Guide
Welding Positions Explained: 1G to 6G and 1F to 4F
Welding positions are coded by a number for the orientation and a letter for the weld type — G for groove, F for fillet — so 3G is a vertical groove weld and 2F is a horizontal fillet.
Position codes appear on welder qualification papers, on procedure specifications and in electrode classifications. The system is simple once you separate the number from the letter: the number gives the orientation of the joint, the letter gives the type of weld.
Groove weld positions
| Code | Position | Description |
|---|---|---|
| 1G | Flat | Plate horizontal, welded from above. The easiest position — gravity holds the puddle in the joint. |
| 2G | Horizontal | Plate vertical, weld axis horizontal. The puddle wants to sag downward, so stringer beads and reduced amperage are needed. |
| 3G | Vertical | Plate vertical, weld axis vertical. Run uphill on most code work; vertical-down is faster but risks lack of fusion. |
| 4G | Overhead | Plate horizontal, welded from below. Gravity works entirely against you, so amperage comes down and the puddle must be kept small. |
| 5G | Pipe horizontal, fixed | Pipe axis horizontal and the pipe does not rotate. The welder works through flat, vertical and overhead in a single pass around. |
| 6G | Pipe at 45°, fixed | Pipe fixed at 45 degrees. Combines every orientation at once and is the standard benchmark for pipe welder qualification. |
Fillet weld positions
| Code | Position | Description |
|---|---|---|
| 1F | Flat fillet | Joint rotated so the weld sits in a 45 degree groove — the easiest fillet to run. |
| 2F | Horizontal fillet | Vertical member with the weld axis horizontal. The most common fillet position in real fabrication. |
| 3F | Vertical fillet | Weld axis vertical, run uphill on most code work. |
| 4F | Overhead fillet | Welded from below. |
What the codes mean for qualification
A welder qualified in a harder position is generally qualified for the easier ones, though the exact rules come from the governing code rather than from convention. A 3G and 4G plate test together typically qualifies a welder for all plate positions. A 6G pipe test is the broadest common qualification because the fixed 45 degree pipe forces the welder through every orientation in a single joint.
How position affects your settings
- Drop amperage 10 to 15% from flat when welding vertical or overhead — a hot puddle will simply fall out of the joint.
- Use stringer beads rather than wide weaves out of position; a wide weave carries too much molten metal.
- Choose a fast-freezing electrode for out-of-position work. E6010, E6011 and E7018 all hold position; E7024 does not and is classified flat and horizontal only.
- In short-circuit MIG, keep heat input low and travel steady. Axial spray transfer cannot be used out of position at all, though pulsed spray can.
- On vertical groove welds, uphill gives better penetration and downhill gives higher travel speed. Most codes require uphill on thicker material.
Position in the electrode classification
The third digit of a carbon steel stick electrode number gives its position capability. A 1, as in E6010 or E7018, means all positions. A 2, as in E7024, restricts the rod to the flat position and horizontal fillets. A 4 means all positions including vertical-down. That digit is a hard limit set by how fast the slag freezes, not a suggestion about difficulty.
Frequently asked questions
What is 6G welding?
A groove weld on pipe fixed at a 45 degree angle, with the pipe unable to rotate. It forces the welder through flat, vertical and overhead orientations in one joint, which is why it is the broadest common pipe qualification test.
What is the difference between 3G and 3F?
The letter gives the weld type. 3G is a vertical groove weld, 3F is a vertical fillet weld. The number, 3, means vertical in both cases.
Which welding position is hardest?
Overhead (4G and 4F) is the hardest single orientation because gravity works entirely against the puddle. 6G is the hardest test because it combines every orientation in one weld.
Should you weld vertical up or down?
Uphill gives deeper penetration and is required by most codes on thicker material. Downhill is faster and suits thin material and pipeline stringer beads with E6010, but it risks slag inclusions and lack of fusion with heavy-slag electrodes like E7018.
Why can't E7024 be used vertical?
The 2 in the classification restricts it to the flat position and horizontal fillets. Its large, fluid, iron-powder-loaded puddle sags out of position and cannot be held in the joint.