New York Low Pressure Boiler COF Practice

What is the second step in preparing a brazed joint after cleaning?

1. Apply heat

2. Apply flux

3. Apply filler metal

4. Check the gauge pressure

The correct answer is: Apply flux

In the process of creating a brazed joint, cleaning the surfaces to be joined is essential, but preparing the joint doesn’t stop there. After cleaning, the next critical step is to apply flux. Flux serves an important role: it helps to prevent oxidation of the base metals during the heating process, which can compromise the quality of the joint. It also aids in the capillary action that draws the molten filler metal into the joint when heated. Applying flux ensures that when the assembly reaches the appropriate temperature, the filler metal can flow properly and create a strong bond between the parts. Without this step, the joint may be weak or ineffective due to contamination or insufficient melting of the filler material. This highlights the importance of the flux application in forming a reliable and structurally sound brazed joint.