Comparison of Soldering, Brazing and Welding

The three processes soldering, brazing and welding have similarity that these are bonding processes. All the three uses filler metal, flux and application of heat. These processes also are dissimilar regarding the cost involved, performance, application area, etc. This comparison is tabulated below.

Comparison between Welding, Soldering and Brazing

Sl. No. Welding Soldering Brazing
1. These are the strongest joints used to bear the load.

Strength of a welded joint may be more than the strength of base metal.

These are weakest joint out of three. Not meant to bear the load. Use to make electrical contacts generally. These are stronger than soldering but weaker than welding. These can be used to bear the load upto some extent.
2. Temperature required is upto 3800oC of welding zone. Temperature requirement is upto 450oC. It may go to 600oC in brazing.
3. Workpiece to be joined need to be heated till their melting point. No need to heat the workpieces. Workpieces are heated but below their melting point.
4. Mechanical properties of base metal may change at the joint due to heating and cooling. No change in mechanical properties after joining. May change in mechanical properties of joint but it is almost negligible.
5. Heat cost is involved and high skill level is required. Cost involved and skill requirements are very low. Cost involved and sill required are in between others two.
6. Heat treatment is generally required to eliminate undesirable effects of welding. No heat treatment is required. No heat treatment is required after brazing.
7. No preheating of workpiece is required before welding as it is carried out at high temperature. Preheating of workpieces before soldering is good for making good quality joint. Preheating is desirable to make strong joint as brazing is carried out at relatively low temperature.

Soldering and brazing are the two allied processes of welding. The major difference between them is huge amount of heat is required in case of welding, low amount of heat is needed in case of brazing and very low amount of heat is consumed in case of soldering. Welding gives the high strength joints which are capable to hear the heavy load. Joints made by brazing are relatively weak and soldering joints are very weak to bear the load. Generally, soldering is used to make electrical contacts. Different methods of brazing are described in this unit. There are no different varieties of soldering method. Only the soldering material called speltor has its different varieties according to application. Different soldering and brazing defects and methods of their removal are  also described in this unit.

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