Soldering and brazing are the processes of joining metal pieces, making use of heat, and a filler metal whose melting point is lower than the melting points of metals to be joined. In soldering, the melting point of solder (or filler metal) is usually less than 427°C, whereas in brazing and braze welding, the melting point of filler metal is higher than 350°C. In soldering and brazing, there is no direct melting of the base metal of workpieces being joined, rather the solder or filler metal flows between the surfaces to be joined through the capillary action. The most common use of soldering and brazing is in joining two dissimilar metals. Differences between soldering and brazing are given in the following:
(a) The melting point of solder or filler metal used in soldering is lower than 427°C, whereas in brazing, the melting point of filler metal is higher than 427°C.