Texture in deep drawing columbium (Nb)-treated interstitial-free steels
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J. HECKLER, AND JAMES A. ELIAS
The development of the c r y s t a l l o g r a p h i c t e x t u r e in h o t - r o l l e d , c o l d - r o l l e d , and r e c r y s t a l lized C b - t r e a t e d i n t e r s t i t i a l - f r e e s t e e l s was investigated using the c r y s t a l l i t e o r i e n t a t i o n d i s t r i b u t i o n a n a l y s i s as well as X - r a y pole f i g u r e s . The influence of c h e m i c a l composition of the s t e e l and p r o c e s s i n g v a r i a b l e s on t e x t u r e and on n o r m a l and p l a n a r a n i s o t r o p y of the r - v a l u e of c o l d - r o l l e d and annealed sheet a r e d i s c u s s e d and c o m p a r e d with those of a l u m i n u m - k i l l e d deep drawing s t e e l s . While, in t e r m s of ideal o r i e n t a t i o n components, the r e c r y s t a l l i z a t i o n texture of a l u m i n u m - k i l l e d s t e e l s can be d e s c r i b e d as having significant amounts of {111}(110) and {111}(112} components. C b - t r e a t e d s t e e l s show these components and in addition even s t r o n g e r {554}(225} and {322}(296) components. Distinctions in the hotr o l l e d texture, the c o l d - r o l l e d texture, and the r e c r y s t a l l i z a t i o n t e x t u r e a r e d e s c r i b e d . Cbt r e a t e d s t e e l s have an e n t i r e l y different p l a n a r d i s t r i b u t i o n of r values or p l a s t i c s t r a i n r a tios c o m p a r e d with a l u m i n u m - k i l l e d s t e e l s . The r e s u l t i n g a v e r a g e r value, r m , is s i g n i f i cantly higher for C b - t r e a t e d s t e e l s and r e s u l t s in s u p e r i o r deep drawing c h a r a c t e r i s t i c s .
PRESSforming o p e r a t i o n s employed to produce p a r t s from l o w - c a r b o n s t e e l sheets involve d e f o r mations c h a r a c t e r i z e d p r i n c i p a l l y by a combination of deep drawing and s t r e t c h i n g . A high d e g r e e of n o r m a l p l a s t i c a n i s o t r o p y ( c h a r a c t e r i z e d by a high a v e r a g e p l a s t i c - s t r a i n r a t i o , r m ) is d e s i r a b l e for good deep d r a w a b i l i t y .'I The d e g r e e of n o r m a l p l a s tic a n i s o t r o p y is i n t i m a t e l y r e l a t e d with c r y s t a l l o graphic texture which is developed in these s t e e l s during p r o c e s s i n g . High r m v a l u e s a r e favored by i n c r e a s i n g the {111} fiber t e x t u r e with the fiber axis being p a r a l l e l to the sheet n o r m a l , while at the s a m e t i m e s u p p r e s s i n g the {001}(110) component, z-~ The r e c r y s t a l l i z a t i o n t e x t u r e s of r i m m e d and A l - k i l l e d l o w - c a r b o n s t e e l s have been e x t e n s i v e l y studied, e'~-11 The s t r o n g e r {111} t e x t u r e p r e s e n t in c o l d - r o l l e d annealed A l - k i l l e d s t e e l s it r e s u l t s in higher r m v a l ues and b e t t e r d r a w a b i l i t y than for r i m m e d s t e e l s . It is g e n e r a l l y accepted that p r e c i p
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