摘要 |
1. A method of extrusion, followed by quenching, of high-strength based aluminium alloys of series 2 000 and 7 000, wherein the extrusion ratio is from 20 to 200, characterised in that : a) extrusion is effected with a lubricant, at a speed of over 15 m/minute ; b) the extrusion temperature is between Ts -50 degrees C and Tm -180 degrees C, Ts being the equilibrium solidus temperature of the alloy, and is adjusted within that range so that the temperature of the metal leaving the die is between Tm and Ts , Tm being the minimum temperature at which the said alloy is solution heat treated ; c) the metal is quenched from extrusion heat at the usual cooling speeds for the alloy in question. |