Process for manufacturing aluminum alloys and aluminium castings

Process for manufacturing parts made of cast alloy, especially aluminium cast or aluminium alloy cast, in a mould and which comprise, after casting, removing from the mould the part which constitutes the cast preform which is still hot and placing it between two halves of a die that defines a cavity having dimensions that are slightly less than those of the mould, forcing the two halves together in order to exert a combined in-depth impact forging and surface hardening effect on said casting placed between the two halves,

• Wherein
• the original feature of the invention involves introducing an intermediate step between the foundry phase in which the cast preform is obtained and the forging phase, with the foundry phase involving casting the liquid aluminium at a temperature of 750° C. in a mould that is heated and kept at a temperature or roughly 400° C., the aluminium cast in the mould in the liquid state tending to cool until it reaches the temperature of the mould of roughly 400° C., thereby producing a preform that is then transferred to a furnace preheated to a temperature of roughly 540° C. in order to ensure solution heat treatment of said cast preform at said temperature of 540° C.,
• transferring the treated preform heated to a die that defines a cavity having dimensions that are slightly less than those of the mould, the two halves of the die being forced together in order to exert an impact forging/die forging force in order to obtain the finished rough forging,
• cooling the forging casting thus obtained at room temperature or accelerated cooling or cooling by quench hardening.