Aluminium alloys

Claim 2

AN AS-CAST ALUMINIUM MAGNESIUM SILICIDE ALLOY EXTRUSION INGOT CONTAINING AL-FE-SI, SAID ALLOY CONSISTING ESSENTIALLY OF 0.3-1.2% MG, 0.2-1.2% SI, UP TO 0.4$ CU AND UP TO 0.1% EACH ZN, MN, 0.05-0.3% FE AS IMPURITY AND 0.15% TOTAL (0.05% EACH) OTHER IMPURITIES, BALANCE ALUMINUM, CHARACTERIZED HY THE PRESENCE OF SR AND/OR CA IN A TOTAL AMOUNT OF 0.01-0.5% FOR CAUSING AT LEAST A MAJOR PROPORTION OF THE ALFE-SI IN THE AS-CAST INGOT TO BE IN THE A PHASE, THEREBY TO REDUCE PICKUP UPON EXTRUSION OF THE INGOT.

Claim 3

An aluminium alloy according to claim 1 in which the total content of Sr and/or Ca is in the range of 0.02-0.05%.

Claim 4

An aluminium alloy according to claim 1 in which the content of Mg is below 0.7% and the sum of the content of Mg and Si is below 1.5%.

Claim 5

A homogenized aluminium magnesium silicide alloy extrusion ingot containing Al-Fe-Si, said alloy consisting essentially of 0.3-1.2% Mg, 0.2-1.2% Si, up to 0.4% Cu and up to 0.1% each Zn, Mn, 0.05-0.3% Fe as impurity and 0.15% total (0.05% each) other impurities, balance aluminium, characterized by the presence of Sr and/or Ca in a total amount of 0.01-0.5%; at least a major proportion of the Al-Fe-Si in the ingot being in the Alpha phase, thereby effecting reduction in pickup upon extrusion of the ingot.

Claim 6

A homogenized aluminium magnesium silicide alloy extrusion ingot containing Al-Fe-Si, said alloy consisting essentially of 0.3-1.2% Mg, 0.2-1.2% Si, up to 0.4% Cu and up to 0.1% each Zn, Mn, 0.05-0.3% Fe as impurity and 0.15% total (0.05% each) other impurities, balance aluminium, characterized by the presence of Sr and/or Ca in a total amount of 0.01-0.5%; at least a major proportion of the Al-Fe-Si in the ingot being in the Alpha phase, thereby effecting reduction in pickup upon extrusion of the ingot.

Claim 7

An aluminium alloy according to claim 4 in which the total content of Sr and/or Ca is in the range of 0.02-0.055.

Claim 8

An aluminium alloy according to claim 4 in which the content of Mg is below 0.7% and the sum of the content of Mg and Si is below 1.5%.

Claim 9

An aluminium alloy ingot extrusion containing Al-Fe-Si, said alloy consisting essentially of 0.3-1.2% Mg, 0.2-1.2% Si, 0.01-0.5% of an alloying element selected from the class consisting of Sr and Ca, 0.05-0.3% Fe, up to 0.4% Cu, up to 0.1% each of Zn and Mn, 0.15% total (0.05% each) other impurities, balance Al, characterized by being essentially free from pickup and having good specular reflectivity, image clarity and whiteness; at least a major proportion of the Al-Fe-Si in the extrusion being in the Alpha phase.

Claim 10

An aluminium alloy ingot extrusion containing Al-Fe-Si, said alloy consisting essentially of 0.3-1.2% Mg, 0.2-1.2% Si, 0.01-0.5% of an alloying element selected from the class consisting of Sr and Ca, 0.05-0.3% Fe, up to 0.4% Cu, up to 0.1% each of Zn and Mn, 0.15% total (0.05% each) other impurities, balance Al, characterized by being essentially free from pickup and having good specular reflectivity, image clarity and whiteness; at least a major proportion of the Al-Fe-Si in the extrusion being in the Alpha phase.