Its possible- route run welding of ss 316L pipes without purging?..

by Prethyush R
( Mumbai, India)

is there any special electrodes / filler wire available for route run welding of SS 316L pipes without using purging.in my requirement no of joints are very large so it is not economic to use gas purging.also Pipes size ranges varies from 2 inch to 8 inch.
Any special electrodes can serve this purpose? or any method of purging that can be used very economicaly to for route run welding?.
Pls adivise

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Miller electric makes gmaw equipment that is supposed to be able to weld a stainless steel root without purge.

http://www.millerwelds.com/resources/articles/RMD-Process-is-Easy-to-Learn

for tig welding, there is a flux called solar flux, that is supposed to allow for tig welding a root without backing purge, but I am not impressed with it.

Purging closed ends furnace pipe

Hi!
I need some help on how to purge furnace pipe for welding with TIG. Never done it and the situation is this;

Metal:CR 2.5%, MO 1%.
There is no open pipe end to insert a purge tube or any sort of dam. The only opening will be the weld joint.

Questions:
1-How do I purge it?
2-Does a ball of rice paper at each side of the weld joint be enough to contain the gas confined to the welding area?

Thanking you for your prompt answer.

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one idea would be to use purge paper a few inches on each side of the weld joint and then insert a small diameter copper tube until the very last inch of root before removing it. would be best inserted in bottom.

purge paper is water soluble and water soluble tape is also available to make a purge dam.

also that alloy is sometimes tig welded without using a purge. I am sure it will go better with a purge but the need for it depends on code requirements.