In a 4G SMAW weld, which F number is used for the fill and cap passes?

In a 4G SMAW weld, which F number is used for the fill and cap passes?

• A. F4 fill and cap (7018)
• B. F3 fill and cap (6010)
• C. F2 fill and cap (6010)
• D. F5 fill and cap (7028)

Answer: (A)

In groove welding, the F-number tells you which filler-metal passes are designated for finishing the weld in a given position. For a 4G (overhead groove) weld, the finish passes—the fill and cap passes—use the F4 designation. The electrode that fits this F4 category is 7018, a low-hydrogen, all-position electrode that deposits smoothly and controls hydrogen in the overhead position. That combination gives reliable fill, good cap quality, and less cracking risk when gravity and slag control are factors. The other choices involve electrodes with different characteristics suited to other parts of the weld or other positions (root passes, verticals, etc.), so they aren’t the standard choice for fill and cap in a 4G weld.

In groove welding, the F-number tells you which filler-metal passes are designated for finishing the weld in a given position. For a 4G (overhead groove) weld, the finish passes—the fill and cap passes—use the F4 designation. The electrode that fits this F4 category is 7018, a low-hydrogen, all-position electrode that deposits smoothly and controls hydrogen in the overhead position. That combination gives reliable fill, good cap quality, and less cracking risk when gravity and slag control are factors.

The other choices involve electrodes with different characteristics suited to other parts of the weld or other positions (root passes, verticals, etc.), so they aren’t the standard choice for fill and cap in a 4G weld.