The 4G position puts the plate flat above your head and the puddle directly over the arc, which means gravity works against every bead you lay. AWS D1.1 governs the test, and most structural shops run it as the second half of a 3G/4G combo: the vertical uphill groove first, then the overhead. Part one covered the 3G SMAW plate test, and the coupon, bevel, and backing setup carry over almost unchanged.
What changes is control. Amperage that worked vertical will drop your fill passes out of the joint overhead, and a cap that piles too high fails visual before a bend specimen is ever cut.
That is the real barrier: 4G is less about heat and more about holding a short arc in a position where the puddle wants to leave.
Understanding the 4G Overhead SMAW Certification Test
Overhead Stick Welding remains one of the last skills that separates a shop welder from a structural fabricator, and the AWS D1.1 4G welder qualification test is still the industry's cleanest way to prove it. If you already read part one of this series on 3G SMAW welding, the 4G is the mirror image of that test performed with the plate fixed above your head.
What the 4G Position Actually Means
In AWS terminology, "4G" designates a groove weld (the G) performed in the overhead position (the 4). The test plates are clamped horizontally with the joint facing straight down at the floor, and you weld upward into the groove while standing or kneeling beneath them. Under AWS D1.1, the standard configuration uses two beveled plates with a 1/4 inch backing bar tacked to the underside of the joint, giving the root pass something to fuse into rather than an open gap.
The key word is groove. A 4G qualification covers groove welds in the overhead position on plate; pipe is a separate test, and fillet coverage is a separate matter under D1.1. Overhead fillets fall under 4F, which is a separate (and easier) qualification. If your work involves overhead T-joints or lap joints exclusively, 4F may be all you need, but most structural employers want the groove ticket because it is the harder test; just do not assume a groove pass carries fillet privileges automatically.
Combo Testing With 3G
Most testing facilities administer 4G as the second half of a 3G/4G combo. The logic is practical: an employer running structural steel almost always needs welders who can handle both vertical and overhead joints, so testing them together saves shop time and coupon material. That said, you can absolutely sit for the 4G on its own if you already hold a current 3G certification or if your work is strictly overhead.
Why Employers Require It
AWS D1.1 is the structural steel welding code adopted across bridge work, building steel, and heavy fabrication in the United States. A 4G SMAW qualification on that code tells a hiring foreman three things without a conversation: you can run 7018 out of position, you understand joint prep and pass sequencing, and your welds have passed guided bend tests witnessed by a certified inspector. That is why the ticket travels well between shops and why it usually bumps your hourly rate.
4G SMAW Test Coupon Dimensions and Joint Preparation
This table gives the coupon dimensions and joint preparation details commonly used for a 4G SMAW qualification test. Exact tolerances can vary by edition and test facility, so verify the current AWS D1.1/D1.1M figure before cutting or beveling plate.
| Parameter | AWS D1.1 Requirement | Why It Matters |
|---|---|---|
| Plate thickness (limited) | 3/8 in thick test coupon | Qualifies production welds through 3/4 in thick. |
| Plate thickness (unlimited) | 1 in thick test coupon | Used when an unlimited qualified production thickness range is required. |
| Coupon width | 3 in wide plate | Standard coupon width for both limited and unlimited test plates. |
| Coupon length | 7 in long for 3/8 in plate; 5 in long for 1 in plate | 1.25 in is discarded from each end before evaluation, leaving the test zone in the middle. |
| Joint type | Single-V groove with steel backing | Backing supports the overhead root pass and prevents excessive melt-through. |
| Root opening | 1/4 in commonly published | Provides enough access for the SMAW electrode to tie into the backing and sidewalls. |
| Root face (land) | No land or root face commonly reported | A zero land helps maintain full penetration at the root when welding overhead. |
| Backing bar thickness | 1/4 in to 3/8 in [6 mm to 10 mm] | Adequate thickness prevents melt-through while supporting the molten weld pool. |
| Backing bar width | 3 in minimum if backing remains for RT; 1 in minimum if backing is removed | Width matches the radiographic testing setup or removal plan. |
| Backing bar contact | Backing shall be in intimate contact with the base metal | Gaps behind the backing can trap slag and cause root defects. |
SMAW Machine Settings for Overhead 4G
E6010 or E7018: the two electrodes dominate 4G overhead qualification, and each asks for a different hand and a different machine setting. E6010 digs deep with a crisp, aggressive arc that forces its way through mill scale and gap variance, which is why many test procedures still call for it on the root pass. E7018 lays down a smoother, lower-hydrogen bead better suited to fill and cap passes where appearance and soundness both matter. Your procedure specification will tell you which one (or both) the test requires, but understanding why each is chosen helps you read the arc instead of just following instructions.
Amperage Ranges Overhead
Overhead welding punishes an overheated puddle, so amperage typically runs lower than the same electrode would use flat. For 3/32 in E6010, expect roughly 40 to 70 amps2; 1/8 in E6010 generally runs 75 to 125 amps. E7018 in 3/32 in typically falls between 65 and 110 amps, while 1/8 in ranges from 90 to 150 amps flat, though overhead work commonly narrows that to around 90 to 120 amps to keep the puddle from sagging. Once you move to 5/32 in E7018, figure roughly 120 to 190 amps3, and 3/16 in stretches from about 180 to 260 amps, though exact windows shift by manufacturer since flux chemistry and iron powder content aren't standardized across brands. As a rule of thumb, expect to drop amperage 10 to 15 percent from your flat-position setting once you're welding overhead.
Why DCEP
Both E6010 and E7018 run on direct current electrode positive, and for overhead work that polarity choice matters. DCEP concentrates heat at the electrode tip while directing a strong, focused arc force into the joint, which helps counteract gravity's pull on the molten puddle. E7018 can also run on AC depending on the machine and rod brand, but DCEP remains the standard choice for test coupons because it gives you the steadiest arc control when you're fighting to keep metal from dripping.
Travel Speed and Puddle Control
General SMAW travel speed guides put 1/8 in electrodes around 5 to 10 inches per minute, with smaller rods running 3 to 9 ipm and larger rods 5 to 12 ipm. Overhead work tends to sit at the faster end of whatever range applies to your rod size, since slower travel lets the puddle grow heavy and droop or sag out of the joint. If you notice the puddle ballooning or icicles forming, that's your cue to speed up slightly, shorten your arc, and avoid lingering in one spot. Overhead technique rewards a tight, controlled arc and a puddle that freezes almost as fast as you deposit it.
4G Overhead Weld Pass Sequence at a Glance
In 4G overhead SMAW, the weld is built from the bottom up in a controlled sequence. Each pass has a distinct electrode angle and bead placement that keeps the molten pool from sagging.
Pass-By-Pass Technique: Root, Fill, and Cap
In 4G SMAW, the difference between a fused root and a sagging repair is usually puddle control, not strength. Overhead welding rewards a short arc, steady travel, and a cap that stops at the toes instead of piling up in the center.
Root pass: short, fast, and fused
Start with a tight root. Some 4G procedure guidance lists a 70-degree travel angle with a 90-degree work angle, while other overhead instruction uses a nearly perpendicular push angle of 0 to 15 degrees. Both setups aim for the same outcome: a short arc, a quick steady forward motion, and no lingering in the puddle. Lower the heat slightly from flat or horizontal settings, keep the electrode close, and move fast enough to prevent sag while still tying into both sidewalls. Constant speed matters more than the exact electrode angle. Watch the puddle rather than the arc. If it begins to droop, speed up or shorten the arc before it falls out of the joint.
Fill passes: clean layering beats wide weaving
A wide weave is tempting for speed, but overhead it often opens the door to slag inclusions and drips. A more controllable 4G approach is to run stringer beads, each covering about one-third to one-half of the previous bead and no wider than two to three electrode diameters. Between every pass, remove all slag and spatter with a wire wheel, chipping hammer, or grinder. Trapped slag in a fill pass will fail a bend test in destructive weld testing as surely as a lack of fusion. If the plate becomes too hot to touch comfortably, let it cool before continuing.
Cap pass: tie in the toes without overbuilding
The cap should be flush to slightly convex, with reinforcement in the 1/16 to 1/8 inch range and no more than 1/8 inch overall. Use controlled cap welding techniques such as a weave or stringer sequence, pause briefly at each toe to wet the edge, then move across the center without dwelling. Run the cap slightly cooler to keep the puddle controllable. The goal is a smooth tie-in on both edges with no undercut. A long arc, excessive weave, or hesitation in the middle will create excess buildup or a drip, especially near the cap edges.
Overhead puddle control: one rhythm across all passes
Across all three passes, the same overhead rules apply. Keep the arc short, avoid dwelling in the center, and push the puddle toward the upper side of the joint so gravity has less time to act. If the weld starts to look heavy, increase travel speed slightly rather than lengthening the arc. A short, controlled movement beats a long sweep every time in the overhead position.
Avoiding Common 4G Defects and Discontinuities
Why do overhead welds fail inspection more often than flat or horizontal ones? Gravity.1 In the 4G position, the molten puddle constantly wants to drop out of the joint before it wets into the base metal, so almost every common defect traces back to heat control and puddle management. Before chasing amperage changes, run through a quick sequence: verify your electrodes are dry, confirm the base metal is clean, shorten your arc, correct your angle, and reduce weave width. Only then fine-tune current and travel speed.2
Undercut and Slag Inclusions
Undercut, the unfilled groove left along the weld toe, is the most common overhead complaint.3 It comes from excessive amperage, fast travel, a long arc, a wide weave, or a bad electrode angle. Fix it by backing off the amperage (within WPS limits), tightening your arc, slowing down, narrowing your weave, and pausing briefly at the toes to let the puddle fill.
Slag inclusions happen when nonmetallic slag runs ahead of the pool and gets trapped in the weld metal.4 Overhead makes this worse because a runny puddle lets slag creep forward. Keep a tight arc, hold a proper drag angle so the arc force pushes slag back, and avoid wide weaves that let it pool. Most critical: chip and wire-brush thoroughly between every pass. Skipping interpass cleaning is the fastest way to fail a bend test.
Porosity and Lack of Fusion
Porosity, gas pockets trapped in the bead, usually points to contamination or damp electrodes.5 Store your rods properly, clean the base metal, hold a tight arc, and verify you are running the correct electrode type. A long arc pulls in atmosphere and is a frequent overhead culprit.
Lack of fusion, where weld metal fails to bond to the base or a prior bead, comes from low amperage, a fast travel speed, a long arc, or poor joint prep.6 The remedy is more heat and slower travel, but be careful: bumping current to fix fusion can immediately create undercut. Correct your work angle and manipulate the puddle to wash into the sidewalls first before you reach for the amperage dial.
Excessive Reinforcement
On the cap pass, resist the urge to pile on filler. Excessive reinforcement, an overly convex bead, comes from slow travel, dwelling in one spot, or center-piling your weave.7 Balance filler deposition against travel speed, keep the puddle small, and lay controlled stringer beads. A flat, uniform cap that blends into the base metal passes visual inspection every time.
AWS D1.1 Visual Acceptance Criteria and Bend Test Requirements
Use the following limits during visual inspection of the completed 4G overhead groove weld. For 4G qualification, the applicable face-bend and root-bend specimens are required; for 10 mm plate or wall thickness, a side-bend test may be substituted for each required face- and root-bend test. Bend specimens must withstand bending to 180 degrees with no cracks exceeding 1/8 in in any dimension.
| Inspection Item | Acceptance Criteria | Reject Condition |
|---|---|---|
| Cracks | Not permitted. | Reject cracks of any size. |
| Groove-weld reinforcement | Maximum 1/8 in [3 mm]. | Reject reinforcement exceeding 1/8 in [3 mm]. |
| Undercut: material less than 1 in [25 mm] thick | Maximum 1/32 in [1 mm], except up to 1/16 in [2 mm] is permitted for an accumulated length up to 2 in [50 mm] in any 12 in [300 mm]. | Reject when depth exceeds 1/32 in [1 mm], except the permitted 1/16 in [2 mm] allowance; reject when the 1/16 in [2 mm] condition exceeds an accumulated 2 in [50 mm] in any 12 in [300 mm]. |
| Undercut: material equal to or greater than 1 in [25 mm] thick | Maximum 1/16 in [2 mm] for any length of weld. | Reject any undercut deeper than 1/16 in [2 mm]. |
| Undercut: primary members transverse to tensile stress | Maximum 0.01 in [0.25 mm] deep under any design loading condition. | Reject undercut deeper than 0.01 in [0.25 mm]. |
| Visible piping porosity: complete joint penetration (CJP) groove welds | No visible piping porosity. | Reject any visible piping porosity. |
| Visible piping porosity: other groove and fillet welds | The sum of visible piping porosity 1/32 in [1 mm] or greater in diameter shall not exceed 3/8 in [10 mm] in any linear inch of weld and shall not exceed 3/4 in [20 mm] in any 12 in [300 mm] length of weld. | Reject when either limit is exceeded: more than 3/8 in [10 mm] summed diameter in any linear inch, or more than 3/4 in [20 mm] summed diameter in any 12 in [300 mm]. |
| Bend test acceptance | Specimens must withstand bending to 180 degrees without cracks exceeding 1/8 in in any dimension. | Reject if any single crack or open discontinuity exceeds 1/8 in in any direction on the convex surface, or if the sum of the greatest dimensions of cracks or open discontinuities exceeding 1/32 in but not exceeding 1/8 in exceeds 3/8 in. |
Related Articles
What Does a 4G Certification Qualify You to Weld?
Passing the 4G is a real accomplishment, but the certification card in your wallet covers less ground than most welders assume. The tradeoff to understand: overhead is one of the hardest positions to weld, yet 4G alone gives you a narrower production scope than a 3G. Knowing exactly what you can and cannot legally weld under AWS D1.1 keeps you out of trouble with inspectors and helps you decide whether to stop here or push on for the combo.
Position Range Qualified by 4G Alone
A 4G SMAW groove test on plate qualifies you for groove welds in the flat (1G) and overhead (4G) positions only. It does not qualify horizontal (2G) or vertical (3G) groove welds.1 That is the key gap compared to 3G, which covers flat, horizontal, and vertical but not overhead.1
On the fillet side, most references treat 4G as covering 1F and 4F fillet welds2, but fillet qualification is a separate matter under D1.1. If your employer or the job's Welding Procedure Specification requires documented fillet qualification, you may need a separate fillet test regardless of your groove ticket. Do not assume a groove pass carries fillet privileges automatically.1
Thickness Range
Thickness qualified tracks the coupon you welded. The common numbers cited from D1.1 qualification tables:
- 3/8 in test coupon: qualifies production thickness from 1/8 in to 3/4 in.3
- 1 in test coupon: qualifies 1/8 in to unlimited thickness.4
- 2020 edition minimum: production thicknesses at or above 1/8 in.
Exact ranges shift slightly by code edition, so verify against the D1.1 version your shop or inspector is working under.
Combining 3G and 4G for Full Position Coverage
This is why the 3G/4G combo is the standard structural welder qualification. Passing both tests on plate qualifies you for groove welds in all plate positions: flat, horizontal, vertical, and overhead.4 Fillet coverage generally extends across all positions as well when both are held2, though the specific fillet scope should still be checked against the qualification table in the edition being applied.
If you took the 4G as part two of the combo (see the 3G SMAW guide for part one), you now hold the full-position plate groove qualification most structural shops ask for. If you tested 4G on its own, plan on adding a 2G or 3G later to broaden what you can legally weld in production.
4G vs 4F vs 6G: Welding Position Differences
Should you follow up your 4G ticket with a 4F or aim straight for 6G pipe? The answer depends on where you want your career to go, since each of these AWS D1.1 qualifications tests a different skill set and opens a different door.
What Each Test Actually Covers
4G is an overhead groove weld on a plate coupon.1 It's the test you just prepared for, and passing it under AWS D1.1 typically qualifies you for flat and overhead plate work; horizontal and vertical plate usually still require a separate qualification, commonly covered by 3G. That's why the 3G plus 4G combo is treated as the standard route to full plate-position coverage.1
4F is the fillet-weld counterpart tested overhead on plate.2 It's less demanding metallurgically than a groove weld since there's no root pass to defeat gravity through an open joint, but it's a genuinely useful credential for structural fabrication shops where fillet welds dominate production work, think base plates, brackets, and connection stiffeners.
6G is a different animal entirely. It's a groove weld on pipe fixed at a 45-degree incline, welded without rotating the pipe.3 Because the welder has to transition through flat, vertical, and overhead orientations in a single continuous joint, 6G pipe welding is widely regarded as the toughest single qualification in structural and pipe welding. Passing it usually demonstrates all-position capability on pipe in one test.3
Where ISO 6947 Fits In
If you ever work for a company using international standards, you'll see position codes like PE instead of 4G or 4F. ISO 6947 designates PE as the overhead welding position, and it's the closest practical match to AWS's overhead qualifications.2 That said, ISO and AWS systems aren't a clean one-to-one swap. Test coupon geometry, acceptance criteria, and documentation requirements differ enough that a PE qualification under ISO won't automatically satisfy an AWS D1.1 requirement, or vice versa.
Choosing Your Next Certification
- Structural fabrication shops: 4F rounds out fillet-weld coverage if that's most of the shop's output.
- Structural code work: 4G (paired with 3G) gets you full plate qualification for AISC and bridge-code fabrication.
- Pipeline, petrochemical, or power work: 6G is the credential employers look for first, since it signals you can handle fixed-position pipe in the field.
Exact coverage always depends on the code edition, coupon thickness, and material group your employer accepts, so confirm specifics before assuming a pass transfers directly to a job requirement.