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Powder forging of a rapidy solidified aluminium silicon alloy powder
increase cooling rates a n d facilitate powder collection. The powders were n e a r spherical in s h a p e a n d were free from s a t e l i t e particles with a geometric m e a n size of 12 to 20 p m w h e n air pressures of 0.44 to 0.71 MPa were used. INFLUENCE OF DELIVERY TUBE POSITION ON TUBE P R E S S U R E AND PARTICLE SIZE DISTRIBTUTION
A.S. Pedersen et al (Riso National Laboratory, Roskilde, D e n m a r k ) . A description was given of the i n s t r u m e n t a t i o n to a gas a t o m i z e r to measure gas pressures as a function of the distance between t h e m e t a l delivery tube a n d t h e gas jet. Pressure in t h e delivery tube varied in t h e range -30 to ÷ 40 kPa with pressure in t h e gas j e t of 0.5 to 7.0 MPa. Particle sizes for Cu-Sn were m e a s u r e d as a function of pressures a n d gas to m e t a l ratio. INNOVATIVE TECHNOLOGY IN PM FOR ADVANCE MATERIALS
A. C h o u d u r y et al (Leybold D u r f e r r i t GmBH, Erlensee, Germany). An account of t h e p r o d u c t i o n of powders of reactive metals was given. New melting t e c h n i q u e s a n d i n e r t gas a t o m i z a t i o n yielded ceramic free fine spherical powders of Zr, Ti a n d t h e i r alloys. Metal melting in CaO crucibles was described. A p p l i c a t i o n t o p r o d u c t i o n of o x i d e s u p e r c o n d u c t o r s was discussed.
PRODUCTION OF TITANIUM ALUMINIDE POWDERS BY PLASMA ROTATING ELECTRODE PROCESS
CENTRIFUGAL COMPACTION OF SUBMICRON HIGH PURITY ALUMINA POWDER
I~ Isonishi et al (Ibraki University, Mito, Japan). The use of t h e p l a s m a r o t a t i n g electrode process for t h e p r o d u c t i o n of Ti-(25 to 50) at%A1 (TiA13,TiAI~ ÷ TiA1 a n d TiA1) i n t e r m e t a l l i c c o m p o u n d s was d i s c u s s e d with respect to powder characteristics a n d process conditions. U n d e r some conditions, large i r r e g u l a r particles were found in mainly spherical powders. This was a t t r i b u t e d to i n h o m o g e n e o u s melting of t h e c o n s u m a b l e electrode.
S. T a s h i m a , H. Kuroki ( U n i v e r i s t y of Hiroshima, Hiroshima, J a p a n ) . Centrifugal compaction of A1203/water slips with 22 to 28wt% w a t e r was described. The forces used were 22 to 28 kG. The a d v a n t a g e s of t h e t e c h n i q u e were reported to be ease of slip p r e p a r a t i o n by ball milling, effects of composition and viscosity are small, no need to remove e n t r a i n e d air, h i g h g r e e n d e n s i t y , n o c o n t a m i n a t i o n from a p l a s t e r m o u l d a n d reduced drying a n d sintering times.
TRAJECTORY AND TEMPERATURE PROFILE OF ATOMIZED METAL DROPLETS DURING SPRAY FORMING
Powder forming and superplastic forming
E-S. Lee, S. A h n (Research Inst. of Industrial Science a n d Technology, Korea). A numerical analysis of h e a t t r a n s f e r a n d g a s / d r o p l e t flow in a spray forming c h a m b e r was presented. Disintegration of the m e t a l s t r e a m in t h e gas j e t a n d d u r i n g cooling a n d solidification were considered. Steady t u r b u l e n t compressible fluid flow a n d a normal distribution of droplet sizes w e r e a s s u m e d . E f f e c t s of gas n o z z l e geometry a n d gas p r e s s u r e on d r o p l e t velocity a n d t e m p e r a t u r e c h a n g e s w i t h time were discussed.
Compaction technologies and processes
INERT GAS ATOMIZATION FOR MANUFACTURE OF HIGH QUALITY METAL POWDERS
HIGH QUALITY G R E E N TITANIUM COMPACTS BY A TWO-STEP P R E S S I N G METHOD
M.Hihmann et al (Leybold Durferrit GmbH, Erlensee, Germany). A n u m b e r of i n n o v a t i o n s i n v o l v i n g v a c u u m i n d u c t i o n melting, cold crucibe melting a n d p l a s m a h e a t sources applied to inert gas a t o m i z a t i o n were outlined. Processes a n d e q u i p m e n t for p r o d u c t i o n of high quality powders were discussed a n d future t r e n d s shown.
J. Asami, N. Hirose (Tokyo Metropolitan Industrial Technology Centre, Tokyo, Japan). It was r e p o r t e d t h a t by t h e use of a twostep compaction procedure the green density o f Ti c o m p a c t s could be significantly increased. The c o m p a c t s were pressed with die wall lubrication in floating die t o o l s u n d e r u n i a x i a l c o m p r e s s i o n conditions.
PREPARATION OF MONOSIZED METAL POWDERS BY PULSATED ORIFICE INJECTION
FLOW COMPACTION OF IRON POWDER WITH CONTROLLED PARTICLE SIZE DISTRIBUTION
Y. Kuroki et al (Tohoku University, Sendai, Japan). A device to cause pulsation of t h e m e t a l s t r e a m in a n atomizer was described. The system was a r r a n g e d so t h a t each pulse yielded one droplet of molten m e t a l of a size comparable with t h e orifice diameter. The s t a n d a r d deviation in particle size was 15%. The kinetics of liquid droplet injection ws discussed.
S. Takahashi, T. Nakagawa (Universiity of Tokyo, Tokyo, J a p a n ) . Production of c u p - s h a p e d p a r t s from fine Fe powders, with controlled particle size distribution and additions of 0.7wt% Zn s t e a r a t e a n d 0.5% l i q u i d parafin, was described. The powder m i x t u r e was compressed a n d m a d e to flow into t h e clearance between die a n d p u n c h by a s t e p p e d punch. Variations in density were m e a s u r e d a n d densities u p to 90% were attained.
52 MPR December 1993
MULTI-LEVEL POWDER FORGING AND POWDER COMPACTION USING MULTIAXIS HYRAULIC P R E S S
T. Kaji et al (Sumitomo Electric Industries, Itami City, J a p a n ) . A multiple axis press was described. Each r a m can be i n d e p e n d e n t l y driven a n d controlled thus permitting multi-level compaction. The p r e s s was r e p o r t e d to e n a b l e fully c l o s e d die forging to be c a r r i e d out. Design of t h e p r e s s a n d applications were outlined. A POWDER FORGED AUTOMOTIVE CONNECTING ROD
L. Albano-Muller et al (Krebsoge Sinterholding GmbH, Radewormwald, Germany). The production of automotive c o n n e c t i n g r o d s was discussed. It was r e p o r t e d t h a t even t h o u g h t h e p o w d e r steel was more expensive t h a n w r o u g h t steel t h e r e was a n overall cost saving of 24% a n d t h a t t h e powder forged con rod offered some technological advantages. Use of a fracture splitting process was held to be r e s p o n s i b l e for t h e cost savings. The process, t h e c o m p o n e n t a n d t h e overall economics were described. POWDER FORGING OF A RAPIDY SOLIDIFIED ALUMINIUM SILICON ALLOY POWDER
I~ Kawase et al (Mitsubishi Metals Corporation, J a p a n ) . An investigation of powder forging of a rapidy solidified A1-Si alloy was described. Disc s h a p e d c o m p a c t s were hot forged a n d h u b s were formed by application of back pressure. The relationship between forgability and back pressure were examined. It was shown t h a t flanged h u b s could be p r o d u c e d in a single operation, the back p r e s s u r e being effective in developing full density a n d avoiding cracks.
A.S. Pedersen et al (Riso National Laboratory, Roskilde, D e n m a r k ) . A description was given of the i n s t r u m e n t a t i o n to a gas a t o m i z e r to measure gas pressures as a function of the distance between t h e m e t a l delivery tube a n d t h e gas jet. Pressure in t h e delivery tube varied in t h e range -30 to ÷ 40 kPa with pressure in t h e gas j e t of 0.5 to 7.0 MPa. Particle sizes for Cu-Sn were m e a s u r e d as a function of pressures a n d gas to m e t a l ratio. INNOVATIVE TECHNOLOGY IN PM FOR ADVANCE MATERIALS
A. C h o u d u r y et al (Leybold D u r f e r r i t GmBH, Erlensee, Germany). An account of t h e p r o d u c t i o n of powders of reactive metals was given. New melting t e c h n i q u e s a n d i n e r t gas a t o m i z a t i o n yielded ceramic free fine spherical powders of Zr, Ti a n d t h e i r alloys. Metal melting in CaO crucibles was described. A p p l i c a t i o n t o p r o d u c t i o n of o x i d e s u p e r c o n d u c t o r s was discussed.
PRODUCTION OF TITANIUM ALUMINIDE POWDERS BY PLASMA ROTATING ELECTRODE PROCESS
CENTRIFUGAL COMPACTION OF SUBMICRON HIGH PURITY ALUMINA POWDER
I~ Isonishi et al (Ibraki University, Mito, Japan). The use of t h e p l a s m a r o t a t i n g electrode process for t h e p r o d u c t i o n of Ti-(25 to 50) at%A1 (TiA13,TiAI~ ÷ TiA1 a n d TiA1) i n t e r m e t a l l i c c o m p o u n d s was d i s c u s s e d with respect to powder characteristics a n d process conditions. U n d e r some conditions, large i r r e g u l a r particles were found in mainly spherical powders. This was a t t r i b u t e d to i n h o m o g e n e o u s melting of t h e c o n s u m a b l e electrode.
S. T a s h i m a , H. Kuroki ( U n i v e r i s t y of Hiroshima, Hiroshima, J a p a n ) . Centrifugal compaction of A1203/water slips with 22 to 28wt% w a t e r was described. The forces used were 22 to 28 kG. The a d v a n t a g e s of t h e t e c h n i q u e were reported to be ease of slip p r e p a r a t i o n by ball milling, effects of composition and viscosity are small, no need to remove e n t r a i n e d air, h i g h g r e e n d e n s i t y , n o c o n t a m i n a t i o n from a p l a s t e r m o u l d a n d reduced drying a n d sintering times.
TRAJECTORY AND TEMPERATURE PROFILE OF ATOMIZED METAL DROPLETS DURING SPRAY FORMING
Powder forming and superplastic forming
E-S. Lee, S. A h n (Research Inst. of Industrial Science a n d Technology, Korea). A numerical analysis of h e a t t r a n s f e r a n d g a s / d r o p l e t flow in a spray forming c h a m b e r was presented. Disintegration of the m e t a l s t r e a m in t h e gas j e t a n d d u r i n g cooling a n d solidification were considered. Steady t u r b u l e n t compressible fluid flow a n d a normal distribution of droplet sizes w e r e a s s u m e d . E f f e c t s of gas n o z z l e geometry a n d gas p r e s s u r e on d r o p l e t velocity a n d t e m p e r a t u r e c h a n g e s w i t h time were discussed.
Compaction technologies and processes
INERT GAS ATOMIZATION FOR MANUFACTURE OF HIGH QUALITY METAL POWDERS
HIGH QUALITY G R E E N TITANIUM COMPACTS BY A TWO-STEP P R E S S I N G METHOD
M.Hihmann et al (Leybold Durferrit GmbH, Erlensee, Germany). A n u m b e r of i n n o v a t i o n s i n v o l v i n g v a c u u m i n d u c t i o n melting, cold crucibe melting a n d p l a s m a h e a t sources applied to inert gas a t o m i z a t i o n were outlined. Processes a n d e q u i p m e n t for p r o d u c t i o n of high quality powders were discussed a n d future t r e n d s shown.
J. Asami, N. Hirose (Tokyo Metropolitan Industrial Technology Centre, Tokyo, Japan). It was r e p o r t e d t h a t by t h e use of a twostep compaction procedure the green density o f Ti c o m p a c t s could be significantly increased. The c o m p a c t s were pressed with die wall lubrication in floating die t o o l s u n d e r u n i a x i a l c o m p r e s s i o n conditions.
PREPARATION OF MONOSIZED METAL POWDERS BY PULSATED ORIFICE INJECTION
FLOW COMPACTION OF IRON POWDER WITH CONTROLLED PARTICLE SIZE DISTRIBUTION
Y. Kuroki et al (Tohoku University, Sendai, Japan). A device to cause pulsation of t h e m e t a l s t r e a m in a n atomizer was described. The system was a r r a n g e d so t h a t each pulse yielded one droplet of molten m e t a l of a size comparable with t h e orifice diameter. The s t a n d a r d deviation in particle size was 15%. The kinetics of liquid droplet injection ws discussed.
S. Takahashi, T. Nakagawa (Universiity of Tokyo, Tokyo, J a p a n ) . Production of c u p - s h a p e d p a r t s from fine Fe powders, with controlled particle size distribution and additions of 0.7wt% Zn s t e a r a t e a n d 0.5% l i q u i d parafin, was described. The powder m i x t u r e was compressed a n d m a d e to flow into t h e clearance between die a n d p u n c h by a s t e p p e d punch. Variations in density were m e a s u r e d a n d densities u p to 90% were attained.
52 MPR December 1993
MULTI-LEVEL POWDER FORGING AND POWDER COMPACTION USING MULTIAXIS HYRAULIC P R E S S
T. Kaji et al (Sumitomo Electric Industries, Itami City, J a p a n ) . A multiple axis press was described. Each r a m can be i n d e p e n d e n t l y driven a n d controlled thus permitting multi-level compaction. The p r e s s was r e p o r t e d to e n a b l e fully c l o s e d die forging to be c a r r i e d out. Design of t h e p r e s s a n d applications were outlined. A POWDER FORGED AUTOMOTIVE CONNECTING ROD
L. Albano-Muller et al (Krebsoge Sinterholding GmbH, Radewormwald, Germany). The production of automotive c o n n e c t i n g r o d s was discussed. It was r e p o r t e d t h a t even t h o u g h t h e p o w d e r steel was more expensive t h a n w r o u g h t steel t h e r e was a n overall cost saving of 24% a n d t h a t t h e powder forged con rod offered some technological advantages. Use of a fracture splitting process was held to be r e s p o n s i b l e for t h e cost savings. The process, t h e c o m p o n e n t a n d t h e overall economics were described. POWDER FORGING OF A RAPIDY SOLIDIFIED ALUMINIUM SILICON ALLOY POWDER
I~ Kawase et al (Mitsubishi Metals Corporation, J a p a n ) . An investigation of powder forging of a rapidy solidified A1-Si alloy was described. Disc s h a p e d c o m p a c t s were hot forged a n d h u b s were formed by application of back pressure. The relationship between forgability and back pressure were examined. It was shown t h a t flanged h u b s could be p r o d u c e d in a single operation, the back p r e s s u r e being effective in developing full density a n d avoiding cracks.