MIG (GMAW) welding with shielding gas and a solid wire electrode produces a clean, slag-free weld without the need to continually stop welding to replace the electrode, as in Stick welding. Increased productivity and reduced clean up are just two of the benefits possible with this process.
Shielding gas can play a significant role in improving, or impeding welding performance.
To achieve these results in your specific application, however, it helps to understand the role of shielding gas, the different shielding gases available and their unique properties.
The primary purpose of shielding gas is to prevent exposure of the molten weld pool to oxygen, nitrogen and hydrogen contained in the air atmosphere. The reaction of these elements with the weld pool can create a variety of problems, including porosity (holes within the weld bead) and excessive spatter.
Different shielding gases also play an important role in determining weld penetration profiles, arc stability, mechanical properties of the finished weld, the transfer process you use and more.
Choosing MIG gun consumables that provide consistent and smooth shielding gas delivery are also important to making successful MIG welds.