Understanding the fundamentals of MIG/MAG welding is essential whether you are a professional or a beginner welder. Among the various welding techniques, MIG welding stands out for its versatility, ease of use, and efficiency. Explore in this article how it works, its advantages, and applications.
What is MIG/MAG welding?
MIG/MAG welding is the short for Metal Inert Gas/Metal Active Gas welding, also known as GMAW (Gas Metal Arc Welding). This welding process is a type of arc welding that uses a continuous wire electrode and a shielding gas to protect the weld pool from contamination.
Metal Inert Gas welding was first patented in the USA in 1949 specifically for welding aluminum. The process utilized a bare wire electrode, with the arc and weld pool being protected by helium gas, which was readily available at that time. By around 1952, the technique gained popularity in the UK for welding aluminum using argon as the shielding gas, and for welding carbon steels using carbon dioxide (CO2).
MIG welding typically uses an inert gas like argon, making it suitable for non-ferrous metals like aluminum. MAG welding, on the other hand, uses active gases like carbon dioxide or a mix of carbon dioxide and argon, making it ideal for ferrous metals such as steel. Compared to Manual Metal Arc (MMA) welding, MIG/MAG welding offers high deposition rates and increased productivity, making it an attractive alternative.
ASPECT |
MIG |
MAG |
Shielding Gas Type |
Inert |
Active |
Shielding Gases |
Argon & Helium |
Carbon Dioxide & Oxygen |
Expenses |
Higher costs |
Lower costs |
Gas reaction with base material |
Non-reactive |
Reactive |
Usage |
Non-ferrous metals, thin materials |
Ferrous metals, thick materials |
Reliability and Penetration |
Good |
Excellent |
Key components of MIG/MAG welding
GMAW welding involves feeding a wire from a spool through a welding torch, which is melted by an electric arc and deposited to form a weld. Proper setup and maintenance of these components are essential for successful welding operations.
The main equipment components are:
➤ Power Source: This provides the necessary electrical current to create the welding arc. It typically includes a control panel to adjust the voltage and amperage.
➤ Welding Torch: This is the tool held by the welder, also known as the welding gun. It directs the wire electrode, shielding gas, and electrical current to the weld joint. The gun typically has a trigger to start and stop the welding process.
➤ Wire Feed System: This mechanism continuously feeds the wire electrode from a spool to the welding torch. It controls the speed at which the wire is fed, which is crucial for maintaining a consistent weld.
➤ Wire Electrode: A consumable wire that serves as both the electrode and the filler material for the weld. It is available in various materials and diameters depending on the welding application.
➤ Shielding Gas Supply: This system supplies the gas that protects the weld pool from atmospheric contamination. Common gases used include argon, helium, carbon dioxide, or mixtures of these gases. The type of gas used depends on the material being welded.
Applications in the industry
➤ Due to its versatility and efficiency, MIG/MAG welding is applied in a variety of industries, such as:
➤ Automotive manufacturing and repair.
➤ Construction and structural steel fabrication.
➤ Manufacturing and assembling products ranging from household appliances to heavy machinery.
➤ Shipbuilding and offshore structures.
Advantages of GMAW welding
MIG/MAG welding benefits |
|
USAGE |
The continuous wire feed and the use of a shielding gas make MIG/MAG welding relatively straightforward, even for beginners. |
SPEED |
The continuous nature of the wire feed allows for faster welding speeds compared to other welding methods. |
VERSATILITY |
MIG/MAG welding can be used on a wide range of metals, including steel, stainless steel, and aluminum. |
QUALITY |
The shielding gas protects the weld from contamination, resulting in cleaner, higher-quality welds. |
EFFICIENCY |
The process allows for longer welds without stopping, increasing productivity. |
Disadvantages of GMAW welding
MIG/MAG welding detriments |
|
COST |
MIG/MAG welding equipment can be expensive, especially for high-quality, industrial-grade machines. This includes the welding machine, wire feeder, shielding gas supply, and related accessories. For small businesses the initial investment might be a significant barrier. |
SETUP |
This welding process is less effective outdoors or in windy conditions because the shielding gas can be easily blown away, leading to weld contamination. This makes it challenging to maintain weld quality without additional protective measures or enclosures to shield the weld area from the wind. |
RESULT |
The surfaces to be welded need to be clean and free from contaminants like rust, oil, and paint. Any impurities on the welding surfaces can lead to poor weld quality, defects, and weak joints. Preparation and cleaning of materials before welding are needed, which can be time-consuming and labor-intensive. |
