Check QW-451 (table). Upper case "T" represents the thickness of the joint (through the weld) and lower case "t" represents the thickness of weld deposited with each F-number (F-number representing the filler metal). The hook is that the welding process must be considered as well as the F-number. In other words, GTA, GMAW, and FCAW may each use a filler metal with the same F-number, but each has to be considered separately. So, if you deposit 3/8 inch of weld using:
A) GTAW with a F6 filler metal, the procedure is qualified for 3/4 inch maximum using GTAW.
B) Then deposit an additional 3/8 inch using FCAW with F6, the procedure is qualified for an additional 3/4 inch of weld or a total of 1 1/2 inches.
C) If you deposit an additional 3/8 inch (on top of the GTAW and the FCAW) using SMAW with F3, the procedure is qualified for an additional 3/4 inch of weld for a total of 2 1/4 inches.
d) If you deposit an additional 13/16 inch using SMAW with F4, the procedure is qualified up to 8 inches.
The entire 8 inches can be welded using SMAW with a F4 filler metal or a combination of the other processes and F numbers as long as their individual limitations are observed, e.g., 3/4 inch maximum using GTAW with a F6 filler metal. The sequence of welding processes is not a concern.
Best regards - Al
Hi Al
Not quite sure I understand the point you are making. If I add up all the deposited thicknesses (t):
GTAW: 3/8"
FCAW: 3/8"
SMAW F3: 3/8"
SMAW F4: 13/16"
Total: 1.9375"
This is more than the 1.5" we are talking about, so I suspect you made an error on the last thickness. To make it work, the SMAW F4 will also need to be 3/8", so I suspect that is what you meant? If that is the case, then you will be qualified to weld 3/4" thickness with each of the above processes, so you be able to deposit a maximum of 3" with this combination. I do not believe that you can add the F3 and F4 thicknesses and claim to be able to weld to 8" with either of the SMAW fillers, because the F number is an essential variable. (Is this what you were trying to say?)
Regards
Niekie
My example did not apply specifically to thickness of your plate. I was attempting to show how the welding process, thickness of the weld deposited (each process considered independently of another), and F-number came into play when determining the thickness range for which the procedure is qualified.
Sorry my feeble attempt at clarification failed.
Best regards - Al