DIFFERENCE BETWEEN WELDING, BRAZING AND SOLDERING

WELDING

1.      It is the process of joining of two or more pieces of metals by applying heat or pressure, or both, with or without filler metal to produce a localized union through fusion or recrystallization across the interface.

2.      Temperature required for welding is upto  3800 °C.

3.      Metals to be joined need to be heated till their melting point.

4.      Mechanical properties of base metal may change at the joint due to heating and cooling.

5.      Welding joints are the strongest joints.

BRAZING

1.      Brazing is a process that joins two pieces of base metal when a melted metallic filler flows across the joint and cools to form a solid bond. The melting point for filler metal should be more then  450°C but lower then base metal.

2.      Temperature may go to 600 °C in brazing.

3.      Metals are heated but below their melting point.

4.      Mechanical properties of base metal may change at the joint due to heating but it is almost negligible.

5.      These joints are stronger then soldering but weaker then welding.

SOLDERING

1.      Soldering is very much similar to brazing and its principle is same as that of brazing. The major difference lies with the filler metal, the filler metal used in case of soldering should have the melting temperature lower than 450 °C.

2.      Temperature requirement is upto 450 °C.

3.      No need to heat base metals.

4.      No change in mechanical properties of base metals after joining.

5.      These are the weakest joints out of three.