tig welding low ferrite 316L S.S.(correction of heat stress fractures)
tig welding low ferrite 316L S.S.(correction of heat stress fractures)
(OP)
i am having problems with heat stress fractures in low ferrite(0%-.2%) 316L sainless!Just wondering if there is something that i can do to correct the problem when making butt weld fussion welds





RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
What do you mean by "heat stress" fractures-base metal cracking? What filler metal and ferrite number?
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
What is happening physically is that the 316 is solidifying in a austenitic mode and the sulfur is being rejected from the austenite dendrites to grain boundaries where it is a weak film. Ferrite doesn't reject sulfur, so a little delta ferrite eliminates the problem. So, does not having the sulfur. That's the easy way to solve the problem. Laser welding would avoid it as would using consumable electrodes with low sulfur or higher ferrite.
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
I don't want to be comercial on line, so I won't. You know what you need, either higher ferrite, lower sulfur, or something clever. Inquire at MFM304@AOL.COM if you want advice eng-tips.com doesn't want posted.
If you can increase ferrite or reduce sulfur, you'll be O.K.
Why doesn't the German casting have higher ferrite? That would be normal. Is this an international design?
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
This is why most tubing has .005 to .017 sulfur, to increase penetration. I have had people tell me that 95 percent of their welders CANNOT weld tubing with lower sulfur levels. We did it every day, but it takes some experience! Valex makes tubing with lower sulfur levels.
The other comments about using a filler wire with ferrite or laser welding will definitely help reduce or eliminate weld cracking, or microfissuring.
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
http://www.srs.gov/general/pubs/fulltext/ms2001544/ms2001544.html
http://www.metrode.com/docs/news/1682paper.pdf
RE: tig welding low ferrite 316L S.S.(correction of heat stress fractures)
Creq = Cr +1.37Mo +1.5Si + 2Nb + 3Ti
Nieq = Ni + .31Mn + 22C + 14.2N