Flux Brazing Alloys

No. 21 and 22 brazing sheet are typically used in Dip Brazing applications. No. 21 is one side clad and No. 22 is a two sided product, with each having a heat treatable core of 6951 and a cladding alloy of 4343.

flux-brazing-alloys

In Dip Brazing, air is excluded from the process since the parts are submerged in molten salt, thereby excluding exposure to air and subsequent oxidation. The molten salt functions both as a heat transfer medium and flux.

The typical application of dip brazed alloys No.21 and No.22 is for parts where strength is required. The 6951 core is a heat treatable alloy, providing additional strength and offering the opportunity to save weight by down gauging. Many of the dip brazed parts find their way in heat transfer applications for the aerospace industry.

Lynch Metals has the largest inventory in the world of these Dip Braze products. The material is stocked in both its Union, NJ and Anaheim, CA facilities in gauges ranging from .020 through .190.

Brazing Sheet Items No. of Sides Clad Core Alloy Cladding Alloy Nominal Cladding Thickness Per Side (Percent of Composite Thickness) Optimum Brazing Range (°F) Optimum Brazing Range (°C)
No. 11 1 3003 4343 10% for .063” and less
5% for .064” and more
1100 – 1140 593 – 616
No. 12 2 3003 4343 10% for .063” and less
5% for .064” and more
1100 – 1140 593 – 616
No. 21* 1 6951 4343 10% for .090” and less
5% for .091” and more
1100 – 1140 593 – 616
No. 22* 2 6951 4343 10% for .090” and less
5% for .091” and more
1100 – 1140 593 – 616
No. 23* 1 6951 4045 4045 10% for .090” and less
5% for .091” and more
1090 – 1120 588 – 604
No. 24* 2 6951 4045 10% for .090” and less
5% for .091” and more
1090 – 1120 588 – 604
No. 33 1 6951/td> 4044 10% for all thicknesses 1100 – 1135 593 – 613
No. 34 2 6951 4044 10% for all thicknesses 1100 – 1135 593 – 613
No. 44 2 6951 4044/7072 15% 4404 one side, 5% 7072 other side
For all thicknesses
1100 – 1135 593 – 613

*In some instances these brazing sheet alloys can be used for vacuum brazing