Shielding Gases
The Right Welding Gas - Working for You
What Are Shielding Gases?
The term welding shielding gases refers to single gases and gas mixtures used in welding to protect the weld area against atmospheric contamination. They are commonly used in processes such as gas metal arc welding (GMAW), i.e. metal inert gas (MIG) and metal active gas (MAG) welding, in tungsten inert gas (TIG) welding and in flux-cored arc welding (FCAW). With these welding processes, an electric arc is used to generate the heat needed to melt and fuse the parent material, while the shielding gas protects the molten weld pool, primary material and filler wire from the oxygen, nitrogen and humidity present in air.
Shielding gases are sometimes referred to as process gases or welding gases. Welding gases is a broader category, however. It can include shielding gases but also refers to gases used for other purposes, such as gases used to generate the heat needed to melt or cut metal, to purge welds or perform other specific welding tasks.
How Can I Benefit from Shielding Gases?
The benefits of shielding gases extend far beyond just protecting the weldment against atmospheric contamination. The right shielding gas or mixture also potentially offers:
- Metallurgical benefits such as improved corrosion resistance
- Mechanical improvements such as stronger weld metals and greater weld integrity
- Cosmetic benefits through an enhanced weld appearance and an optimized weld bead shape
- Less rework effort thanks to reduced risk of porosity, insufficient penetration and fusion defects
- Speed gains through faster deposition rates and less spatter
- Financial savings due to lower weld costs and improved welder productivity
As one of the leading suppliers of industrial gases, we have a long-standing commitment to the welding industry. Our global team of application engineers has expertise in all shielding gas processes and can advise you on the gas or mixture best suited to your individual welding task. In addition, we offer extensive safety, training and maintenance support to keep your operations running smoothly.
Our shielding gases are marked under different trademarks around the world. Visit your local site to find out what welding gases are available in your region.
How do I Select The Right Shielding Gas from Linde?
Choosing the right shielding gas is important for your business, marking the transformation from cost factor to profitability enabler. The choice will depend on the most important outcomes you want from your shielding gas, depending on whether you wish to prioritize welding speed, defect rate, mechanical/metallurgical properties, weld appearance or a combination of these factors.
To guide the process, ask yourself questions such as:
- How important is my weld appearance?
- Is spatter near the weld area a concern?
- Is deep penetration required or should penetration be limited to minimize burn-through of the joint?
- Is welding fume a concern and should fume be reduced?
- How thick is my base material and is it clean or oily/scaled?
- What position will I weld in as this can impact my choice of process/metal transfer?
- Is welding speed a key criterion?
- What level of welder proficiency is required?
Our experts can help you select the shielding gas blend that best meets your requirements without having to compromise speed for quality. Supporting GMAW, TIG and FCAW processes, our comprehensive portfolio of welding and cutting solutions spans:
- Shielding gases for carbon and low-alloy steels
- Shielding gases for stainless steel
- Shielding gases for non-ferrous materials
What Shielding Gas Blends Are Commonly Used for Welding?
The blend best suited to your welding task depends on a number of factors including the primary material, filler wire, welding process and welding procedure specification (WPS). In general, however, the process gas mixtures listed below are recommended for the following welding method / metal combinations.
Argon/helium mixtures are generally suited to the MIG welding of aluminum alloys and TIG welding of all materials. Various argon/carbon dioxide/oxygen mixtures have been developed for the MIG welding of carbon and alloy steels. A range of helium/argon/carbon dioxide mixtures are adapted to the MIG welding of stainless steel and some nickel alloys. Argon/hydrogen mixtures are used primarily for the TIG and plasma welding of austenitic stainless steel. Mixtures with a higher hydrogen content are normally used for plasma cutting. Argon/carbon dioxide mixtures are suited to the welding of carbon, alloy and stainless steels. The percentage of carbon dioxide present in the blend can range from 2% to 25%. Argon/oxygen mixtures were developed for the MIG welding of stainless steel, although mixtures with a higher oxygen content are often used for MIG welding of carbon steel. If a shielding gas is required for FCAW, either pure carbon dioxide or argon/carbon dioxide mixtures are commonly used.
Other custom blends are available for specialist welding applications such as "high deposition rate" MIG welding gases and argon/nitrogen mixtures for TIG welding of duplex stainless steel.
Concrete Examples: Cost and Productivity Gains of Shielding Gases
In the following you can read about some of the many ways that welding gases from Linde translate into tangible operational and financial benefits for your business.
Weld metal properties
The shielding gas can directly influence the strength, ductility, toughness and corrosion resistance of a weld. For instance, carbon dioxide in the shielding gas for MAG welding of stainless steel can compromise corrosion resistance of the resulting weld metal. All of our stainless steel MAG welding gases have carbon dioxide levels below 3% to ensure that carbon pickup doesn’t increase carbon in the weld metal above the 0.03% specified maximum for the weld metal.
Weld shape and quality
Another good example of how the shielding gas can affect the quality or integrity of the weld metal can be found in the welding of aluminum. The addition of helium to argon in shielding gases overcomes the challenges sometimes associated with pure argon, namely porosity, lack of penetration and fusion defects. The high thermal conductivity of helium means more energy is transferred into the weld, producing a hotter weld pool for improved fusion and slower freezing times. This gives entrapped gas more time to escape.
Welding performance
The addition of hydrogen to argon for TIG welding of austenitic stainless steel produces a more fluid arc, significantly accelerating welding speeds. A further example of how shielding gases can improve welding performance is in the MAG welding of carbon steels. The addition of carbon dioxide to argon halves the amount of spatter, creating flat welds with low levels of reinforcement. This spatter value is halved again with our three-component mix including small amounts of oxygen.
Some Names to Look Out For
Our welding gases portfolio is marketed under different local brands or trademarks worldwide. Some typical names include CORGON®, CRONIGON®, VARIGON®, ALUGON®, FORMIER®, MIGMIX GOLDTM, STARGOLDTM, STARGONTM, ARGOSHIELD®, SPECSHIELD® and STAINSHIELD®. Contact your Linde expert to check availability and naming in your region.