Brazing sheet
In one embodiment, a brazing sheet comprises: a core layer, a braze liner on the first side of the core layer; and a waterside liner on the second side of the core layer. The core layer is comprised of a 3xxx series aluminum alloy. The waterside liner is an aluminum alloy comprising: 7-20 wt % Zn; up to 0.25 wt % Si; up to 0.1 wt % Cu; up to 0.25 wt % Mn; up to 0.1 wt % Mg; and up to 0.1 wt % Cr. In some embodiments, the brazing sheet has a thickness of 60-180 microns. In some embodiments, the waterside liner comprises 1-15% of the thickness of the brazing sheet.
1. A brazing sheet comprising:
a. a core layer comprising:
i. a 3xxx series aluminum alloy;
ii. a first side;
iii. a second side;
b. a braze liner on the first side of the core layer; and
c. a waterside liner on the second side of the core layer, wherein the waterside liner is an aluminum alloy comprising in a first pre-braze state before thermo-mechanical processing
7-20 wt. % Zn and
up to 0.1 wt. % Cu, the brazing sheet having been thermo-mechanically processed to diffuse a portion of the Zn in the waterside liner into the core resulting in a second pre-braze state, the portion of the Zn diffused adapted to provide a solidus of the core and the waterside liner ≥600° C., a total thickness ≥0.06 mm and <0.20 mm and a post-braze Zn concentration difference of >2.2% between a central position within the thickness of the brazing sheet and a surface of the waterside liner, distal to the core.
2. The brazing sheet of claim 1 wherein the waterside liner comprises 10-20 wt. % Zn.
3. The brazing sheet of claim 1 wherein the waterside liner comprises 12-20 wt. % Zn.
4. The brazing sheet of claim 1 wherein the waterside liner comprises 9-12 wt. % Zn.
5. The brazing sheet of claim 1 wherein the core layer comprises one or more of:
a. 0.5-1.25 wt. % Si;
b. 0.5-1.25 wt. % Cu;
c. 0.5-2.0 wt. % Mn;
d. up to 0.15 wt. % Mg;
e. up to 0.1 wt. % Cr;
f. up to 0.1 wt. % Zn; and
g. 0.1-0.2 wt. % Ti.
6. The brazing sheet of claim 1 wherein the brazing sheet has a thickness of 60-180 microns.
7. The brazing sheet of claim 1 wherein the brazing sheet has a thickness of 60-150 microns.
8. The brazing sheet of claim 1 wherein the brazing sheet has a thickness of 80-150 microns.
9. The brazing sheet of claim 1 wherein the brazing sheet has a thickness of 60-100 microns.
10. The brazing sheet of claim 1 wherein the brazing sheet has a thickness and the waterside liner comprises 7-15% of the thickness.
11. The brazing sheet of claim 1 wherein the brazing sheet has a thickness and the waterside liner comprises 7-10% of the thickness.
12. The brazing sheet of claim 1 wherein the brazing sheet has a thickness and the waterside liner comprises 5-15% of the thickness.
13. The brazing sheet of claim 1 wherein the brazing sheet has a thickness and the waterside liner comprises 5-10% of the thickness.
14. A brazing sheet comprising:
a. a core layer comprising:
i. a 3xxx series aluminum alloy;
ii. a first side;
iii. a second side;
b. a braze liner on the first side of the core layer; and
c. a waterside liner on the second side of the core layer, wherein the waterside liner is an aluminum alloy comprising:
i. ≥16 wt. % Zn;
ii. up to 0.25 wt. % Si;
iii. up to 0.1 wt. % Cu;
iv. up to 0.25 wt. % Mn; and
v. up to 0.1 wt. % Mg
the brazing sheet having a total thickness between 60 microns to 180 microns.