Special Process: Brazing
Brazing is a metal-joining process in which a filler metal is heated above its melting point and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected by a suitable atmosphere, usually a flux.
Capillary Action
The fundamental principle of brazing. The filler metal is drawn into the tight-fitting gap between base materials through surface tension, similar to how a paper towel wicks up water.
Filler Metals
Alloys with a melting point below that of the base materials. They must be able to 'wet' the surfaces of the base materials to form a metallurgical bond.
Flux or Atmosphere
Brazing requires a clean, oxide-free surface. This is achieved either with a chemical flux that cleans and protects the joint, or by performing the process in a controlled atmosphere (like vacuum or inert gas).
Brazing Process Calculator
Select the two base materials you want to join to get a recommendation for the appropriate filler metal and process parameters.
Select materials and calculate to see results.
• This calculator provides general guidelines for brazing. Parameters can vary significantly based on joint design, part thickness, heating method, and specific alloy grades.
• Always consult the filler metal manufacturer's specifications and perform tests for critical applications.
Advantages:
- Extremely clean, high-integrity joints.
- No flux required, eliminating post-braze cleaning and potential flux entrapment.
- Uniform heating and cooling minimizes distortion.
- Ability to process multiple joints at once in a batch.
- Ideal for reactive materials (like titanium) and complex geometries.
Best Use Cases:
- Aerospace components (e.g., turbine blades, heat exchangers).
- Medical implants and devices.
- Semiconductor manufacturing equipment.
- High-performance automotive parts.
Advantages:
- Suitable for high-volume production.
- Protective atmosphere reduces the need for flux.
- Excellent process for joining dissimilar metals.
- Can be highly automated.
Best Use Cases:
- Automotive assemblies (e.g., fuel rails, torque converters).
- HVAC components.
- Mass production of steel and stainless steel assemblies.
Advantages:
- Highly versatile and portable.
- Low initial equipment cost.
- Ideal for repairs, one-off jobs, and simple geometries.
- Operator has direct control over the heating process.
Best Use Cases:
- Plumbing and HVAC repairs.
- Jewelry making.
- Small-scale production and prototyping.
- Joining parts in locations that are difficult to access.
Advantages:
- Extremely fast and repeatable heating cycles.
- Highly localized heating minimizes heat-affected zone and distortion.
- Energy efficient and easily automated for high-volume production.
- Clean process, often requiring minimal or no flux when done in controlled atmosphere.
Best Use Cases:
- Joining carbide tips to cutting tools.
- Automotive component assembly (e.g., motor shafts, connectors).
- Electrical component manufacturing.
- High-speed, repetitive joining tasks.
Silver Alloys (BAg)
The most versatile and widely used group. They have low melting points, excellent flow characteristics, and can join most ferrous and non-ferrous metals.
Common Use: General-purpose brazing, HVAC, electrical components, plumbing.
Copper Alloys (BCu)
Includes pure copper, copper-phosphorus, and copper-zinc alloys. Copper-phosphorus alloys are self-fluxing on copper.
Common Use: Joining copper to copper (HVAC), furnace brazing of steel.
Aluminum-Silicon Alloys (BAlSi)
Used specifically for brazing aluminum alloys. They have a melting point close to that of the aluminum base metals.
Common Use: Automotive heat exchangers (radiators, condensers), aluminum assemblies.
Nickel Alloys (BNi)
Offer excellent high-temperature strength and corrosion resistance.
Common Use: Aerospace applications, jet engine components, high-performance turbines, stainless steel brazing.
