Welding titanium: how to get good gas coverage
Titanium is sensitive to oxygen and nitrogen, even when it already looks cool. When welding titanium, the colour of the weld shows you whether your gas coverage was good enough. This is what to look out for.
What does the colour show?
The colour on and beside the weld tells you how much oxygen has reached it:
- Silver or light straw: good gas coverage. This is what you want.
- Dark straw to purple: a bit too much oxygen got in. Often still usable for non-critical applications, but not ideal.
- Blue: clearly insufficient coverage.
- Grey or powdery white: heavily contaminated, the material has become more brittle. This work is usually rejected.
How to get better gas coverage
- Shield the back side and the cooling weld too. With titanium it is not only the weld pool, but also the weld that is still hot that must stay under gas. That is done with a post-flow time, a trailing shield or back purge gas on the inside of a pipe.
- Use a bigger cup with a gas lens. A gas lens gives a calm gas flow, and a bigger cup covers more.
- Keep it clean. Degrease the workpiece and use clean gloves and clean tools. Titanium is sensitive to contamination from oil and fingerprints.
- Let the post-flow time run long enough until the weld has cooled.
- Check your hoses and fittings for leaks. A small leak can already let in enough air.
Why Pyrex helps
With a transparent Pyrex cup you see the weld pool and the gas while you weld. That helps you spot problems sooner, before the weld has discoloured. Read more in Pyrex or ceramic.
Our parts for titanium
Take a look at our Pyrex cups, gas lenses and diffusers and the selection guide to find the right combination for your torch.