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Field effects in sintering tungsten carbide-cobalt powders
Had
materials
FIELD EFFECTS IN SINTERING TUNGSTEN CARBIDE-COBALT POWDERS J.Oakes, J.Groza. (University of California, USA.) Application of electric fields to enhance sintering was discussed. A comparison was made between field-assisted sintered WC-Co and conventionally sintered material made from nm and pm sized powders. Some densitication issues were identified. These were related to Co and V contents, thermodynamics, grain size and surface activation. PROCESSING ULTRAFINE TUNGSTEN CARBIDE POWDERS INTO HIGH QUALITY CERMETS D.F.Carroll, C.L.Connor. (The Dow Chemical Co, USA.) Performance requirements for cemented carbides were reviewed. It was reported that high quality ultrafine WC powder had been produced with grain sizes 0.2 to 0.8 pm. Processing of ultrafine WC-Co was discussed. Addition of growth inhibitors, VC and CrsC,, was optimized with regard to %Co. A processing package was presented.
SLOT
LIQUID PHASE TRANSFORMATION REACTIONS IN SINTERING TUNGSTEN CARBIDE-COBALT
Specimens were processed with thermocouples attached. Structures and properties were determined.
G.Leitner et al. (Fraunhofer Inst. for Ceramic Technologies and Sintering, Germany.) Changes, outgassing and solution of W and C in the Co matrix during heating of WC-Co compacts were discussed with regard to particle rearrangement, diffusion and liquid phase formation, and investigations described. Effects were shown to be related to process conditions. The results were reported to demonstrate new optimization possibilities.
Sinter hardening EFFECT OF PART SIZE AND DENSITY ON SINTER HARDENING OF TWO STEELS E.Duchesne et al. (Ecole Polytechnique of Montreal, Canada.) Sinter hardening of PM steel parts was discussed. Results of sinter hardening were reviewed with reference to furnace thermal profiles and actual cooling rates of cylindrical parts of various size and density made from two steels of differing widely hardenabilities.
EFFECT OF PROCESS CONDITIONS ON SINTER HARDENING RESPONSE OF A STEEL J.Causton et al. (Hoeganaes Corp, River-ton, USA.) The use of sinter hardening was reviewed with regard to process efficiency. A study of the effect of cooling rate on properties of FLC-4608 was described. Variables affecting cooling rate were correlated with structures and properties. EFFECTS OF SINTERING PARAMETERS ON PROPERTIES OF SINTERHARDEN’EDMATER.IALS F.Chagnon, Y.Trudel. (Quebec Metal Powders Ltd, Canada.) Formation of martensite during cooling from the sintering temperature was discussed with reference to factors influencing the amount of martensite formed. The effect of sintering temperature on structure and properties was investigated for a low alloy Ni-Cr-MoMn steel, intended for sinter hardening. Structure/property relationships were discussed.
HEATER
Upcoming issues of Metal Powder Report will cover a wide range of topics of interest to the powder metallurgy (PM) community.
If your company
or organization
is active in any
of these areas, the editor would be happy to learn of your developments. l
July/August
What was new at PM2TEC’98 Machining of PM components High strength components l
offers an rncreas in green density
4.5 and
September
Developments in sintering Advances in PM modelling Process instrumentation PM World Congress preview the powder and can be fitted to all press types.
In coorporation
l
October
PM training and education Advances in hardmetals and hard materials Aerospace applications for PM
Contact.’ Simon Pickering, Editor, Metal Powder Report, PO Box 150, Kidlington, Oxford OX5 lAS, UK; tel: +44-1865-843722; fax:, +44-1865-853149; e-mail: s.pickering@elsevier co. uk.
2 MPR May 1998
materials
FIELD EFFECTS IN SINTERING TUNGSTEN CARBIDE-COBALT POWDERS J.Oakes, J.Groza. (University of California, USA.) Application of electric fields to enhance sintering was discussed. A comparison was made between field-assisted sintered WC-Co and conventionally sintered material made from nm and pm sized powders. Some densitication issues were identified. These were related to Co and V contents, thermodynamics, grain size and surface activation. PROCESSING ULTRAFINE TUNGSTEN CARBIDE POWDERS INTO HIGH QUALITY CERMETS D.F.Carroll, C.L.Connor. (The Dow Chemical Co, USA.) Performance requirements for cemented carbides were reviewed. It was reported that high quality ultrafine WC powder had been produced with grain sizes 0.2 to 0.8 pm. Processing of ultrafine WC-Co was discussed. Addition of growth inhibitors, VC and CrsC,, was optimized with regard to %Co. A processing package was presented.
SLOT
LIQUID PHASE TRANSFORMATION REACTIONS IN SINTERING TUNGSTEN CARBIDE-COBALT
Specimens were processed with thermocouples attached. Structures and properties were determined.
G.Leitner et al. (Fraunhofer Inst. for Ceramic Technologies and Sintering, Germany.) Changes, outgassing and solution of W and C in the Co matrix during heating of WC-Co compacts were discussed with regard to particle rearrangement, diffusion and liquid phase formation, and investigations described. Effects were shown to be related to process conditions. The results were reported to demonstrate new optimization possibilities.
Sinter hardening EFFECT OF PART SIZE AND DENSITY ON SINTER HARDENING OF TWO STEELS E.Duchesne et al. (Ecole Polytechnique of Montreal, Canada.) Sinter hardening of PM steel parts was discussed. Results of sinter hardening were reviewed with reference to furnace thermal profiles and actual cooling rates of cylindrical parts of various size and density made from two steels of differing widely hardenabilities.
EFFECT OF PROCESS CONDITIONS ON SINTER HARDENING RESPONSE OF A STEEL J.Causton et al. (Hoeganaes Corp, River-ton, USA.) The use of sinter hardening was reviewed with regard to process efficiency. A study of the effect of cooling rate on properties of FLC-4608 was described. Variables affecting cooling rate were correlated with structures and properties. EFFECTS OF SINTERING PARAMETERS ON PROPERTIES OF SINTERHARDEN’EDMATER.IALS F.Chagnon, Y.Trudel. (Quebec Metal Powders Ltd, Canada.) Formation of martensite during cooling from the sintering temperature was discussed with reference to factors influencing the amount of martensite formed. The effect of sintering temperature on structure and properties was investigated for a low alloy Ni-Cr-MoMn steel, intended for sinter hardening. Structure/property relationships were discussed.
HEATER
Upcoming issues of Metal Powder Report will cover a wide range of topics of interest to the powder metallurgy (PM) community.
If your company
or organization
is active in any
of these areas, the editor would be happy to learn of your developments. l
July/August
What was new at PM2TEC’98 Machining of PM components High strength components l
offers an rncreas in green density
4.5 and
September
Developments in sintering Advances in PM modelling Process instrumentation PM World Congress preview the powder and can be fitted to all press types.
In coorporation
l
October
PM training and education Advances in hardmetals and hard materials Aerospace applications for PM
Contact.’ Simon Pickering, Editor, Metal Powder Report, PO Box 150, Kidlington, Oxford OX5 lAS, UK; tel: +44-1865-843722; fax:, +44-1865-853149; e-mail: s.pickering@elsevier co. uk.
2 MPR May 1998