Introduction:
There has always been a debate about MIG and MAG welding. Some argue that the difference is mainly a matter of terminology—MIG being the preferred term in the U.S. and MAG more commonly used in the UK, much like the differences between British and American English. From this perspective, MIG and MAG are essentially the same process, with only their names setting them apart.
Others, however, point to a more technical distinction: the type of shielding gas used. In this view, the "I" in MIG stands for inert gases, while the "A" in MAG refers to active gases, each influencing the welding process differently.
So, is the difference just a matter of naming, or does it extend beyond terminology? Let’s break it down.
GMAW's Work Process and the Role of Shielding Gas
Let's take an example: In GMAW, shielding gas protects the weld pool from contamination and oxidation, ensuring a cleaner and more stable weld. In contrast, SMAW does not use shielding gas, leading to the formation of slag—a solid layer that forms as the gas cloud settles on the molten metal. While slag provides some protection, it must be removed after welding, and if not properly handled, it can weaken the weld by trapping impurities.
MIG and MAG are both subtypes of GMAW, distinguished primarily by the type of shielding gas used. MIG welding employs inert gases like argon (Ar) and helium (He), which do not chemically interact with the weld pool, resulting in cleaner and more stable welds. In contrast, MAG welding utilizes active gases such as carbon dioxide (CO₂) and oxygen (O₂), which influence arc behavior, penetration depth, and metallurgical properties of the weld. This fundamental difference affects their application, weld quality, and suitability for different materials.
Key Differences Between MIG and MAG
| Feature | MIG Welding | MAG Welding |
|---|---|---|
| Shielding Gas | Inert gases (Ar, He) | Active gases (CO₂, Ar+CO₂, or Ar with O₂<5%) |
| Suitable Materials | aluminum, copper, magnesium and titanium. | unalloyed, low-alloy and high-alloy materials |
| Weld Quality | Clean, minimal oxidation | Stronger penetration, but more spatter |
Does Shielding Gas Influence Welding Equipment Selection?
MIG and MAG welding equipment is nearly identical, with minor differences. Both use MIG welding machines that regulate voltage, wire speed, and shielding gas flow to maintain a stable arc. Most components, including welding torches, gas regulators, hoses, and consumables, are interchangeable, with shielding gas being the primary distinction. Multi-process welders often include MIG as an option, covering both MIG and MAG welding.
The Bernard Q400 MIG Gun, manufactured by Vanes Electric, is designed for high-performance welding applications. It is rated at 400A with CO₂ and 350A with mixed gases, offering a 60% duty cycle (6 minutes out of 10) for reliable, continuous welding. As part of MIG consumables, the variable contact tips T-0XX Series support wire sizes ranging from .023" to 1/8", providing compatibility with different welding needs and ensuring reliable performance. Check our Bernard MIG gun parts page to choose the right accessories for your application.
FAQs
Q: Can I use a MIG gun without shielding gas?
A: Yes, you can, but you need to use flux-cored wire instead of solid wire（FCAW-S). Flux-cored wire generates its own shielding gas, protecting the weld pool from contamination. Ensure you select the right flux-cored wire for your application and adjust the machine settings accordingly.
Final Thoughts
MIG and MAG differ in shielding gas composition, not just terminology. MIG uses inert gases like argon and helium, making it suitable for non-ferrous metals. MAG, on the other hand, relies on active gases like CO₂ or O₂ mixtures, commonly used for ferrous materials. Despite these distinctions, the industry often refers to all GMAW welders as MIG welders, causing confusion. Recognizing these differences helps ensure the correct welding process is used for each material.
