Purging for Tig welding – low cost enclosures make it easy and improve welding technique

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 1 December 2004

Keywords

Citation

(2004), "Purging for Tig welding – low cost enclosures make it easy and improve welding technique", Anti-Corrosion Methods and Materials, Vol. 51 No. 6. https://doi.org/10.1108/acmm.2004.12851fab.001

Publisher

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Emerald Group Publishing Limited

Copyright © 2004, Emerald Group Publishing Limited


Purging for Tig welding – low cost enclosures make it easy and improve welding technique

Purging for Tig welding – low cost enclosures make it easy and improve welding technique

Keywords: Welding, TIG, Metals

Welding of stainless steel, titanium and other exotic or reactive metals often needs to be effected in an inert atmosphere, made easy and cost-effective by the use of welding enclosures from Huntingdon Fusion Techniques Ltd (HFT). Tig welding of these materials involves purging with argon to keep oxygen levels controlled at concentrations as low as 20 ppm (0.002 per cent) and it is often impractical to form a seal around the workpieces to eliminate air leakage and guarantee an inert environment throughout the welding process.

HFT's Argweld&reg Flexible Welding Enclosures can be a fraction of the price of rigid enclosures such as welding chambers and allow more movement so that the operator is able to properly manipulate the workpiece and welding torch, working closer to the workpiece, often impossible with rigid chambers. This improves welding technique and makes for more consistent welds, avoiding joint failure (Plate 1).

Available in diameters of 900-1,800 mm, they are equipped with two pairs of glove ports and mulitiple feed-throughs for gas, torch and cable glands for electrical supplies.

Plate 1 HFT's Argweld® Flexible welding Enclosures

Using HFT Argweld® Flexible Welding Enclosures allows precise monitoring and control of the atmosphere around the torch and weld pool. The weld has to be made to maintain the properties of the materials being joined and bad welds experienced with too much oxygen present can cause porosity, rusting and discolouration as well as making the joint unsound.

When welding repairs in stainless steel, the purge shield made by the tig torch is usually sufficient to protect the weld. However, this is insufficient in many cases, for instance, with intricate welds or those in titanium and the completely purged environment afforded by flexible enclosures is required or, at the least, desirable.

With intricate weld requirements, for instance, when repairing castings or joining detailed metalwork, welds have to be effected with small currents to protect the material from deformity or loss of detail. In such cases, MulitiStrikee tungsten electrodes are recommended since the even and multiple-dopant distribution allows excellent low-current performance as well as stable, targeted arcing. Flexible Welding Enclosures make an ideal environment for this work since the welder does not have to worry about shield gas being directed away from the weld.

HFT manufactures a wide range of welding and weld purging accessories including Argweld® purge monitors, calibrated for oxygen levels at SS and titanium weld levels down to 0.01 per cent, Pipestoppers® expandable plugs for pipes and tubes, inflatable purging systems and Argweld® backing tape for even, clean welds. On long and deep welds where the material takes time to cool, trailing shields from HFT are available to shield the weld area behind the torch, preventing oxidisation in the hot metal after the torch has passed.

HFT has a comprehensive distributor and after sales network in the UK and throughout the world. Call 01554 836836 or e-mail sales@huntingdonfusion.com for details of distributors in your area.