New welders may hear or see the term gas metal arc welding, commonly abbreviated as GMAW, used within the welding community. In this blog post, we’ll uncover the intricacies of GMAW’s true meaning to help both inexperienced and experienced welders sharpen their welding knowledge and vocabulary.

Are GMAW and MIG Welding the Same Thing?

In welding, the terms GMAW and metal inert gas (MIG) are often used interchangeably, but they don’t necessarily mean the same thing. GMAW, or gas metal arc welding, is an umbrella term that covers both metal active gas (MAG) welding and metal inert gas (MIG) welding.

MIG and MAG welding are both welding methods that use an electrical arc as their heat source, a consumable wire as their electrode, and a shielding gas to protect the weld. As suggested by their names, the key difference between the two is the type of gas they use: inert or active.

MIG welding uses inert gases, including argon and helium, while MAG welding uses active gases, such as hydrogen, nitrogen, oxygen, and carbon dioxide. In MIG, the gas simply shields the weld from external contamination, but in MAG, the gas plays an active role in the chemical reaction and fusion that occurs in the weld pool.

Therefore, MIG welding is a subset of GMAW. However, in the welding community, it is very common for the two terms to be used interchangeably.

What is GMAW Welding Used For?

GMAW is popular for many welders due to its adaptability, ease of use, and the high-quality welds it can produce. It is used in various industries, including automotive, construction, and manufacturing, for everything from fabricating car frames to fixing farm equipment. Its versatility in handling various materials and thicknesses can make it a good choice for both industrial applications and personal projects.

GMAW vs. Other Welding Techniques

Let’s compare GMAW with other popular welding techniques. Understanding the differences can help you choose the right tools for the job.

GMAW vs. FCAW Welding

Flux-cored arc welding (FCAW) is similar to GMAW, but it uses a special tubular wire filled with flux. Flux is a mixture of alloying materials, minerals, and chemicals that when melted, can be designed to add to the chemistry of the weld and/or to produce a gas to protect the molten weld puddle. FCAW with a gasless flux cored wire can be used with great benefit when welding outdoors where environmental conditions, such as wind, might disperse the shielding gas used in GMAW and negatively affect the resulting weld’s integrity. In other cases, FCAW using wires intended to be used a shielding gas may be selected based on the required production speed and throughput, transfer mode, or specific weld profile of a given project.

GMAW vs. SMAW Welding

Shielded metal arc welding (SMAW), or stick welding[KS1] , is another common technique. Unlike GMAW, SMAW doesn’t use a shielding gas. Instead, the flux that coats the electrode provides a gas shield around the weld as it is heated.

SMAW is more easily used in outdoor conditions as well as hard-to-reach welding areas, as it requires less bulky equipment and the welding cables can be extended long distances. However, GMAW can provide higher production speeds on well-prepped materials and is generally considered easier to use, contributing to its popularity.

Breaking Down the GMAW Setup

Understanding the equipment and how to set it up can give you a clearer picture of how each piece works together to produce strong, durable welds.

The Equipment

The GMAW setup typically begins with a MIG welder, which is a combined welding power source and wire feeder. For industrial production rates and thicker materials, the optimal choice may be a separate industrial GMAW power source and wire feeder.

The setup will also include:

• • A welding gun
• • A spool of welding wire
• • A cylinder of welding gas
• • A regulator/flowmeter to control the welding gas flow
• • A hose to deliver the gas from the cylinder to the machine
• • A ground cable and clamp
• • Interconnect cables connecting the power source and wire feeder (if separate).

The Role of Shielding Gas

Shielding gas is vital in GMAW. It helps protect the weld and weld area from atmospheric gases like nitrogen and oxygen that can cause defects in the weld. GMAW commonly uses gases such as argon, carbon dioxide, helium, or a mixture of these. Additional components like hydrogen or nitrogen may also be included, depending on the material being welded, desired weld qualities, and the intended use of the welded piece.

The Welding Wire

The consumable welding wire electrode is fed through the welding gun at a controlled speed, acting as both the filler material and the conductor for the electric arc. The type and thickness of material being welded will determine the grade, composition, and diameter of the wire to be used.

The Advantages of GMAW

Numerous factors contribute to GMAW’s popularity with new and experienced welders alike. Here’s a quick rundown of its key benefits:

• • Versatility: It’s suitable for a wide range of metals and thicknesses.
• • Efficiency: The continuous wire feed means longer welds can be made with fewer stops and starts, saving time and protecting the overall quality of the weld.
• • Ease of Use: GMAW is relatively easy to learn and perform, making it popular with beginners.

   

Common Applications of GMAW

To give you a sense of GMAW’s flexibility, here are some common applications:

• • Automotive Manufacturing and Repairs: GMAW is a staple in the auto industry and is also used in auto repair shops for framework, bodywork, and exhaust systems.
• • Construction: GMAW is used to construct high load-bearing bridges, power plants, refineries, food service machinery, buildings, and other vital infrastructure.
• • Manufacturing: GMAW is used to create all kinds of welded products, from those seen in consumer goods to those used in heavy machinery.

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NOTE
This information is offered as a general overview and is not a substitute for the education, training, and skill required to use a welding torch or other welding equipment safely and effectively.