Ultra high Vacuum , non magnetic welds

By NX687 Date 05-29-2013 01:03

Good Morning

We use 316L and argon TIG ,

but if we dared to use filler rod would it be best to use just the parent metal as a filler rod

or would this supposed non ferrite filler rod be better ,

I just want no magnetism in the weld area ,

and I suppose their is more chance of weld cracking with out the ferrite type filler rod

By 803056

Date 05-29-2013 03:13

Austenitic grains are less tolerant of certain elements that promote cracking. Small mounts of ferrite allow these same elements to go into solution thereby preventing fissures.

Can I ask what the ultra high vacuum and nonmagnetic welds have to do with each other? Are you fabricating chambers for electron beam machines?

Best regards - Al

By NX687 Date 05-29-2013 04:36

Thanks
Mass Spec with ion beam, close proximity parts

In your opinion would laser polishing be better than electropolish for sealing micropores or fissures

We have had luck with just Argon TIG , no rod at all ,

suppose we can stay with that

By cddolan74 (**)

Date 05-29-2013 11:58

If you are able to continue with no filler than you should. If needed, should be aware of sulfur and phosphorous content. you need some ferrite to reduce hot cracking that 316 is prone to.

By ozniek

Date 06-10-2013 13:32

Hi

Some filler manufacturers make consumables with zero% Ferrite, but with other additions to reduce the propensity for micro-fissuring of the weld. This is normally used in cryogenic service, but I suspect that it will also be good for you. I know that Metrode makes such fillers.

Hope that helps.

Regards
Niekie