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Hot forging of sintered porous blanks
HIGH STRENGTH
PM STEEL WITH
HIGH HARDENABILITY HIGH COMPRESSIBILITY
MADE FROM POWDER
T. Tsutsui et al (Hitachi Powdered Metals, Chiba, Japan) The properties of steel parts, with high hardenability, were discussed with regard to improvements arising from the use of powders with high compressiblity. Alloy elements in steel were selected for their ferrite hardening coefficient and hardenability multiplying factor. It was reported that improvements in hardenability and compressiblity could be obtained by optimizing Ni, Cr and MO contents. MANGANESE
ALLOYED SINTERED
STEEL PREPARED
FROM ELEMENTAL
POWDERS
H. Danninger et al (Technical Ilniversity of Vienna, Vienna, Austria) The role of Mn in improving hardening of steel was discussed. An investigation of the effects of Mn in low C sintered steels was described. Homogenization of the Mn content was shown to be of critical importance and the occurance of gas transport of Mn was noted, pores being filled with Mn vapour at sintering temperatures. MEASUREMENT OF RESIDUAL SURFACE STRESSES IN SINTERED AND CARBURIZED STEEL PARTS G.M. la Vecchia et al (University of Brescia, Brescia, Italy) The need to understand the factors controlling surface hardness and fatigue of steel gear alloys was reviewed with respect to properties. Surface hardening, to introduce surface compressive stresses and to enhance fatigue properties, was discussed. Measurements of surface stresses were reported.
Sinfering consolicfafion HOT FORGING OF SINTERED POROUS BLANKS L.A. Harkov et al (Technical University, Chelyabinsk, Russia) It was reported that fully dense hollow shaped parts with curved surfaces had been produced from Fe powders alloyed with Ni, Cr, MO or W. The process steps were press, sinter, heat treatment and hot forging. Models of hot forging were used to calculate dimensions, shape and porosity and to determine technological conditions.
sintering of compacts made from coated and uncoated powders was investigated and properties and structures compared. The coatings were reported to enhance sintering. SINTERING
BEHAVIOUR
MATERIALS
AN’D ATMOSPHERE
OF PM
CONTROL G. Leitner
et al (Fraunhofer Inst. for Ceramic Technology, Dresden, Germany) The effects of sintering atmosphere on properties of sintered parts were discussed. The use of in situ gas analysis to monitor and control sintering atmosphere was desribed and results were given for WCCo, TiAl and ceramics. Results of thermal analysis were given. CONTRIBUTION
OF DIFFERENTIAL
reference to high magnetic energy density and reduction in part weight and volume. It was reported that alloy composition had been optimized and magnets coated with Sn, Zn or Ni to protect against corrosion. POWDER METALLURGY AND MODERN PERMANENT MAGNETS F. Vial (IJGIMAG SA, Saint Pierre d’Allevard, France) (In French). The application of PM to the production of permanent magnets was discussed with reference to the properties and applications, in electrical machines, of NdFe-B alloys. Improvetnents are reported to accrue from better understanding of microstructures and the effects of process variables.
ANALYSIS TO STUDY OF METALLIC POWDERS AND SINTERING
COMPOSITE MAGNETIC
F. Lemoisson (Centre des Materiaux de I’ENSMP, Evry, France) The application of DTA to the study of metal powders and sintering was described. Results for supersolidus sintered high speed steels, superalloys, Al alloys and Ni aluminide composites were given. DTA was compared with other thermal methods and microstructural analysis.
MATERIALS
WITH SOFT
PROPETIES
Y. Bienvenu,
Metal injection
moulcfing
EFFECT OF POWDER TYPE ON PROPERTIES OF INJECTION MOULDED HIGH SPEED STEEL PARTS H. Miura, T. Honda (Kumamoto University, Kumamoto, Japan) The MIM production process applied to HSS parts was described in the context of an investigation of the effects of process parameters and powder characteristics. Strengths exceeding 3 GPa and Rockwell hardnesses of 70 C were reported. PROPERTIES OF MATERLALS AND STRUCTURAL PARTS MADE BY METAL INJECTION MOULDING H. Cohrt et al (Schunk Sintermetalltechnik GmbH, Giessen, Germany) Injection moulding of metal and plastic parts were compared with reference to part shapes, mechanical properties and optimization of microstructures. Microstructural evolution and structure/ property relationships were discussed in respect of low alloy steels, surface condition and dimensional tolerances.
Magnetic materials
INFLUENCE OF PARTICLE COATING ON SINTERING BEBAVIOUR OF IRON POWDER
RARE EARTH PERMANENT MAGNETS AND IMPROVEMENTS IN PERFORMANCE
K-P. Wieters (University of Technology of Dresden, Dresden, Germany) The coating of carbonyl Fe powder with elements, Cu, Mo and Ni was described. The
M. Katter et al (Vacuumschmelze GmbH, Hanau, Germany) The magnetic properties of sintered NdFe-B and SmCo were discussed with
P. Lansson, M. Persson (Hiiganls AR, H6gan&s, Sweden ) Application of PM methodologies in the production of soft magnetic materials was discussed. Development of composite materials was outlined and it was shown that complex shaped parts can be made. It was reported that computer aided design had been used. RECENT DEVELOPMENTS IN PM MAGNETIC MATERIAL PROPERTIES AND APPLICATIONS D.R. &an (Windfall Products Inc. St. Mary’s, Pennsylvania, USA) Testing methods and data for a range of sintered magnetic materials were described. Property /structure relationships were discussed with regard to the effects of process conditions. An application, an automotive linear solenoid, was evaluated. NANOCRYSTALLINE IRON-ZIRCONIUMBORON-COPPER SOFT MAGNETS A. Inoue et al (Tohoku [Jniversity, Sendai, Japan) It was reported that nanocrystalline Fe7at&Zr-G%B-1XCu compacts had been prepared by hot pressing amorphous powders to a density of 99.9%. The properties were shown to be superior to those of alloys made in other ways. TEXTURE AND ULTRASONIC PROCESSING OF MAGNETIC POWDERS G. Yaglo (Don State Ilniversity, Rostow-on Don, Russia.) Physical aspects of the interaction of fine powders with magnetic fields and ultrasonic radiation, to produce textured structures were described. Equations were derived relating powder characteristics with field conditions. The application to powder fluidization in a mould was analysed. MPR April 1995 41
PM STEEL WITH
HIGH HARDENABILITY HIGH COMPRESSIBILITY
MADE FROM POWDER
T. Tsutsui et al (Hitachi Powdered Metals, Chiba, Japan) The properties of steel parts, with high hardenability, were discussed with regard to improvements arising from the use of powders with high compressiblity. Alloy elements in steel were selected for their ferrite hardening coefficient and hardenability multiplying factor. It was reported that improvements in hardenability and compressiblity could be obtained by optimizing Ni, Cr and MO contents. MANGANESE
ALLOYED SINTERED
STEEL PREPARED
FROM ELEMENTAL
POWDERS
H. Danninger et al (Technical Ilniversity of Vienna, Vienna, Austria) The role of Mn in improving hardening of steel was discussed. An investigation of the effects of Mn in low C sintered steels was described. Homogenization of the Mn content was shown to be of critical importance and the occurance of gas transport of Mn was noted, pores being filled with Mn vapour at sintering temperatures. MEASUREMENT OF RESIDUAL SURFACE STRESSES IN SINTERED AND CARBURIZED STEEL PARTS G.M. la Vecchia et al (University of Brescia, Brescia, Italy) The need to understand the factors controlling surface hardness and fatigue of steel gear alloys was reviewed with respect to properties. Surface hardening, to introduce surface compressive stresses and to enhance fatigue properties, was discussed. Measurements of surface stresses were reported.
Sinfering consolicfafion HOT FORGING OF SINTERED POROUS BLANKS L.A. Harkov et al (Technical University, Chelyabinsk, Russia) It was reported that fully dense hollow shaped parts with curved surfaces had been produced from Fe powders alloyed with Ni, Cr, MO or W. The process steps were press, sinter, heat treatment and hot forging. Models of hot forging were used to calculate dimensions, shape and porosity and to determine technological conditions.
sintering of compacts made from coated and uncoated powders was investigated and properties and structures compared. The coatings were reported to enhance sintering. SINTERING
BEHAVIOUR
MATERIALS
AN’D ATMOSPHERE
OF PM
CONTROL G. Leitner
et al (Fraunhofer Inst. for Ceramic Technology, Dresden, Germany) The effects of sintering atmosphere on properties of sintered parts were discussed. The use of in situ gas analysis to monitor and control sintering atmosphere was desribed and results were given for WCCo, TiAl and ceramics. Results of thermal analysis were given. CONTRIBUTION
OF DIFFERENTIAL
reference to high magnetic energy density and reduction in part weight and volume. It was reported that alloy composition had been optimized and magnets coated with Sn, Zn or Ni to protect against corrosion. POWDER METALLURGY AND MODERN PERMANENT MAGNETS F. Vial (IJGIMAG SA, Saint Pierre d’Allevard, France) (In French). The application of PM to the production of permanent magnets was discussed with reference to the properties and applications, in electrical machines, of NdFe-B alloys. Improvetnents are reported to accrue from better understanding of microstructures and the effects of process variables.
ANALYSIS TO STUDY OF METALLIC POWDERS AND SINTERING
COMPOSITE MAGNETIC
F. Lemoisson (Centre des Materiaux de I’ENSMP, Evry, France) The application of DTA to the study of metal powders and sintering was described. Results for supersolidus sintered high speed steels, superalloys, Al alloys and Ni aluminide composites were given. DTA was compared with other thermal methods and microstructural analysis.
MATERIALS
WITH SOFT
PROPETIES
Y. Bienvenu,
Metal injection
moulcfing
EFFECT OF POWDER TYPE ON PROPERTIES OF INJECTION MOULDED HIGH SPEED STEEL PARTS H. Miura, T. Honda (Kumamoto University, Kumamoto, Japan) The MIM production process applied to HSS parts was described in the context of an investigation of the effects of process parameters and powder characteristics. Strengths exceeding 3 GPa and Rockwell hardnesses of 70 C were reported. PROPERTIES OF MATERLALS AND STRUCTURAL PARTS MADE BY METAL INJECTION MOULDING H. Cohrt et al (Schunk Sintermetalltechnik GmbH, Giessen, Germany) Injection moulding of metal and plastic parts were compared with reference to part shapes, mechanical properties and optimization of microstructures. Microstructural evolution and structure/ property relationships were discussed in respect of low alloy steels, surface condition and dimensional tolerances.
Magnetic materials
INFLUENCE OF PARTICLE COATING ON SINTERING BEBAVIOUR OF IRON POWDER
RARE EARTH PERMANENT MAGNETS AND IMPROVEMENTS IN PERFORMANCE
K-P. Wieters (University of Technology of Dresden, Dresden, Germany) The coating of carbonyl Fe powder with elements, Cu, Mo and Ni was described. The
M. Katter et al (Vacuumschmelze GmbH, Hanau, Germany) The magnetic properties of sintered NdFe-B and SmCo were discussed with
P. Lansson, M. Persson (Hiiganls AR, H6gan&s, Sweden ) Application of PM methodologies in the production of soft magnetic materials was discussed. Development of composite materials was outlined and it was shown that complex shaped parts can be made. It was reported that computer aided design had been used. RECENT DEVELOPMENTS IN PM MAGNETIC MATERIAL PROPERTIES AND APPLICATIONS D.R. &an (Windfall Products Inc. St. Mary’s, Pennsylvania, USA) Testing methods and data for a range of sintered magnetic materials were described. Property /structure relationships were discussed with regard to the effects of process conditions. An application, an automotive linear solenoid, was evaluated. NANOCRYSTALLINE IRON-ZIRCONIUMBORON-COPPER SOFT MAGNETS A. Inoue et al (Tohoku [Jniversity, Sendai, Japan) It was reported that nanocrystalline Fe7at&Zr-G%B-1XCu compacts had been prepared by hot pressing amorphous powders to a density of 99.9%. The properties were shown to be superior to those of alloys made in other ways. TEXTURE AND ULTRASONIC PROCESSING OF MAGNETIC POWDERS G. Yaglo (Don State Ilniversity, Rostow-on Don, Russia.) Physical aspects of the interaction of fine powders with magnetic fields and ultrasonic radiation, to produce textured structures were described. Equations were derived relating powder characteristics with field conditions. The application to powder fluidization in a mould was analysed. MPR April 1995 41