As the name implies, the heat to melt and flow the braze filler metal in this process is provided by the flame of a torch. Because torch brazing is done in air, flux is used to protect the braze surfaces from oxidation and to assist with the braze filler metal flow. The braze filler metal is either pre-placed or fed into the joint by Thermal-Vac's skilled operators after uniformly heating both surfaces being joined to braze temperature. After brazing, the assemblies are cleaned to remove scale and flux residue.
Most metals can be torched braze, with the exception of a few such as titanium and zirconium. If a stainless steel assembly is to be torch brazed, alloys such as 304L, 316L, 321, and 347 should be used.
Silver braze alloys (BAg) are the primary filler metals used by Thermal-Vac. The silver filler metals can be used, with an appropriate flux, for torch brazing most ferrous and non-ferrous metals. Copper-phosphorous alloys (BCuP) are used for appropriate copper to copper assemblies. This family of filler metals is self-fluxing on pure copper alloys. However, appropriate flux is required on all other metals.
Industry standards for hydrogen brazing include:
- Mil-B-007883C, Type II
- AWS C3.4: 1999
