# US 2019/0316232 A1 · Lower wing skin metal with improved damage tolerance properties

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- Number: US 2019/0316232 A1
- Document ID: US20190316232A1
- Status: Published application
- Kind: A1
- Application number: 16/455,897
- Filed: 2019-06-28
- Published: 2019-10-17
- Earliest claimed: 2013-09-30
- Assignees: Constellium Issoire
- Applicants: Constellium Issoire
- Inventors: Bernard Bes
- Web page: https://patentgrep.com/patent/US20190316232A1

## CPC

- C22C 21/16: with magnesium
- B22D 21/007: {with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C}
- B22D 27/20: Measures not previously mentioned for influencing the grain structure or texture; Selection of compositions therefor
- B64C 3/26: Construction, shape, or attachment of separate skins, e.g. panels
- C22C 21/12: with copper as the next major constituent
- C22C 21/14: with silicon
- C22F 1/04: of aluminium or alloys based thereon
- C22F 1/057: of alloys with copper as the next major constituent
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B22D: CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES (shaping of plastics or substances in a plastic state B29C; metallurgical processing, selection of substances to be added to metal C21, C22)
- B64C: AEROPLANES; HELICOPTERS
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)

## Abstract

The invention relates to a rolled product with state T351, having thickness of between 15 and 50 mm, made from aluminium alloy having the following composition, in % by weight, Cu: 3.85-4.15; Mg: 0.95-1.25; Mn: 0.45-0.57; Zr: 0.09-0.16; Ti: 0.005-0.1; Fe: <0.070; Si: <0.060; with Cu+Mg≤5.15; other lesser elements 0.05 each and less than 0.15 in total, the remainder being aluminium.

## Claims

### Claim 1

A manufacturing process for a rolled product in T351 temper, comprising:
preparing and casting an aluminum alloy of thickness from 15 to 50 mm comprising, as a percentage by weight,
Cu: 3.85-4.15,
Mg: 0.95-1.25,
Mn: 0.45-0.57,
Zr: 0.09-0.16,
Ti: 0.005-0.1,
Fe: <0.070,
Si: <0.060,
with Cu+Mg 5≤5.15,
other elements <0.05 each and less than 0.15 in total, the remainder being aluminum;
adding a grain-refining agent of AlTiB type to obtain a rolling slab;
optionally homogenizing said slab at a temperature from 480° C. to 510° C.;
optionally hot rolling said homogenized slab to obtain a plate of thickness e from 15 to 50 mm;
solution heat treating said plate at a temperature from 480 to 505° C. for a time t in hours such that t≥e/7;
quenching said solution heat treated plate;
cold stretching said quenched plate with a deformation of from 1.5 to 3%; and
carrying out natural aging at room temperature.

### Claim 2 (depends on 1)

The process according to claim 1, wherein said solution heat treatment is performed at a temperature from 495° C. to 505° C.

### Claim 3 (depends on 2)

The process according to claim 2, wherein said time t is such that t≤e/t≤4.5.

### Claim 4 (depends on 2)

The process according to claim 2, wherein said time t is such that t≤e/5.0.

### Claim 5 (depends on 2)

The process according to claim 2, wherein said time t is such that t≤e/5.5.

### Claim 6 (depends on 1)

The method according to claim 1, wherein hot rolling is performed.

### Claim 7 (depends on 6)

The method according to claim 6, wherein an average temperature during hot rolling to thickness 60 mm is at least 450° C.

### Claim 8 (depends on 6)

The method according to claim 6, wherein during hot rolling, an outgoing temperature is at least 410° C.

### Claim 9 (depends on 1)

The method according to claim 1, wherein homogenizing is performed.

### Claim 10 (depends on 6)

The method according to claim 6, wherein homogenizing is performed.

### Claim 11 (depends on 9)

The method according to claim 9, wherein homogenizing occurs at a temperature in a range from 480 to 510° C.

### Claim 12 (depends on 9)

The method according to claim 9, wherein homogenizing occurs at a temperature in a range from 490 to 508° C.

### Claim 13 (depends on 1)

The method according to claim 1, wherein thickness e is in a range from 20 to 40 mm.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the plate has a ratio of UTS(L) to TYS(L) at 0.2% elongation greater than 1.25.

### Claim 15 (depends on 14)

The method according to claim 14, wherein the ratio is greater than 1.30.

### Claim 16 (depends on 14)

The method according to claim 14, wherein TYS(L) at 0.2% elongation is at least 350 MPa.

### Claim 17 (depends on 14)

The method according to claim 14, wherein TYS(L) at 0.2% elongation is at least 365 MPa.

### Claim 18 (depends on 1)

An aluminum rolled product in T351 temper, prepared by the process according to claim 1.

### Claim 19 (depends on 10)

An aluminum rolled product in T351 temper, prepared by the process according to claim 10.

### Claim 20 (depends on 18)

The aluminum rolled product of claim 18, wherein TYS(L) at 0.2% elongation is at least 350 MPa.