GMAW / MIG Welding of Aluminum Alloys
Evolving Portfolio of Welding Gases to Support Growing Adoption of Aluminum Alloys
Meeting Today's Decarbonization Challenges
After steel, aluminum alloys are the second most popular structural metal. Demand for this metal is driven by its unique combination of properties, which have the potential to meet modern industrial challenges like fuel-efficient transportation, transitioning to more renewable forms of energy, decarbonization and materials circularity. With a density just one third that of carbon steel, these alloys offer better corrosion resistance, higher electrical and heat conductivity and excellent recyclability. Given these attributes, it is no surprise that aluminum has become the metal of choice in many growth areas.
The rising use of aluminum has seen a diversification in the choice of joining technologies with non-thermal, mechanical, friction, adhesive, and beam welding now also in the mix. Consequently, arc-based welding, especially gas metal arc welding (GMAW) or metal inert gas (MIG) welding, is under constant pressure to evolve. Conventional arc types like short-circuit or spray transfer modes have shifted increasingly to pulsed arcs, driven by modern synergic welding equipment. In addition, the last two decades have seen industry welcome a series of electronically controlled new welding arc types, adapted to both the specific welding challenges of aluminum and to the requirements of specific industries – spanning everything from automotive to aerospace, from rail to shipping, and from photovoltaics to battery frames. More recent GMAW arc control types include tandem, pulsed wires, alternative current, reduced energy short circuit, mixed short-pulsed modes, and double pulsed mode.
Getting the Welding Gas Right
Given the high chemical reactivity of aluminum and its alloying elements with oxygen, inert argon is the welding gas predominantly used for GMAW / MIG welding.
The inert gas helium is sometimes used to partially substitute argon as it is effective in overcoming aluminum’s challenging physical properties. With its superior thermal conductivity and specific heat, helium additions to argon transfer heat more effectively to the molten pool and the components to be welded. This translates into quality benefits like sound penetration and reduced porosity, combined with productivity gains at higher welding speeds.
In addition, active gas dopants can be extremely useful. For over three decades, we have been pioneering research and development work on welding gases with active gas dopants for improved arc stabilization. GMAW or MIG arc stability in aluminum welding is dependent on the surface condition of the components. Factors that can disturb a MIG arc when using pure argon include oxide layers with different thicknesses and moisture content, surface residue or contamination from pre-processing, joining of different alloys, different material thicknesses, and the joining of wrought with cast aluminum. The consequences can be immediate weld defects or unacceptable failure rates in automated mass production. This is where small additions of active gases like oxygen can help – by stabilizing the arc despite unfavorable welding conditions. As dopants are added in volumes of maximum 0.05% (500 ppm), the inert character of the process is usually maintained without negatively impacting the weld metallurgy.
The table below lists the main properties of aluminum alloys, their welding challenges and the benefits of our GMAW / MIG welding gases.
| Specific properties of aluminum alloys | GMAW / MIG welding challenges | How our welding gases can help | Your potential benefits | |||
| High thermal conductivity |
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| Susceptibility to hydrogen and solubility jump |
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| Naturally forming, variable, oxide layer on the surface |
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| Variety of physical properties associated with various wrought or cast alloys, delivery forms and surfaces |
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Customized Blends on Demand
Based on arc physics and the latest findings from material science research, we have developed a comprehensive portfolio of gases for GMAW / MIG welding with aluminum. This portfolio includes regional variations to support local customer preferences. While most requested gas blends are available in cylinders and bundles, large industrial customers can benefit from a new generation of digital mixers and analyzers enabling them to produce customized blends directly on site.
Comprehensive Offering
As a leading and trusted gas supplier to welding companies, we offer a broad portfolio to support individual needs and welding conditions. This portfolio spans two different lines so you can fine-tune your GMAW / MAG welding of aluminum alloys and achieve your specific goals.
The table below lists the main features and benefits of our two product lines for GMAW / MIG welding of aluminum alloys.
| COMPETENCE LINETM | PERFORMANCE LINETM | |||
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| Typical gas blends |
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| Examples of product available in certain regions |
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The images below illustrate the benefits of stabilizing the MIG arc with an active dopant such as 500 ppm O2 in Ar. These include reduced risk of weld defects plus lower failure and scrap rates when welding under different surface conditions.
The image on the left shows arc disturbance with standard Ar, whereas the one on the right demonstrates the outcome with doped gas blends from our PERFORMANCE LINETM.
The pictures below illustrate how the MIG pulsed welding arc can be directionally stabilized to avoid burn-through on thinner components and thus overcome failure risks when welding "thick-to-thin".
The left image shows arc deflection to the "hotter" component with standard Ar, whereas the right image demonstrates the result when using Ar + He + an active dopant such as O2.
Additions of helium (He) and/or active dopants to argon can require small adjustments to the welding voltage to compensate for slight changes to the physical arc discharge conditions and to create the optimum arc length for the job. If you want to explore the advantages of our PERFORMANCE LINETM gases for your aluminum GMAW / MIG welding job , please contact a Linde expert.
A Selection of Names
Our welding gases portfolio is marked under different local brands worldwide, including: ALUGON®, ALUSHIELD®, ARGOSHIELD®, CORGON®, CRONIGON®, FORMIER®, MIGMIX GOLDTM, PURESHIELD®, SPECSHIELD®, STAINSHIELD®, STARGOLDTM, STARGONTM and VARIGON®. As an international company, our products comply with local regulations and market requirements. Contact your local Linde representative to check availability in your region.