Metal Inert Gas (MIG) welding is an arc welding process that utilizes a continuous strong wire electrode heated and fed into the weld pool from a welding gun. The two base materials are softened together forming a join. The gun takes care of a shielding gas close by the electrode shielding the weld pool from airborne contaminants.
The basic role of shielding gas is to prevent exposure of the molten weld pool to oxygen, nitrogen, and hydrogen containing all-around atmosphere. The reaction of these components with the weld pool can create many problems, including porosity, and extreme splatter.
The most common of the reactive gases utilized in MIG welding is Carbon Dioxide (CO2). It is the one in particular that can be utilized in its unadulterated structure without the addition of inert gas. CO2 is additionally the most economical, considering when material costs are the primary need. Unadulterated CO2 gives deep weld infiltration, which is valuable for welding thick material. Moreover, it additionally creates a less stable arc and more spatter than when it is blended in with different gases. It is likewise restricted to just the short circuit process.
These are some of the advantages of MIG Welding using CO2
1. Performance
CO2 gas is inert in nature . In welding’s heat, CO2 gets reactive, which in turn results in a lot of advantages including better joint penetration which helps smaller machines handle thicker metal. It has a more aggressive cleaning action that cuts through mill scale and rust. It is also capable of higher welding speeds.
As compared to other gases, CO2 is 4.5 times less costly to weld with than a straight C25. The low cost of operation is the main reason for MIG welding with pure CO2.
2. Lowered Costs
| CO2 | C25 | |
| Initial Cost | Rs. 11,000 | Rs. 25,000 |
| Initial Cost/Hour | Rs. 1200 | Rs.5000 |
| Refill Cost | Rs. 2600 | Rs. 5,600 |
| Refill Cost/ Hour | Rs. 298 | Rs. 1400 |
The other most common shielding gases used in MIG welding other than carbon dioxide are nitrogen, propane, hydrogen, and helium. Helium utilized on non-ferrous metals, helium can likewise be utilized on stainless steels. It functions admirably with thick metals because of its wide and profound penetration capacities. A reactive gas, oxygen is typically utilized in modest quantities when added to shielding gases, as a rule between 1-9%. This improves weld pool fluidity, just as arc stability and penetration in stainless steel, mild carbon, and low alloy metals. Hydrogen fills in as a shielding gas in high-temperature applications, for example, for stainless steels. It is frequently blended in with argon for use on austenitic stainless steel. Nitrogen is utilized as a purging gas for welding stainless steel tubes. Added to argon in modest quantities, it can likewise be utilized as a shielding gas for stainless steels. Propane is typically utilized in piece yards for cutting carbon steel where cut quality isn’t important. On the off chance that your application doesn’t require high cut quality, propane is a fairly cost-effective option.
3. More Refilling Options
Convenience is a major in addition while considering the refilling options. It can generally be refilled at a local welding supplier or at fire extinguisher service companies, aquarium suppliers, sporting goods stores that sell paintball equipment and local home brew shops
Conclusion:
MIG welding is versatile and can be used with a wide variety of metals and alloys. Since a flux is not used, there is no chance for the entrapment of slag in the weld metal resulting in high quality welds. The MIG process can be operated several ways, including semi and fully automatic. High quality welds can be produced much faster