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Close dimensional tolerances through material selection
pressure. Surface carbides were formed excessively high temperatures,
Materials tolerance
at
for improved
VISUALIZATION BEHAVIOUR FILLING
OF POWDER FOR GRAVITY DIE
S. Takemoto, M. Kondon. (Toyota Motor Co., Japan.) The need for dies to be uniformly filled in order to attain improved dimensional tolerance was discussed. A study of die filling was described. Apparatus to visualize die filling was developed which allowed observation of effects of die cavity shape and feed shoe speed on filling behaviour and size segregation of atomized Fe powder. It was reported that size segregation was independent of these factors. Powder behaviour was described with reference to particle size distribution. PART MANUFACTURING AND MODELLING WITH SYSTEMS
EXPERIENCE ANCORBOND
TOLERANCES SELECTION
M. Larsson, 0. Thornblad. (Hans AB, Hans, Sweden.) Dimensions and tolerances were discussed with reference to the need for sinterlng sizing operations and difficulties with strong materials which restrict finishing to close tolerance. A model to calculate dimensional scatter was prepared which took material and process variations into account. This was reported to allow prediction of optimum part and manufacturing process conditions to attain best dimensional precision at lowest cost.
Novel
materials
PARTICLE SIZE EFFECTS ON SINTERING AND PROPERTIES TITANIUM-ALUMINIUM-VANADIUM POWDERS
J.D. Bolton, B.S. Becker. Bradford, Bradford, UK)
OF
(University
COMPOUND
of
MATERLALS
BY PM
K Piscang, B. Ullich. (Dresden University of Technology, Dresden, Germany.) Production of compound materials, such as Fe/Fe!ii, Fe/316L stainless steel and FeSi/stainless steel, were reviewed with reference to layered structures, production by PM methods and hlction welding. An investigation of these materials was described in which sintering was varied by changes in powder characteristics. Formation of intermetallic compounds and relevent tlhermodynamics were discussed.
Surface
S.H. Luk et al. (Hoeganaes Corp, Riverton, New Jersey USA) Improvements in PM part production accruing from the use of binder treated powders were discussed. Researches and practical experiences were reported to improve understanding of the process. Die filling and powder segregation were studied in order to alleviate problems of the lack of uniformity. Apparatus to study powder segregation in the die was described. Microstructure and elemental mapping were used to correlate laboratory data with manufacturing experience. CLOSE DIMENSIONAL THROUGH MATERW
Structure of hip replacement components was discussed with regard to service life of prostheses, currently about 15 years, the need to increase this and the use of compliant layers to lubricate joints. A study of density graded materials, based on Ti-6%Al-4%V powders of differing particle sizes, was described. The object was to make parts with a dense core and a coarse outer layer.
modification
LOW PRESSURE CARBURIZING STEELS
AND PLASMA OF ALLOYED PM
M. Rossi et al. (Polytechnico de Torino, Italy.) Carburizing of steel was discussed with regard to the requirement for hard wear and fatigue resistant surfaces on parts with a tough shock resistant core. Methods applicable to PM parts were reviewed. An investigation of the effects of process conditions in low pressure and plasma carburizing of a range of steels was carried out to ascertain the viability of the method. Structures and properties were determined. ELECTROCHEMISTRY MICROSTRUCTURE NITRIDED SINTERED
AND OF PLASMA STEELS
C.V. Franc0 et al. (Federal University of St. Catherine, Brazil.) It was reported that steels with different amounts of Ni and MO had been plasma nitrided. MO markedly increased surface hardness but Ni reduced hardness. In NaCl and NaNOs corrosion tests a low pitting potential was found attack being between particles. SURFACE ADVANCED
MODIFICATION PROTECTIVE
BY COATINGS
M.Sisodia et aE. (University of Rajastan, India.) Investigations of surface modification by various coating techniques were described. The objective was to establish a viable approach to substrate surface modification and the effects of these in a range of applications.
Sin tering ROBUST DESIGN
optimization
SINTERED STEEL BY ROBUST OF EXPERIMENTATION
B.Bergquist, B.Hildenwalll. (Linkoping University, Sweden.) The importance of mechanical performance and dimensional stability were emphasized and studies to attain this were described. A study of a P Steel, to find conditions giving higher tensile strength and proof stress, without loss of dimensional stability or -tensile elongation, was described. Statistical experimental design was used. It was reported that performance and dimensional stability could be maximized and stabilized. REACTIONS IN REACTIVE OF ALUMINIUM-TITANIUM COMPOSITES
SIN-TERING DIBORIDE
J.Duszczyk et al. (Delft IJniversity of Technology, The Netherlands.) Use of reactive techniques for production of in situ composites was reviewed with note taken of the possibility for high volume and small size of reinforcements and cleanliness of the matrix/ reinforcement interface. The paper reported a study of reactions and phases in Al-‘f-B. The solubility of B in Al was shown to be rate controlling and that TiBz only formed after decomposition of transient AlBz. Decomposition of AIBz was shown to be endothermic and formation of TiBz is exothermic. Composites with fine reinforcements were formed.
Warm
compaction
PRODUCTION COMPACTION POWDERS
EXPERIENCE OF ‘DENSMIX’
OF WARM
U.Engstrom, B.Johansson. (Hans AB, Hans, Sweden.) Development of a new group of powders, ‘Densmix’, intended for warm compaction was reported. Densities attained were comparable with those resulting from double press/double sinter routes. Production experiences were outlined with regard to green and sintered properties, tolerances and variety of part shapes. KEY PARAMETERS FOR WARM COMPACTION OF HIGH DENSITY MATERIALS
S.St.Laurent, F.Chagnon. (Quebec Metal Powders Ltd., Montreal, Canada.) Warm compaction w.as discussed with regard to the characteristics required in the powder mix, green and sintered properties and process conditions. Laboratory experiments and production trials were used to ident@ key process parameters and their effects on ejection forces and properties. Powder flo~w and apparent density were important factors. MPR January
1997
37
Materials tolerance
at
for improved
VISUALIZATION BEHAVIOUR FILLING
OF POWDER FOR GRAVITY DIE
S. Takemoto, M. Kondon. (Toyota Motor Co., Japan.) The need for dies to be uniformly filled in order to attain improved dimensional tolerance was discussed. A study of die filling was described. Apparatus to visualize die filling was developed which allowed observation of effects of die cavity shape and feed shoe speed on filling behaviour and size segregation of atomized Fe powder. It was reported that size segregation was independent of these factors. Powder behaviour was described with reference to particle size distribution. PART MANUFACTURING AND MODELLING WITH SYSTEMS
EXPERIENCE ANCORBOND
TOLERANCES SELECTION
M. Larsson, 0. Thornblad. (Hans AB, Hans, Sweden.) Dimensions and tolerances were discussed with reference to the need for sinterlng sizing operations and difficulties with strong materials which restrict finishing to close tolerance. A model to calculate dimensional scatter was prepared which took material and process variations into account. This was reported to allow prediction of optimum part and manufacturing process conditions to attain best dimensional precision at lowest cost.
Novel
materials
PARTICLE SIZE EFFECTS ON SINTERING AND PROPERTIES TITANIUM-ALUMINIUM-VANADIUM POWDERS
J.D. Bolton, B.S. Becker. Bradford, Bradford, UK)
OF
(University
COMPOUND
of
MATERLALS
BY PM
K Piscang, B. Ullich. (Dresden University of Technology, Dresden, Germany.) Production of compound materials, such as Fe/Fe!ii, Fe/316L stainless steel and FeSi/stainless steel, were reviewed with reference to layered structures, production by PM methods and hlction welding. An investigation of these materials was described in which sintering was varied by changes in powder characteristics. Formation of intermetallic compounds and relevent tlhermodynamics were discussed.
Surface
S.H. Luk et al. (Hoeganaes Corp, Riverton, New Jersey USA) Improvements in PM part production accruing from the use of binder treated powders were discussed. Researches and practical experiences were reported to improve understanding of the process. Die filling and powder segregation were studied in order to alleviate problems of the lack of uniformity. Apparatus to study powder segregation in the die was described. Microstructure and elemental mapping were used to correlate laboratory data with manufacturing experience. CLOSE DIMENSIONAL THROUGH MATERW
Structure of hip replacement components was discussed with regard to service life of prostheses, currently about 15 years, the need to increase this and the use of compliant layers to lubricate joints. A study of density graded materials, based on Ti-6%Al-4%V powders of differing particle sizes, was described. The object was to make parts with a dense core and a coarse outer layer.
modification
LOW PRESSURE CARBURIZING STEELS
AND PLASMA OF ALLOYED PM
M. Rossi et al. (Polytechnico de Torino, Italy.) Carburizing of steel was discussed with regard to the requirement for hard wear and fatigue resistant surfaces on parts with a tough shock resistant core. Methods applicable to PM parts were reviewed. An investigation of the effects of process conditions in low pressure and plasma carburizing of a range of steels was carried out to ascertain the viability of the method. Structures and properties were determined. ELECTROCHEMISTRY MICROSTRUCTURE NITRIDED SINTERED
AND OF PLASMA STEELS
C.V. Franc0 et al. (Federal University of St. Catherine, Brazil.) It was reported that steels with different amounts of Ni and MO had been plasma nitrided. MO markedly increased surface hardness but Ni reduced hardness. In NaCl and NaNOs corrosion tests a low pitting potential was found attack being between particles. SURFACE ADVANCED
MODIFICATION PROTECTIVE
BY COATINGS
M.Sisodia et aE. (University of Rajastan, India.) Investigations of surface modification by various coating techniques were described. The objective was to establish a viable approach to substrate surface modification and the effects of these in a range of applications.
Sin tering ROBUST DESIGN
optimization
SINTERED STEEL BY ROBUST OF EXPERIMENTATION
B.Bergquist, B.Hildenwalll. (Linkoping University, Sweden.) The importance of mechanical performance and dimensional stability were emphasized and studies to attain this were described. A study of a P Steel, to find conditions giving higher tensile strength and proof stress, without loss of dimensional stability or -tensile elongation, was described. Statistical experimental design was used. It was reported that performance and dimensional stability could be maximized and stabilized. REACTIONS IN REACTIVE OF ALUMINIUM-TITANIUM COMPOSITES
SIN-TERING DIBORIDE
J.Duszczyk et al. (Delft IJniversity of Technology, The Netherlands.) Use of reactive techniques for production of in situ composites was reviewed with note taken of the possibility for high volume and small size of reinforcements and cleanliness of the matrix/ reinforcement interface. The paper reported a study of reactions and phases in Al-‘f-B. The solubility of B in Al was shown to be rate controlling and that TiBz only formed after decomposition of transient AlBz. Decomposition of AIBz was shown to be endothermic and formation of TiBz is exothermic. Composites with fine reinforcements were formed.
Warm
compaction
PRODUCTION COMPACTION POWDERS
EXPERIENCE OF ‘DENSMIX’
OF WARM
U.Engstrom, B.Johansson. (Hans AB, Hans, Sweden.) Development of a new group of powders, ‘Densmix’, intended for warm compaction was reported. Densities attained were comparable with those resulting from double press/double sinter routes. Production experiences were outlined with regard to green and sintered properties, tolerances and variety of part shapes. KEY PARAMETERS FOR WARM COMPACTION OF HIGH DENSITY MATERIALS
S.St.Laurent, F.Chagnon. (Quebec Metal Powders Ltd., Montreal, Canada.) Warm compaction w.as discussed with regard to the characteristics required in the powder mix, green and sintered properties and process conditions. Laboratory experiments and production trials were used to ident@ key process parameters and their effects on ejection forces and properties. Powder flo~w and apparent density were important factors. MPR January
1997
37