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Fundamantal aspects of PM magnetic materials
powders were reviewed with regard to composition and process conditions. An investigation of the effects of %C and sintering temperature on the microstructure of Fe-0.5%Mo-4%Ni-15%Cu-(0.25, 0.55 and 0.85)% combined C, sintered at 1120 to 1300”C, with close control of a fixed post-sintering cooling rate, was described. The structures were characterized for proportions of phases and properties using quantitative image analysis. EFFECTOFSTRUCTUREANDPORE MORPHOLOGY ON PROPERTIES OF FERROUS PM MATERIALS
T.F.Murphy et al. (Hoeganaes Corp, Riverton, USA.) Fatigue strength of ferrous PM materials was reviewed with consideration of grain size, characteristics of microstructural constituents and stereological parameters. The paper described an attempt to determine the contribution of each of these. Fatigue testing was carried out on an ANCORDENSE steel and conventional material premixes to evaluate the effects of pore structure and process variables. Ni was added at particle sizes of 5 and 50 pm. High and conventional sintering temperatures were used. Quantitative metallography was used to evaluate the structures.
Compaction technologies ANALYSIS OF SINGLE PUNCH COMPACTION OF MULTI-COMPONENT PM PARTS
D.Apelian et al. (Worcester Polytechnic Inst., USA.) Production of multi-component parts by PM and containing different powders was discussed with consideration of density distribution, which influences part performance and tool distortion due to variations in pressure. An analysis to predict these distributions was carried out using single punch compaction of cylindrical parts consisting of an inner cylindrical zone of one powder and an annular region of another. A mathematical model was presented, which, for prescribed conditions, predicts the pressures exerted by each zone in the part, compacted height, position of the interface between the two powders, green densities and the effects of powder characteristics on these.
and it was noted that there is a minimum pressure required to ensure crackfree rods. The effects caused by extrusion of rods with internal channels was considered. The ratio of inlet to outlet size was examined for different nozzles. The results of tests, showing favourable pressure distributions obtained by varying nozzle geometry, were presented. EFFECT OF PARTICLE SIZE DISTRIBUTION ON COMPRESSIBILITY
S.Ward et al. (Pennsylvania State University, USA.) A study of the effects of particle size distribution, for five powders, pressed without admixed lubricant, during die compaction with die wall lubrication, was described. The objective was to optimize particle size distribution to ensure maximum particle packing for each powder to attain highest compressibility, without adverse effect on costs.
Magnetic materials EFFECT OF LUBRICANTS ON IRON COMPACTS FOR LOW FREQUENCY AC APPLICATIONS
CGelinas et al. (Quebec Metal Powders Ltd, Canada.) Use of high purity Fe powder, without any additives, for production of soft magnetic Fe parts for low frequency AC applications, was discussed. Parts can also be made from lubricated Fe powders but the lubricant must be removed. The effects of various lubricants on electrical, magnetic and mechanical properties of green sintered, heat treated and resin bonded materials were described. EFFECT OF HEAT TREATMENT ON IRON COMPACTS FOR LOW FREQUENCY AC APPLICATIONS
C.Gelinas et al. (Quebec Metal Powders Ltd, Canada.) Properties of pure PM Fe materials, for low frequency AC applications, were reviewed with respect to the use of lubricants, process condition and interparticle bonding. An investigation of the effects of different heat treatment conditions, temperature (450 to 550°C) and process atmosphere on electrical, magnetic and mechanical properties of Fe with 0.75wt%EBS materials and resin impregnated magnets was described and the results were presented.
and part design were presented with consideration of the B-H curve, permeability, saturation flux density and electrical resistivity. Typical examples of parts were described. FUNDAMANTAL ASPECTS OF PM MAGNETIC MATERIALS
G.Beane et al. (I.A.P. Research Inc, USA.) Procedures for measurement of magnetic properties were discussed. Results of an inter-laboratory study were presented. Differences between results for different laboratories were attributed to phase shifts resulting from improper instrumentation. It was reported that a new, non-organic encapsulated powder had been developed with low loss characteristics and high saturation magnetization. This was suggested as an alternative to laminated materials. TESTING AND EVALUATION OF COMPOSITE IRON POWDER
D.Gay. (Delphi Automotive Systems, USA. ) Testing of composite Fe powders was discussed. Equipment and test results for each stage from bulk powder to finished structural and magnetic parts were described. Data were explained and applications were presented including optimization of warm pressing, compressibility curves and parameters for computer modelling.
Sintering processes MICROSTRUCTURE COARSENING DURING LIQUID PHASE SINTERING
R.M.German. (Pennsylvania State University, USA.) Microstructure coarsening during liquid phase sintering was discussed with regard to results for diffusion controlled grain growth. A Rayleigh grain size distribution, for the solid structure, was identified and it was shown that there is a continuous driving force for coarsening. Kinetics, grain contiguity, solid and liquid state contributions to sintering, grain agglomeration and solid-liquid dihedral angle were considered. Theoretical and experimental results were compared. Results for WNi-Fe, VC-Ni, Fe-Cu, Pb-Sn, TaC-Co and Co-Cu were used.
PRESSURE DISTRIBUTION IN EXTRUDER NOZZLES RELATED TO NOZZLE SHAPE
SOFT MAGNETIC MATERIALS AND COMPONENT DESIGN
ATTAINMENT OF NEAR FULL DENSITY OF TOOL STEEL BY MIM AND SUPERSOLIDUS LIQUID PHASE SINTERING
K.J.Friedrichs. (Konrad Friedrichs Carbide Factory, Germany.) Pressure distribution in the nozzles of powder extrusion dies was discussed
G.Beane et al. KAF? Research Inc, USA.) Use of PM soft magnetic materials was reviewed. Fundamentals of relationships between magnetic properties
R.M.German et al. (Pennsylvania State University, USA.) M2 high speed steels, with low or high C contents, were injection moulded
40 MPR January 1999
T.F.Murphy et al. (Hoeganaes Corp, Riverton, USA.) Fatigue strength of ferrous PM materials was reviewed with consideration of grain size, characteristics of microstructural constituents and stereological parameters. The paper described an attempt to determine the contribution of each of these. Fatigue testing was carried out on an ANCORDENSE steel and conventional material premixes to evaluate the effects of pore structure and process variables. Ni was added at particle sizes of 5 and 50 pm. High and conventional sintering temperatures were used. Quantitative metallography was used to evaluate the structures.
Compaction technologies ANALYSIS OF SINGLE PUNCH COMPACTION OF MULTI-COMPONENT PM PARTS
D.Apelian et al. (Worcester Polytechnic Inst., USA.) Production of multi-component parts by PM and containing different powders was discussed with consideration of density distribution, which influences part performance and tool distortion due to variations in pressure. An analysis to predict these distributions was carried out using single punch compaction of cylindrical parts consisting of an inner cylindrical zone of one powder and an annular region of another. A mathematical model was presented, which, for prescribed conditions, predicts the pressures exerted by each zone in the part, compacted height, position of the interface between the two powders, green densities and the effects of powder characteristics on these.
and it was noted that there is a minimum pressure required to ensure crackfree rods. The effects caused by extrusion of rods with internal channels was considered. The ratio of inlet to outlet size was examined for different nozzles. The results of tests, showing favourable pressure distributions obtained by varying nozzle geometry, were presented. EFFECT OF PARTICLE SIZE DISTRIBUTION ON COMPRESSIBILITY
S.Ward et al. (Pennsylvania State University, USA.) A study of the effects of particle size distribution, for five powders, pressed without admixed lubricant, during die compaction with die wall lubrication, was described. The objective was to optimize particle size distribution to ensure maximum particle packing for each powder to attain highest compressibility, without adverse effect on costs.
Magnetic materials EFFECT OF LUBRICANTS ON IRON COMPACTS FOR LOW FREQUENCY AC APPLICATIONS
CGelinas et al. (Quebec Metal Powders Ltd, Canada.) Use of high purity Fe powder, without any additives, for production of soft magnetic Fe parts for low frequency AC applications, was discussed. Parts can also be made from lubricated Fe powders but the lubricant must be removed. The effects of various lubricants on electrical, magnetic and mechanical properties of green sintered, heat treated and resin bonded materials were described. EFFECT OF HEAT TREATMENT ON IRON COMPACTS FOR LOW FREQUENCY AC APPLICATIONS
C.Gelinas et al. (Quebec Metal Powders Ltd, Canada.) Properties of pure PM Fe materials, for low frequency AC applications, were reviewed with respect to the use of lubricants, process condition and interparticle bonding. An investigation of the effects of different heat treatment conditions, temperature (450 to 550°C) and process atmosphere on electrical, magnetic and mechanical properties of Fe with 0.75wt%EBS materials and resin impregnated magnets was described and the results were presented.
and part design were presented with consideration of the B-H curve, permeability, saturation flux density and electrical resistivity. Typical examples of parts were described. FUNDAMANTAL ASPECTS OF PM MAGNETIC MATERIALS
G.Beane et al. (I.A.P. Research Inc, USA.) Procedures for measurement of magnetic properties were discussed. Results of an inter-laboratory study were presented. Differences between results for different laboratories were attributed to phase shifts resulting from improper instrumentation. It was reported that a new, non-organic encapsulated powder had been developed with low loss characteristics and high saturation magnetization. This was suggested as an alternative to laminated materials. TESTING AND EVALUATION OF COMPOSITE IRON POWDER
D.Gay. (Delphi Automotive Systems, USA. ) Testing of composite Fe powders was discussed. Equipment and test results for each stage from bulk powder to finished structural and magnetic parts were described. Data were explained and applications were presented including optimization of warm pressing, compressibility curves and parameters for computer modelling.
Sintering processes MICROSTRUCTURE COARSENING DURING LIQUID PHASE SINTERING
R.M.German. (Pennsylvania State University, USA.) Microstructure coarsening during liquid phase sintering was discussed with regard to results for diffusion controlled grain growth. A Rayleigh grain size distribution, for the solid structure, was identified and it was shown that there is a continuous driving force for coarsening. Kinetics, grain contiguity, solid and liquid state contributions to sintering, grain agglomeration and solid-liquid dihedral angle were considered. Theoretical and experimental results were compared. Results for WNi-Fe, VC-Ni, Fe-Cu, Pb-Sn, TaC-Co and Co-Cu were used.
PRESSURE DISTRIBUTION IN EXTRUDER NOZZLES RELATED TO NOZZLE SHAPE
SOFT MAGNETIC MATERIALS AND COMPONENT DESIGN
ATTAINMENT OF NEAR FULL DENSITY OF TOOL STEEL BY MIM AND SUPERSOLIDUS LIQUID PHASE SINTERING
K.J.Friedrichs. (Konrad Friedrichs Carbide Factory, Germany.) Pressure distribution in the nozzles of powder extrusion dies was discussed
G.Beane et al. KAF? Research Inc, USA.) Use of PM soft magnetic materials was reviewed. Fundamentals of relationships between magnetic properties
R.M.German et al. (Pennsylvania State University, USA.) M2 high speed steels, with low or high C contents, were injection moulded
40 MPR January 1999