Welding Stainless Steel

[Landlubber]

Hi folks,

Looking for current advice on welding stainless steel wet exhaust pipes.

I am trying to avoid the usual rusty weld syndrome often seen in this area.

Could one of you welders please advise on pipe/tube specs and fill rod and gas mixes please.

Specifically in the 50 to 1000hp range.

Ta

[lazeyjack]

use 316l filler wire
flood the tube with argon, that is you have to plug ends, , with gas hose in one end
prep the joint, but keep it tight,, root pass,TIG I am forgetting the best grade apart from 316l there is another grade resists warm salt better, will find it in a shake or two, I,m a bit rusty myself
I used avesta 2205 for shafts, dunno if you can get in sched tube
but you should use same grade wire as parant
You should realise that ss is a very poor material when it comes to warm salt and sulphur
if you are dry stack then 316 l will do fine,
trouble is some of these chinese and korean 316,s rust(

[Landlubber]

Thanks lazy, exactly what my mate has just emaild me to do, like everything in life, it is easy when you know how.

The filling of the tube is the obvious answer to the base problem. Thank you.

[murdomack]

Hi Landlubber,

The rusty weld syndrome you mention is actually most often caused by the tools and not necessarily by the welding.
You should use seperate tools with stainless as cross contamination from carbon steel is what causes the rust even when you are using all the correct weld procedures.
Use cutting and grinding abrasive wheels that are made of aluminium oxide or some other non-carbon material. Same with abrasive cloth, make sure it is totally non-ferous, again aliminium oxide is the ussual one. Try not to use files and saws that can leave carbon residue on the stainless. When you are finished use a stainless steel wire brush to polish it all up, if you are not sure test the bristles with a magnet.
You can use pickling pastes and all sorts of stuff, but the simplest and cheapest way is to keep your metals segregated.

[rugludallur]

After welding up the exhaust make sure you "pickle" the area with acid paste, this will remove residual oxidized material and prevent rusty welds.

Regards

Jarl
www.dallur.com