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.

Induction Brazing Steel Tube
Objective: To heat an oil suction assembly (steel tubing and filter cap) to 1,850°F (1010°C) within 15 seconds for a brazing application.
Material 0.125" (3.2mm) diameter steel tube and filter cap assembly, high temperature brazing flux, copper ring.
Temperature 1850°F(1010°C)
Frequency 500 kHz
Equipment • DW-UHF-6KW-I induction heating system equipped with a remote workhead containing 0.66 μF capacitors • An induction heating coil designed and developed specifically for this application.
Process A two-turn, specially-contoured helical induction coil is used to heat the tube assembly near the joint area. A copper ring and high temperature flux are then applied to the joint area. Power is applied for 15 seconds until the braze flows.
Results/Benefits Induction heating provides:
• Easy loading and unloading of parts
• Heat very precise areas within production tolerances
• Hands free heating that involves minimal operator skill for manufacturing
