lol, just gotta say it js55, you are way too cool in a geeky kinda way, lol!! ;-)
I'll preface this with my knowledge is limited on the matter. However; I understood that for FSS the FF wasn't as important as the proper balance of interstitial elements.
I understood that tungsten was added to FSS alloys to slow down the sigma and chi phases, but lowered the toughness as the associated precipitates are course in nature, aligning along the dendrite and grain boundaries. Nickel was added with the tungsten to balance this out, which by addition forces an increase in fine grain precipitates.
Therefore, ferrite factors are not so important with this, but rather the balance of tungsten nickel in the right quantities.
That's about the extent of information I have on file for the issue. If someone has information to the contrary, please let me know.
Regards,
Gerald
Gerald,
To my knowledge you are exactly right. And thanks for the input. Thats sorta the type of info I was looking for. I know with the newer SFSS's the FF would not be such issue, if even an issue at all, since cracking susceptibility has been minimized (take a look at the carbon content in the SFSS's). But I think there is still alot of the older standard type FSS's being spec't.
I was also suspecting that the FF idea probably evlolved into numerous FF's(similar to CE's), though I don't know for sure.
"If someone has information to the contrary, please let me know."......Me too. I think FSS's will find their way into more services as end users look for ways to save. Especially as they 'dial in' the metallurgy of these alloys, and realize that austenitics aren't required for more moderate corrosion applications.
Forum