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Manufacture of a hot-work roll by hot isostatic pressing
PM
A study of HIP of Fe-1.75% Ni-1.5% Cu0.5% Mo powder with additions of 0.4 or 0.6% graphite was described, structure and properties being investigated. The results of the tests on HIP steels were c o m p a r e d with pressed and sintered materials. MANUFACTURE OF A HOT-WORK ROLL BY HOT ISOSTATIC P R E S S I N G T. Hisada, T. Tomioka, (Daido Steel Co Ltd, Nagoya, J a p a n ) . It was reported t h a t a hot-work roll, for wire rod rolling, had been fabricated by HIP. A hard, heat resistant, surface was combined with a tough Cr-Mo steel core. The roll was shown to have a service life five times t h a t of a conventional chill cast roll. E F F E C T S OF OXYGEN HOT ISOSTATIC P R E S S I N G ON P R O P E R T I E S OF MANGANESE-ZINC F E R R I T E S H. Ochiai, O. Kimura, (Shonan Institute of Technology, Kanagawa, J a p a n ) . The effects of HIP t r e a t m e n t in O on MnZn ferrites were described. It was r e p o r t e d t h a t the physical p r o p e r t i e s of the materials were e n h a n c e d as a result of the treatment.
P o w d e r extrusion MECHANICAL STRENGTH OF E X T R U D E D ATOMIZED AMORPHOUS POWDERS OF MAGNESIUM ALLOY A. Inoue et al (Tohoku University, Sendal, Japan). It was reported t h a t a m o r p h o u s Mg base alloy powders had been produced in a novel a t o m i z e r with a m e a n particle size of 25 pm. The powders were sealed at low O and moisture in a can and e x t r u d e d at 400°C. The e x t r u d e d material was of full density and had a m i x e d structure of Mg and two o t h e r constituents. The tensile strength was said to be 590 MPa, double t h a t of conventional Mg alloys. E F F E C T S OF CARBIDE SIZE ON P R O P E R T I E S OF HOT E X T R U D E D PM HIGH S P E E D STEEL A. Murase, G. Abe (Sanyo Special Steel Co Ltd, Himeji, J a p a n ) . N atomized HSS powder was e n c a p s u l a t e d , cold isostatically p r e s s e d and hot extruded. It was reported t h a t the m a x i m u m carbide particle size was 10 pm and could be closely controlled within this limit. Heat t r e a t m e n t response, mechanical and fatigue p r o p e r t i e s were discussed. It was concluded t h a t a carbide particle size range of 2 to 3 ~m resulted in the m o s t stable properties. METAL POWDER CONSOLIDATED P R O C E S S E S DURING HOT EXTRUSION OF SUPERALLOY PIPE PRODUCTS Y. Ohashi et al (Sumitomo Metal Industries
LITERATURE
REVIEW
Co Ltd, Tokyo, J a p a n ) . The production of Cr-Mo steel pipe with a coating of 625 superalloy was described. The pipe was e x t r u d e d from a wrought steel core with the superalloy powder. It was r e p o r t e d t h a t a fully d e n s e bimetallic pipe was p r o d u c e d without defects. The result was a t t r i b u t e d to the billet h e a t i n g t e c h n o l o g y u s e d a n d p e n e t r a t i o n of p o w d e r into the steel surface. The deformation behaviour during processing was discussed. E F F E C T S OF SILICON CARBIDE PARTICLE SIZE AND CONCENTRATION ON P R O P E R T I E S OF ALUMINIUM-IRON ALLOY G. S t a n i e k et al ( A e r o s p a c e R e s e a r c h Establishment, Koln, Germany). A1-6% Fe alloys with additions of 10 or 20 vol% of SiC with particle sizes 4 to 16 pm were p r e p a r e d from Ar atomized p o w d e r s by m i x i n g , c o n s o l i d a t i o n , degassing and extrusion. Tensile and fracture t o u g h n e s s tests were carried out and the results correlated with microstructures. It was r e p o r t e d t h a t with increasing SiC volume fraction the stiffness was substantially increased and s t r e n g t h increased slightly. Ductility decreased with large particle size.
Sintering m e c h a n i s m s and microstructural control DENSIFICATION AND MICROSTRUCTURAL DEVELOPMENT DURING S I N T E R I N G OF METAL POWDERS R. Watanabe (Tohoku University, Sendai, Japan). Solid state sintering m e c h a n i s m s were discussed with reference to mass transfer, structural evolution, store structure and closure, p a r t i c l e p a c k i n g a n d s i n t e r e d density. The p i n n i n g force of r e s i d u a l porosity against grain boundary migration, p o r e / b o u n d a r y separation and a t t a c h m e n t and its role in densification a n d grain growth were taken into account t o g e t h e r with the Zener rule for grain growth and grain size distribution. P R E S S U R E SINTERING MECHANISMS W.~ Kaysser, (Institute of Materials Research, Koln, Germany). High pressure/high temperature sintering m e c h a n i s m s were reviewed with consideration given to basic p h e n o m e n a such as plastic flow, diffusion and creep. The m e c h a n i s m s were incorporated into micromechanical calculations which also account for particle size distributions and p a r t i c u l a t e r e i n f o r c e m e n t in c o m p o s i t e materials. Correlations between microstructure and densification on the basis of ordering were illustrated.
Examples were presented including extrusion, H I P o f A1 a l l o y s a n d intermetallics, compositionally graded materials and fibre reinforced materials. CONTRIBUTIONS OF VOLUME AND SURFACE D I F F U S I O N DURING HIGH T E M P E R A T U R E SINTERING OF COPPER H. Ichonose, H. Igarashi, (University of Osaka, Osaka, J a p a n ) . The contributions of diffusion m e c h a n i s m s in sintering were evaluated using a three-wire model in which a thin Cu wire was plated with Mo and t h e n with Cu. It was considered t h a t surface and volume diffusion were the only operative mechanisms. Neck growth rate was found to d e p e n d on the thickness of the Cu plating and it was deduced t h a t volume diffusion predominated. DIMENSIONAL CHANGE DURING SINTERING DUE TO ANISOTROPIC MOVEMENTS OF PARTICLES H. Kuroki. (Hiroshima University, Hiroshima, J a p a n ) . Anisotropic dimensional changes occurring during sintering were discussed. E x p e r i m e n t s on Fe-Cu and stainless and high speed steels were described sintering b e i n g w i t h or w i t h o u t liquid p h a s e s . D i m e n s i o n a l c h a n g e s w e r e s h o w n to o r i g i n a t e at all i n t e r - p a r t i c l e c o n t a c t s , distances between particles decreasing and increasing, porosity being decreased and it was d e m o n s t r a t e d t h a t t h e r e was less m o v e m e n t in the denser, pressed, direction. ANALYSIS OF FINAL STAGE OF SINTERING IN P R E S E N C E OF A LIQUID PHASE K-H. Kim, S-J.L. Kang. (Korea Advanced Institute of Science and Technology, Daejon, Korea). A theory for the final stage of liquid p h a s e sintering was presented. The volume of liquid for pore filling was calculated by consideration of grain shape accommodation and microstructural homogenization. The calculated curve for densification was reported to agree with e x p e r i m e n t a l results. Differences with Kingery's theory were described and discussed. E F F E C T S OF NICKEL AND PHOSPHORUS ON SINTERING AND MICROSTRUCTURE OF TUNGSTENCOPPER ALLOY J.S. Lee et al (Hanyang University, Ansan, Korea). A study of the effects of Ni and P additions on the liquid p h a s e sintering of W-Cu alloys was described. Correlations were established between the W skeleton structure and Cu infiltration in W-20wt% Cu. Additions of Ni and P were reported to
MPR January 1994 41
A study of HIP of Fe-1.75% Ni-1.5% Cu0.5% Mo powder with additions of 0.4 or 0.6% graphite was described, structure and properties being investigated. The results of the tests on HIP steels were c o m p a r e d with pressed and sintered materials. MANUFACTURE OF A HOT-WORK ROLL BY HOT ISOSTATIC P R E S S I N G T. Hisada, T. Tomioka, (Daido Steel Co Ltd, Nagoya, J a p a n ) . It was reported t h a t a hot-work roll, for wire rod rolling, had been fabricated by HIP. A hard, heat resistant, surface was combined with a tough Cr-Mo steel core. The roll was shown to have a service life five times t h a t of a conventional chill cast roll. E F F E C T S OF OXYGEN HOT ISOSTATIC P R E S S I N G ON P R O P E R T I E S OF MANGANESE-ZINC F E R R I T E S H. Ochiai, O. Kimura, (Shonan Institute of Technology, Kanagawa, J a p a n ) . The effects of HIP t r e a t m e n t in O on MnZn ferrites were described. It was r e p o r t e d t h a t the physical p r o p e r t i e s of the materials were e n h a n c e d as a result of the treatment.
P o w d e r extrusion MECHANICAL STRENGTH OF E X T R U D E D ATOMIZED AMORPHOUS POWDERS OF MAGNESIUM ALLOY A. Inoue et al (Tohoku University, Sendal, Japan). It was reported t h a t a m o r p h o u s Mg base alloy powders had been produced in a novel a t o m i z e r with a m e a n particle size of 25 pm. The powders were sealed at low O and moisture in a can and e x t r u d e d at 400°C. The e x t r u d e d material was of full density and had a m i x e d structure of Mg and two o t h e r constituents. The tensile strength was said to be 590 MPa, double t h a t of conventional Mg alloys. E F F E C T S OF CARBIDE SIZE ON P R O P E R T I E S OF HOT E X T R U D E D PM HIGH S P E E D STEEL A. Murase, G. Abe (Sanyo Special Steel Co Ltd, Himeji, J a p a n ) . N atomized HSS powder was e n c a p s u l a t e d , cold isostatically p r e s s e d and hot extruded. It was reported t h a t the m a x i m u m carbide particle size was 10 pm and could be closely controlled within this limit. Heat t r e a t m e n t response, mechanical and fatigue p r o p e r t i e s were discussed. It was concluded t h a t a carbide particle size range of 2 to 3 ~m resulted in the m o s t stable properties. METAL POWDER CONSOLIDATED P R O C E S S E S DURING HOT EXTRUSION OF SUPERALLOY PIPE PRODUCTS Y. Ohashi et al (Sumitomo Metal Industries
LITERATURE
REVIEW
Co Ltd, Tokyo, J a p a n ) . The production of Cr-Mo steel pipe with a coating of 625 superalloy was described. The pipe was e x t r u d e d from a wrought steel core with the superalloy powder. It was r e p o r t e d t h a t a fully d e n s e bimetallic pipe was p r o d u c e d without defects. The result was a t t r i b u t e d to the billet h e a t i n g t e c h n o l o g y u s e d a n d p e n e t r a t i o n of p o w d e r into the steel surface. The deformation behaviour during processing was discussed. E F F E C T S OF SILICON CARBIDE PARTICLE SIZE AND CONCENTRATION ON P R O P E R T I E S OF ALUMINIUM-IRON ALLOY G. S t a n i e k et al ( A e r o s p a c e R e s e a r c h Establishment, Koln, Germany). A1-6% Fe alloys with additions of 10 or 20 vol% of SiC with particle sizes 4 to 16 pm were p r e p a r e d from Ar atomized p o w d e r s by m i x i n g , c o n s o l i d a t i o n , degassing and extrusion. Tensile and fracture t o u g h n e s s tests were carried out and the results correlated with microstructures. It was r e p o r t e d t h a t with increasing SiC volume fraction the stiffness was substantially increased and s t r e n g t h increased slightly. Ductility decreased with large particle size.
Sintering m e c h a n i s m s and microstructural control DENSIFICATION AND MICROSTRUCTURAL DEVELOPMENT DURING S I N T E R I N G OF METAL POWDERS R. Watanabe (Tohoku University, Sendai, Japan). Solid state sintering m e c h a n i s m s were discussed with reference to mass transfer, structural evolution, store structure and closure, p a r t i c l e p a c k i n g a n d s i n t e r e d density. The p i n n i n g force of r e s i d u a l porosity against grain boundary migration, p o r e / b o u n d a r y separation and a t t a c h m e n t and its role in densification a n d grain growth were taken into account t o g e t h e r with the Zener rule for grain growth and grain size distribution. P R E S S U R E SINTERING MECHANISMS W.~ Kaysser, (Institute of Materials Research, Koln, Germany). High pressure/high temperature sintering m e c h a n i s m s were reviewed with consideration given to basic p h e n o m e n a such as plastic flow, diffusion and creep. The m e c h a n i s m s were incorporated into micromechanical calculations which also account for particle size distributions and p a r t i c u l a t e r e i n f o r c e m e n t in c o m p o s i t e materials. Correlations between microstructure and densification on the basis of ordering were illustrated.
Examples were presented including extrusion, H I P o f A1 a l l o y s a n d intermetallics, compositionally graded materials and fibre reinforced materials. CONTRIBUTIONS OF VOLUME AND SURFACE D I F F U S I O N DURING HIGH T E M P E R A T U R E SINTERING OF COPPER H. Ichonose, H. Igarashi, (University of Osaka, Osaka, J a p a n ) . The contributions of diffusion m e c h a n i s m s in sintering were evaluated using a three-wire model in which a thin Cu wire was plated with Mo and t h e n with Cu. It was considered t h a t surface and volume diffusion were the only operative mechanisms. Neck growth rate was found to d e p e n d on the thickness of the Cu plating and it was deduced t h a t volume diffusion predominated. DIMENSIONAL CHANGE DURING SINTERING DUE TO ANISOTROPIC MOVEMENTS OF PARTICLES H. Kuroki. (Hiroshima University, Hiroshima, J a p a n ) . Anisotropic dimensional changes occurring during sintering were discussed. E x p e r i m e n t s on Fe-Cu and stainless and high speed steels were described sintering b e i n g w i t h or w i t h o u t liquid p h a s e s . D i m e n s i o n a l c h a n g e s w e r e s h o w n to o r i g i n a t e at all i n t e r - p a r t i c l e c o n t a c t s , distances between particles decreasing and increasing, porosity being decreased and it was d e m o n s t r a t e d t h a t t h e r e was less m o v e m e n t in the denser, pressed, direction. ANALYSIS OF FINAL STAGE OF SINTERING IN P R E S E N C E OF A LIQUID PHASE K-H. Kim, S-J.L. Kang. (Korea Advanced Institute of Science and Technology, Daejon, Korea). A theory for the final stage of liquid p h a s e sintering was presented. The volume of liquid for pore filling was calculated by consideration of grain shape accommodation and microstructural homogenization. The calculated curve for densification was reported to agree with e x p e r i m e n t a l results. Differences with Kingery's theory were described and discussed. E F F E C T S OF NICKEL AND PHOSPHORUS ON SINTERING AND MICROSTRUCTURE OF TUNGSTENCOPPER ALLOY J.S. Lee et al (Hanyang University, Ansan, Korea). A study of the effects of Ni and P additions on the liquid p h a s e sintering of W-Cu alloys was described. Correlations were established between the W skeleton structure and Cu infiltration in W-20wt% Cu. Additions of Ni and P were reported to
MPR January 1994 41