US 11,654,516 B2
Aluminium multilayer brazing sheet for fluxfree brazing
Bechir Chehab, Voiron (FR); and Carole Loable, Courbevoie (FR)
Assigned to CONSTELLIUM NEUF-BRISACH, Biesheim (FR)
Appl. No. 16/771,611
Filed by CONSTELLIUM NEUF-BRISACH, Biesheim (FR)
PCT Filed Dec. 10, 2018, PCT No. PCT/EP2018/084091
§ 371(c)(1), (2) Date Jun. 10, 2020,
PCT Pub. No. WO2019/115422, PCT Pub. Date Jun. 20, 2019.
Claims priority of application No. 1762018 (FR), filed on Dec. 12, 2017.
Prior Publication US 2021/0170532 A1, Jun. 10, 2021
Int. Cl. B23K 35/02 (2006.01); C22C 21/02 (2006.01); B23K 35/28 (2006.01); B23K 1/20 (2006.01); B32B 15/01 (2006.01); F28F 21/08 (2006.01); C23G 1/12 (2006.01); C23G 1/22 (2006.01); C23F 1/20 (2006.01); C23F 1/36 (2006.01); B23K 103/10 (2006.01); B23K 101/14 (2006.01)
CPC B23K 35/288 (2013.01) [B23K 1/20 (2013.01); B23K 35/0238 (2013.01); B32B 15/016 (2013.01); C22C 21/02 (2013.01); C23F 1/20 (2013.01); C23F 1/36 (2013.01); C23G 1/125 (2013.01); C23G 1/22 (2013.01); F28F 21/084 (2013.01); F28F 21/089 (2013.01); B23K 2101/14 (2018.08); B23K 2103/10 (2018.08)] 16 Claims
OG exemplary drawing
 
1. A process for the production of an aluminum multilayer hazing sheet which comprises:
a core layer made of a 3xxx alloy consists of, in weight %: up to 0.7% Si, up to 0.7% Fe, 0.3 to 1.1% Cu, 0.5 to 1.8% Mn, up to 0.3% Ti, 0.1 to 0.18% Mg, up to 0.1% Zn, Zr and/or Cr and/or V each up to 0.3%, other elements less than 0.05% each and less than 0.15% in total, balance being aluminum and
a brazing layer made of a 4xxx alloy on one or both sides of the core layer, wherein the brazing layer 4xxx alloy consists of, in weight %: 7 to 13% Si, up to 0.7% Fe, up to 0.5% Cu, 0.1 to 0.3% Bi, up to 500 ppm Sr, other elements less than 0.05% each and less than 0.15% in total, balance being aluminum,
the process comprising in succession: providing layers to be assembled or simultaneous casting of layers to obtain a sandwich; rolling of a resulting sandwich to obtain a sheet; and treating a surface of the sheet with an alkaline or acidic etchant.