GB505728A - Improvements in or relating to light aluminium alloys - Google Patents

Abstract

505,728. Alloys ; heat - treatment. ELECTRIQUE ASSOCIATION COOPERATIVE D'OUVRIERS EN MATERIEL ELECTRIQUE, and BANCO, J. June 7, 1938, No. 16847. Convention date, March 11. [Classes 72 and 82 (i)] A light alloy with high elastic limit, strength, and freedom from intercrystalline corrosion comprises 5-6À5 per cent of zinc, 2-3À5 per cent of magnesium, 0À15-0À5 per cent of silicon, 0À2-0À6 per cent of each of molybdenum and cobalt, 0-0À12 per cent of potassium, 0-0À25 per cent of barium, 0-0À1 per cent of antimony, 0-0À5 per cent of tungsten, 0-1 per cent of nickel, 0-0À4 per cent of titanium, the remainder being aluminium. The alloys may be tempered at 450-550‹ C. or double tempered at 530-550‹ C. or may be tempered at at least 480‹ C., aged for 8 days at the surrounding temperature, and then tempered at 80-160‹ C. for 3-17 hours. Moreover they may be rendered easy for wire-drawing or stretching by immersion for 24-48 hours in a mixture of nitrates of sodium and potassium at 420‹ C. prior to thermal treatment whereby metals such as magnesium are removed from the surface. Specific alloys may be (a) heated to 450-550‹ C. cooled in air, water or other liquid aged, for instance by being held at 48 hours at the surrounding temperature, and tempered at 80-169‹ C. for 3-17 hours, and (b) double tempered at 530‹ C., aged at the surrounding temperature for 48 hours, and tempered. In making the alloys, silicon, manganese, and magnesium serve as deoxidizers, 95 per cent of these metals so employed remaining as constituents of the alloy. Potassium and barium are added as the respective chlorides in amount equal to 0À25 per cent and 0À5 per cent of the alloy respectively, whereby oxides are reduced and gases eliminated, and the metals in question added to the alloy.