Induction Brazing Copper T Pipe With Induction Heating Machine

Objective

Evaluate replacing of flame copper t pipe brazing with induction brazing.

Equipment

DW-HF-25kw high frequency induction heating machine

Materials

• Copper main tube – 1.13” (28.7 0mm) OD 1.01” (25.65 mm) ID
• Riser tube copper – 0.84” (21.33 0mm) OD, 0.76” (19.30 0mm) ID

Power:
Power manually reduced from max output of 10kW to 15kW to provide even heat distribution on the assembly with the modified test coil.
NOTE: Heat time can be improved with custom coil design.

Temperature:
Approximately 704° C (1300° F)

Time: 25sec

Process Steps:

The copper tubes were cleaned and assembled. Two preformed alloy rings were made from available alloy in lab for the demonstration. The wire used measured 0.787mm (0.031”) in diameter Both the riser an base copper tubes were pre-fluxed with white braze flux. The assembly was placed in the test coil per the video bellow and the alloy flowed to form a joint at the “T” interface in 30seconds.

Results and Conclusions:

The target heat time for the smallest T joint assembly is 20 seconds
. Using a lab test coil, we were able to effect a braze in the interface section of the tubes (copper) in 30 seconds.