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Developments in alloy powders for high performance structural applications
Methods for the fabrication of WC-Co c e m e n t e d carbides with graded structures varying in composition in the range 10 to 30wt%Co are described. Solid and liquid state sintering processes were used t o g e t h e r with HIP to improve the final density of some samples. BONDING OF MOLYBDENUM-NICKEL BORIDE HARD METALS WITH S T E E L S S. Ozaki et al (Toyo K o h a n Co Ltd, Kudamatsu, J a p a n ) J. J a p a n Soc, P o w d e r a n d P o w d e r M e t a l l u r g y , Vol 40, No 8, 1993, 815-819. (In J a p a n e s e ) . An investigation of a novel h a r d m e t a l consisting of Mo2NiB2 in a Ni base matrix containing Cr and Mo is described. The h a r d m e t a l s can be b o n d e d to steel and bond shear s t r e n g t h s up to 700 MPa are reported. Residual stresses in t h e joints were m e a s u r e d and are attributed to the differential t h e r m a l e x p a n s i o n b e t w e e n h a r d m e t a l and substrate. C R E E P CHARACTERISTICS OF TITANIUM-MOLYBDENUM CARBIDENICKEL C E R M E T S. Kinoshita et al (Toshiba Tungaloy Co Ltd, Kawasaki, J a p a n ) J. J a p a n Soc. P o w d e r a n d P o w d e r M e t a l l u r g y , Vol 40, No 8, 1993, 820-822. (In J a p a n e s e ) . It is noted t h a t N e n h a n c e s t h e creep resistance of TiC-Mo2C-Ni and e x p e r i m e n t s to confirm and quantify this are described Nitrided TiC-Mo2C-Ni is c o m p a r e d with TiC-Mo2C-Ni-TiN and t h e nitrided alloy is r e p o r t e d to show e n h a n c e d creep resistance even though it contained less N.
USE OF PM PARTS IN SINGLE CYLINDER INTERNAL COMBUSTION ENGINES H. Fenglin (Powder Metallurgy Co., Beijing, China) P M Technology, Vol 11, No 4, 1993, 271-282. (In Chinese). Applications of PM c o m p o n e n t s in a single cylinder IC engine are illustrated. Recent progress in the p r o d u c t i o n of such p a r t s is described and discussed.
Miscellaneous ANOTHER STRONG YEAR FOR POWDER METALLURGY P.K. J o h n s o n (AMPI, Princeton, New Jersey, USA), Int. J. P o w d e r Metallurgy, Vol 30, No 2, 1994, 199-204. A review of developments and t r e n d s in t h e PM industry is presented. Particular attention is g i v e n to a u t o m o t i v e a p p l i c a t i o n s , t r e n d s in m e t a l p o w d e r s , e q u i p m e n t developments, PM p a r t s and p r o d u c t s and metal injection moulding. It is r e p o r t e d t h a t t h e PM i n d u s t r y has a t t a i n e d a new stage of acceptance and reliability a n d it is suggested t h a t the industry will continue to show growth.
pM2TEC'94. The a b s t r a c t s which follow are of p a p e r s which were p r e s e n t e d at the International Conference on Powder Metallurgy a n d P a r t i c u l a t e M a t e r i a l s w h i c h was held in Toronto, Canada, from 8th to l l t h May 1994.
Metal injection moulding
J.H. Reinshagen, R.P. Mason (Ametek Inc, Pennsylvania, USA), Int. J. P o w d e r Metallurgy, Vol 30, No 2, 1994, 165-172. The d e m a n d s from the users of PM p a r t s for improved properties is discussed with regard to powder with better properties. Recent d e v e l o p m e n t s in stainless steels with e n h a n c e d corrosion resistance and mechanical p r o p e r t i e s arising from t h e use of improved powders are described. DEVELOPMENTS IN FRICTION MATERIALS U S E D IN AUTOMOTIVE BRAKING H. Fengjia, H. Boyun ( C e n t r a l S o u t h University of Technology, Changsha, Hunan, China) P M Technology, Vol 11. No 3, 1993, 207-217. (In Chinese). Trends in the development of friction materials for use in automotive braking systems are discussed. The urgent need for further research was emphasized.
64
MPR December 1994
COMPARISON OF WATER AND GAS ATOMIZED STAINLESS S T E E L POWDER U S E D FOR MIM L. Cai, R.M. German (Pennsylvania State University, Pennsylvania, USA). Water and gas atomized 3176L stainless steel p o w d e r s were c o m p a r e d for theil suitability for use in MIM. The objectiw was to reduce p o w d e r costs and to improve dimensional stability and a wide range ol m a t e r i a l a n d p r o c e s s p a r a m e t e r s was s t u d i e d . The i r r e g u l a r s h a p e of w a t e l atomized powder was r e p o r t e d to cause anisotropic shrinkage during sintering. Gas atomized powders gave a more uniform shrinkage. The w a t e r atomized powders gave h i g h e r density. F e e d s t o c k powdeI loadings were comparable.
Mechanical properties
PM parts DEVELOPMENTS IN ALLOY POWDERS FOR HIGH PERFORMANCE STRUCTURAL APPLICATIONS
o b j e c t b e i n g to i m p r o v e d i m e n s i o n a ! control. Use was m a d e of in-situ feedbac]~ control to limit variations in p a r t weigh| and dimensions. Debinding was a two stelc s o l v e n t / t h e r m a l stage a n d sintering was iv N/H. Longer sintering time was r e p o r t e d tc improve anisotropic shrinkage. Mechanical p r o p e r t i e s were increased on sintering in 1~ with no loss of corrosion resistance.
ECONOMICAL MIM STAINLESS S T E E L FROM CARBONYL IRON POWDER PREMIXES J.E. J a p k a (ISP Co, USA). The p r e p a r a t i o n of stainless steel MIM feedstock from carbonyl Fe with Ni and Cr was reported. A new debinding step was used and p a r t s were sintered to a low %C. The m i x t u r e was a substitute for 20 ~m atomized stainless steel powder and gave uniform structure and was a s u b s t i t u t e for 20 pm atomized stainless steel powder and gave uniform structure and composition. Data concerning density, m i c r o s t r u c t u r e and corrosion resistance were given. E F F E C T S OF P R O C E S S CONDITIONS ON DIMENSIONAL CONTROL OF MIM STAINLESS STEEL G.R. White, R.M. German (Pennsylvania State University, Pennsylvania, USA). An investigation of injection moulding of 316L stainless steel was d e s c r i b e d t h e
EVALUATION OF FRACTURE T O U G H N E S S OF PM S T E E L S I~C. Wang, T. Prucher (Concurrent Technologies Corp, USA). The i m p o r t a n c e of fracture t o u g h n e s s in e n g i n e e r i n g d e s i g n w a s d i s c u s s e d and regard was given to t e s t methods. The lack of d a t a on PM steels was noted. Data for a range of sintered steels was p r e s e n t e d and c o m p a r e d with t h a t for similar wrought steels. Effects of density and porosity on f r a c t u r e t o u g h n e s s on PM s t e e l s was analyzed. FRACTURE T O U G H N E S S OF A S I N T E R H A R D E N I N G ALLOY S T E E L Y.T. Chen et al (Pitney Bowes Inc, Stamford, Connecticut, USA). Sinter h a r d e n i n g steels were discussed. Data for tensile p r o p e r t i e s and fracture toughness, for a steel in varying conditions, were p r e s e n t e d and discussed. SURFACE E N D U R A N C E LIMIT FOR PM ALLOY S T E E L S H.I. Sanderow, T. P r u c h e r ( C o n c u r r e n t Technologies Corp, USA). Surface fatigue and spalling of sintered machine p a r t s were discussed with respect to service c o n d i t i o n s . A ring t e s t , to s i m u l a t e service c o n d i t i o n s for rolling c o n t a c t fatigue, was described. Surface e n d u r a n c e limits for a range of h a r d e n e d and t e m p e r e d PM steels were presented.
USE OF PM PARTS IN SINGLE CYLINDER INTERNAL COMBUSTION ENGINES H. Fenglin (Powder Metallurgy Co., Beijing, China) P M Technology, Vol 11, No 4, 1993, 271-282. (In Chinese). Applications of PM c o m p o n e n t s in a single cylinder IC engine are illustrated. Recent progress in the p r o d u c t i o n of such p a r t s is described and discussed.
Miscellaneous ANOTHER STRONG YEAR FOR POWDER METALLURGY P.K. J o h n s o n (AMPI, Princeton, New Jersey, USA), Int. J. P o w d e r Metallurgy, Vol 30, No 2, 1994, 199-204. A review of developments and t r e n d s in t h e PM industry is presented. Particular attention is g i v e n to a u t o m o t i v e a p p l i c a t i o n s , t r e n d s in m e t a l p o w d e r s , e q u i p m e n t developments, PM p a r t s and p r o d u c t s and metal injection moulding. It is r e p o r t e d t h a t t h e PM i n d u s t r y has a t t a i n e d a new stage of acceptance and reliability a n d it is suggested t h a t the industry will continue to show growth.
pM2TEC'94. The a b s t r a c t s which follow are of p a p e r s which were p r e s e n t e d at the International Conference on Powder Metallurgy a n d P a r t i c u l a t e M a t e r i a l s w h i c h was held in Toronto, Canada, from 8th to l l t h May 1994.
Metal injection moulding
J.H. Reinshagen, R.P. Mason (Ametek Inc, Pennsylvania, USA), Int. J. P o w d e r Metallurgy, Vol 30, No 2, 1994, 165-172. The d e m a n d s from the users of PM p a r t s for improved properties is discussed with regard to powder with better properties. Recent d e v e l o p m e n t s in stainless steels with e n h a n c e d corrosion resistance and mechanical p r o p e r t i e s arising from t h e use of improved powders are described. DEVELOPMENTS IN FRICTION MATERIALS U S E D IN AUTOMOTIVE BRAKING H. Fengjia, H. Boyun ( C e n t r a l S o u t h University of Technology, Changsha, Hunan, China) P M Technology, Vol 11. No 3, 1993, 207-217. (In Chinese). Trends in the development of friction materials for use in automotive braking systems are discussed. The urgent need for further research was emphasized.
64
MPR December 1994
COMPARISON OF WATER AND GAS ATOMIZED STAINLESS S T E E L POWDER U S E D FOR MIM L. Cai, R.M. German (Pennsylvania State University, Pennsylvania, USA). Water and gas atomized 3176L stainless steel p o w d e r s were c o m p a r e d for theil suitability for use in MIM. The objectiw was to reduce p o w d e r costs and to improve dimensional stability and a wide range ol m a t e r i a l a n d p r o c e s s p a r a m e t e r s was s t u d i e d . The i r r e g u l a r s h a p e of w a t e l atomized powder was r e p o r t e d to cause anisotropic shrinkage during sintering. Gas atomized powders gave a more uniform shrinkage. The w a t e r atomized powders gave h i g h e r density. F e e d s t o c k powdeI loadings were comparable.
Mechanical properties
PM parts DEVELOPMENTS IN ALLOY POWDERS FOR HIGH PERFORMANCE STRUCTURAL APPLICATIONS
o b j e c t b e i n g to i m p r o v e d i m e n s i o n a ! control. Use was m a d e of in-situ feedbac]~ control to limit variations in p a r t weigh| and dimensions. Debinding was a two stelc s o l v e n t / t h e r m a l stage a n d sintering was iv N/H. Longer sintering time was r e p o r t e d tc improve anisotropic shrinkage. Mechanical p r o p e r t i e s were increased on sintering in 1~ with no loss of corrosion resistance.
ECONOMICAL MIM STAINLESS S T E E L FROM CARBONYL IRON POWDER PREMIXES J.E. J a p k a (ISP Co, USA). The p r e p a r a t i o n of stainless steel MIM feedstock from carbonyl Fe with Ni and Cr was reported. A new debinding step was used and p a r t s were sintered to a low %C. The m i x t u r e was a substitute for 20 ~m atomized stainless steel powder and gave uniform structure and was a s u b s t i t u t e for 20 pm atomized stainless steel powder and gave uniform structure and composition. Data concerning density, m i c r o s t r u c t u r e and corrosion resistance were given. E F F E C T S OF P R O C E S S CONDITIONS ON DIMENSIONAL CONTROL OF MIM STAINLESS STEEL G.R. White, R.M. German (Pennsylvania State University, Pennsylvania, USA). An investigation of injection moulding of 316L stainless steel was d e s c r i b e d t h e
EVALUATION OF FRACTURE T O U G H N E S S OF PM S T E E L S I~C. Wang, T. Prucher (Concurrent Technologies Corp, USA). The i m p o r t a n c e of fracture t o u g h n e s s in e n g i n e e r i n g d e s i g n w a s d i s c u s s e d and regard was given to t e s t methods. The lack of d a t a on PM steels was noted. Data for a range of sintered steels was p r e s e n t e d and c o m p a r e d with t h a t for similar wrought steels. Effects of density and porosity on f r a c t u r e t o u g h n e s s on PM s t e e l s was analyzed. FRACTURE T O U G H N E S S OF A S I N T E R H A R D E N I N G ALLOY S T E E L Y.T. Chen et al (Pitney Bowes Inc, Stamford, Connecticut, USA). Sinter h a r d e n i n g steels were discussed. Data for tensile p r o p e r t i e s and fracture toughness, for a steel in varying conditions, were p r e s e n t e d and discussed. SURFACE E N D U R A N C E LIMIT FOR PM ALLOY S T E E L S H.I. Sanderow, T. P r u c h e r ( C o n c u r r e n t Technologies Corp, USA). Surface fatigue and spalling of sintered machine p a r t s were discussed with respect to service c o n d i t i o n s . A ring t e s t , to s i m u l a t e service c o n d i t i o n s for rolling c o n t a c t fatigue, was described. Surface e n d u r a n c e limits for a range of h a r d e n e d and t e m p e r e d PM steels were presented.