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Welding header tube and flange in stainless

Posted: Wed Sep 20, 2017 6:45 pm
by jumpinjackflash
:D I know my safety wire is composed of 18% chromium / 8% nickel {302 or 304} . I do like to weld thin materials with it. Question is how would it hold up on a header flange and tube in unknown grades of SS? Or would 309l be the natural safe go to? Going to make "step headers" - 1.375 to 1.5 tube sizes
Thanks in advance......that's where I am with the airplane project...hope to hear it run soon.

Re: Welding header tube and flange in stainless

Posted: Wed Sep 20, 2017 7:35 pm
by weldin mike 27
This may be a dirty lie, but I am under the impression that 316 is a good choice for most grades and 300 series stainless. 309 and 312 are for welding steel to ss and unknown grades of steel

Re: Welding header tube and flange in stainless

Posted: Wed Sep 20, 2017 8:26 pm
by Poland308
weldin mike 27 wrote:This may be a dirty lie, but I am under the impression that 316 is a good choice for most grades and 300 series stainless. 309 and 312 are for welding steel to ss and unknown grades of steel
Same here. I use 316 or 308 for dissimilar grades of 300 ss

Re: Welding header tube and flange in stainless

Posted: Fri Sep 22, 2017 2:22 pm
by noddybrian
I too use 316 for most things stainless as I got a job lot cheap - never had a problem - the lock wire is interesting re-purpose of something I imagine you have on hand - but from a layman's perspective I would say it won't have any deoxidisers etc in that a welding rod would so may not be best suited - could work if everything was surgically clean I guess as there would be little need for them - best price option for small wire designed to weld is buy a little 1/2kg spool of stainless mig wire & straighten some out.

Re: Welding header tube and flange in stainless

Posted: Sat Sep 23, 2017 8:34 am
by Arno
noddybrian wrote: best price option for small wire designed to weld is buy a little 1/2kg spool of stainless mig wire & straighten some out.
This...

Stainless TIG filler wire is usually of a (very) low carbon content and slightly elevated alloying elements to combat the tendency of the metal in the weld puddle to develop chromium-carbide and deplete the corrosion resistance effect of the chromium in the weld bead. The dilution of the base metal with the filler should balance out the resulting weld composition again.

Eg: http://www.esabna.com/euweb/awtc/lesson5_10.htm

So using a regular stainless wire (like lock-wire) as a filler could work, but you'd need to make sure to keep any heat input very short and fast to reduce the effect of the formation of chromium carbide.

Bye, Arno.