Discuss how gas welding is different from brazing process. List the applications of gas Welding.

4. A]Discuss how gas welding is different from brazing process. List the applications of gas Welding.

Brazing Process :

1. The melting point of filler and base metal is different. Normally, the filler metal is chosen because it has a lower melting point than the base metal. A low fuming bronze is the common filler metal used for braze welding.
2. According to the American Welding Society, the filler metal to be used must possess a melting point above 425ºC (800ºF).
3. Many times, braze welding is confused with brazing; however, both these techniques differ in many ways. In the brazing process, the filler metal is filled into the tight-fitting joint through capillary action; however, in braze welding, the filler metal is deposited in many ways other than capillary action.
4. In this process, the molten filler material flows into prepared surfaces of higher melting point alloys or metals to form a strong molecular bond. The temperature of the base metal is increased to the point where a filler metal will form a smooth film on the joint surface.
5. Braze welding is mainly used for joining various types of steels. However, it utilizes lower temperatures than fusion welding, and it mainly involves oxy-acetylene process.
6. The intense heat produced by oxy-acetylene flame quickly increases the temperature of the base metal to the point of formation of a film. In this process, the welder can easily control the temperature of the base metal, the flame condition, as well as the melting temperature of the filler rod.

Gas Welding Process :

1. The base and the filler metal (if used) are melted together using a flame produced by the welding torch. Mainly, the tip of the torch is used during this melting process.
2. The molten metals— a base metal and a filler metal are mixed together, and they fuse upon cooling, to form a seamless strong piece.
3. In case the filler metal is not used then the base metal as well as the metal to be fused are melted to a particular temperature.
4. The filler metals are mainly used for metals having thickness above 3/16″.
5. Mainly used for welding different types of steels, the steel surface to be welded is cleaned prior to the process. This is performed to ensure the surface is free from grease, oil, scaling, rusting, or any other impurities, which may affect the quality of the weld.
6. Oxy-acetylene is the fuel recommended for gas welding, which is why this oxy-fuel welding technique is also referred to as acetylene welding.

Application for Gas Welding :

1. For joining most ferrous and non-ferrous metals, carbon steels, alloy steels, cast iron, aluminum and its alloys, nickel, magnesium, copper and its alloys, etc.

2. For joining thin metals.

3. For joining metals in automotive and aircraft industries.

4. For joining metals in sheet metal fabricating plants.

5. For joining materials requires a relatively slow rate of heating and cooling, etc.