Furnace brazing is extensively used when the parts to be brazed can be assembled with brazing filler metal preplaced near the joint. The preplaced filler metal may be in the form of wire, foil, paste or ring. When the brazing is carried out in reducing atmosphere like N2/H2 or dissociated ammonia, separate fluxes are not required in the joint or with filler metal.
Short times at brazing temperature, uniform heating and cooling are essential for high quality brazing.
For materials like stainless steel, high atmosphere purity is an additional requirement. Continuous brazing furnaces are a preferred choice for bulk production with consistent quality.
Commonly used brazing methods are
Brazing has three distinct characteristics.
Joining or uniting of an assembly of two or more parts into one structure; is achieved by heating the assembly or region of the part to the joined to a temperature of 450 °C (842 °F) or above
Assembled parts and brazing filler metal are heated to a temperature high enough to melt the filler metal and not the parts.
The molten filler material seeps into the joint by capillary action, wets the bare metal surfaces, solidifies on cooling and thus creates a bond between the two surfaces.
The LGC furnace reduces considerable gas consumption for large parts which require high head room clearance. Atmosphere lock doors at the entry and exit of this type of mesh belt furnace ensure high atmosphere purity while at the same time reducing gas consumption considerably.