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A compact rotating disc atomizer for production of reactive powders
PROPERTIES OF ‘ANCORDENSE’ PROCESSED HIGH PERFORMANCE MATERIALS
shown to be l/4 of that atomized in the first stage only. Mechanisms were discussed with regard to particle morphology.
FINITE ELEMENT SIMULATION OF SINTERING OF CEMENTED CARBIDE COMPACTS
A.J.Rawlings et al. (Hoeganaes Corp, Riverton, New Jersey, USA) Properties of Ancordense processed materials were analyzed in detail, the evaluation including strength, impact and fatigue. Tests were carried out on conventionally and high temperature sintered alloys in as-sintered and heat treated conditions.
A NOVEL INTERNAL MIXING GAS ATOMIZER FOR PRODUCTION OF FINE POWDER
DBouvard, O.Gillia. (Inst. National Polytechnique, Grenoble, France.) Stresses and shape changes during sintering of metals and ceramics were discussed. Sintering of WC-Co was simulated by a finite element ‘ABAQUS’ program in an effort to predict the final shape of a compact. Parameters were determined by experiment. A range of part geometries was considered. Predicted and measured results were compared.
Atomization IMPULSE ATOMIZATION FOR ECONOMY AND FLEXIBILITY IN POWDER PRODUCTION H.Henein, L.C.Marin. (University of Alberta, Canada.) The Impule Atomization Process was described. This was reported to allow control of particle size and size distribution, morphology and microstructure. Examples given included, Cu, Zn, Al and Al alloys. Process economics were discussed. A COMPACT ROTATING DISC ATOMIZER FOR PRODUCTION OF REACTIVE POWDERS M.G.Osbome, LEAnderson. (Ames Laboratory, USA) A new centrifugal atomizer was described. The device uses spray quenching and was used for rare earth metals and alloys for magnetic and electrical uses. The method allows increased passivation of rare earths which results in less oxidation of the powders. CENTRIFUGAL DISPERSION OF METALLIC BARSTOCK IN INDUCTIVE PLASMA F.Folio et al. (University of ClermontFerrand, France.) A novel atomizer for producing high purity, fine metal powder from bar was described. As the bar is drawn into the machine it is inductively heated to below the melting point and plasma melted. Molten metal droplets are atomized on a dispersion head rotating at 60 000 rpm. The particles solid@ in Ar. Results were discussed for industrial potential. A STUDY OF TWO STAGE ATOMIZATION P.Cooper, J.D.Ayers. (Naval Research Laboratory, USA) A two-stage atomization process was described. In stage 1 a liquid metal stream is impact atomized by spinning impellers. The resulting spray is further atomized by a repidly rotating cup containing a continuous oil film. Tests on Sn were described. The final powder size was
38 MPR January 1997
JJDunkley, M.S.Sheikaliev. (Atomizing Systerns Ltd., Sheffield, UK) Types of atomizer nozzle, close coupled, free fall and internal mixing, were compared and discussed with reference to efficiency. It was reported that a new internal mixing nozzle had been used to make powders of similar size to products of other nozzles but at markedly lower gas flow rates and pressures.
Fatigue EFFECTSOFPORESTRUCTUREON BENDING FATIGUE STRENGTH OF SINTERED STEEL P.Beiss, M.Dalgic. (Inst. for Materials Science, Germany.) Bending fatigue strength of sintered 4%Ni-1.5%Cu-0.5%Mo steel, made from water atomized or sponge Fe powder, with alloy elements diffusion bonded, sintered at 1120 to 1280°C to densities of 6.2 to 7.0 gm.cm-3, was investigated up to lo7 cycles. Alloys made from atomized powder were superior. Results were correlated with pore structures. ASSESSMENT OF PERFORMANCE OF SINTERED CRANKSHAFT BEARING CAP A. Romero et al. (Sintermetal SA Ripollet, Spain.) Responsibility for part design was discussed and the tendenncy for PM designers to be involved with part function in a system was noted. The case of an automotive part was used as an example of how this was done. Studies entailed strain guage measurement, finite element analysis, scatter in properties and derivation of safety margins. Safety factors were verified by fatigue testing simulating service conditions.
Refractory and hard materials and alloys SINTERING OF TUNGSTEN CARBIDENICKEL CONTAINING CHROMIUM CARBIDE G.S.Upadhyaya, D.Banerjee. (Indian Inst. of Technology, India) Effects of Ni as a replacement for Co in WC-lO%Co, on densification and of 2%Cr3Cz were investigated. Ni was reported to hinder densification and to reduce hardness. The use of CrsCz was shown to make up the loss in hardness and to increase transverse rupture strength and corrosion resistance.
OPTIMIZATION OF SINTERING BY GAS PHASE CONTROL IN SITU
G.Leitner et al. (tiunhofer Inst., Dresden, Germany.) It was reported that thermal analysis and mass spectroscopy had been used to study out- gassing and sintering of hard materials. Volatile products of dewaxing and sintering were characterized with regard to temperature. Various processes were shown to affect the C balance with resultant detrimental property changes. Methods of control were shown. THREE-DIMENSIONAL MICROSTRUCTURES OF TUNGSTEN HEAVY ALLOYS SINTERED IN MICROGRAVITY R.G.Iacocca, R.M.German. (Pennsylvania State University, Pennsylvania, USA) It was reported that use of advanced image analysis techniques had made it possible to construct 3-dimensional images by sectioning of microstructures at discrete depths. This had been applied to W heavy alloys, which had been sintered in microgravity conditions, to analyze connectivity, contiguity grain shape and pore morphology. HOT EXPLOSIVE COMPACTION OF TUNGSTEN-TITANIUM AND MOLYBDENUM-TITANIUM ALLOYS LJ.Kecskes. (US Army Research Laboratory, USA) A novel hot explosive compaction technique, app$ed to W-Ti and MO-Ti powders, was described. The metal powder mix was surrounded by a calculated quantity of the exothermic material which when ignited produced heat and shock waves to consolidate the metal powder to near full density. Features of the process and microstructures were discussed. HOT SHOCK-WAVE COMPACTION OF HARDMETALS AND TUNGSTEN HBAVY ALLOYS AB.Peikrishvili et al. (Academy of Sciences, Republic of Georgia.) A study of high temperature and pressure shock-wave compaction of WC-Co and W-Ni-Fe alloy powders was described. It
shown to be l/4 of that atomized in the first stage only. Mechanisms were discussed with regard to particle morphology.
FINITE ELEMENT SIMULATION OF SINTERING OF CEMENTED CARBIDE COMPACTS
A.J.Rawlings et al. (Hoeganaes Corp, Riverton, New Jersey, USA) Properties of Ancordense processed materials were analyzed in detail, the evaluation including strength, impact and fatigue. Tests were carried out on conventionally and high temperature sintered alloys in as-sintered and heat treated conditions.
A NOVEL INTERNAL MIXING GAS ATOMIZER FOR PRODUCTION OF FINE POWDER
DBouvard, O.Gillia. (Inst. National Polytechnique, Grenoble, France.) Stresses and shape changes during sintering of metals and ceramics were discussed. Sintering of WC-Co was simulated by a finite element ‘ABAQUS’ program in an effort to predict the final shape of a compact. Parameters were determined by experiment. A range of part geometries was considered. Predicted and measured results were compared.
Atomization IMPULSE ATOMIZATION FOR ECONOMY AND FLEXIBILITY IN POWDER PRODUCTION H.Henein, L.C.Marin. (University of Alberta, Canada.) The Impule Atomization Process was described. This was reported to allow control of particle size and size distribution, morphology and microstructure. Examples given included, Cu, Zn, Al and Al alloys. Process economics were discussed. A COMPACT ROTATING DISC ATOMIZER FOR PRODUCTION OF REACTIVE POWDERS M.G.Osbome, LEAnderson. (Ames Laboratory, USA) A new centrifugal atomizer was described. The device uses spray quenching and was used for rare earth metals and alloys for magnetic and electrical uses. The method allows increased passivation of rare earths which results in less oxidation of the powders. CENTRIFUGAL DISPERSION OF METALLIC BARSTOCK IN INDUCTIVE PLASMA F.Folio et al. (University of ClermontFerrand, France.) A novel atomizer for producing high purity, fine metal powder from bar was described. As the bar is drawn into the machine it is inductively heated to below the melting point and plasma melted. Molten metal droplets are atomized on a dispersion head rotating at 60 000 rpm. The particles solid@ in Ar. Results were discussed for industrial potential. A STUDY OF TWO STAGE ATOMIZATION P.Cooper, J.D.Ayers. (Naval Research Laboratory, USA) A two-stage atomization process was described. In stage 1 a liquid metal stream is impact atomized by spinning impellers. The resulting spray is further atomized by a repidly rotating cup containing a continuous oil film. Tests on Sn were described. The final powder size was
38 MPR January 1997
JJDunkley, M.S.Sheikaliev. (Atomizing Systerns Ltd., Sheffield, UK) Types of atomizer nozzle, close coupled, free fall and internal mixing, were compared and discussed with reference to efficiency. It was reported that a new internal mixing nozzle had been used to make powders of similar size to products of other nozzles but at markedly lower gas flow rates and pressures.
Fatigue EFFECTSOFPORESTRUCTUREON BENDING FATIGUE STRENGTH OF SINTERED STEEL P.Beiss, M.Dalgic. (Inst. for Materials Science, Germany.) Bending fatigue strength of sintered 4%Ni-1.5%Cu-0.5%Mo steel, made from water atomized or sponge Fe powder, with alloy elements diffusion bonded, sintered at 1120 to 1280°C to densities of 6.2 to 7.0 gm.cm-3, was investigated up to lo7 cycles. Alloys made from atomized powder were superior. Results were correlated with pore structures. ASSESSMENT OF PERFORMANCE OF SINTERED CRANKSHAFT BEARING CAP A. Romero et al. (Sintermetal SA Ripollet, Spain.) Responsibility for part design was discussed and the tendenncy for PM designers to be involved with part function in a system was noted. The case of an automotive part was used as an example of how this was done. Studies entailed strain guage measurement, finite element analysis, scatter in properties and derivation of safety margins. Safety factors were verified by fatigue testing simulating service conditions.
Refractory and hard materials and alloys SINTERING OF TUNGSTEN CARBIDENICKEL CONTAINING CHROMIUM CARBIDE G.S.Upadhyaya, D.Banerjee. (Indian Inst. of Technology, India) Effects of Ni as a replacement for Co in WC-lO%Co, on densification and of 2%Cr3Cz were investigated. Ni was reported to hinder densification and to reduce hardness. The use of CrsCz was shown to make up the loss in hardness and to increase transverse rupture strength and corrosion resistance.
OPTIMIZATION OF SINTERING BY GAS PHASE CONTROL IN SITU
G.Leitner et al. (tiunhofer Inst., Dresden, Germany.) It was reported that thermal analysis and mass spectroscopy had been used to study out- gassing and sintering of hard materials. Volatile products of dewaxing and sintering were characterized with regard to temperature. Various processes were shown to affect the C balance with resultant detrimental property changes. Methods of control were shown. THREE-DIMENSIONAL MICROSTRUCTURES OF TUNGSTEN HEAVY ALLOYS SINTERED IN MICROGRAVITY R.G.Iacocca, R.M.German. (Pennsylvania State University, Pennsylvania, USA) It was reported that use of advanced image analysis techniques had made it possible to construct 3-dimensional images by sectioning of microstructures at discrete depths. This had been applied to W heavy alloys, which had been sintered in microgravity conditions, to analyze connectivity, contiguity grain shape and pore morphology. HOT EXPLOSIVE COMPACTION OF TUNGSTEN-TITANIUM AND MOLYBDENUM-TITANIUM ALLOYS LJ.Kecskes. (US Army Research Laboratory, USA) A novel hot explosive compaction technique, app$ed to W-Ti and MO-Ti powders, was described. The metal powder mix was surrounded by a calculated quantity of the exothermic material which when ignited produced heat and shock waves to consolidate the metal powder to near full density. Features of the process and microstructures were discussed. HOT SHOCK-WAVE COMPACTION OF HARDMETALS AND TUNGSTEN HBAVY ALLOYS AB.Peikrishvili et al. (Academy of Sciences, Republic of Georgia.) A study of high temperature and pressure shock-wave compaction of WC-Co and W-Ni-Fe alloy powders was described. It