Objetivo The objectives are to develop zirconia and silicon nitride ceramic materials suitable for dies for hot extrusion of metals. Experimental trials have shown that electro-machinable ceramics dies with non-circular apertures can be used for aluminium extrusion. Although the dies tested in trials reported here had limited life, more recent trials ondies having much shorter bearing lengths have been more promising and these have been used to extrude 20 billets without sign of deterioration so far. Methods of housing inserts to minimize their exposure to tensile stress have been developed and these findings could have wider application with benefit to other insert materials such as cemented carbides metal-matrix composites and other materials with limited toughness. More detailed results are summarized below: - Silicon nitride and zirconia base ceramics having electro-discharge machining properties similar to those of steel have been prepared. - Finite element simulations show that stress concentration at corners of apertures can be compensated by applying pressure to the outside of the insert. - Such external pressure can be applied by shrink fitting and can be increased by the use of a three component assembly including a shrink-ring. - The loss of external pressure at the operating temperature of the die due to differential expansion can be overcome by the use of tungsten carbide as a shrink-ring material. Peripheral cracking of inserts is found to be due to an axial tensile stress generated in the process of shrink-fitting. This problem can be ameliorated by lubrication of the insert/housing interface prior to shrink-fitting, the use of thinner inserts and tungsten carbide shrink-rings. The problem has not occurred in recent trials where these measures have been adopted.The ceramics are to be made electrically conductive so that they can be cut by conventional EDM machining techniques. The aim is also to improve the engineering design of the dies so that more complex shapes can be extruded without damage to the die. Ámbito científico natural scienceschemical sciencesinorganic chemistryinorganic compoundsnatural scienceschemical sciencesinorganic chemistrytransition metalsengineering and technologymechanical engineeringmanufacturing engineeringsubtractive manufacturingnatural scienceschemical sciencesinorganic chemistrymetalloidsengineering and technologymaterials engineeringceramics Programa(s) FP2-BRITE/EURAM 1 - Specific research and technological development programme (EEC) in the fields of industrial manufacturing technologies and advanced materials applications (BRITE/EURAM), 1989-1992 Tema(s) Data not available Convocatoria de propuestas Data not available Régimen de financiación Data not available Coordinador BNF Fulmer Aportación de la UE Sin datos Dirección Wantage Business Park Denchworth Road OX12 9BJ Wantage Reino Unido Ver en el mapa Coste total Sin datos Participantes (12) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo AEA Technology plc Reino Unido Aportación de la UE Sin datos Dirección Harwell Laboratory OX11 0RA Didcot Ver en el mapa Coste total Sin datos Boliden MKM Ltd Reino Unido Aportación de la UE Sin datos Dirección Ver en el mapa Coste total Sin datos Ceramiques Techniques Desmarquest SA Francia Aportación de la UE Sin datos Dirección 2 avenue Albert Einstein 78190 Trappes Ver en el mapa Coste total Sin datos DYNAMIC-CERAMIC LTD Reino Unido Aportación de la UE Sin datos Dirección Weston Road, Crewe Hall CW1 6UA CREWE Ver en el mapa Enlaces Sitio web Opens in new window Coste total Sin datos Europa Metalli-LMI-Trefimetaux Francia Aportación de la UE Sin datos Dirección 11 rue de l'Hotel de Ville 92411 Courbevoie Ver en el mapa Coste total Sin datos Hydro Aluminium Uphusen GmbH Alemania Aportación de la UE Sin datos Dirección Uphuser Heerstraße 7 2807 Achim Ver en el mapa Coste total Sin datos INESPAL España Aportación de la UE Sin datos Dirección Avda Elche 109 03008 ALICANTE Ver en el mapa Coste total Sin datos Laminoirs du Dauphine - Etablissements Bonmartin Francia Aportación de la UE Sin datos Dirección Rue de la Metallurgie 38420 DOMENE Ver en el mapa Coste total Sin datos Le Bronze Industriel Francia Aportación de la UE Sin datos Dirección 49 rue de Paris 93001 BOBIGNY Ver en el mapa Coste total Sin datos Outokumpu Copper Oy Finlandia Aportación de la UE Sin datos Dirección 60 28101 PORI Ver en el mapa Coste total Sin datos Thomas Bolton and Johnson Reino Unido Aportación de la UE Sin datos Dirección ST10 2HF Stoke-on-Trent Ver en el mapa Coste total Sin datos Tioxide Ltd Reino Unido Aportación de la UE Sin datos Dirección 137-143 Hammersmith Road W14 0QL London Ver en el mapa Coste total Sin datos