Effect of hot-rolling texture on the plastic strain ratio of low-carbon steels
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The effect of h o t - r o l l i n g texture on the p l a s t i c s t r a i n r a t i o of a c o n t i n u o u s l y c a s t l o w - c a r b o n s t e e l and a v a c u u m - m e l t e d l o w - c a r b o n i r o n has b e e n i n v e s t i g a t e d as a function of the t e m p e r a ture of hot r o l l i n g . N o r m a l cold r o l l i n g and a s i m u l a t e d box a n n e a l , in dry hydrogen to d e c a r b u r i z e , were e m p l o y e d s u b s e q u e n t l y . The m i c r o s t r u c t u r e and t e x t u r e at e v e r y stage of the p r o c e s s was e x a m i n e d , and the p l a s t i c s t r a i n r a t i o (R value) of the final s t r i p was d e t e r m i n e d . R e s u l t s indicate that R v a r i e s s t r o n g l y with the h o t - r o l l i n g t e m p e r a t u r e . O p t i m u m R v a l u e s were obtained when the h o t - r o l l i n g t e m p e r a t u r e was 925 ~ to 950~
IN 1950 Lankford
e t a l . 1 r e p o r t e d that d r a w a b i l i t y of c o l d - r o l l e d and a n n e a l e d s h e e t s was c l o s e l y r e l a t e d to the p l a s t i c a n i s o t r o p y n o r m a l to the sheet s u r f a c e . The evolution of the p l a s t i c s t r a i n r a t i o , R, as d e t e r m i n e d f r o m s i m p l e t e n s i l e t e s t s , has allowed for b e t t e r e v a l u ation of d r a w a b i l i t y . B u r n s and Heyer 2 s t u d i e d the r e l a t i o n s h i p between /~ (average value of R m e a s u r e d in t h r e e d i r e c t i o n s ) and t e x t u r e s and concluded that the c u b e - o n - c o r n e r o r i e n t a t i o n , (111)[110] , tended to i n c r e a s e /~ and to i m p r o v e d r a w a b i l i t y . In r e c e n t y e a r s a l a r g e amount of work has b e e n devoted to the study of the effects of n u m e r o u s v a r i a b l e s upon the d r a w a b i l i t y of l o w - c a r b o n s t e e l s h e e t s . T h e s e i n c l u d e hotr o l l i n g conditions, c o i l i n g t e m p e r a t u r e , amount of cold r e d u c t i o n , pre and p o s t c o l d r o l l i n g heat t r e a t m e n t s , final a n n e a l i n g t e c h n i q u e s , as well a s the effects of s m a l l additions of a l l o y i n g e l e m e n t s . Hot m i l l p r a c t i c e for l o w - c a r b o n s t e e l s h e e t s with acceptable d r a w a b i l i t y h a s b e e n s t a n d a r d i z e d for a long time. Hindson 3 h a s r e v i e w e d the d e s i r a b l e hotr o l l i n g p r a c t i c e s and the c o n t r o l of m i c r o s t r u c t u r e for s u b s e q u e n t d r a w a b i l i t y . N o r m a l l y the f i n i s h i n g t e m p e r a t u r e is n e a r the e q u i l i b r i u m A3 t e m p e r a t u r e , a l though slightly lower t e m p e r a t u r e s m a y be used p r o vided that f e r r i t e does not f o r m . Whiteley and Wise 4 s t u d i e d the effect of h o t - r o l l i n g t e m p e r a t u r e on the h o t - r o l l e d t e x t u r e and the s u b s e q u e n t a n n e a l e d t e x t u r e of r i m m e d s t e e l . T h e y found that after high
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