Soldering is the process of joining two or more metals by melting a filler metal (solder alloy) into the joint, the filler metal having a lower melting point than the work piece. Soldering differs from welding in that soldering does not involve melting the work pieces.
There are two forms of soldering, Include :
1. Brazing which uses a non-iron metal (Non - ferrous metal)for the filler and the melting temperature of the filler alloy more than 450 °C
2. Soft soldering, which originally used a tin-lead alloy as the filler metal,