation with the output and quality of billet, and decides if the high efficiency continuous casting is able to go with a swing. Quality of billets is related to the solidifying process and casting billets solidify completely in secondary cooling zone, so the research of solidifying in secondary cooling zone is significant to understand solidification behavior and insure the products quality. For many years, people study continuous casting by means of experiments, measurement and numerical simulating. With the development of computing technique, numerical simulating has become an important method for continuous casting study.One-dimension thermal field of round billet and two-dimension thermal field of square are simulated according to heat-transfer rational and finite difference method. Implicit difference scheme is used to get discrete equation of round billet thermal field and calculated by shooting method; central difference scheme is used to get discrete equation of square billet.Through the analysis of crystallizer, the results show that decreasing the thickness of crystallizer could increase the thickness of billet, but it is not visible, and decreasing the thickness of crystallizer could make the temperature field of crystallizer uniform. So the thickness of crystallizer should decrease under the condition of enduring enough intensity of crystallizer. If billet section is squareness,using circular arc in the corner of crystallizer could improve the heat transfer of crystallizer and billet, it is in favor of forming the thickness of billet and protecting the crystallizer.The program for one-dimension heat transfer model of round billet and two-dimension heat transfer model of square billet are developed by c language. According to calculating, thermal field distribution of cross section at different time is founded; on the condition of different pulling rate, different degree of superheat and different intensity of cooling, the law of billet surface temperature and thickness are researched in the process of solidification.Through the simulation of surface temperature, changing behavior of surface temperature in different operational condition is analyzed. The results show that pulling rate and intensity of secondary cooling zone are major factor to control freezing rate and quality in the process of solidification, but the influence of degree of superheat on surface temperature and billet thickness growing is less than the forward. So appropriate combination is required between velocity and intensity of secondary cooling zone to improve output and ensure quality in practical produce.The results simulated also supply theory gist for self-designed continuous caster.