Alcan International Limited

Anthony J Bryant

Ernest P Butler

David J Field

Walter Bennett

John H Ablewhite

An extrusion ingot of an Al-Mg-Si alloy, has substantially all the Mg present in the form of particles having an average diameter of at least 0.1 microns of beta'-phase Mg.sub.2 Si in the substantial absence of bet-phase Mg.sub.2 Si. The ingot may be made by casting an ingot of the alloy, homogenizing the ingot, cooling the homogenized ingot to a holding temperature of 250.degree. C. to 425.degree. C. at a cooling rate of at least 400.degree. C./h, holding the ingot for 0.25 to 3 hours, and cooling. The ingot has improved extrusion properties.

Al-Mg-Si extrusion alloy

An extrusion ingot of an Al-Mg-Si alloy, has substantially all the Mg present in the form of particles having an average diameter of at least 0.1 microns of beta'-phase Mg.sub.2 Si in the substantial absence of beta-phase Mg.sub.2 Si. The ingot may be made by casting an ingot of the alloy, homogenising the ingot, cooling the homogenised ingot to a holding temperature of 250.degree. C. to 425.degree. C. at a cooling rate of at least 400.degree. C./h, holding the ingot for 0.25 to 3 hours, and cooling. The ingot has improved extrusion properties.

Al-Mg-Si extrusion alloy and method

In the thermal ageing of extruded sections of age-hardenable aluminum alloys the sections are progressed through a system having an initial low temperature zone and a subsequent high temperature zone. In order to secure uniform ageing the sections are progressed in a direction transverse to their length and conveniently are arranged in a single layer and spaced apart to ensure acceptably uniform rate of heating to ageing temperature.

Growing community of inventors

Banbury, United Kingdom

Anthony J Bryant