Does a WPS qualified vertical-uphill also cover vertical-downhill welding?

No. Vertical progression — uphill or downhill — is listed in AWS D1.1:2025 Table 6.6 as an essential variable for SMAW, GMAW, FCAW, and GTAW. Changing progression requires a separate PQR qualification or a separate prequalified WPS that explicitly permits the new progression.

Is vertical-downhill welding allowed on prequalified WPSs under AWS D1.1?

Only in limited configurations. Prequalified WPSs permit vertical-downhill for fillet welds and certain flare groove welds in specific circumstances, but CJP groove welds in the vertical position require uphill progression under prequalified rules. Vertical-down on CJP groove welds requires a full PQR.

What's the engineering reason AWS D1.1 restricts vertical-downhill?

Vertical-downhill is faster and produces a shallower, flatter bead. The weld pool tends to run ahead of the arc, reducing fusion at the root and sidewalls. In groove welds especially, inadequate fusion is a serious structural deficiency. The code restricts downhill because the physics work against reliable fusion on thicker material.

If a welder is qualified 3G uphill, can they weld 3G downhill without a separate test?

No. Welder qualification tracks position and progression separately. A 3G uphill qualification does not extend to 3G downhill. The welder would need to test the specific progression they are performing.

Vertical welding progression: uphill vs. downhill on a WPS

AWS D1.1:2025 Table 6.6 lists vertical progression as an essential variable. A downhill-qualified WPS does not cover uphill — and vice versa. Here's what that means in practice.

Vertical welding seems like it should be one category — you're welding on a vertical surface, end of story. But AWS D1.1:2025 treats uphill and downhill as distinct conditions. The direction of travel is an essential variable, meaning a WPS (and the PQR behind it) must specifically qualify the progression used in production.

Understanding why progression matters — and what the code actually requires — helps CWIs and QC managers avoid an audit finding hiding in plain sight.

Why progression is an essential variable

The weld pool behaves differently depending on whether you travel uphill or downhill. When you weld vertical-uphill (also called 3G-uphill or progression-up), gravity acts against the pool running away from the arc. The puddle stays under control, the arc penetrates into the base metal, and fusion at the sidewalls and root is generally reliable.

Vertical-downhill reverses that dynamic. The pool wants to flow in the same direction as travel — downward — which means it can run ahead of the arc. When the pool gets between the arc and the base metal, you lose fusion. On thin sheet metal, downhill is acceptable and common (it's faster and produces less distortion). On structural plate thicknesses, that fusion loss becomes a structural liability.

AWS D1.1:2025 codifies this difference by listing progression as an essential variable in Table 6.6. Changing from uphill to downhill, or from downhill to uphill, requires the WPS to be supported by a PQR that tested the new progression — or a prequalified WPS that explicitly permits it.

What the prequalified path allows

Prequalified WPSs under AWS D1.1:2025 (Clause 5 prequalified provisions) do not require a PQR, but they come with restrictions on what progression is permitted.

For fillet welds and flare groove welds in the vertical position, AWS D1.1 permits both uphill and downhill progression on a prequalified WPS, subject to the applicable base metal group, electrode classification, and size limits.

For complete joint penetration (CJP) groove welds in the vertical position (3G), the prequalified path requires uphill progression. If you want to run a CJP groove weld vertical-downhill, you cannot use the prequalified route — you must develop a PQR. No PQR, no downhill on CJP groove welds, full stop.

This is a common gap in fab shop WPS libraries. A shop that has been running vertical-downhill CJP welds on prequalified WPSs without testing is operating outside the prequalified limits, even if the welds have passed UT or RT.

Progression on the PQR qualification path

When a WPS is supported by a PQR, the test coupon was run in a specific progression. That progression is documented on the PQR, and it limits the production WPS.

Practical implications:

A PQR run vertical-uphill supports a WPS that specifies vertical-uphill only.
A PQR run vertical-downhill supports a WPS that specifies vertical-downhill only.
To cover both progressions, you need two PQRs — or a test that specifically addresses both, which AWS D1.1 does not provide a standard path for in a single coupon.

Most fab shops that need vertical coverage in both directions maintain two vertical PQRs and two corresponding WPS variants, or they restrict production to uphill only and avoid the issue.

Welder qualification follows the same logic

Welder performance qualification (WPQ) under AWS D1.1 also tracks progression. When a welder tests in the 3G position, the test specifies whether it was uphill or downhill. The qualification that results covers that progression for that position.

A welder with a 3G-uphill qualification is not qualified to weld 3G-downhill in production. If inspection catches a welder running downhill on a joint that the WPS specifies uphill (or vice versa), that is a dual nonconformance: the welder is outside their qualification and the WPS is being violated.

For shops that run both progressions in production — perhaps using downhill for tack welds or weld passes on thin material and uphill for structural fill and cap passes — the WPS must explicitly address each progression, the supporting PQRs must cover each, and the welders must hold qualification for each.

Common audit findings related to progression

Auditors and third-party inspectors looking at WPS libraries regularly find:

WPS specifies "vertical" without noting uphill or downhill. The form has a blank next to "position" filled in as "3G" but no progression call-out. Under AWS D1.1, this is an incomplete WPS — progression must be stated.

Prequalified WPS permits vertical-downhill on CJP groove welds. The shop wrote a prequalified WPS and left progression unspecified or indicated downhill. That WPS does not comply with AWS D1.1 prequalified requirements for CJP groove welds.

Welder qualification matrix doesn't separate progressions. The WPQ log shows "3G" under position qualification but doesn't record uphill vs. downhill. When a specific production weld requires a particular progression, there's no way to confirm the welder is qualified for it.

Documenting progression correctly on a WPS

The Annex M WPS form has a position/progression field. Fill it in explicitly:

"Vertical — uphill (3G-uphill)" or
"Vertical — downhill (3G-downhill)"

If the WPS covers multiple positions and progressions, list each combination. Do not write just "3G" and leave progression blank — that's a deficiency waiting to be found.

When a CWI reviews a WPS before welding begins, progression is one of the items to confirm against the actual joint configuration and the welder's qualification record. If the WPS calls for uphill and the welder's only 3G qualification was downhill, work stops until the issue is resolved — before the first arc is struck, not after the weld is in.

The software verification path

A WPS management system that enforces essential variable rules can flag progression mismatches automatically — comparing the WPS-specified progression against the PQR progression on file. That check catches the problem at the document level, not during a third-party audit.

See related coverage of essential variable scope in AWS D1.1:2025 Table 6.6 explained and welding position qualification limits under AWS D1.1. For WPS and PQR management that tracks progression as part of the essential variable matrix, see our WPS software.

Rule library based on AWS D1.1:2025; verify against your governing edition. The AHJ or contract may specify an earlier edition with different prequalified progression restrictions.