GB891678A - Extrusion and heat treatment of aluminum alloys - Google Patents

Abstract

891,678. Heat treating aluminium alloys. REYNOLDS METALS CO. March 16, 1960 [March 17, 1959], No. 9312/60. Class 72. [Also in Group XXII] In the hot extrusion of a heat treatable aluminium alloy, the extruded product 30 issuing from the die 18 has its hardening constituents maintained in solid solution and is quenched whilst being restrained from warping. A billet of aluminium alloy containing magnesium silicide is heated to 800-1050‹F. for sufficient time to allow solution of the soluble constituents, then quenched in water to 600-1000‹F., inserted in a heated billet container 12 and extruded through a die 18. The latter is mounted with a backing piece 20 in a holder 22 supported through members 24, 26 against a press platen 34. A cooling fluid, which may be air or water, is circulated through a groove 46 in the die from a valve-controlled supply pipe 52. To support the extruded product 30, which is of circular or T section, Figs. 5, 6 (not shown), during initial cooling, there are provided carbon rings 28, 38 having orifices slightly larger than the extruded section. The rings 38 are in a canister 36 surrounded by an induction coil 70 for reheating the product prior to quenching, if necessary. Alternatively a gas fired pass-through furnace may be disposed behind the canister 36. The product is quenched by water discharged from spray rings 60 in a canister 56 mounted on a run-out table 54; any warping is prevented by further carbon guide rings 68. Alternatively for some alloys quenching may be effected by streams of air at room temperature. Spray rings may also be provided in the first canister 36. Precipitation heat treatment to a higher temper may be effected. Specific examples are given for the extrusion and heat treatment of particular alloys.