Weld Purging is the act of removing oxygen from the vicinity of a joint before, during and after welding. Metals that require weld purging include stainless steels, titanium, and zirconium.
Weld Purging various sizes of tubes and pipes can be challenging as well as expensive, which is why many welders today continue to construct their own dams to cut costs. Homemade dams made from material such as foam, sponge or paper can often lead to loss of welds when they leak or slip from position thus flooding the welding zone with air.
Huntingdon Fusion Techniques (HFT®) now offers low-cost Weld Purge Film® Kits, which can be cut to each pipe size.
Luke Keane, Technical Sales Manager for HFT® says: Weld Purge Film is great for when mechanical purging devices cannot be retrieved. The Film can be used to create an impermeable barrier, but can be easily washed away after use without leaving any residue.
Weld Purge Film® Kits can be used on pipe diameters up to 900 mm (36 inches) and for temperatures up to 300°C (572°F) without the material burning, coming loose and losing the weld purge.
The water-soluble Weld Purge Film® allows dams to be cut easily with the safety knife provided and once they are fixed into position using the water-soluble Weld Purge Super Adhesive® provided, produce an impenetrable purge barrier that can easily be washed away during hydrostatic testing of the pipe or just by normal wash-out.
These Kits are meant save operators high costs by minimizing gas usage dramatically reducing purge time and eliminating the need to clean or even a failed weld. Weld Purge Film® Kits have been designed and developed by HFT®, containing product accessories needed to manufacture dams that will not come loose during welding.
Other technical advantages of using water-soluble film instead of other materials include:
Transparency of the film dams allows the welder to see the weld root as it is being laid.
Vapor pressure of the film is very low and does not outgas harmful elements during welding that can mix with the hot metal and cause metallurgical defects.
The Argweld® Film does not contain water, unlike paper and sponge products do.
After welding, the water-soluble film is simply washed away and dissolved down to molecular level, leaving no trace.
Press release and image courtesy of Huntingdon Fusion Techniques®