American Welding Society Forum
am planning to qualify a wps with a cjp joint , smaw process, 6" pipe with root E6010 and fill/cap with E7018.Is mixing of electrode is acceptable in aws d1.1?
Interesting question. At first glance I was tempted to say yes, but upon reflection the F number is an essential variable. Since the WPS is qualified on the basis of test coupon thickness, how would one accommodate only part of the thickness being deposited with one F number and the remaining thickness deposited with a different F number?
Perhaps the way out is to qualify one pipe assembly with an F3 electrode and a second assembly with an F4 electrode. Both PQRs would then be used to support the WPS that included both F numbers.
Best regards - Al
thank you guys.......so here the f no is the villain...... so lets take another scenario by E 7016 with root and fill/cap by E 7018 , here the F no is same ...so now i think its acceptable with aws d1.1.....valuable comments please
This might be one of the rare occasions where an SWPS might be a reasonable solution (hold your nose Al)
There might just be an SWPS that covers your base metal, filler/s, pipe diameter and bevel angles.
The next possible solution might be to use a backing ring and Low Hydrogen all the way out.
I said *might* 3 times Al
Could it be E6013 instead of E7018?
Or E7016 (root & capping)
or could it be the use of E6010 is for backup weld?
You have to watch those F numbers. They will get you into trouble every time.
Best regards - Al
What about welding by E 7016 with root and fill/cap by E 7018 , here the F no is same ...so now i think its acceptable with aws d1.1.....valuable comments please
Stay with the same F-number, same process, and same base metal and all should be fine.
In addition to Al's comment, you do realize that both 7016 and 7018 are low hydrogen electrodes? So especially since they are the same 'F' number, and why wouldn't they be, there is no problem.
I will throw out another aspect that I am wondering if this thought is coming into play with your original query: Many people will see welders using two different processes or electrodes and say, 'you can't do that. You are 'intermixing' your welds.'
So, what are they talking about? It only applies in most cases, structural in particular, to structural seismic members where D1.8 and/or AISC Seismic codes are applicable. Even then, it only applies to mixing FCAW-S with other electrodes and/or processes. Gas shielded with self shielded FCAW is still a problem.
They have problems going together and you end up with problems with weld notch toughness and cracking.
If FCAW-S is not in the mix then there is nothing to worry about other than the normal cautions making sure you have all the correct WPS's and PQR's when and where necessary. There is little said about intermixing except as it applies in the seismic codes. Many applications use it everyday: pipe welding with a different process or at least electrode for the root than used for fill and cap, structural tacking with a different process than what is used to weld it out, etc.
He Is In Control, Have a Great Day, Brent
You can combine WPSs to permit using more than one process on the same joint. If the WPSs are qualified by testing, then the WPS used for production must be supported by multiple PQRs.
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