Hi Al!
I remember in a previous thread sometime last year regarding the use of a SMO 654 Avesta grade of stainless to be welded on to a carbon steel and one of the participants in the thread would not accept the premise that even minute increases of Cu within the grain boundaries could be one of the reasons why the welds would be more vulnerable to failing due the increased potential of solidification cracking if one did not carefully choose the appropriate filler metal grade for the application:
http://www.bohler-uddeholm.com/english/26_ENG_HTML.php"Inconel 625 is a ERNiCrMo-3 as opposed to a ERNiCrMo-13 filler... So if you can find a filler that's close to the chemical composition of the P16 then use it as well especially for "Dissimilar" welding as is your specific application... Also, Inconel 625 has a small amount of Cu (Copper)which may be detrimental to the weld grain boundaries upon solidification when welding the 654 SMO to the carbon steel which is the application the poster described.
What's important as well is this: when the weld is NOT to be subsequently annealed, an overalloyed filler metal should be used... Because of the high corrosion resistance of 654 SMO, the degree of overalloying required is unusually high and so in comparison to Inconel 625 filler, there's not enough Mo for overalloying which is why P16, or a chemical composition equivalent is recommended instead for use on 654 SMO. It's all explained quite plainly and quite clearly in these two .pdf's as well as in the Avesta Welding Manual as well."
http://www.futurealloys.com/654smo.pdfhttp://www.outokumpu.com/42534.epibrwhttp://www.bohler-uddeholm.cz/czech/files/Prirucka_Avesta_AJ.pdfNonetheless, after posting this information up, the person who was really unprofessional towards me for not being a welding engineer, and who in other threads constantly questioned my integrity as well as my understanding and knowledge as well as my own personal experiences in welding and fabricating a very wide variety of different metals, etc... This person was eventually banned fron the forum because he exhibited similar behavior towards other folks in here also which left Ross no choice but to ban him...
Now I may not be a Degreed welding engineer and I never said to anyone here that I was one but, welding engineering principles & practices have been incorporated into my BLOOD for the last FORTY YEARS yet, this individual didn't want to even acknowledge me just on the notion because I wasn't a Degreed welding engineer!!! My response to him was a little more than "Well too friggin BAD!!!" And yet, that's basically what I meant and then some in my response to his ignorance and obnoxious attitude! ;) He could have been an excellent contributor here if he wasn't such a Dip$h!t! ;)
Oh well, some people just don't know any better, and it's kind of like your signature Al: "You can always tell a welder, but you can't tell him much."
All the best to you Al!!! :) :) :)
Respectfully,
Henry