The brazing process uses a filler metal to join two metals with a higher melting point. The brazing metal always has a melting point higher than 840 degrees Fahrenheit but lower than the melting point of the metals being joined. Brazing services have a number of advantages over other joining operations, although brazing is not without its own set of concerns.
First, brazing works for practically all metals. You only need a metal with a lower melting point than the metals being joined. Copper, for instance, is a common joining metal—both as an alloy and in pure form. Unalloyed copper is used to braze steel and tungsten carbide. Copper-zinc, which has a lower melting point than copper, is used to braze both iron and copper. It is also widely used in steel brazing. Silver alloys called silver solders are used for a wide range of ferrous and non-ferrous metals, including stainless steel, brass and nickel.
Brazing is exceptionally useful when joining metals with different melting points. The main prerequisite is simply that the filler metal has a lower melting point than the metals being linked. Because brazing forms such a strong, sealed joint, it is uniquely suited to operations of this kind. Clean, oxide-free surfaces help ensure stronger bonds when joining metals. Occasionally, certain metals will be plated to enhance their wettability, which is an important function of the surface tensions between the metals involved in the process.
In addition to its metallurgical advantages, brazing services also have various practical benefits. Brazing is very cost-efficient due to the lower temperatures needed to melt the filler metal. It also has proven effective in automated production operations, even for the manufacture of complicated products. The process also provides the best option in many situations.
As mentioned, brazing also suffers a few disadvantages. Most brazements are only about one-third the strength of the materials being joined. Also, brazed components may be difficult to repair, because brazed joints will weaken if the joined metals are heated. Lastly, brazements are often more susceptible to corrosion due to their composition. Still, brazing services are a great choice for many joining operations.
