Stirring and its effect on aluminum deoxidation of steel in the ASEA-SKF furnace: Part I. Plant scale measurements and p
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r e c e n t y e a r s l a d l e r e f i n i n g p r o c e s s e s have g e n e r ated c o n s i d e r a b l e i n t e r e s t as a m e a n s of s t a i n l e s s s t e e l p r o c e s s i n g . As the t e r m ladle r e f i n i n g i m p l i e s , a c o m m o n f e a t u r e of t h e s e o p e r a t i o n s is that the r e fined m e t a l m a y be poured i m m e d i a t e l y into m o l d s and thus the use of an i n t e r m e d i a t e t r a n s f e r ladle is e l i m i nated. In one of t h e s e new d e v e l o p m e n t s , the VOD P r o c e s s , a s t a i n l e s s s t e e l m e l t is r e f i n e d in vacuo b y top blown oxygen, while s o m e agitation is b e i n g p r o v i d e d b y a s m a l l quantity of bottom blown argon. An a l t e r n a t i v e is the ASEA-SKF o p e r a t i o n , ~ w h e r e m o l t e n s t e e l is heated and a r e d u c i n g s l a g is m e l t e d in a r e f i n i n g ladle b y m e a n s of an e l e c t r i c a r c and a g i tated e l e c t r o m a g n e t i c a l l y while exposed to the a t m o s p h e r e . In a s u b s e q u e n t phase of the o p e r a t i o n the s y s t e m is evacuated while m a i n t a i n i n g the m a g n e t i c s t i r r i n g . D u r i n g this t i m e the alloying additions a r e made and the c o m b i n e d effect of v a c u u m t r e a t m e n t and e l e c t r o m a g n e t i c s t i r r i n g is thought to p r o m o t e both efficient deoxidation and d e s u l f u r i z a t i o n . At Kawasaki Steel C o r p o r a t i o n both the VOD and the ASEA-SKF p r o c e s s e s a r e used l a r g e l y as f i n i s h i n g o p e r a t i o n s for s t a i n l e s s s t e e l , where the final bath c o m p o s i t i o n is a d j u s t e d through alloy additions and deoxidation is b e i n g c a r r i e d out. F o r this r e a s o n , the d e v e l o p m e n t of a b e t t e r u n d e r s t a n d i n g of s t i r r i n g p h e n o m e n a and its effects on deoxidation a r e of p r i m e i n t e r e s t . In a r e c e n t p a p e r work has b e e n p r e s e n t e d on m i x i n g and deoxidation k i n e t i c s in the VOD o p e r a t i o n ; a the p u r p o s e of the work to be d e s c r i b e d in the p r e s e n t p a p e r is to r e p o r t on p l a n t s c a l e t r i a l s u n d e r t a k e n with K. NAKANISHIand T. FUJII are Senior Researcher and Researcher, respectively, Research Laboratories, Kawasaki Steel Corp., Chiba 280, Japan. J. SZEKELYis Professor of Chemical Engineering,SUNY at Buffalo, Buffao, N.Y. 14214. Y. MIHARAand S. IWAOKAare respectively, Assistant Manager,Technical and Quality Control Section and General Manager, Manufacturing Department, Nishinomiya Works, Kawasaki Steel Corp., Nishinomiya-shi,Hyogo-ken 662, Japan. Manuscript submitted April 5, 1974. METALLURGICALTRANSACTIONSB
the view of o b t a i n i n g a b e t t e r u n d e r s t a n d i n g of m i x i n g p h e n o m e n a and of deoxidation k i n e t i c s in the e l e c t r o m a g n e t i c a l l y s t i r r e d ASEA-SKF p r o c e s s . While n u m e r o u s s t u d i e
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