Ductile-brittle transition in interstitial free iron alloys
- PDF / 639,784 Bytes
- 2 Pages / 612 x 792 pts (letter) Page_size
- 61 Downloads / 197 Views
a l l c a s e s w a s by c l e a v a g e , F i g . 2 . S i n c e a l l o y s u s e d by L e s l i e et a l . a p p a r e n t l y did not c o n t a i n a n y a l u m i n u m , i t i s p o s s i b l e t h a t r e s i d u a l o x y g e n m a y be r e s p o n s i b l e f o r t h e l a c k of g r a i n s i z e d e p e n d e n c e o f t r a n s i t i o n t e m p e r a t u r e o b s e r v e d by t h e s e a u t h o r s . F o r the F e r -
T a b l e I . I m p a c t D u c t i l e - B r i t t l e T r a n s i t i o n Temperatures
INDRA GUPTA
Grain Size* Material
IN a r e c e n t p a p e r L e s l i e
el a l . 1 r e p o r t e d that in a n
" i n t e r s t i t i a l f r e e " i r o n ( F e - 0.15 p c t Ti) t h e r e i s l i t t l e a p p a r e n t g r a i n s i z e d e p e n d e n c e of the d u c t i l e b r i t t l e t r a n s i t i o n t e m p e r a t u r e ( D B T T ) . They f u r t h e r s t a t e d t h a t it is s a f e to a s s u m e t h a t a s i m i l a r b e h a v i o r w o u l d be o b s e r v e d in " i n t e r s t i t i a l f r e e " b i n a r y i r o n a l l o y s . In v i e w of the i m p a c t t h a t t h e s e r e s u l t s c o u l d have on f u t u r e r e s e a r c h i n u n d e r s t a n d i n g t h e d u c t i l e b r i t t l e t r a n s i t i o n in i r o n b a s e a l l o y s , t h i s c o m m u n i c a tion r e p o r t s d a t a w h i c h a r e c o n t r a r y t o the a b o v e o b servations. L e s l i e a n d S o b e r2 h a v e s h o w n that an a d d i t i o n of 0.15 pct T i t o i r o n c o m b i n e s w i t h t h e i n t e r s t i t i a l s a n d the m a t e r i a l b e h a v e s a s e s s e n t i a l l y a n " i n t e r s t i t i a l f r e e " i r o n . The two " i n t e r s t i t i a l f r e e " a l l o y s s t u d i e d in the p r e s e n t w o r k , n a m e l y i r o n a n d F e - N i , h a d t h e following compositions:
Fe Fe-Ni
Ti
A1
Ni
0.15 wt p c t 0.16 wt p c t
0 . 0 3 4 wt p c t 0 . 0 3 5 wt p c t
-1.84 wt p c t
p
Approx ASTM No. DBTT, °F
30.6 190t Fe (0.15 wt pct Ti) 338 37t 244t
6,8 1.4 0 6.2 0.7
-47 +15 ~+50 -60 +5
Full size (10 mm wide) Full size (10 mm wide) Full size (10 mm wide) Subsize (6.66 mm wide) Subsize (6.66 mm wide)
Fe-Ni 22.8 (0.16 wt pct Ti) 160
7.5 2.0
-105 -50
Full size Full size
Ferrovac-E (75 ppm C+N)
6.6 2.2
25 65
32t 150t
INDRA G U P T A is Research Engineer, Inland Steel Research Laboratories, East Chicago, Ind. Manuscript submitted July 7 , 1970. MI:TALI.(tR(;IC,%I
FRANSA('TIONS
Subsize (6.66 mm wide) Subsize (6.66 mm wide)
*Grain size taken as mean linear intercept. fGrain size obtained by recrystallization below the A3 temperature.
260 []... A
220
180
D i f f e r e n t g r a i n s i z e s i n b o t h a l l o y s w e r e o b t a i n e d by hot r o i l i n g o r f u r n a c e c o o l i n g f r o m a b o v e t h e A~ t e m p e r a t u r e . In the c a s e of i r o n , d i f f e r e n t g r a i n s i z e s w e r e a l s o o b t a i n e d by c o l d w o r k i n g ( r o l l i n g o r u n i axial tension) a n d subsequent recrystalliz
Data Loading...
