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Ask the expert: What is the best gas for TIG welding austenitic stainless steel?

The secret to an excellent welding job is improved productivity, fewer rejects and a better working environment. But which gas can deliver all of this, while TIG welding austenitic stainless steel? Kevin Sherry, UKI Lead Welding Applications Specialist at Air Products, explains why two percent hydrogen added to pure argon is the magic ingredient.

As with the other types of stainless steels, austenitic stainless steels are corrosion and oxidation resistant due to the presence of chromium that forms a self-healing protective film on the surface of the steel. Despite their toughness and strength, they are the most easily weldable of the stainless steel family and can be welded by all welding processes. But how can you improve the welding gas quality to deliver an even better result?

Argon is generally used during the TIG welding (tungsten inert gas) process, due to its heavy weight that blankets the weld, but there are quality and productivity advantages in mixing it with other gases in the process, such as hydrogen.

Adding just two percent hydrogen to pure argon will save welders time and money, while creating a more enhanced welding performance that produces a large range of benefits: increased welding speed, improved penetration, lower gas consumption and overall costs, and lower ozone emissions. The hydrogen enhanced gas, such as Air Products’ Inomaxx® TIG welding gas, also produces less surface oxidation, which improves the finished quality of the weld and requires less post-weld cleaning. This gas also meets or exceeds the requirements of ISO 14175 and AWS A5.32 welding consumables, giving welders the reassurance they’re meeting international quality standards.

Alternatively, switching from pure argon to N5 NH5 (five percent hydrogen in nitrogen) mixture when purging and backing gas for austenitic stainless steel will remove any remaining oxygen inside the pipe or object that is being welded to avoid contamination, while improving the root bead penetration at a lower amperage.

To experience the benefits of Inomaxx® TIG and N5 NH5 backing gas at your site, you can contact the Air Products team on 0800 389 0202 or email apukinfo@airproducts.com to arrange a free expert assessment. You’ll also receive free advice about using different gases to improve productivity and efficiency with a comprehensive evaluation of your weld processes and practices.

Air Products

Air Products (NYSE:APD) is a world-leading Industrial Gases company in operation for nearly 80 years. The Company provides industrial gases and related equipment to dozens of industries, including refining, chemical, metals, electronics, manufacturing, and food and beverage. Air Products is also the world’s leading supplier of liquefied natural gas process technology and equipment. The Company develops, engineers, builds, owns and operates some of the world’s largest industrial gas projects, including gasification projects that sustainably convert abundant natural resources into syngas for the production of high-value power, fuels and chemicals.

The Company had fiscal 2019 sales of $8.9 billion from operations in 50 countries and has a current market capitalization of about $55 billion. More than 17,000 passionate, talented and committed employees from diverse backgrounds are driven by Air Products’ higher purpose to create innovative solutions that benefit the environment, enhance sustainability and address the challenges facing customers, communities, and the world. For more information, visit www.airproducts.com.

For many industries, the gases we supply are a lifeline. Whether operating a facility right at your site or delivering products by truck or pipeline, we want you to think of Air Products as a key part of your business.  We offer thousands of products to a multitude of different industries.  This scope, knowledge and experience has enabled us to develop a deeper understanding of your particular needs.

The consistency and quality of the gases we supply are also vitally important.  We strive to not only meet international industry standards, but also satisfy the most demanding requirements for on-spec products and superior technology and services.

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