Effect of prior aging on the creep properties of type 316L stainless steel

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Fig. 2-Corrosion resistance of Fe-8A1-0.01C vs Fe-7Cr-8A1-0.05C in (a) 20 pet NaOH (boihng) for 120 11, (b) 5 pct salt spray for 192 h, (c) 1 pct FeC13 for 168 h. Annealed at 845~ Actual size. After Howe. 9

l o c a t i o n d e n s i t y . H o w e v e r , at h i g h e r m a g n i f i c a t i o n , the d i s t r i b u t i o n of d i s l o c a t i o n s was h e t e r o g e n e o u s , with some areas showing a uniform distribution while others exhibiting nonuniform arrangements, i.e., a particular heavy density forming cell structures, per Fig. l(b). T h e t e n s i l e p r o p e r t i e s of t h e s e e x p e r i m e n t a l a l l o y s a r e s i g n i f i c a n t l y h i g h e r t h a n t h o s e o b t a i n a b l e in a n u m b e r of e s t a b l i s h e d f e r r i t i c (and a u s t e n i t i c ) g r a d e s , f o r e x a m p l e T y p e 409 s t e e l , l l . 5 C r b a s e w i t h o r without 0 . 8 N i and w i t h e i t h e r 0 . 0 6 C - 0 . 0 2 T i o r j u s t 0 . 0 2 C . 7,s C o n s e q u e n t l y , a l l o y s of t h i s t y p e d e s e r v e f u r t h e r c o n s i d e r a t i o n f r o m t h e s t a n d p o i n t of t h e i r p e r f o r m a n c e w h e n c a r b o n c o n t e n t i s r a i s e d to 0.02 pct, a practical limit utilizing the AdD process as now d e m o n s t r a t e d on the s u p e r f e r r i t i c g r a d e s . A p plication where corrosion resistance may be seconda r y to o x i d a t i o n r e s i s t a n c e c o u l d be e m p h a s i z e d but a l l o y s h a v i n g 7 to 1 0 C r and 5 to 8A1 a p p e a r to h a v e r e s i s t a n c e c o m p a r a b l e to T y p e 410 and 430 in m o s t c o r r o s i v e m e d i a . A s an e x a m p l e , F i g . 2 s h o w s t h e n e g l i g i b l e l o s s in b o i l i n g 20 p c t s o d i u m h y d r o x i d e (0.005 ipy) and the d e c r e a s e in p i t t i n g b y 5 p c t s a l t s p r a y in a 7 C r - S A 1 - 0 . 0 5 C a l l o y s t u d i e d by H o w e 9 o v e r t w e n t y y e a r s a g o . It w o u l d b e e x p e c t e d t h a t c o r r o s i o n r e s i s t a n c e a b o v e the 7 C r l e v e l c o u l d be i m p r o v e d f u r t h e r by l o w e r i n g c a r b o n c o n t e n t to t h e l e v e l s now p o s s i b l e t h r o u g h t h e A d D p r o c e s s . METALLURGICAL TRANSACTIONS A

Effect of Prior Aging on the Creep Properties of Type 316L Stainless Steel G. A. C. BOYD,

AND

J. L. HENSHALL

AISI Type 316 stainless steel is used for the construction of high temperature plant and is a candidate structural material for the fast-breeder reactor. It is generally fabricated in the solution treated or slightly cold worked state and is thus only metastable at operating temperatures of approximately 750 K and above. Several investigators I-4 have studied the complex precipitation sequences which occur

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