Soldering is a joining process used to join different metals by melting solder. Solder is a metal alloy that is usually made up of tin and lead which is melted using a hot iron. The iron is heated to temperature above 600F, which then cools to create a strong electrical bond. Solder is sold in spool of wire or in bars. Solder wire is comprised of different alloys or pure tin. Each metal requires a certain type of soldering wire to create a strong bond because the combinations of metals that comprise soldering wire melt at different temperatures.
Soft soldering wire that contains lead is comprised of combinations of tin, lead, silver, cadmium and copper. Combinations of lead and tin are the most common. These solders melt in the range from 361 to 421 degree.
With the higher percentage of lead, the higher is the melting point. All types of soldering wires are manufactured in India by Rathoure Metal and Smelting.