FCAW 2

[Praktiker]

Hallo experts, I am new in the Forum.
According to AWS D1.1:
-FCAW is a prequalified process.
-GMAW-S is not prequalified.
If I need to weld Groove Plate 3G, with Metal Cored Wire (150 A, 18V)is a short cirquid mode. is it a prequalified process or not?

Thank you in advance

 

[gtaw]

I believe metal core electrode is still included in the A5.18 specification, thus it is considered to be a variant of GMAW.

Short circuiting transfer mode is not prequalified, thus one would have to qualify the procedure in accordance with Clause 4 of AWS D1.1 if that is the applicable welding code.

Best regards - Al

 

[Praktiker]

Thanks Al

 

[MGIverson]

Even though the parameters you list would be in the short circuiting transfer mode for solid wire, running the same parameters with metal cored wire may result in a current density high enough to move you out of the short circuting transfer. It is very rare to experience short circuiting transfer with a cored wire. My guess is that you may be in the globular transfer range which would fall under the prequalified parameters of AWS D1.1

 

[Praktiker]

Thanks MGIverson for your answer.

But actualy I can not see (verify) that my WPS is welded on short cirquiting or in globular tranfer range. Or is it an other way?

Thank you in advance

 

[MGIverson]

It would be very difficult to tell if you are in the short circuit mode of transfer or if you are in the globular mode of transfer without high speed photography. The safest thing to do would be to run a PQR plate and qualify the procedure - that is what I would do. And by the way Metal Core wire is considered GMAW not FCAW.

If you don't mind, let me ask a couple of questions.

I am assuming that you are welding very thin parts considering the parameters that you listed. Why then have you chosen Metal Core wire for this process? Metal Core wire is usually chosen for the increased deposition rates that go along with making heavier welds. If possible, I would consider switching to a smaller solid wire - maybe .035 for the parameters that you listed.

Part of the reason I would suggest a solid wire is that you are operating far outside of the recommended operating parameters for the given wire. I don't know which brand of wire you are using but if you reference page 3 of the attached document you will see the recommended operating parameters for metal core wire. By running at such a low heat input you may not be recognizing the benefits of the metal core wire and your deposited weld metal may not be of the proper metallurgical properties.

 

[Praktiker]

Thank you MGIverson, I appreciate your interest in my problem.

That is the thing: I have to work with metal cored wire, because my company has a lot of stock of this type of wire, and I need to adapt my production. Thatfor I make WPS for 3G/3F welds,in thick plates, where the range of parameters is very low.

You look to be very familiar with the problem.

Thank you very much for your help.