A Mathematical model of the closed mold (Watts) horizontal continuous casting process
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c l o s e d m o l d (Watts) h o r i z o n t a l c o n t i n u o u s c a s t i n g p r o c e s s i s a p o t e n t i a l l y v e r y a t t r a c t i v e r e c e n t dev e l o p m e n t 1 i n the a r e a of c o n t i n u o u s c a s t i n g . T h e s y s t e m i s s k e t c h e d in F i g s . l(a) to l(c) w h e r e it is s e e n i n (a) that i n i t i a l l y m o l t e n s t e e l i s d i s c h a r g e d f r o m a t u n d i s h (1) t h r o u g h a n o z z l e (2) into a h o r i z o n t a l , w a t e r - c o o l e d c l o s e d end mold (3). F i g . l(b) d e p i c t s the s y s t e m s o m e t i m e a f t e r the c o m m e n c e m e n t of the c a s t i n g p r o c e s s , when a s o l i d i fied s h e l l of s u f f i c i e n t t h i c k n e s s has b e e n f o r m e d , the m o l d i s m a d e to m o v e away f r o m the tundish; the exp o s e d s u r f a c e of the s h e l l (4) is cooled by w a t e r s p r a y s (5) and then by r a d i a t i o n s u b s e q u e n t l y m o l t e n s t e e l i s supplied to the mold f r o m the t u n d i s h t h r o u g h the " p i p e " f o r m e d by the s o l i d i f i e d c r u s t . F i g . l(c) d e p i c t s the s h e l l and the m o l t e n m e t a l s t r e a m i n g r e a t e r d e t a i l . T h i s f i g u r e a l s o shows the c o o r d i n a t e s y s t e m for c a s t i n g a s l a b of half t h i c k n e s s , W. F o r a c o n s t a n t c a s t i n g s p e e d i.e., mold t r a v e l r a t e , Uo, the l i n e a r v e l o c i t y of the m e t a l s t r e a m , u(t, x) w i l l be v a r i a b l e b e c a u s e of the n o n u n i f o r t u i t y of the s o l i d i f i e d s h e l l . The s h a p e s k e t c h e d for the s o l i d i f i e d s h e l l i s a r b i t r a r y at t h i s s t a g e b e c a u s e t h i s shape will have to be d e t e r m i n e d s u b s e q u e n t l y f r o m the a n a l y s i s . T h e o p e r a t i o n of the s y s t e m m a y b e c o n t i n u e d while the " o p e n p i p e " i s m a i n t a i n e d , s u c h that m o l t e n m e t a l c a n be s u p p l i e d to the m o v i n g m o l d . The p r i n c i p a l a t t r a c t i v e n e s s c l a i m e d for the W a t t s H o r i z o n t a l C o n t i n u o u s C a s t i n g S y s t e m (WHCCS) i s V. STANEK is with Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6 - Suchdol, Czechoslovakia. J. SZEKELY, formerly of the Department of Chemical Engineering, State University of New York at Buffalo, is now Professor of Materials Engineering,Massachusetts Institute of Technology, Cambridge, MA 02139. Manuscript submitted August 19, 1975. METALLURGICALTRANSACTIONSB
that in contrast to conventional continuous casting operations, the molten metal stream is turbulent throughout and m o v e s past the solidified shell at a finite velocity. This relative motion of the molten stream, together with the turbulence in the bulk of the melt is thought to suppress dendrite formation and thus minimize segregation. It has been suggested that because of this reason,
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