High Frequency Brazing Stainless Steel Fittings

Objective
High Frequency Brazing stainless steel fittings to corogated (SS) hoses. The hoses are with sizes ID 1.575in (40mm) and ID 2.99in (76 mm).  The customer has never used induction heating before and is not familiar with the induction process. The goal of this test is to prove the strength of the joints.



Equipment


DW-UHF-10KW induction brazing machine

Materials
• Flexible metal hose
• Ag45Sn brazing alloy

Test 1
Key Parameters
Flexible metal hose with ID 1.575in (40mm)
Equipment: DW-UHF-10KW induction brazing heater, custom coil – ID 1.654in (42mm), 1 turn
Temperature: approximately 1382°F (750°C)
Power: Pre-curie – 7kW
Time: 28seconds

Test 2
Key Parameters
Flexible metal hose with ID 2.913in (74mm)
Equipment: DW-UHF-10kw induction brazing heater, custom coil – ID 2.992in (76mm), 1 turn
Temperature: approximately 1382°F (750°C)
Power: Pre-curie – 8 kW
Time: 1 minute 20 seconds

Process:

1. Hose and fittings are prepared with borax flux paste in the surface area.


2. Brazing rod is prepared in form of a ring fitting around the diameter of the joint.


3. The hose and the fittings are placed into the coil.


4. Induction heating is applied to the area until the braze is completed.

Results/Benefits:

1. Power supply DW-UHF-10KW induction brazing machine meets the requirements for this process.


2. For better performance for bigger diameter joints, we recommend power supply DW-UHF-10KW  induction brazing heater.A special custom coil can be designed as well.


3. For the tests, static induction was used (see video), but flexible leads and coil or our DW-UHF series are also recommended.

Induction heating provides:

• Strong durable joints


• Selective and precise heat zone, resulting in less part distortion and joint stress


• Less oxidation


• Faster heating cycles


• More consistent results and suitability for large volume production, without the need for batch processing


• Safer than flame brazing

 

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