Vacuum Furnace Brazing in Brief
Lytron uses vacuum brazing to manufacture cold plates, plate fin heat exchangers, and oil coolers. Why?
Advantages
Compared to other metallurgical techniques for joining aluminum, vacuum furnace brazing offers numerous technical and economic advantages. These include:
- High-strength, void-free, leak-tight joints approaching parent metal strength - proof pressures up to 800psi, burst pressures up to 1300psi
- Consistently reproducible, close-tolerance results -- Lytron can control the joining surface tolerance ± 0.00075"
- Single process production of complex assemblies with multiple joints lowers costs without compromises in quality
- Uniform thermal conductivity
- Flux-free process eliminates corrosive residue
- Ability to fill long, otherwise inaccessible joints
- Minimal distortion due to uniform heating and cooling
- Effective stress relief
- Parent metal protected from fusing or damage
- No surface deterioration during processing
Basics of Brazing
Brazing is akin to soldering. By definition, brazing takes place above 840oF (440oC), usually in the 1100oF (593oC) to 1500oF (815oC) range, while soldering occurs below 840oF (440oC). Both involve wetting the metallic surfaces to be joined with a molten brazing alloy, which spreads by capillary action and then, upon cooling, forms a strong metallurgically-bonded joint. Brazing is favored for applications requiring stronger joints and/or temperature resistance up to about 350oF (176oC).
How Vacuum Furnace Brazing Works
Vacuum furnace brazing generally proceeds according to this sequence:
- Clean components-to-be-brazed using vapor degreasing
- Mount components in brazing fixtures, which keep parts aligned during processing
- Convey loaded brazing fixtures into furnace
- Perform vacuum brazing, concurrently pulling vacuum down to about 8 torr. and ramping heat up to about 1100oF (593oC).
- After brazing, inject dry nitrogen into furnace
- Remove brazed assemblies and fixtures
- Air cool and dismount completed assemblies
Click here for more information on Lytron's vacuum brazing process.