Besides using mechanical means, brazing ranks are one of the very oldest methods used to join metals. It was extremely widespread when metalworkers sought to join gold and silver with base metals. For filler, the metalworkers employed metals with low melting points. These included lead and tin as well as copper alloys. Later the addition of various gums and salts helped to improve the process and, in the 1970s, furnace brazing became the more common method for commercial concerns.
Furnace brazing is performed using different types of furnaces. Among the more common kinds are a vacuum and continuous/mesh belt. This semi-automated process occurs in a vacuum furnace or partial vacuum – both environments allow the operators control over the gas. The parts, after a thorough cleaning, are heated to the specified temperature. This is the point at which the dissimilar (to the parts) filler metal flows. Cooling or quenching the brazements occurs next within a separate compartment or zone in the furnace. This produces the specified metal properties and joins the two metal components. It is possible to use this process for both simple and complex designs. It is successful in uniting singular or multi-joint assemblies
Base Metals for Furnace Brazing
When looking at the options, always look at metals more suitable for the technique. Certain ones are more amenable to the process including:
Aluminum and aluminum alloys
Cobalt and cobalt alloys
Copper and copper alloys
Magnesium and magnesium alloys
Nickel and nickel alloys
Niobium, molybdenum, tantalum, tungsten, and their alloys
Steel: Alloy, Low-carbon mild, high-carbon, tool and stainless
Titanium, zirconium, and beryllium, and their alloys
Consider not only the suitability of the metal for the project but also how difficult it will be to use the process of furnace brazing with the metal before making a final decision.