Welding Position: Plate and Pipe Designations
The position language
Positions use a number plus G (groove) or F (fillet): 1 flat, 2 horizontal, 3 vertical, 4 overhead. For plate, 3G has the joint axis vertical with the face perpendicular to the bench; 4G is overhead. Pipe uses a different scheme: 1G is a rolled pipe with the weld kept flat, 2G is a vertical pipe with a horizontal weld, 5G is a horizontal fixed pipe welded all the way around (flat, vertical and overhead in one pass sequence), and 6G is a fixed pipe inclined at 45 degrees, the most demanding test because every position appears with no rotation.
Technique by position
Flat allows the highest current, largest puddle and fastest travel. Horizontal tends to sag, so trim the current slightly and watch the upper toe for undercut. Vertical-up, usually at lower current with a short arc and a controlled weave at the leading edge of the puddle, gives better penetration and is the common root-pass choice with cellulosic electrodes; vertical-down is faster with less penetration and needs a tight arc. Overhead uses the lowest current and a small puddle with a slight push angle to hold the metal up.
Worked example
If a flat test runs well at 130 A, start vertical-up near 110-115 A (roughly 10-15% lower) and overhead near 100-110 A, then tune to the puddle.
Traps
Mixing 5G and 6G, assuming a 3G plate test covers 6G pipe, and forgetting that "vertical" alone does not specify up or down; progression is often an essential variable.