Brazing has often been overlooked by designers, possibly due to a poor historical image. The modern brazing process and materials are a far cry from this perception however - it has become an exceptional joining process that makes possible engineering assemblies with joint strengths that cannot be achieved by any other means.

Contact: Alan McCracken on 0121 567 3216, Mobile: 07771 523119, Email: a.mccracken@kepston.co.uk



Typical Applications

Furnace Brazing is still one of the least appreciated manufacturing techniques with many engineers being unaware of its existence or its advantages as a method of joining two or more parts together.

Kepston use furnace atmospheres that permit the brazing of multi-jointed components in mild steel and/or Stainless Steel without the use of flux.

Typical Applications
The list of potential applications is substantial, however, the most common categories are:

  • Hydraulic Fittings
  • Heat Exchanges
  • Tube Manipulations
  • Machined Assemblies
  • Pressed Assemblies
  • Fabrications
  • Wire Formed Assemblies

Joint Design

Brazing relies on capillary attraction. Therefore, the joint design is crucial in the success of the brazing. An unbroken capillary path with gaps not exceeding 0.1mm are required for most applications.

Whenever possible, joints should be self-supporting or self-jigging as furnace jigs can be expensive, they may move in the heat during the process and they occupy furnace space adding to the unit costs.

Joint Strength
A correctly designed and brazed joint should produce a strength of joint that is in excess of the parent metal.

Furnace Brazing Is Also Commonly Referred To As...

Copper Brazing, Bright Brazing, Mesh Belt Brazing & Atmosphere Brazing.


Advantages & Disadvantages

Surface Condition
Components should be clean, free from swarf, rust and excess grease before brazing.
It should be noted that score marks, shot blasted or roughened areas in the region of the brazed joint will pull the braze filler metal away from the joint.
Post Braze Processes.

Due to the high melting point of the braze material [1083°C for Copper] most commonly used hardening and case hardening heat treatments can be carried out after brazing. Also most plating processes take well on copper brazed components.

Main Advantages of Furnace Brazing

  1. A uniformed heating & cooling rate can reduce the potential for distortion.
  2. Joint strengths greater than the parent metal are possible.
  3. Parent metals are not fused or damaged.
  4. Stresses are relieved during brazing.
  5. No surface deterioration takes place during the process.
  6. Dissimilar metals can be brazed together.
  7. Different metal thickness are permissible in brazed joints.
  8. Multiple joints can be brazed at once.
  9. Long and inaccessible joints can be filled successfully.
  10. Furnace brazing facilitates the manufacture of complex & delicate assemblies which might be impossible to achieve by any other method
  11. Skilled labour is not required to carry out the process.
  12. Rapid reproducible results are obtainable.
Disadvantages of Furnace Brazing
  1. Close fits are necessary to facilitate the capillary action.
  2. Component parts will be annealed during the process.
  3. Provision for location of the brazing material has to be allowed for in the design.