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Relationship between residual carbon and MIM process variables
PM
MIM F E E D S T O C K FOR RAPID CATALYTIC D E B I N D I N G D. Weinand, M. Bloemacher, (BASF AG, Ludwigshafen, Germany). The use of r a p i d catalytic debinding, in which a b i n d e r b a s e d on a polyacetyl resin is used, was described. Process conditions and experiences were discussed. Equipment design and operating conditions were outlined. THERMAL D E B I N D I N G OF CARBONYL IRON/POLYAMIDE B I N D E R M I X T U R E S T.S. Yoon et al ( R e s e a r c h I n s t i t u t e of Science a n d Technology, Pohang, Korea). A study of t h e t h e r m a l d e b i n d i n g of carbonyl Fe/polyamide binders was described. It was reported that the debinding was enhanced in reducing a t m o s p h e r e s . Mechanisms were discussed. P R E S E N T A N D F U T U R E OF POWDER I N J E C T I O N M O U L D I N G IN JAPAN T. Nakagawa, (University of Tokyo, Tokyo, Japan). The role of injection moulding of m e t a l s a n d ceramics in J a p a n was reviewed. It was considered t h a t PIM is a suitable process for t h e production, particularly, of small m a c h i n e parts. F u r t h e r r e f i n e m e n t s to t h e process were t h o u g h t to be needed. B I N D E R REMOVAL M E C H A N I S M S IN THERMAL D E B I N D I N G O F POWDER COMPACTS H.H. Angerman, O. Van der Biest, (Katholieke Universiteit, Leuven, Belgium). D a t a concerning b i n d e r removal r a t e s were reviewed. The model b i n d e r s studied were two component systems with widely differing d e b i n d i n g t e m p e r a t u r e s . Removal of t h e c o m p o n e n t w i t h t h e lower melting point was considered to be d e t e r m i n e d by d i f f u s i o n in t h e o t h e r component. Reference was m a d e to more c o m p l e x systems. Catalytic effects d u e to t h e m e t a l p o w d e r s were t a k e n i n t o account. SOLVENT D E B I N D I N G OF I N J E C T I O N MOULDED BODIES I. Nanjo et al ( S u m i t o m o Metal Mining Co, Tokyo, J a p a n ) . An investigation of the solvent d e b i n d i n g of MIM c o m p a c t s c o n t a i n i n g carbonyl Fe a n d polyethylene/wax b i n d e r with a wetting agent was described. Effects of t i m e a n d t e m p e r a t u r e on t h e thickness of t h e d e b o u n d layer were studied a n d it was r e p o r t e d t h a t t h e growth of t h e d e b o u n d layer followed a parabolic rate l a w d i f f u s i o n of t h e w a x b e i n g r a t e determining. The p r e s e n c e of t h e wetting a g e n t was s h o w n to e n h a n c e t h e r a t e of debinding.
LITERATURE
REVIEW
D E T E C T I O N O F G A S E S IN C L O S E D P O R E S OF INCOMPLETELY DENSIFIED COPPER AND IRON COMPACTS H. Ito, I~ Hayashi (University of Tokyo, Tokyo, J a p a n ) . It w a s r e p o r t e d t h a t in s t u d i e s of sintering of MIM Cu a n d Fe c o m p a c t s t h e m a x i m u m relative density a t t a i n e d was 95%. It was p r o p o s e d t h a t t h i s could be a t t r i b u t e d to gases t r a p p e d in closed pores. The gases released a t t h e i n s t a n t of tensile fracture were examined by mass spectroscopy. The results were considered to s u p p o r t t h e hypothesis. ALLOY S T E E L POWDERS FOR METAL INJECTION MOULDING Y. Yoshida, (Mitsubishi Steel Manufacturing Co Ltd, Kukushima~ J a p a n ) . The p r o d u c t i o n of high p r e s s u r e gas atomized alloy steel powders was reported. The p r o p e r t i e s were d e s c r i b e d a n d t h e suitability of t h e powders for MIM was discussed. RELATIONSHIP BETWEEN RESIDUAL CARBON A N D MIM P R O C E S S VARIABLES ICM. Lee et al (Hanyang University, Seoul, Korea). Analyses of %C in MIM p a r t s a t e a c h process stage were reported. The objective of t h e s t u d y was to e n a b l e control of C c o n t e n t of f i n i s h e d c o m p o n e n t s to be attained. Residual C was shown to increase for 0.8% u p to 1.9% d e p e n d i n g on d e b i n d i n g conditions. The residual C was r e p o r t e d to be controllable by selection of s i n t e r i n g a t m o s p h e r e . H r e s u l t e d in a r e d u c t i o n of %C a n d little c h a n g e w a s f o u n d in v a c u u m sintering. OPTIMIZATION O F I N J E C T I O N M O U L D I N G O F IRON-NICKEL ALLOY L.W.H. Chem et al ( I n d u s t r i a l Technology Research Institute, Hsinchu, Talwan). Injection moulding, debinding and s i n t e r i n g o f Fe-8% Ni w a s a n a l y s e d statistically by t h e Taguchi m e t h o d as a function of eight process p a r a m e t e r s . The results were s h o w n to e n a b l e t h e processing to be optimized. Mechanical p r o p e r t i e s a n d m i c r o s t r u c t u r e s were described.
New non-ferrous materials D E V E L O P M E N T S IN PM N O N - F E R R O U S MATERIALS F.H. Froes, C. S u r y a n m y a n & (University of Idaho, Moscow, Idaho, USA). Recent d e v e l o p m e n t s in PM light alloys, b a s e d on AI, Mg, Be, Ti a n d intermetallic Ti aluminides were critically reviewed.
Innovative process methods including rapid solidification and mechanical alloying, particularly, were considered. It was shown t h a t PM allows e n h a n c e m e n t of material characteristics a n d is c o s t effective. W R O U G H T P M A L U M I N I U M ALLOYS IN J A P A N Y. Taked& ( S u m i t o m o Electric I n d u s t r i e s Ltd, Itami City, J a p a n ) . A p p l i c a t i o n s of PM e x t r u d e d a n d p o w d e r forged AI-Si alloys were reviewed. Note was t a k e n of technical d e v e l o p m e n t s a n d collaborations between s u p p l i e r a n d customer. Costs were s h o w n to b e reduced. E m p h a s i s was placed on t h e tribological r e q u i r e m e n t s for some applications. MECHANICAL P R O P E R T I E S O F PM ALUMINIUM-SILICON ALLOYS CONTAINING CERIUM H. S h i k a t a et al (Hitachi Powdered Metals Co Ltd, Tokyo, J a p a n ) . A n i n v e s t i g a t i o n of t h e e f f e c t s of a d d i t i o n s of Ce to A1-25% Si alloys a n d t h e effects of h o t forging conditions o n t h e m e c h a n i c a l p r o p e r t i e s was described. It was r e p o r t e d t h a t t h e o p t i m u m Ce c o n t e n t was 2% a n d t h a t t h e p r e s e n c e of Ce e n h a n c e d s t r e n g t h a n d w e a r resistance. E F F E C T S O F PRIMARY SILICON SIZE ON FATIGUE O F POWER F O R G E D ALUMINUM-SILICON ALLOYS M. J o n o et al ( S u m i t o m o Electric I n d u s t r i e s Lyd, Itami City, J a p a n ) . The p r o p e r t i e s of A1-25% Si 2024 alloys were discussed a n d it was r e p o r t e d t h a t powder forging of atomized powders gave improvements in strength and machinability compared with ingot metallurgy materials. Fatigue s t r e n g t h was investigated as a function of Si particle size and fatigue crack initiation and propagation mechanisms. P R O P E R T I E S O F TERNARY ALUMINIUM-SILICON ALLOYS MADE FROM RAPIDLY S O L I D I F I E D POWDERS T. Hirano, T. Fujita, (Riken Corp, Kashiwazaki, J a p a n ) . Studies of h e a t t r e a t e d AI-Si alloys w i t h a d d i t i o n s of 3% Cu a n d 1% M 3 with Ni, Mn or Ni a n d m a d e from rapidly solidified p o w d e r s were described. It w a s n o t e d that intermetallic compounds were formed and that the microstructures were fine and homogeneous. The s t r e n g t h s were h i g h e r t h a n c a s t / w r o u g h t m a t e r i a l s with improved t h e r m a l stability and high temperature strength. Wear resistance was enhanced by the further addition of SiC and low coefficients of expansion were reported.
MPR January 1994 39
MIM F E E D S T O C K FOR RAPID CATALYTIC D E B I N D I N G D. Weinand, M. Bloemacher, (BASF AG, Ludwigshafen, Germany). The use of r a p i d catalytic debinding, in which a b i n d e r b a s e d on a polyacetyl resin is used, was described. Process conditions and experiences were discussed. Equipment design and operating conditions were outlined. THERMAL D E B I N D I N G OF CARBONYL IRON/POLYAMIDE B I N D E R M I X T U R E S T.S. Yoon et al ( R e s e a r c h I n s t i t u t e of Science a n d Technology, Pohang, Korea). A study of t h e t h e r m a l d e b i n d i n g of carbonyl Fe/polyamide binders was described. It was reported that the debinding was enhanced in reducing a t m o s p h e r e s . Mechanisms were discussed. P R E S E N T A N D F U T U R E OF POWDER I N J E C T I O N M O U L D I N G IN JAPAN T. Nakagawa, (University of Tokyo, Tokyo, Japan). The role of injection moulding of m e t a l s a n d ceramics in J a p a n was reviewed. It was considered t h a t PIM is a suitable process for t h e production, particularly, of small m a c h i n e parts. F u r t h e r r e f i n e m e n t s to t h e process were t h o u g h t to be needed. B I N D E R REMOVAL M E C H A N I S M S IN THERMAL D E B I N D I N G O F POWDER COMPACTS H.H. Angerman, O. Van der Biest, (Katholieke Universiteit, Leuven, Belgium). D a t a concerning b i n d e r removal r a t e s were reviewed. The model b i n d e r s studied were two component systems with widely differing d e b i n d i n g t e m p e r a t u r e s . Removal of t h e c o m p o n e n t w i t h t h e lower melting point was considered to be d e t e r m i n e d by d i f f u s i o n in t h e o t h e r component. Reference was m a d e to more c o m p l e x systems. Catalytic effects d u e to t h e m e t a l p o w d e r s were t a k e n i n t o account. SOLVENT D E B I N D I N G OF I N J E C T I O N MOULDED BODIES I. Nanjo et al ( S u m i t o m o Metal Mining Co, Tokyo, J a p a n ) . An investigation of the solvent d e b i n d i n g of MIM c o m p a c t s c o n t a i n i n g carbonyl Fe a n d polyethylene/wax b i n d e r with a wetting agent was described. Effects of t i m e a n d t e m p e r a t u r e on t h e thickness of t h e d e b o u n d layer were studied a n d it was r e p o r t e d t h a t t h e growth of t h e d e b o u n d layer followed a parabolic rate l a w d i f f u s i o n of t h e w a x b e i n g r a t e determining. The p r e s e n c e of t h e wetting a g e n t was s h o w n to e n h a n c e t h e r a t e of debinding.
LITERATURE
REVIEW
D E T E C T I O N O F G A S E S IN C L O S E D P O R E S OF INCOMPLETELY DENSIFIED COPPER AND IRON COMPACTS H. Ito, I~ Hayashi (University of Tokyo, Tokyo, J a p a n ) . It w a s r e p o r t e d t h a t in s t u d i e s of sintering of MIM Cu a n d Fe c o m p a c t s t h e m a x i m u m relative density a t t a i n e d was 95%. It was p r o p o s e d t h a t t h i s could be a t t r i b u t e d to gases t r a p p e d in closed pores. The gases released a t t h e i n s t a n t of tensile fracture were examined by mass spectroscopy. The results were considered to s u p p o r t t h e hypothesis. ALLOY S T E E L POWDERS FOR METAL INJECTION MOULDING Y. Yoshida, (Mitsubishi Steel Manufacturing Co Ltd, Kukushima~ J a p a n ) . The p r o d u c t i o n of high p r e s s u r e gas atomized alloy steel powders was reported. The p r o p e r t i e s were d e s c r i b e d a n d t h e suitability of t h e powders for MIM was discussed. RELATIONSHIP BETWEEN RESIDUAL CARBON A N D MIM P R O C E S S VARIABLES ICM. Lee et al (Hanyang University, Seoul, Korea). Analyses of %C in MIM p a r t s a t e a c h process stage were reported. The objective of t h e s t u d y was to e n a b l e control of C c o n t e n t of f i n i s h e d c o m p o n e n t s to be attained. Residual C was shown to increase for 0.8% u p to 1.9% d e p e n d i n g on d e b i n d i n g conditions. The residual C was r e p o r t e d to be controllable by selection of s i n t e r i n g a t m o s p h e r e . H r e s u l t e d in a r e d u c t i o n of %C a n d little c h a n g e w a s f o u n d in v a c u u m sintering. OPTIMIZATION O F I N J E C T I O N M O U L D I N G O F IRON-NICKEL ALLOY L.W.H. Chem et al ( I n d u s t r i a l Technology Research Institute, Hsinchu, Talwan). Injection moulding, debinding and s i n t e r i n g o f Fe-8% Ni w a s a n a l y s e d statistically by t h e Taguchi m e t h o d as a function of eight process p a r a m e t e r s . The results were s h o w n to e n a b l e t h e processing to be optimized. Mechanical p r o p e r t i e s a n d m i c r o s t r u c t u r e s were described.
New non-ferrous materials D E V E L O P M E N T S IN PM N O N - F E R R O U S MATERIALS F.H. Froes, C. S u r y a n m y a n & (University of Idaho, Moscow, Idaho, USA). Recent d e v e l o p m e n t s in PM light alloys, b a s e d on AI, Mg, Be, Ti a n d intermetallic Ti aluminides were critically reviewed.
Innovative process methods including rapid solidification and mechanical alloying, particularly, were considered. It was shown t h a t PM allows e n h a n c e m e n t of material characteristics a n d is c o s t effective. W R O U G H T P M A L U M I N I U M ALLOYS IN J A P A N Y. Taked& ( S u m i t o m o Electric I n d u s t r i e s Ltd, Itami City, J a p a n ) . A p p l i c a t i o n s of PM e x t r u d e d a n d p o w d e r forged AI-Si alloys were reviewed. Note was t a k e n of technical d e v e l o p m e n t s a n d collaborations between s u p p l i e r a n d customer. Costs were s h o w n to b e reduced. E m p h a s i s was placed on t h e tribological r e q u i r e m e n t s for some applications. MECHANICAL P R O P E R T I E S O F PM ALUMINIUM-SILICON ALLOYS CONTAINING CERIUM H. S h i k a t a et al (Hitachi Powdered Metals Co Ltd, Tokyo, J a p a n ) . A n i n v e s t i g a t i o n of t h e e f f e c t s of a d d i t i o n s of Ce to A1-25% Si alloys a n d t h e effects of h o t forging conditions o n t h e m e c h a n i c a l p r o p e r t i e s was described. It was r e p o r t e d t h a t t h e o p t i m u m Ce c o n t e n t was 2% a n d t h a t t h e p r e s e n c e of Ce e n h a n c e d s t r e n g t h a n d w e a r resistance. E F F E C T S O F PRIMARY SILICON SIZE ON FATIGUE O F POWER F O R G E D ALUMINUM-SILICON ALLOYS M. J o n o et al ( S u m i t o m o Electric I n d u s t r i e s Lyd, Itami City, J a p a n ) . The p r o p e r t i e s of A1-25% Si 2024 alloys were discussed a n d it was r e p o r t e d t h a t powder forging of atomized powders gave improvements in strength and machinability compared with ingot metallurgy materials. Fatigue s t r e n g t h was investigated as a function of Si particle size and fatigue crack initiation and propagation mechanisms. P R O P E R T I E S O F TERNARY ALUMINIUM-SILICON ALLOYS MADE FROM RAPIDLY S O L I D I F I E D POWDERS T. Hirano, T. Fujita, (Riken Corp, Kashiwazaki, J a p a n ) . Studies of h e a t t r e a t e d AI-Si alloys w i t h a d d i t i o n s of 3% Cu a n d 1% M 3 with Ni, Mn or Ni a n d m a d e from rapidly solidified p o w d e r s were described. It w a s n o t e d that intermetallic compounds were formed and that the microstructures were fine and homogeneous. The s t r e n g t h s were h i g h e r t h a n c a s t / w r o u g h t m a t e r i a l s with improved t h e r m a l stability and high temperature strength. Wear resistance was enhanced by the further addition of SiC and low coefficients of expansion were reported.
MPR January 1994 39