Effect of belt furnace variables on corrosion resistance of austenitic stainless steels

Effect of belt furnace variables on corrosion resistance of austenitic stainless steels

PM Nanoscale materials STATE-OF-THE-ART OF PARTICULATE NANOPHASE MATERIALS R.V. Andrievski (Inst. for New Chemical Problems, Moscow, R u s s i a ) ...

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Nanoscale materials STATE-OF-THE-ART OF PARTICULATE NANOPHASE MATERIALS

R.V. Andrievski (Inst. for New Chemical Problems, Moscow, R u s s i a ) . Applications, p r o p e r t i e s a n d fabrication, by PM m e t h o d s , of n a n o p h a s e materials, w i t h g r a i n s i z e s b e l o w 100 n m , w a s d i s c u s s e d w i t h r e g a r d to p r o d u c t i o n difficulties. Hardness of nanophase materials, intermetallies and refractory c o m p o u n d s were c o n s i d e r e d a n d e m p h a s i s w a s placed on s t r u c t u r e a n d properties. PRODUCTION OF ALUMINIUMC O B A L T - N I C K E L - Y T T R I U M ALLOYS FROM AMORPHOUS POWDERS

A. Inoue et al. (Tohoku University, Sendai, Japan). It was r e p o r t e d t h a t PM h a d been u s e d to prepare AI-Ni-Co-Y alloys from a m o r p h o u s powders. The p r o p e r t i e s were e v a l u a t e d . Al-13.7%Ni-l.4%Co-5.9%Y w a s r e p o r t e d to have a s t r e n g t h of 860 MPa a n d 2% elongation at rooin t e m p e r a t u r e after extrusion. SYNTHESIS IN FINE GRAIN BINARY AND TERNARY RARE EARTHTRANSITION METAL COMPOUNDS

M. Febri et al. (Ecole Superieure de Physique de Grenoble, St.Martin d'Heres, France). The u s e of r e d u c t i o n - d i f f u s i o n , in a m o l t e n Ca bath, for s y n t h e s i s of Sin-Co a n d Nd-Fe-B w a s d i s c u s s e d with regard to u s i n g t h e m e t h o d to m a k e o t h e r s i m i l a r c o m p o u n d s s u c h as Nd-Co a n d Y-Fe-B. P r o d u c t i o n of alloys w a s r e p o r t e d a n d s o m e were t h e r m o d y n a m i c a l l y stable. FABRICATION OF NANOCOMPOSITE TUNGSTEN-COPPER POWDERS

T.H. Kim, J.S. Lee. ( H a n y a n g University, A n s a n , Korea). A t t e m p t s to p r e p a r e a n d fabricate W-Cu n a n o c o m p o s i t e s p o w d e r s by a t t r i t i o n milling a n d r e d u c t i o n in H were described. The powders were characterized with r e s p e c t to milling t i m e a n d were s h o w n to c o n s i s t of W particles, 30-50 n m in size, h o m o g e n e o u s l y d i s t r i b u t e d in t h e Cu phase.

PM2TEC'95 The a b s t r a c t s which follow are from p a p e r s which were p r e s e n t e d at t h e I n t e r n a t i o n a l C o n f e r e n c e on Powder Metallurgy and Particulate Materials which was held in Seattle, USA, from 14th to 17th May 1995.

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MPR December 1995

LITERATURE

REVIEW

High d e n s i t y p r e s s e d a n d sintered steels EFFECTS OF PROCESSING METHODS ON MECHANICAL CHARACTERISTICS OF HIGH PERFORMANCE STEELS

I.W. Donaldson, F.J. Hanejko ( H o e g a n a e s Corp, Riverton, New Jersey, USA). It w a s n o t e d t h a t t h e p r o p e r t i e s of s i n t e r e d ferrous m a t e r i a l s are affected by composition and processing method. A s t u d y of t h e novel A n c o r d e n s e process, b a s e d on a single c o m p a c t i o n stage, w a s described. The r e s u l t s are c o m p a r e d with t h o s e for t h e s a m e m a t e r i a l , d o u b l e p r e s s e d - a n d - s i n t e r e d . A case s t u d y of a part was presented. DOUBLE PRESSED-AND-SINTERED COPPER AND NICKEL STEELS

V.S. Styskin (Wakefield Cox]), Wakefield, USA). Double p r e s s e d - a n d - s i n t e r e d ferrous m a t e r i a l s were d i s c u s s e d with regard to i m p r o v e m e n t s in m e c h a n i c a l p r o p e r t i e s a n d t h e n e e d for h i g h l y c o m p r e s s i b l e powder. An investigation of Cu-Ni steels, m a d e by d o u b l e p r e s s - a n d - s i n t e r , w a s described. C o m p o s i t i o n a n d p r e s i n t e r i n g temperature w e r e r e p o r t e d to a f f e c t d i m e n s i o n s a n d properties. EFFECT OF COMPACTION TEMPERATURE ON SINTERED PROPERTIES OF HIGH DENSITY PM MATERIALS

F. C h a g n o n , Y. T r u d e l ( Q u e b e c Metal Powders Ltd, Quebec, C a n a d a ) . The i m p o r t a n c e of m i n i m i z i n g residual p o r o s i t y to a t t a i n m a x i m u m p r o p e r t i e s w a s e m p h a s i z e d . The role of w a r m c o m p a c t i o n in a t t a i n m e n t of m a x i m u m d e n s i t y w a s d i s c u s s e d . A s t u d y of t h e effects of c o m p a c t i o n at 25-250°C a n d 690 MPa, steel p o w d e r grade, g r a p h i t e type a n d %Ni w a s d e s c r i b e d for s p e c i m e n s s i n t e r e d at 1 1 2 0 C for 25 m i n u t e s . Best p r o p e r t i e s were a t t a i n e d at t h e h i g h e s t compaction temperatures.

Sintering of stainless steel EFFECT OF BELT FURNACE VARIABLES ON CORROSION RESISTANCE OF AUSTENITIC STAINLESS STEELS

E. Klar, P.K. Samal (SCM Metal P r o d u c t s Inc, Cleveland, Ohio, USA). It w a s n o t e d t h a t if f u r n a c e a t m o s p h e r e a n d cooling rate are n o t correct in belt f u r n a c e s i n t e r i n g of s t a i n l e s s steel in H or N-H t h e n oxides, carbides a n d / o r nitrides n m y f o r m on t h e steel surface. It w a s r e p o r t e d t h a t a h i g h e r dew p o i n t a n d lower cooling rate can be tolerated, for corrosion r e s i s t a n c e of 316L a n d 317L in 15%NaC1. M a x i m u m corrosion r e s i s t a n c e r e q u i r e d a dew p o i n t of 50°C a n d rapid gas quenching.

FERRITIC STAINLESS STEEL WITH HIGH MAGNETIC PROPERTIES AND CORROSION RESISTANCE

K.II. Moyer et al. (Magna Tech PM Laboratories, USA). It was r e p o r t e d t h a t a novel ferritic s t a i n l e s s steel, which h a d good m a g n e t i c p r o p e r t i e s a n d corrosion p r o p e r t i e s after 1000 h o u r s i m m e r s i o n in 5%NaCI, h a d been prepared. Most m a t e r i a l s are found to fail after only 100 hours. The alloy was m a d e from Fe powder less t h a n 10 p m in size a n d Cr powder to m a k e a 430 c o m p o s i t i o n on sintering. Process conditions were c o m p a r e d with prealloyed 434L powder. Properties were described.

Cemented carbides APPLICATION PROCESSING AND CHARACTERIZATION OF TUNGSTEN CARBIDE-COBALT POWDERS

P. Seegopaul, L.E. M c C a n d i s h ( N a n o d y n e Ine, USA) The p r o d u c t i o n of n a n o - s t r u c t u r e d WC Co m a t e r i a l s , by s t a n d a r d i n d u s t r i a l p r o c e s s e s a n d c o n d i t i o n s was reported. O c o n t a m i n a t i o n w a s r e m o v e d by tI treatment during delnbrication. C o n d i t i o n s for d e f e c t a v o i d a n c e w e r e e s t a b l i s h e d . Spray dtTing a n d lluidized bed t e c h n i q u e s were used. Capability of t h e m e t h o d s u s e d was d e m o n s t r a t e d . THERMOANALYTICAL SIMULATION OF SINTERING OF HARDMETALS

G. L e i t n e r et al. ( F r a u n h o f e r Inst. for Ceramic Technology a n d Sintered Materi als, Germany). The need for detailed d a t a to enable o p t i m i z a t i o n of s i n t e r i n g of h a r d m e t a l s was discussed with reference to delubrication, d e g a s s i n g a n d densification. Simulated and experimental investigations of t h r e e h a r d m e t a l s w e r e d e s c r i b e d . Optimum time/temperature profiles were deduced. SINTERING OF HARDMETALS WITH GRADIENT STRUCTURE

R. Vidu, P. Nicolae. (Metallurgical Research Inst, R o m a n i a ) . Production of h a r d m e t a l s , with g r a d i e n t s t r u c t u r e s , by multi-layering w a s discussed. A WC-15%Co alloy, with a s t r u c t u r e layered by grain size, from 2-10 tam was i n v e s t i g a t e d together with a WC-TiC-Co layered material. O p t i m u m sintering conditions were e s t a b l i s h e d

Sintering and dimensional control D I M E N S I O N A L C H A N G E IN M I X E D POWDER SINTERING R.M. G e r m a n ( P e n n s y l v a n i a State University, Pennsylvania, USA).