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Sintering and properties of titanium boride hardmetals
Ceramic Technology, Dresden, Germany). A study of the reaction between various forms of TiO2, (rutile and anatase) and different forms of carbon black was described. The reactions produce TiC and the objective was to determine the effects of different precursors on particle sizes and distribution. Various physical and chemical techniques were used and it was reported that the reduction process goes through lower Ti oxides until cubic TiC is formed. PRODUCTION OF TITANIUM CARBIDE BY SHS P. Davis et al, (London and Scandinavia Metallurgical Co, Rotherham, UI0. Manufacture of TiC powder by SHS was described. The method disperses a large volume of TiC in a metallic matrix and work using Fe was outlined. Use of Ni or Co was considered to be possible. A dispersion of 85% of spherical TiC in Fe was produced and powders of various sizes were evaluated for hard facing, powder metalhirgy and molten metal applications. The wear behaviour of the materials was described. RAPID ROUTINE METHOD FOR DETERMINATION OF NITROGEN IN TITANIUM CARBONITRIDES M.EJ. Birch, (London and Scandinavia Metallurgical CO, Rotherbam, UK). The need for a rapid method for determination of N, at the level of 20% m/ m, N, in cermets was discussed and various techniques were compared. It w a s considered that a modified Kjeldahl apparatus gave acceptable results but was slow and was subject to operator variability. A Leco 436 apparatus, which was designed for trace element analysis; was unreliable because of the small specimen size needed to avoid detector saturation. After modification to accommodate high levels of N the instrument allowed rapid and reliable determination of N in a range of Ti (C,N) materials. DEVELOPMENT, MANUFACTURE AND APPLICATION OF NEW GRADES OF LOW TUNGSTEN AND TUNGSTENFREE HARDMETALS Y.M. Korolev and A.IJmikeev, (Refractory and Hard Metals Research Institute, Moscow, Russia). The use of TiC-Ti(C,N) based Cermets as substitutes for WC-Co and TiC-WC-TaC-Co materials in a wide range of applications was discussed. It was reported that low W and W-free cermets, with a Ni binder have been used for metal cutting and that wear resistance, cutting performance and corrosion resistance can be enhanced by a Cr coating, TIC-Fe cermets have been used for wire drawing dies, wood working tools and corrosion resistant sintered parts. The eutectic alloy, (Ti~Mo)C-Mo was said to
retain its wear resistance above !O00°C and can be used for nietal forming dies. FULLY AUTOMATED POWDER PRESS SYSTEMS FOR COMPACTING AND HANDLING ~ G TOOL INSERTS G. Moser, (Dorst-Maschinen und Anlagenbau, Kochel, Germany). Recent developments in mechanical and hydraulic presses for use in the production of hardmetal, cermet and ceramic cutting tool inserts were described. Particular attention was given to increased machine utilization and automation including process monitoring and quality control. Systems for rapid tool and powder changes, materials handling a n d numerical control of machines were outlined. Future prospects w e r e considered taking technical and economic aspects into account. NEW SPHERICAL MONODISPERSE AND NON-AGGLOMERATED COBALT POWDERS F. Fievet et al, (University of Paris, France). The production of ultrafine (0.5 ~m), non-pyrophoric Co powders by reduction of Co hydroxide was described. The powder was reported to have a very narrow range of p a r t i c l e sizes with n o n - a g g l o m e r a t e d s p h e r i c a l grains. A d j u s t m e n t of t h e process conditions were said to make it possible to produce powders with any size between 0.5 and 4.0 9m. The powder was found to blend well with other powders and to be s u i t a b l e for m a n u f a c t u r e of hardmetals.
FULLY CONTROLI.~.D SEQUENCE OF COMPACTION IN THE MAN-trFACTURE OF CUTTING TOOL INSERTS O. Wigren, (Result AB, Hamosand, Sweden). The demands to which cutting tool insert makers are subjected were outlined. Competition, cost pressures, demands for quality and precision and decreasing order sizes were considered. The measures needed to a c c o m m o d a t e t h e s e ; a u t o m a t i o n , increased machine use and improved product quality, were discussed. The need for fully controlled sequence of compaction with close dimensional tolerance and reproducibility was emphasized. RECENT ADVANCES IN VACUUM AND OVERPRESSURE SINTERING K Bauer and D. Ermel, (Leybold Durferit GmbH, Hanau, Germany). Vacuum and overpressure sintering processes were reviewed and it was shown that there have been improvements in processes, equipment and costs. Highlights of these were reported. New applications and process results were described.
THREE-CHAMBER SINTERING FURNACE FOR SINTERING HARDMETALS F. Bless, (Ipsen Industries International GmbH, Kleve, German). A new design of three-chamber, semicontinuous sintering furnace was described. There are de-waxing, sintering and cooling zones, each separated by vacuum tight doors which are designed to allow a pushpull system to transfer loads between chambers without interruptions to the process. Operation of the system is by computer. Addition of a buffer storage s y s t e m a l l o w s t h e f u r n a c e to be incorporated in a manufacturing cell. PROCESSES DURING DEWAXING AND SINTERING OF HARDMETALS G. Leitner et al, (Frauenhofer Institution for Ceramic Technology, Dresden, Germany). The importance of dewaxing procedures for compacted hardmetals was discussed with reference to the avoidance of changes in C c o n t e n t , c o n t r o l of c h e m i c a l composition and reduction of dewazing time. The dewaxing of hardmetals was st u d i ed by use of t h e r m o g r a v i m e t r i c analysis (TGA) and infra-red and mass spectroscopy of the gaseous products. The results were discussed for WC-Co and WCTiC.Co containing paraffin or polyethylene glycol waxes. SINTERING OF ULTRAFINE COBALT CEMENTED TUNGSTEN CARBIDE HARDMETALS A. Bock et al, (Technical University of Vienna, Austria). Studies of WC powder characterization and sintering of ultrafine (0.2 to 0.5 ~m) WC- 10wiT%Co were reported. Attention was given to relationships between powder characteristics, sintering processes and p r o p e r t i e s of s i n t e r e d a l l o y s w i t h emphasis on WC grain growth during sintering and inhibition of grain growth by additions of VC. SINTERING AND PROPERTIES OF TITANIUM BORIDE HARDMETALS T. Jungling et al, (University of Karlsruhe, Germany). The sintering of boride cermets and the formation of borides of the binding phase during sintering, and resulting embrittlement, were discussed. Thermodynamics, sintering experiments a n d X - r a y a n a l y s i s w e r e u s e d f or clarifications. Measures to inhibit matrix borides were deduced. It was reported that the proportion of an Fe or austenitic binder could be varied. The mechanical properties were assessed f o r a fully alloy with a ductile binder. Vicker's hardness above 2000 and Kl¢ above 12 MPa, m "1/2 were obtained.
MPR September 1992 41
retain its wear resistance above !O00°C and can be used for nietal forming dies. FULLY AUTOMATED POWDER PRESS SYSTEMS FOR COMPACTING AND HANDLING ~ G TOOL INSERTS G. Moser, (Dorst-Maschinen und Anlagenbau, Kochel, Germany). Recent developments in mechanical and hydraulic presses for use in the production of hardmetal, cermet and ceramic cutting tool inserts were described. Particular attention was given to increased machine utilization and automation including process monitoring and quality control. Systems for rapid tool and powder changes, materials handling a n d numerical control of machines were outlined. Future prospects w e r e considered taking technical and economic aspects into account. NEW SPHERICAL MONODISPERSE AND NON-AGGLOMERATED COBALT POWDERS F. Fievet et al, (University of Paris, France). The production of ultrafine (0.5 ~m), non-pyrophoric Co powders by reduction of Co hydroxide was described. The powder was reported to have a very narrow range of p a r t i c l e sizes with n o n - a g g l o m e r a t e d s p h e r i c a l grains. A d j u s t m e n t of t h e process conditions were said to make it possible to produce powders with any size between 0.5 and 4.0 9m. The powder was found to blend well with other powders and to be s u i t a b l e for m a n u f a c t u r e of hardmetals.
FULLY CONTROLI.~.D SEQUENCE OF COMPACTION IN THE MAN-trFACTURE OF CUTTING TOOL INSERTS O. Wigren, (Result AB, Hamosand, Sweden). The demands to which cutting tool insert makers are subjected were outlined. Competition, cost pressures, demands for quality and precision and decreasing order sizes were considered. The measures needed to a c c o m m o d a t e t h e s e ; a u t o m a t i o n , increased machine use and improved product quality, were discussed. The need for fully controlled sequence of compaction with close dimensional tolerance and reproducibility was emphasized. RECENT ADVANCES IN VACUUM AND OVERPRESSURE SINTERING K Bauer and D. Ermel, (Leybold Durferit GmbH, Hanau, Germany). Vacuum and overpressure sintering processes were reviewed and it was shown that there have been improvements in processes, equipment and costs. Highlights of these were reported. New applications and process results were described.
THREE-CHAMBER SINTERING FURNACE FOR SINTERING HARDMETALS F. Bless, (Ipsen Industries International GmbH, Kleve, German). A new design of three-chamber, semicontinuous sintering furnace was described. There are de-waxing, sintering and cooling zones, each separated by vacuum tight doors which are designed to allow a pushpull system to transfer loads between chambers without interruptions to the process. Operation of the system is by computer. Addition of a buffer storage s y s t e m a l l o w s t h e f u r n a c e to be incorporated in a manufacturing cell. PROCESSES DURING DEWAXING AND SINTERING OF HARDMETALS G. Leitner et al, (Frauenhofer Institution for Ceramic Technology, Dresden, Germany). The importance of dewaxing procedures for compacted hardmetals was discussed with reference to the avoidance of changes in C c o n t e n t , c o n t r o l of c h e m i c a l composition and reduction of dewazing time. The dewaxing of hardmetals was st u d i ed by use of t h e r m o g r a v i m e t r i c analysis (TGA) and infra-red and mass spectroscopy of the gaseous products. The results were discussed for WC-Co and WCTiC.Co containing paraffin or polyethylene glycol waxes. SINTERING OF ULTRAFINE COBALT CEMENTED TUNGSTEN CARBIDE HARDMETALS A. Bock et al, (Technical University of Vienna, Austria). Studies of WC powder characterization and sintering of ultrafine (0.2 to 0.5 ~m) WC- 10wiT%Co were reported. Attention was given to relationships between powder characteristics, sintering processes and p r o p e r t i e s of s i n t e r e d a l l o y s w i t h emphasis on WC grain growth during sintering and inhibition of grain growth by additions of VC. SINTERING AND PROPERTIES OF TITANIUM BORIDE HARDMETALS T. Jungling et al, (University of Karlsruhe, Germany). The sintering of boride cermets and the formation of borides of the binding phase during sintering, and resulting embrittlement, were discussed. Thermodynamics, sintering experiments a n d X - r a y a n a l y s i s w e r e u s e d f or clarifications. Measures to inhibit matrix borides were deduced. It was reported that the proportion of an Fe or austenitic binder could be varied. The mechanical properties were assessed f o r a fully alloy with a ductile binder. Vicker's hardness above 2000 and Kl¢ above 12 MPa, m "1/2 were obtained.
MPR September 1992 41