Metal Fabrication Resource Center

Frequently Asked Questions (FAQs)

Why controlling gas flow rates matters: Air Products explains why controlling gas flow rates matters and how it can help to achieve a quality weld...

Air Products explains why controlling gas flow rates matters and how it can help to achieve a quality weld.

> Why is it important to control the gas flow rate?

> How do you choose the right gas flow rate?

> What can you do to ensure the flow rate is being controlled properly?

> How can you find out what is the right flow rate for the application?

> Is there any new technology available that can help me to control the gas flow rate?

NOTE: See the answers to these questions below.

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Why is it important to control the gas flow rate?

A uniform flow of gas is needed to shield the molten metal by blanketing it properly to avoid atmospheric contamination, which can lead to increased levels of oxidation or even porosity of the finished weld. Of course, flow rates can vary and it is important to select the right flow rate for each application as this can improve efficiency and ensure a quality weld.

If you would like to Ask the Expert a specific question or for further advice on quality standards, please email apukinfo@airproducts.com.

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How do you choose the right gas flow rate?

There’s more to choosing the right gas flow rate than you might think. Most MIG/MAG and TIG welding applications use argon-based shielding gases – a gas which is heavier than air – and these typically need lower flow rates than helium-based mixtures, as helium is much lighter than air. The thickness of the material should also be considered. For example, for thinner materials of 1–3 mm thick, a lower flow rate of around 8–12 liters per minute is usually preferred and this can increase to a flow rate of around 15-20 liters per minute for thicker materials. Where mixtures containing helium gas are used, flow rates can go even higher. Finally, flow rates can also vary according to the type of application – for example, manual welding typically requires a lower flow rate than mechanized or automated welding systems.

If you would like to Ask the Expert a specific question or for further advice on quality standards, please email apukinfo@airproducts.com.

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