308 filler question

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What's the difference between 308 and 308L?-Matt------------------------------------------
Reply:L suffix means low carbon content alloy.  Low carbon variants are more resistant to chromium carbide precipitation; which degrades the corrosion resistance of the weld HAZ.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:The "L" in 300 series stainless means low carbon.Lower carbon means higher corrosion resistance.
Reply:Thanks. My LWS guy said he only carries regular 308 because some jobs spec it on the blueprints. I guess he doesn't get very many requests for it.I'm pretty new to stainless, so I'm still learning alloy identification/proper selection of fillers.-Matt------------------------------------------
Reply:The "L" is lower carbon in it than the 'regular' filler.Regular 308 is 0.08% carbon max, 308L is 0.03% carbon max.Some 308 is dual-listed as 308/308L.  Check the label and/or catalog.Slight clarification, carbon in the stainless alloy can react with the chromium in the stainless alloy (the chromium is what mostly makes the steel 'stainless') in the weld puddle and along the HAZ and turn into chromium carbide aka carbide precipitation.  Because the chromium is no longer 'just' chromium, it is not there to act as the 'stainless' thing and that means that the weld bead and/or the HAZ could be no longer or not as stainless as the steel should/could be.Check the label/catalog for the wire you have or are interested in.  Most of the time, you can use a 308/308L listed filler for either 'regular' or low-carbon parent work.  The best laid schemes ... Gang oft agley ...
Reply:I should have worded that "the only reason my LWS carries 308 is because it's spec'ed for some jobs." instead of "he only carries 308"  i.e. My LWS doesn't stock a lot of 308 (no L) because only a few people ask for it specifically. I just finished a small TIG repair job on a SS hand cart, I used 1/16" 308L. I'm still getting used to SS so I made sure it was a non-critical piece where a possible flaw isn't going to kill anyone. SS carries heat differently, but I think it's actually a little easier than mild once you get the jist of it. I got some free practice time, customer was tickled pink with the work, and I made a small profit.  Wasn't quite perfect, but it was much better quality work than the original fabricator did.-Matt------------------------------------------