Objective 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. Fields of science natural scienceschemical sciencesinorganic chemistryinorganic compoundsnatural scienceschemical sciencesinorganic chemistrytransition metalsengineering and technologymechanical engineeringmanufacturing engineeringsubtractive manufacturingnatural scienceschemical sciencesinorganic chemistrymetalloidsengineering and technologymaterials engineeringceramics Programme(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 Topic(s) Data not available Call for proposal Data not available Funding Scheme Data not available Coordinator BNF Fulmer EU contribution No data Address Wantage Business Park Denchworth Road OX12 9BJ Wantage United Kingdom See on map Total cost No data Participants (12) Sort alphabetically Sort by EU Contribution Expand all Collapse all AEA Technology plc United Kingdom EU contribution No data Address Harwell Laboratory OX11 0RA Didcot See on map Total cost No data Boliden MKM Ltd United Kingdom EU contribution No data Address See on map Total cost No data Ceramiques Techniques Desmarquest SA France EU contribution No data Address 2 avenue Albert Einstein 78190 Trappes See on map Total cost No data DYNAMIC-CERAMIC LTD United Kingdom EU contribution No data Address Weston Road, Crewe Hall CW1 6UA CREWE See on map Links Website Opens in new window Total cost No data Europa Metalli-LMI-Trefimetaux France EU contribution No data Address 11 rue de l'Hotel de Ville 92411 Courbevoie See on map Total cost No data Hydro Aluminium Uphusen GmbH Germany EU contribution No data Address Uphuser Heerstraße 7 2807 Achim See on map Total cost No data INESPAL Spain EU contribution No data Address Avda Elche 109 03008 ALICANTE See on map Total cost No data Laminoirs du Dauphine - Etablissements Bonmartin France EU contribution No data Address Rue de la Metallurgie 38420 DOMENE See on map Total cost No data Le Bronze Industriel France EU contribution No data Address 49 rue de Paris 93001 BOBIGNY See on map Total cost No data Outokumpu Copper Oy Finland EU contribution No data Address 60 28101 PORI See on map Total cost No data Thomas Bolton and Johnson United Kingdom EU contribution No data Address ST10 2HF Stoke-on-Trent See on map Total cost No data Tioxide Ltd United Kingdom EU contribution No data Address 137-143 Hammersmith Road W14 0QL London See on map Total cost No data