Study On Heat Transfer In Mould And Optimization Of Performance For Mould Flux Of FTSC Thin Slab Cast In Tangshan Iron And Steel CO.

Optimization of flux in physical property and chemical components, as one of three critical techniques for thin slab casting, are attached much more importance than before. The first FTSC caster in China was established in Tang Shan Iron and Steel CO. in December 2002. Since it puts into production, there are some accidents happened on occasion, such as cracks, slag inclusion in surface, enclosed slag and mould breakout, which have a severe influence on normal production. Thereby it is urgent to optimize mould flux performance.First, the performance of current mould flux used in Tang Gang FTSC is researched. Then Experimental study and theoretical analysis about chemical components, melting temperature, melting speed, crystallizing point and mineral composition of five kinds of thin slab flux are carried through. Finally, it is concluded that current mould fluxes can't satisfy the requirement of thin slab casting.Mathematical model of heat transfer for thin slab is established in this paper according to the large-scale finite element software– ANSYS, on the basis of which analog simulation of solidifying process for thin slab is carried through. The temperature distribution and growth history of solidifying shell have been described successfully. The influences of different processing parameters on mould heat transfer are also researched, which provide a theoretical basis for setting down rational processing parameters, improving slab quality and reducing mould breakout.In addition, with researching the formation mechanism of slag film, the mathematical model about the film state between mould and solidifying shell is established, and the existential form and state of slag film are discussed, by which the melting temperature of mould flux for low carbon steel SHPC is calculated. Through varying processing parameters, it can be found that there is still a certain thickness of liquid film at the outlet of mould. Thereby lubricating at the form of liquid state in the whole solidifying process can be realized.Crystallizing point suitability for flux of low carbon steel SPHC is determined according to its solidifying characteristic and heat transfer features. Then the optimum viscosity is confirmed by principles ofη1300?Vmatching and stability.