Mixing of welding processes/electrodes

[braceh]

I am a CWI working under AWS D1.1 almost %100 of the time and I have a question. Is there anywhere in the code that directly prohibits the use of both SMAW E7018 and FCAW E71T-8 electrodes to compile the same weld? A contractor is proposing to tack weld with E7018 and complete final welding with E71T-8. I think the obvious solution from an inspector's stand point would be, "please show me your WPS for this," since table 4.5 item# 4 under filler metal says that a WPS written for classification A5.1 would not be applicable to a weld performed under classification A5.20 and vice-versa. However, I am asking from more of a structural and metallurgical standpoint as it might be possible to perform a WPS qualification using the two processes. Any help would be appreciated...

 

[gtaw]

Since you work with D1.1 most of the time I assume you have a copy to review.

Both FCAW and SMAW are prequalified processes. The contractor can write a WPS that uses the processes in any combinatin provided all the other provisions of prequalification are met.

Best regards - Al

 

[braceh]

I am not 100 percent sure that the first remark is not useless sarcasm. Like I previously stated I do work with D1.1, and I am familiar with what is contained within that code. I already figured that a WPS could be written to support such combinations that is why I even included a statement saying so, also like previously stated I was asking whether or not there are any drawbacks from mainly a structural or metallurgical standpoint.

 

[gtaw]

It wasn't meant to be sarcasm. It was meant to a polite way to say you need to get a copy if you don't already have one. You would be surprised to know how many times I encounter contractors and inspectors that don't even know the color of the cover.

E7018 is a safe bet for nearly any application provided it is a matching filler metal for the steel being welded.

There are times when the flux of the FCAW weld will be dificult to completely remove when the FCAW passes over the tack. Other than that, no problem I am aware of.

Best regards - Al

 

[connectegr]

Structurally I don't see any problem. Both processes are using the same filler metal and are even self-shielded. I do not think AWS D1.1 requires that the welds and tack welds be completed by the same process. For example backing is frequently tack welded using SMAW E7018, then the weld is completed using SAW or other weld process. The WPS used to apply the tack weld is independent of the WPS for the completed weld. As a CWI, you may request written verification from the EOR.

If I recall this is in the fabrication section of D1.1, Chapter 5. 5.18 or somewhere close. Sorry I am answering on my cellphone.

http://www.FerrellEngineering.com

 

[HgTX]

Combining FCAW-S with other processes can be iffy. D1.1 doesn't consider it to be much of a problem for ordinary applications, but see D1.1-2008 Table 4.14 footnote a for special requirements in applications requiring Charpy testing.

Hg

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