6xxx Alloy With High Recycled Material Content
The present invention is directed to a 6xxx series aluminum alloy composition, comprising, consisting essentially of, or consisting of (by weight %) of 0.5-1.5% Si, 0.1-0.7% Cu, 0.5-1.5% Mg, 0.3-1.2% Zn, 0.05-0.35% Cr and allowable impurities of 0.8% Fe, 0.8% Mn, 0.15% Zr, 0.15% Ti, with other elements restricted as unavoidable impurities limited to 0.05% each and 0.15% total with the balance being aluminum. This 6xxx series aluminum alloy is capable of being produced with high amounts of post-consumer recycled material which significantly reduces environmental impact from producing this material, while still meeting and in most cases exceeding material attribute requirements for general engineering applications.
1 . A 6xxx series aluminum alloy having a composition comprising, (by weight %):
0.5-1.5% Si;
0.1-0.7% Cu;
0.5-1.5% Mg;
0.3-1.2% Zn;
0.050-0.35% Cr;
≤0.8% Fe;
≤0.8% Mn;
≤0.15% Zr;
≤0.15% Ti;
with other elements restricted as unavoidable impurities limited to 0.05% each and ≤0.15% total with the balance being aluminum.
2 . The 6xxx series aluminum alloy of claim 1 comprising,
0.8-1.4% Si;
0.1-0.7% Cu;
0.8-1.4% Mg;
0.3-1.1% Zn;
0.5.-0.30% Cr;
≤0.6% Fe;
≤0.8% Mn;
≤0.15% Zr;
≤0.15% Ti.
3 . The 6xxx series aluminum alloy of claim 1 including greater than 75% scrap.
4 . The 6xxx series aluminum alloy of claim 1 including greater than 90% scrap.
5 . An extruded, forged or rolled product manufactured from the 6xxx series aluminum alloy of claim 1 having a yield tensile strength greater than 295 MPa (42.8 ksi).
6 . An extruded, forged or rolled product manufactured from the 6xxx series aluminum alloy of claim 1 having a yield tensile strength greater than 320 MPa (46.4 ksi).
7 . An extruded, rolled or forged product manufactured from the 6xxx series aluminum alloy of claim 1 having excellent machinability performance as defined by achieving a B grade or better in the ASM machinability test.
8 . An extruded, rolled or forged product manufactured from the 6xxx series aluminum alloy of claim 1 having a thickness of 0.25-10 inches.
9 . An extruded, rolled or forged product manufactured from the 6xxx series aluminum alloy of claim 8 having a thickness of 1-10 inches.
10 . A method of manufacturing the 6xxx series aluminum alloy of claim 1 comprising,
a) casting using conventional direct chill casting methods;
b) homogenizing at 950° F. to 1060° F. (510-571° C.) for 2 to 10 hours;
c) preheating to 800° F.-1000° F. (427-538° C.);
d) hot working by extrusion, forging or rolling;
e) water quenching;
f) optionally stretching for stress relief and straightening, and
g) artificially aging at a temperature between 250-375° F. for 6-20 hours.
11 . A method of manufacturing the 6xxx series aluminum alloy of claim 10 , wherein said hot working is extrusion.
12 . A method of manufacturing the 6xxx series aluminum alloy of claim 1 comprising,
a) casting using conventional direct chill casting methods;
b) optionally homogenizing at 950° F. to 1060° F. (510-571° C.) for 2 to 10 hours;
c) preheating to a rolling temperature of 600° F.-1000° F. (316-538° C.);
d) hot rolling;
e) solution heat treatment at a temperature of 950° F. to 1070° F.,
f) quenching to room temperature,
g) optionally stretching for stress relief and straightening, and
h) artificially aging at a temperature between 250-375° F. for 6-20 hours.
13 . A method of manufacturing the 6xxx series aluminum alloy of claim 1 comprising,
a) casting using conventional direct chill casting methods;
b) homogenizing at 950° F. to 1060° F. (510-571° C.) for 2 to 10 hours;
c) preheating to an extrusion temperature of 450° F.-1000° F. (232-538° C.) and then extruding;
d) optionally drawing the extrusions;
e) solution heat treatment at a temperature of 950° F. to 1070° F.,
f) quenching to room temperature,
g) optionally stretching for stress relief and straightening, and
h) artificially aging at a temperature between 250-375° F. for 6-20 hours.