Ferritic SS welding

Date 06-01-2007 13:46

While I will admit that I am certainly no expert on E-Brite I think there are some basics that hold. Off hand I see no problem metallurgically for welding the 26-1 with 309 (I glady await a correction if my assessment is incorrect).
But that to me would not be the primary question. E-Brite would be speced for a very specific service reason. The stuff ain't cheap. So you have to ask yourself what that service is and will any filler metal of your choice provide the properties necessary. In other words the is no avoiding engineering your filler metal choice on this one.
This is always the case with any of these exotic and specific, or proprietary alloys.
I'd call the E-Brite folks and ask them.

By rafael Angarita (*)

Date 06-01-2007 15:36

Ok js55, very tahnks. I`ve read that MIG or TIG are beter than SMAW for welding ferritic ss.
I`ll be waiting for your coments.

By js55

Date 06-01-2007 17:25

I can't confirm or deny that SMAW is better or worse. Whatever that may mean. I think that with SMAW you certainly take a greater chance of losing Cr across the arc than you do with GTAW. And the 26 is there for a reason. Usually oxidation resistance is high on the priority list for alloys like this.
And to my knowledge there isn't a coated 446LMo available yet.

By chuck meadows (***)

Date 06-02-2007 15:47

Maybe you've heard that MIG or TIG is better than SMAW because there is no matching SMAW for 26-1. The chromium content of the 309MoL (Cr=23-25%) series is noticably lower than the recommended 446LMo where Cr=25-27.5%. The only ferritic SMAW filler listed in ANSI/AWS A5.4 is E430, while the fillers listed in ANSI/AWS A5.9 for the ferritics and superferritics are ER430, ER409, ER409kCb, and the superferritic ER446LMo.

By chuck meadows (***)

Date 06-02-2007 15:36

I believe the UNS for 26-1 is S44626, unless there is an S44625 that I'm not aware of. If you are wanting to use SMAW for welding the superferritic 26-1, then a 309L or 309MoL is fine since there is no 446MoL in the SMAW group. But, if you can use GMAW, there is a 446LMo in the gas shielded process. Make sure you use an "L" grade if you use the 309 series because 26-1 has a maximum carbon content of only 0.006%. Due to the high purity of both base metal and filler metal (446LMo), cleanliness is of the utmost importance. Of equal importance is the shielding gas coverage to eliminate the presence of oxygen and nitrogen.