MAG Welding of Carbon Steels

Choose the Best Gas for Carbon Steels - Choose Linde

Process gases for GMAW with solid wire electrodes.

A welding gas portfolio that evolves with your needs, from productivity gains to welding fume reductions

The term "carbon steels" collectively refers to various unalloyed and low-alloyed steels, including fine-grained structural steels, mild steels, high-strength steels and coated steels. All of these have carbon as the main alloying element in iron, and do not classify as stainless steels.

If you decide to use gas metal arc welding (GMAW) / metal active gas (MAG) welding with solid fillers on these materials, you will require an oxidizing blend. Inert gases will not be an option as pure argon or argon/helium mixes will not create a stable welding arc. High-quality solid fillers available on the market are typically certified for use in combination with specific oxidizing gases.

Due to their compelling quality and economy advantages, argon-based gas blends with carbon dioxide (CO₂) and/or oxygen (O₂) as the active components are now much more widely used than pure CO₂ for GMAW/MAG welding of carbon steels. But as the technology evolves, the amount of active gas added to argon (Ar) as the base gas is continuously being re-evaluated. The mix ratio plays a decisive role in the welding process itself and the weld result. Below are just some of the variables that influence the choice of welding gas:

Benefits of Varying the CO₂/O₂ ratios in GMAW/MAG Welding Gas Mixes

Gases with a higher CO₂ content

More tolerant parameter window to obtain required penetration, especially in out-of-position welding
Robust arc stability on unclean, oxidized or coated surfaces
Increased heat transfer and input with lower risk of porosity

Gases with a lower CO₂ content

Less spatter, less surface oxidation and silicates, resulting in less post-weld or inter-pass cleaning effort
Suited to modern, electronically controlled and synergic welding equipment, ideal for automation, robots and cobots
Suited to conventional arc transfer processes such as short-circuit and spray modes, but excellent for pulsed mode and new generation of electronically controlled short, spray, multi-pulse or combined arc types
Improved mechanical properties in deposited weld metal, since less of the alloying elements from the filler are burnt off
Reduced welding fume emission rates from the arc
More sustainable production, reducing fugitive emissions of CO₂ as a greenhouse gas

Gases containing O₂

Easier droplet detachment from molten wire, arc perceived as "smooth"
Lower molten pool viscosity, good wetting, appealing surface especially on clean and thin sheet welding

Getting the Composition Right

The general rule of thumb when deciding on the active gas, CO₂ or O₂ content is "as little as possible and as much as necessary".

In high-performance applications where the CO₂ content has been reduced for the reasons mentioned, the addition of helium (He) can compensate for the loss of heat transfer to the component resulting from the lack of CO₂. Replacing 15-35% of Ar with He in GMAW mixes of lower reactivity enables higher welding speeds with the desired wetting and penetration profiles.

With the growing adoption of mechanization, automation and pulse arc techniques, gas blends with a reduced CO₂ or O₂ content are becoming increasingly popular.

Recent studies have contributed to this trend, demonstrating how welding gases with lower CO₂ content can also reduce welding fume emission rates directly at the source - in the GMAW arc. Several OSH institutions reference, in the hierarchy of controls, optimization of welding gas composition as a substitution type measure to complement other existing fume control measures.

As a leading and trusted gas supplier to welding companies, we offer a comprehensive portfolio to support individual needs and success factors. This portfolio spans three different lines so you can fine-tune your GMAW/MAG carbon steel welding operations and achieve your specific goals.

The table below lists the main features and benefits of our three product lines.

	COMPETENCE LINE^TM	PERFORMANCE LINE^TM	PREVENTION LINE^TM
Benefits to you	Enables welding applications to meet industry standards	Higher welding performance, especially with advanced materials and arc processes	Can reduce welding fume emissions at the source - in the GMAW arc
Typical gas blends	Ar with 15 to 25% CO₂ Ar with 8-12% O₂ Ar with CO₂ + O₂ > 15% Pure CO₂	Ar with CO₂ and He Ar with moderate CO₂ + O₂ content	Ar with up to 10% CO₂ Ar with up to 5% O₂ Ar with CO₂ + O₂ <10%
Examples of products available in certain regions	CORGON^® 18 STARGOLD^TM 25 ARGOSHIELD^TM Heavy	CORGON^® 10He30 STARGON^TM VS ARGOSHIELD^TM 100	CORGON^® 8 MIGMIX GOLD^TM ARGOSHIELD^TM Light

As an international company, we comply with local regulations and market requirements. Please contact your local Linde representative to see what gases and blends are available in your area.

More Information on

Supply Modes

Curious to dive deeper?

Talk to one of our experts and see how you can optimize MAG welding of carbon steels with our tailored gas blends

Contact Your Local Representative