There are numerous brazing methods are available. Some of them are Induction Brazing, Furnace Brazing, copper brazing torch, infrared brazing, laser brazing, dip brazing, resistance brazing.
Brazing process steps:
Step 1: Both joints are cleaned (not polished) and fluxed
Step 2: A heat (about 450° C) is applied to the base metal, were the filler metal is melted. Excess heat burn the fluxes. So we have to repeat the process again.
Step 3: Filler metal is applied to the joint
Step 4: Filler metal adheres to both the surfaces forming a bead
Various classifications of Brazing’s are:
Hand Torch brazing:
In torch brazing, flux is applied to the part surfaces and a torch is used to direct a flame against the work in the surrounding area of the joint. A reducing flame is typically used to inhibit oxidation. After the work piece joint areas have been heated to a suitable temperature, filler wire is added to the joint, usually in wire or rod form. Fuels used in torch brazing include acetylene, propane and other gases with air or oxygen.
Furnace brazing uses a furnace to supply heat for brazing and is best suited to medium and high production. In medium production (usually in batches), the components and brazing metal are loaded into furnace, heated to brazing temperature and then cooled and removed.
Induction brazing utilized heat from electrical resistance to a high frequency current induced in the work. The parts are pre-loaded with filler metal and placed in a high frequency AC field. The parts do not directly contact the induction coils. Frequency ranges from 5 kHz to 5 Mhz.
Heat to melt the filler metal in resistance brazing is obtained by resistance to the flow of electrical current through the parts. As distinguished from induction brazing, the parts are directly connected to the electrical circuit in resistance brazing. The equipment is similar to that used in induction welding, except that a lower power level is required for brazing.
In dip brazing, either a molten salt bath or a molten bath accomplishes heating. In both methods, assembled parts are immersed in the baths contained in a heating pot. Solidification occurs when the parts are removed from the bath.
Infrared brazing uses heat from a high intensity infrared lamp. Some IR lamps are capable of generating up to 5000 W of radiant heat energy, which can be directed at the work-piece for brazing.