How to Choose the Right Shielding Gas For Your Weld
One of the most important decisions in the welding process is choosing which shielding gas to use for each job. The shielding gas you choose has a significant impact on the outcomes your business achieves.
The right shielding gas will lead to productivity gains, improved weld quality and, ultimately, higher profits.
With that in mind, what shielding gas is best for your specific welding needs? In this blog, Simcoe Gases takes a look at what a shielding gas actually is, what gases are typically used in the welding process and what their unique benefits are.
What is shielding gas?
Shielding gases are inert or semi-inert gases that are used during the welding processes to protect the quality of your weld and the material you are working on from oxygen, hydrogen, nitrogen and water vapour.
Oxygen, hydrogen, nitrogen and water vapour, which all exist in the atmosphere, can be harmful to your weld, and can lead to contamination and oxidation in molten metal. They also impact the welding process, having an impact on welding speed, weld penetration, surface shape patterns and other aspects of the weld.
The use of a shielding gas significantly improves the quality of metal fabrication, ensuring the finished weld is clean and strong.
What shielding gases can be used in welding?
There are four common shielding gases that welders use, all of which have different properties and factors to consider when they are applied to the welding process. The four most shielding gases used are:
These gases - which fall into two categories, inert or semi-inert - all have their own unique benefits and drawbacks when used in any given application, and can be mixed with each other to form speciality welding gases.
How are semi-inert gases used in welding?
Gases with low reactivity are known as semi-inert, and can be used in the welding processes as either a pure gas or as a blend. Here are the most commonly used sem-inert gases used in the welding process
Hydrogen: Often used in combination with other gases, hydrogen is added to shielding gas blends for its ability to deepen penetration and increase welding speeds. Hydrogen is particularly used on grades of stainless steel that are sensitive to oxygen.
Nitrogen: Nitrogen can be used in the welding process to increase weld penetration and arc stability, and is typically used in a blend with other gases.
Oxygen: Oxygen is typically mixed with other gases and used in amounts of between 1-8%. Mixtures of 98 percent argon/2 percent oxygen and 92 percent argon/8 percent oxygen are common gas mixtures. Oxygen is generally used for its benefits of arc stabilization, spatter minimizations and metal transfer improvement.
Carbon dioxide: Carbon dioxide is the most common type of shielding gas used in the welding process, and can be used in its pure form without the addition of an inert gas. It’s particularly useful in metal inert gas (MIG) welding because it increases weld speed, penetration and mechanical properties.
How are inert gases used in welding?
Inert gases, also known as noble gases, are a type of gas that does not undergo chemical reaction under a set of given conditions. The two inert gases used in welding are argon and helium.
Argon: Argon is the most abundant gas in the Earth’s crust, and can be used in a range of welding applications for superior results. When mixed with other gases, argon provides a desirable combination of arc stability, puddle control and reduced spatter. Argon also produces a narrower penetration profile - useful for fillet and butt welds.
Helium: Helium is a good shielding gas for thick metals as it produces a wide, deep penetration profile. Since it creates a hotter arc in the welding process, helium allows for faster travel speed and higher productivity rates. The cost of the gas, however, is more expensive.
What is the best shielding gas for your welding process?
As you can see, there are a huge number of options when it comes to finding a shielding gas for your specific welding job. The materials being used, application and processes involved all have an impact on what the best shielding gas is for you.
Finding the right solution for your specific weld is a crucial component to a high-quality finish.
Need help finding the right shielding gas for your unique needs? Contact Simcoe Gases today. Our team of industrial gas experts would love to help you find a shielding gas for unique welding requirements.