A good flux should have following desirable properties:
1. It should have low melting temperature than the base metal.
2. It should easily and readily react with metallic oxides and form a low melting temperature fusible slag to float on the top of the weld.
3. It should be easily chipped-off after solidification.
4. It should also act as better cleaning agent.
5. It should not adversely affect the base metal.
6. It should not chemically react with the base metal.
7. It must not cause corrosion on the finished weld.
Applications of Gas Welding:
Oxy-acetylene gas welding is widely used in practical field.
Some important applications are:
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 those requires relatively slow rate of heating and cooling, etc.
Advantages of Gas Welding:
The following are the advantages of gas welding:
1. Portable and Most Versatile Process:Gas welding is probably portable and most versatile process. The ranges of gas welding products are very wide. It can be applied to variety of manufacturing, maintenance and repair work.
2. Better Control over the Temperature:Gas welding provides better control over the temperature of the metal in the weld zone by controlling the gas flame.
3. Better Control over Filler-Metal Deposition Rate:In gas welding, the source of heat and filler metal are separate unlike arc welding. This provides better control over filler-metal deposition rate.
4. Suitable to Weld Dissimilar Metals:The gas welding can be suitable to weld the dissimilar metals with suitable filler and flux material.
5. Low Cost and Maintenance:The cost and maintenance of the gas welding equipment’s is low as compared to some other welding processes. The equipment is versatile, self-sufficient and portable.
Disadvantages of Gas Welding:
1. Not Suitable for Heavy Sections:Since the heat produced is not sufficient and hence heavy sections cannot be joined economically.
2. Less Working Temperature of Gas Flame:The flame temperature is less than the temperature of the arc.
3. Slow Rate of Heating:The rate of heating and cooling is relatively slow. In some cases this is advantageous.
4. Not Suitable for Refractory and Reactive Metals:Refractory metals like tungsten, molybdenum and reactive metals like titanium and zirconium cannot be welded by gas welding process.
5. Larger Heat affected Area:Gas welding results in a larger heat affected area due to prolonged heating of joint.
6. Flux Shielding is not so Effective:Flux-shielding in gas welding is not as effective as in case of TIG or MIG welding. The oxidation cannot be avoided completely.
7. Problem in Storage and Handling of Gases:More safety problems are associated with the storage and handling of explosive gases e.g., acetylene and oxygen.
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