Concrete composition for the manufacture of moulds, mould and process for the manufacture of a mould

Process for the manufacture of a mould consisting of two half-moulds made of metallized concrete, comprising the following stages:

• production of master models of the said half-moulds, using a resin
• metallisation of the said master models
• casting a concrete composition comprising (1) a binder which comprises from 10 to 30% of an alkaline-earth mineral substance selected from the group consisting of calcium aluminate or calcium silicoaluminate metallurgical slags, aluminous cements of the calcium monoaluminate and calcium dialuminate types, silico-aluminous cements, calcium or barium silicates and alkaline-earth metal oxides which have been calcined beforehand, of the magnesia, dolomite, lime and barytes group, from the group consisting of 14 to 54% of a constituent made up of fine particles of a compound other than an oxide, 90% of which have a particle size of between 1 and 150 .mu.m with a median diameter of between 3 and 20 .mu.m, these fine particles comprising particles of a substance which has a thermal conductivity higher than approximately 30 W/mK, selected from silicon carbides, silicon carbonitrides, silicon nitrides, boron carbides, titanium carbides and tungsten carbides, and from 14 to 54% of a constituent made up of ultrafine particles at least 70% of which have a particle size smaller than 1 .mu.m with a median diameter of between 0.3 and 0.8 .mu.m, (2) water in a ratio water/binder lower than 0.20, with the addition of a dispersant, and (3) fillers comprising from 200 to 300 parts in weight of metal granulates for 100 parts in weight of the said alkaline-earth mineral substance and from 600-800 parts in weight of metal fibers for 200 parts in weight of the said alkaline-earth mineral substance, wherein the concrete composition has a thermal conductivity at 200.degree. C. which is equal to or higher than 5 W/mK,
• allowing the concrete to set,
• heat treating the concrete, and
• recovering the said two half-moulds after cooling.