Segregation at halfway cracks in continuously cast steel
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s i z e . I n e r t ion s p u t t e r etching was u t i l i z e d to obtain the a p p r o x i m a t e depth d i s t r i b u t i o n of d i f f e r e n t e l e m e n t s a w a y f r o m the f r a c t u r e s u r f a c e s . Both of t h e s e I N T E R N A L c r a c k i n g i s often o b s e r v e d in c o n t i n u o u s l y t e c h n i q u e s have been r e v i e w e d in d e t a i l e l s e w h e r e , but c a s t s t e e l b i l l e t s and s l a b s . T h e c r a c k s a r e g e n e r a l l y it i s i m p o r t a n t to note that AES p r o v i d e s the e l e m e n t a l i n t e r d e n d r i t i c and exhibit s m o o t h i n t e r f a c e s containing a high d e n s i t y of i n c l u s i o n s . 1 T h e a p p e a r a n c e of the c o m p o s i t i o n of the top few a t o m i c l a y e r s of a s u r f a c e c r a c k s i n d i c a t e that they f o r m by a h o t - t e a r i n g p r o c e s s and the SAM technique c o u p l e s this s u r f a c e s e n s i t i v i t y in which s e p a r a t i o n o c c u r s along an i n t e r d e n d r i t i c with s p a t i a l r e s o l u t i o n . 4-6 The r a t e of r e m o v a l d u r i n g liquid l a y e r . the i n e r t ion etching p r o c e d u r e was c a l i b r a t e d u t i l i z i n g On the b a s i s of d e f o r m a t i o n s t u d i e s at high t e m p e r Ta2Os f i l m s of known t h i c k n e s s . Although the use of a t u r e s it has b e e n p r o p o s e d that g r a i n b o u n d a r y f a i l u r e such a s t a n d a r d is not d i r e c t l y a p p l i c a b l e to rough n e a r m e l t i n g t e m p e r a t u r e s o c c u r s by i n c i p i e n t melting s t e e l f r a c t u r e s u r f a c e s , it p r o v i d e s a c o n v e n i e n t u p p e r due to the p r e s e n c e of a high c o n c e n t r a t i o n of p h o s p h o l i m i t on the r e m o v a l r a t e and has been shown to be a r u s at the b o u n d a r i e s . 2 It has a l s o b e e n r e p o r t e d that r e a s o n a b l y a c c u r a t e m e t h o d of d e t e r m i n i n g a p p r o x i m a t e high sulfur l e v e l s in c o n t i n u o u s l y c a s t s t e e l r e s u l t s in a depth d i s t r i b u t i o n s of c h e m i c a l v a r i a t i o n s at i n t e r h i g h e r i n c i d e n c e of longitudinal s u r f a c e c r a c k s . 3 face s .6 E x a m i n a t i o n of the s u r f a c e of a halfway c r a c k by nonA t y p i c a l a n a l y s i s c o n s i s t e d of f r a c t u r e in s i t u (to d i s p e r s i v e X - r a y a n a l y s i s on a s c a n n i n g e l e c t r o n m i p r e v e n t a t m o s p h e r i c c o n t a m i n a t i o n of the r e a c t i v e c r o s c o p e (SEM) r e v e a l s no s o l u t e c o n c e n t r a t i o n at the m e t a l s u r f a c e s ) , followed by SAM a n a l y s i s , including s u r f a c e o t h e r than at i s o l a t e d i n c l u s i o n s 3 The p r e s e n t s e c o n d a r y e l e c t r o n (SED) i m a g e s , A u g e r c h e m i c a l i n v e s t i g a t i o n was u n d e r t a k e n to d e t e r m i n e if s o l u t e m a p
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