Optimized orbital TIG welding results thanks to a PPM oxygen analyzer?

In an earlier article, “How to avoid coloration of a weld”, we saw that in some areas of application, a discoloration on the inside of a tube is intolerable since it cannot be amended afterwards due to limited access or the inner surface condition (electro-polished).

These areas of application include for example the industry of pharmaceutics or semiconductors, as “high-purity” is mandatory in these fields.

In many cases, the welder tends to use too much gas when purging to ensure that all the oxygen has been flushed out and that the inside of the tube is sufficiently inerted, in order to avoid having to rework or even worse, throw out the work piece. This method has the benefit of being simple, but it most definitely has a number of downsides.

Needless to say, scrapping a work piece or having to rework it after the welding is expensive, but a very pure gas such as argon is a significant cost factor that is often underestimated.

With a digital oxygen analyzer, a welder can save purging gas while being sure to achieve high-quality, repeatable and oxidation free welds.

The set threshold value is usually less than 60 PPM (parts per million) for stainless steel which translates to 0.05% oxygen in a given measurement volume. This value, the PPM level is to be defined by the operator according to the industry’s specifications.