The 4 welding positions explained
What are the 4 welding positions?
Welding positions describe the orientation of the joint and the welder relative to gravity during the weld: flat, horizontal, vertical, and overhead. Each position changes how molten metal behaves, since gravity pulls the weld pool differently depending on orientation, and each is tested and qualified separately in code-qualification testing.
Flat position (1G / 1F)
Flat is the easiest position to weld in: the joint runs horizontally with the welder working from above, and gravity holds the weld pool in place. In test nomenclature, 1G designates a flat-position groove weld test and 1F designates a flat-position fillet weld test. G stands for groove weld and F stands for fillet weld, two different joint types used in qualification testing.
Horizontal position (2G / 2F)
Horizontal position work runs along a horizontal axis on a vertical face, so the weld pool tends to sag downward under gravity instead of staying centered the way it does in flat position. 2G designates the horizontal groove test, and 2F designates the horizontal fillet test.
Vertical position (3G / 3F)
Vertical position welds run up or down a vertical joint. Gravity pulls straight down along the direction of travel, which makes controlling the weld pool harder than in flat or horizontal work. 3G designates the vertical groove test, and 3F designates the vertical fillet test.
Overhead position (4G / 4F)
Overhead position places the welder beneath the joint, welding upward against gravity for the entire weld. It is generally considered the most demanding of the four positions to control. 4G designates the overhead groove test, and 4F designates the overhead fillet test.
Why certification tests separate positions
A welder qualifies to a specific position or combination of positions, not to welding in general. Employers and certification tests, including the position-specific tests referenced in the AWS D1.1 structural welding code, confirm a welder can produce a sound weld in the position the job requires. A welder who tests and qualifies 1G is qualified for flat-position groove work; that qualification does not carry over to 4G overhead work without separately testing and qualifying in that position. That is why job postings and code-qualification records specify a position code rather than the word "welding" alone.
On an actual jobsite, out-of-position work, vertical and overhead in particular, is common in construction and structural steel work, where a joint's location is fixed by the structure rather than chosen for convenience. A welder who only holds a flat-position qualification is not able to take on that portion of the job until testing to the position it requires.
Position testing applies across welding processes
Position qualification is not tied to a single welding process. A welder can test in a given position using stick welding (SMAW), MIG welding (GMAW), or TIG welding (GTAW); the position code describes the joint orientation, not which process produced the weld. That is why a job posting or a code-qualification record often lists a process and a position together, for example a specific process qualified in the 3G vertical position, rather than the position alone.
How this shows up in code qualification
The D1.1 structural welding code is one place these position tests get applied directly: a welder qualifying to D1.1 for structural steel work tests in the position or positions the employer's work requires, using the G and F designations above. Our certification codex covers how D1.1 fits alongside AWS's other credentials, and the D1.1 certification page covers what that specific code governs.
FAQ
What do the numbers 1G, 2G, 3G, and 4G mean?
They designate groove weld qualification tests in flat, horizontal, vertical, and overhead position, in that order. The equivalent fillet weld tests use F instead of G: 1F, 2F, 3F, 4F.
Is a welder qualified in one position qualified in all positions?
No. Qualification is position-specific. A welder who passes a 1G flat-position test is not automatically qualified for 3G vertical or 4G overhead work.
Which welding position is hardest?
Overhead is generally considered the most demanding of the four, since the welder works against gravity for the entire weld. Difficulty across the other three varies by joint type and welder experience.
Where are these position codes used?
Employers and code-qualification tests, including tests under the AWS D1.1 structural welding code, use these codes to specify and confirm which position or positions a welder is qualified to work in.
Does position qualification depend on which welding process is used?
No. Position codes describe joint orientation, not process. A welder can qualify in a given position using stick, MIG, or TIG welding, and job postings typically specify both the process and the position required.