Aluminium alloy strip for brazing

• US 20070158386A1
• Filed: 11/24/2004
• Published: 07/12/2007
• Est. Priority Date: 11/28/2003
• Status: Active Grant

• Current Assignee: Constellium
• Original Assignee: Alcan Rhenalu (Alcan), Alcan Rolled Products- Ravenswood LLC (Alcan)
• Inventors: Henry, Sylvain, Dulac, Sandrine
• Granted Patent: US 7,926,701 B2
• Time in Patent Office: Days
• US Class Current: 228/101
• CPC Class Codes: B23K 1/0012 Brazing heat exchangers
• CPC Class Codes: B23K 1/008 Soldering within a furnace B23K1/012 takes precedence
• CPC Class Codes: B23K 2101/14 Heat exchangers
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 35/002 at least one of the workpieces being of light metal
• CPC Class Codes: B23K 35/0238 layered
• CPC Class Codes: B23K 35/286 Al as the principal constituent
• CPC Class Codes: B23K 35/3613 Polymers, e.g. resins
• CPC Class Codes: B32B 15/016 all layers being formed of aluminium or aluminium alloys
• CPC Class Codes: C22C 21/00 Alloys based on aluminium
• CPC Class Codes: C22C 21/14 with silicon
• CPC Class Codes: C22C 21/16 with magnesium

Abstract

The invention relates to a method for assembling sheets of aluminium alloy, comprising a welding without flux, in a controlled atmosphere, at a temperature of 580 to 620° C. a rapid cooling and, optionally, reheating to a temperature of 80 to 250° C. in which at least one of the sheets has a core alloy comprising (wt. %), Si 0.3 1.0, Fe<1.0, Cu 0.3 1.0, Mn 0.3 2.0, Mg 0.3 3.0, Zn<6.0, Ti<0.1, Zr<0.3, Cr<0.3, Ni<2.0, Co<2.0, Bi<0.5, Y<0.5, other elements <0.05 each, to a total of 0.15, the remainder being aluminium and covered on at least one face with a welding aluminium alloy, comprising 4 to 15 % silicon and 0.01 to 0.5% of at least one of the elements Ag, Be, Bi, Ce, La, Pb, Pd, Sb, Y or a mixed metal. The method is particularly suitable for the non-flux welding of heat exchangers.

Claims

1. Process for assembly of aluminum alloy plates comprising fluxless brazing under controlled nitrogen and/or argon atmosphere at a temperature of between 580°

C. and 620°

C. and rapid cooling and in which at least one of the plates includes a core alloy with composition (% by weight);

Si 0.3-1.0;

Fe<

1.0;

Cu 0.3-1.0;

Mn 0.3-2.0;

Mg 0.3-3.0;

Zn<

6.0;

Ti<

Cr<

0.3;

Ni<

2.0;

Co<

2.0;

Bi<

0.5;

Y<

0.5;

other elements <

0.05 each and 0.15 total, remainder aluminum,

and is coated on at least one face with an aluminum brazing alloy containing 4% to 15% of silicon and 0.01% to 0.5% of at least one of the elements element selected from the group consisting of Ag, Be, Bi, Ce, La, Pb, Pd, Sb, Y or mischmetal.

2. Process according to claim 1, characterized in that the copper content of the core alloy is between 0.35% and 1%.

3. Process according to claim 1, characterized in that the manganese content of the core alloy is between 0.3% and 0.7%.

4. Process according to claim 1, characterized in that the manganese content of the core alloy is between 0.35% and 0.7%.

5. Process according to claim 1, characterized in that the zinc content of the core alloy is less than 0.2%.

6. Process according to claim 1, characterized in that the bismuth content of the core alloy is between 0.05% and 0.5%.

7. Process according to claim 1, characterized in that the yttrium content of the core alloy is between 0.01% and 0.5%.

8. Process according to claim 1, characterized in that composition of the core alloy is (% by weight):

Si 0.3-1.0;

Fe<

0.5;

Cu 0.35-1.0;

Mn 0.3-0.7;

Mg 0.35-0.7;

Zn<

0.2;

Ti<

0.1;

Zr<

0.3;

Cr<

0.3;

Ni<

1.0;

Co<

1.0;

Bi<

0.5;

Y<

0.5;

other elements <

0.05 each and 0.15 total, remainder aluminum.

9. Process according to claim 1, characterized in that the brazing alloy is cladded onto the core alloy by co-rolling.

10. Process according to claim 1, characterized in that the brazing alloy coating is composed of particles.

11. Process according to claim 1, characterized in that it is used for manufacturing of heat exchangers and that aging is conducted in hot parts during operation of exchangers.

12. Process according to claim 1, comprising aging at a temperature of between 80°

C. and 250°

C. after rapid cooling.

13. Process according to claim 10, wherein the particles are coated by a polymer resin.

14. A process for brazing aluminum alloy plates comprising:

(a) coating one or more plates with a cladding alloy comprising between 4% to 15% by weight silicon and 0.01% to 0.5% by weight of at least one element selected from the group consisting of Ag, Be, Bi, Ce, La, Pb, Pd, Sb, Y or mischmetal;

(b) subjecting the one or more plates to fluxless brazing under controlled nitrogen and/or argon atmosphere at a temperature of between 580°

C. and 620°

C., and

(c) rapidly cooling the plates,

at least one of the plates including a core alloy comprising between 0.3% and 1.0% by weight silicon, between 0.3% and 3.0% by weight magnesium, between 0.3% and 2.0% by weight manganese, and between 0.3% and 1.0% by weight copper.

15. The process according to claim 14 also comprising aging at a temperature of between 80°

C. and 250°

C. after rapid cooling.

16. The process according to claim 14, wherein the core alloy also comprises between 0.05% and 0.5% by weight bismuth and/or 0.01% to 0.5% by weight yttrium.

17. The process according to claim 14, wherein the core alloy comprises between 0.35% and 0.7% by weight magnesium.

18. The process according to claim 14, wherein the core alloy comprises (% by weight):

Si 0.3-1.0;

Fe<

0.5;

Cu 0.35-1.0;

Mn 0.3-0.7;

Mg 0.35-0.7;

Zn<

0.2;

Ti<

0.1;

Zr<

0.3;

Cr<

0.3;

Ni<

1.0;

Co<

1.0;

Bi<

0.5;

Y<

0.5;

other elements <

0.05 each an 0.15 total, remainder aluminum.