US 7,029,543 B2Granted

Process for making aluminum alloy sheet having excellent bendability

AssigneeNovelis Inc.

InventorsMichael Jackson Bull, David James Lloyd

Life of this patent

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Abstract

A process is described for producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles. An aluminum alloy containing 0.50 to 0.75 by weight Mg, 0.7 to 0.85% by weight Si, 0.1 to 0.3% by weight Fe, 0.15 to 0.35% by weight Mn, and the balance Al and incidental impurities, is used and is semi-continuously cast into ingot. The cast alloy ingot is subjected to hot rolling and cold rolling, followed by solution heat treatment of the formed sheet. The heat treated sheet is quenched to a temperature of about 60–120° C. and the sheet is then coiled. This coil is then pre-aged by slowly cooling the coil from an initial temperature of about 60–120° C. to room temperature at a cooling rate of less than 10° C./hr.

Claims10

Dependent claims

A process of producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles, the process comprising the steps of:

semi-continuously casting an aluminum alloy comprising 0.50 to 0.75% by weight Mg, 0.7 to 0.85% by weight Si, 0.1 to 0.3% by weight Fe, 0.15 to 0.35% by weight Mn, and the balance Al and incidental impurities,
subjecting the cast alloy ingot to hot rolling and cold rolling to an intermediate gauge,
batch annealing the intermediate gauge sheet,
further cold rolling the annealed sheet to final gauge and heat treating the further cold rolled sheet,
quenching the heat treated sheet to a temperature of about 60–1200° C. and coiling the sheet, and
pre-aging the coil by slowly cooling the coil from an initial temperature of about 60–1200° C. to room temperature at a cooling rate of less than 10° C./hr., thereby obtaining a sheet having a bendability (r/t) value of less than 0.2.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/863,557Filed 8 Jun 2004 · continuation
Priority: 3 May 2001
Published: US 2004/0250928 A116 Dec 2004
Granted: 18 Apr 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

C22F 1/043
Of aluminium or alloys based thereon: of alloys with silicon as the next major constituent
C22C 21/02
Alloys based on aluminium: with silicon as the next major constituent
C22C 21/08
With magnesium as the next major constituent: with silicon
C22F 1/05
Of aluminium or alloys based thereon: of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions

Family

Application60/288,382Us provisional application · filed 3 May 2001
Application10/138,844Parent of this continuation · filed 2 May 2002
US 2004/0250928 A1Pre-grant publication · published 16 Dec 2004
US 6,780,259 B2Parent of this continuation
US 2003/0029531 A1Published application
US 7,029,543 B2This patent

From the US filing history. Foreign family members aren’t listed.