I tried adding this on to another post but no response so is there a problem using 316 filler with lower grades of SS, I have ben using mostly 308 filler for most any grade of SS ( mostly 304)tig and mig but is there a reason to not use 316 filler with all 300 series stainless? Thanks Jim
I'm not a metallurgist, so this is not an "official" answer, but I've welded a lot of stainless. Always best to use the right wire for the job, but I've welded a lot of stainless (MIG and TIG) and have never had a problem using a higher grade filler wire on lower grades of stainless. I think it's pretty common to use 308/308L on 304. I'd check with the wire manufacturer for the "official" answer. Hope this helps.
308 has less nickel and more chromium than 316. Different corrosion resistance. An excerpt from http://www.weldreality.com
When to use a 308L, 309L or 316L filler metal
308L and 308LSi is predominately used on austenitic stainless steels, such as types 301, 302, 304, 305 and cast alloys CF-8 and CF-3.
For high temperature applications such as in the electrical power industry, higher carbon 308H electrodes will provide superior creep resistance than does 308L .
Use 309L and 309LSi when joining 309 or mild steels / low alloy steels to stainless steels. Use 309 when joining dissimilar stainless steels such as 409 to itself or to 304L stainless. CG-12 is the cast equivalent of 309.
Some 308L applications may be substituted with 309L filler metal, but 316L or 316 applications generally require molybdenum. Note, 309L contains no molybdenum.
316L and 316LSi should be used with 316L and 316 base metals. CF-8M and CF-3M are the cast equivalents of 316 and 316L, respectively.
Type 347 stainless steel filler metal is used for 347 and 321 base materials because it matches these stabilized grades.
CF-8C is the cast equivalent of 347. Type 347 filler metal is also suitable most 308L filler metal applications.
i tried using 308 on 316, needless to say, it fell apart!! after that, i buy the correct rod
if i don't have it, i don't weld matteo
They also sell a 312ss rod that is supposed to be recomended for welding dissimilar materials. Not a magic rod but I have found it usefull when you do not know the exact grade of ss you are working with.
There's no problem welding 304 with a 316 wire. I only buy 316L tig wire. 308L wire is normaly recomended and is actualy cheaper but I prefer to only carry 1 type and 316 covers all I need. If you do a lot of 304 and no 316 at all then buy 308. If you can justify both then buy both.
In order for 316 base metal to retain its properties in the weld it should be welded with a 316L filler. 308 will still weld it fine. But usualy when you're using 316 instead of 304. There's a corrosion resistance reason, so use 316 filler. Molybdenum is what makes all the difference in the corrosion resistance of it.
308L will also weld the 321 stainless but the 347 will give better weld properties. I've also welded fairly heavy sections of 431 hardenable stainless with 308L tig wire with great results, just needs preheat. Stainless is fairly forgiving. Forget about welding 303 though.
Not that I am cheap ,but the reason I posted the question is that I have a roll of 316 Dual shield wire (pricey to buy) and I don't want to waste it and any 316 work I do is usually light tig work and I usually use 304 for larger structural projects and sometimes like to mig them. Technically it might not be the perfect filler but it seems to work as SND claims and the welds look good and they don't "fall apart" at least in the short term (?) Thanks Jim
my understanding of this is that if the alloying elements in the filler do not match up properly with the parent metal you can have problems with the weld being much less ductile than the surrounding metal. This is supposed to be a problem mostly when you need serious structural integrity. I suppose if your parts were going to need to be stress tested/certified, you might want to check up with the wire manufacturer to find out about any drawbacks of using 316l on 304 parent metal if that is the case.
If I were doing a job for a customer I would be sure to do it right. proper alloy for the job. If it is for me, I might cut a few corners here and there, using my best judgement. If it what you are making is a small part that takes no serious loading, I would do it. if not, don't be cheap, do it right. Failure and rework of a job or possible injury from a weld failure is poor economy in the long run.
check out that weld reality site. lots of good information. maybe the guys at your local welding supply know some stuff too?