# US 2016/0250720 A1 · Multilayer brazing sheet for vacuum braze applications

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- Number: US 2016/0250720 A1
- Document ID: US20160250720A1
- Status: Published application
- Kind: A1
- Application number: 15/053,201
- Filed: 2016-02-25
- Published: 2016-09-01
- Earliest claimed: 2015-02-26
- Assignees: Alcoa Inc.
- Applicants: Alcoa Inc.
- Inventors: Baolute Ren
- Web page: https://patentgrep.com/patent/US20160250720A1

## CPC

- B23K 35/0238: {layered}
- B23K 35/286: {Al as the principal constituent}
- B23K 35/288: {with Sn or Zn}
- B32B 15/016: {all layers being formed of aluminium or aluminium alloys}
- C22C 21/00: Alloys based on aluminium
- C22C 21/02: with silicon as the next major constituent
- C22C 21/06: with magnesium as the next major constituent
- C22C 21/08: with silicon
- C22C 21/14: with silicon
- C22C 21/16: with magnesium
- C22C 21/18: with zinc
- Y10T 428/12764: Next to Al-base component
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A five layer sheet for vacuum brazing has a core layer of 3XXX aluminum alloy and two interliner layers of 5XXX aluminum alloy bonded to the core layer. Two layers of 4XXX aluminum alloy are bonded to the two interliner layers. An elevated quantity of Mg in the interliner layers can provide enhanced strength, facilitate brazing and provide corrosion protection. A low zinc composition for the sheet also facilitates vacuum brazing.

## Claims

### Claim 1

A multi-layer sheet material, comprising:
a core layer of 3XXX aluminum alloy; comprising in weight %:
0.1-2.0 Si,
Up to 0.7 Fe
0.1-2.0 Cu
0.8-1.8 Mn
0.05-1.2 Mg
Up to 0.10 Cr
Up to 0.10 Zn
One of each Ti and Zr, or both, 0.10-0.20.
a first interliner layer of 5XXX aluminum alloy bonded on one side of the core layer;
a second interliner layer of 5XXX aluminum alloy bonded on a second side of the core layer distal to the first interliner layer;
a first brazing layer of 4XXX aluminum alloy bonded to the first interliner layer distal to the core layer;
a second brazing layer of 4XXX aluminum alloy bonded to the second interliner layer distal to the core layer, wherein the first and second interliners are formed from an aluminum alloy comprising in weight % 0.1-0.40 Si; 0.1-0.5 Fe; up to 0.05 Cu; up to 0.3 Mn; 0.1-1.10 Mg; up to 0.05 Cr; up to 0.05 Zn; 0.01-0.2 Ti, the remainder being aluminum and impurities.

### Claim 2 (depends on 1)

The material of claim 1, wherein the core layer is treated by a pre-hot rolling thermal treatment.

### Claim 3 (depends on 1)

The material of claim 1, wherein the first and second brazing layers have a max Zn level of 0.2 wt %.

### Claim 4 (depends on 1)

The material of claim 1, wherein the first and second brazing layers have Mg in an amount from 0.16 to 2.5 wt %.

### Claim 5 (depends on 1)

The material of claim 1, wherein the core layer comprises in wt % 0.1 to 1.0 Si, up to 0.6 Fe, 0.3 to 0.8 Cu, 1.0 to 1.6 Mn, 0.1 to 0.6 Mg, up to 0.03 Cr, up to 0.05 Zn and 0.1-0.2 Ti, the remainder being Al and impurities.

### Claim 6 (depends on 5)

The material of claim 5, wherein the core layer comprises in wt % 0.05-0.1 Si, 0.1-0.2 Fe, 0.4-0.6 Cu, 1.0-1.3 Mn, 0.1-0.3 Mg, 0.002-0.006 Cr, 0.01-0.02 Zn and 0.15-0.18 Ti.

### Claim 7 (depends on 5)

The material of claim 5, wherein the core layer comprises in wt % 0.5 to 0.9 Si, 0.3 to 0.7 Fe, 0.4 to 0.7 Cu, 1.0 to 1.5 Mn, 0.2 to 0.5 Mg.

### Claim 8 (depends on 3)

The material of claim 3, wherein Zn is present in an amount no more than that of an impurity.

### Claim 9 (depends on 1)

The material of claim 1, wherein at least one of the interliner layers comprise in wt % 0.2-0.4 Si, 0.1-0.2 Fe, 0.01-0.04 Cu, 0.01-0.05 Mn, 0.3-0.5 Mg, 0.01-0.04 Cr, 0.01-0.04 Zn and 0.02-0.08 Ti.

### Claim 10 (depends on 1)

The material of claim 1, wherein at least one of the interliner layers comprise in wt % 0.1-0.18 Si, 0.13-0.2 Fe, 0.001-0.01 Cu, 0.001-0.005 Mn, 0.4-0.7 Mg, 0.001-0.006 Zn and 0.01-0.02 Ti.

### Claim 11 (depends on 1)

The material of claim 1, wherein at least one of the interliner layers comprise in wt % 0.1-0.18 Si, 0.13-0.2 Fe, 0.001-0.003 Cu, 0.001-0.005 Mn, 0.5-1.05 Mg, 0.001-0.005 Zn and 0.01-0.02 Ti.

### Claim 12 (depends on 1)

The material of claim 1, wherein the first brazing layer comprises in wt % 9.0-11.0 Si, up to 1.0 Fe, 0.1-0.3 Cu, up to 0.20 Mn, 0.5-2.5 Mg, up to 0.05 Zn, the remainder being Al and impurities.

### Claim 13 (depends on 1)

The material of claim 1, wherein the second brazing layer comprises in wt % 11.5-12.5 Si, 0.1-0.3 Fe, 0.1-0.3 Cu, 0.01-0.1 Mn, 0.1-0.2 Mg, 0.001-0.01 Cr, 0.01-0.05 Zn and 0.01-0.02 Ti, the remainder being Al and impurities.

### Claim 14 (depends on 12)

The material of claim 12, wherein the second brazing layer comprises in wt % 11.5-12.5 Si, 0.1-0.3 Fe, 0.1-0.3 Cu, 0.01-0.1 Mn, 0.1-0.2 Mg, 0.001-0.01 Cr, 0.01-0.05 Zn and 0.01-0.02 Ti, the remainder being Al and impurities.

### Claim 15 (depends on 6, 14)

The material of claim 6, wherein the first and second brazing layers are the first and second brazing claim 14.

### Claim 16 (depends on 7, 14)

The material of claim 7, wherein the first and second brazing layers are the first and second brazing claim 14.

### Claim 17 (depends on 1)

The material of claim 1, wherein the clad ratio is 8-18% for the braze layers and 8-18% for the interliner layers.

### Claim 18

A sheet material for brazing, comprising:
a core of a homogenized 3xxx aluminum alloy;
a first interliner on a first side of the core;
a second interliner on a second side of the core;
a first braze liner on the first interliner;
and a second braze liner on the second interliner, wherein the first and second interliners are formed from an aluminum alloy having, in weight %; 0.1-0.40 Si; 0.10-0.5 Fe; up to 0.05 Cu; up to 0.3 Mn; 0.3-1.10 Mg; up to 0.05 Cr; up to 0.05 Zn; 0.05-0.2 Ti, the remainder being aluminum and impurities and wherein the first and second braze liners are each formed from a 4xxx aluminum alloy.

### Claim 19 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners comprise, in weight %, 0.12-0.4 Si.

### Claim 20 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners comprise in weight %, up to 0.4 Fe.

### Claim 21 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners comprise, in weight %, up to 0.03 Cu.

### Claim 22 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners comprise, in weight %, up to 0.3 Mn.

### Claim 23 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners comprise, in weight %, 0.3-1.0 Mg.

### Claim 24 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners each comprise, in weight %, up to 0.03 Cr.

### Claim 25 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners each comprise, in weight %, up to 0.03 Zn.

### Claim 26 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners each comprise, in weight %, up to 0.3 Fe.

### Claim 27 (depends on 18)

The sheet material of claim 18, wherein the first and second interliners each comprise, in weight %, 0.08-0.16 Ti.