3G and 4G Welding Test: The Complete Guide to Plate Qualification

A young structural welder walked into a fabrication shop interview expecting to prove himself on the job, only to be told: ‘Come back when you’ve passed your 3G and 4G.’ He had two years of experience and could lay a clean bead in the flat position, but nobody would put him on a bridge girder without paper proving he could weld vertical and overhead. That single test — two steel plates, one welded upright and one above his head — is the gatekeeper between shop practice and real all-position structural work, and this guide explains exactly what it is, what it qualifies you for, and how to pass it.

What Is a 3G and 4G Welding Test? A Real-World Overview

The 3G and 4G welding test is a welder performance qualification test performed on plate groove weld coupons. In plain terms: you take two beveled steel plates, clamp them into a fixture, and weld a single-V groove joint. For the 3G coupon, that plate sits vertically and you weld the groove in the vertical position, almost always climbing uphill. For the 4G coupon, the plate is mounted horizontally with the groove facing downward, so you weld the joint from underneath, over your head. Pass both coupons, and structural steel employers treat you as an all-position plate welder.

The tests are not a invention of any individual shop. They are defined in the AWS B2.1 specification for welder qualification and administered under the rules of the AWS Structural Welding Code D1.1. Every candidate welds to a written Welding Procedure Specification (WPS) that fixes the electrode, amperage range, plate thickness, preheat, and progression direction, so the test measures your ability to follow a procedure as much as it measures your hand skill.

Decoding the AWS Position Code

AWS notation is compact but consistent. The number before the letter tells you the welding position, and the letter tells you the joint type. G stands for groove weld (a joint between two beveled plates), and F stands for fillet weld (a T-joint or lap joint).

• 1G — flat groove weld, with the welder working down onto the joint from above.
• 2G — horizontal groove weld, with the joint axis horizontal and the weld deposited on a vertical face.
• 3G — vertical groove weld, with the joint axis running up and down. Vertical uphill is the default progression for structural groove welds on thicker plate.
• 4G — overhead groove weld, with the welder depositing metal from below the joint.

One point trips up almost every beginner, so it is worth stating twice: on a 4G coupon the plate sits horizontal and the joint axis is horizontal, but the welding is done overhead. Gravity pulls the puddle toward your face, not into the joint, which is exactly why 4G has the reputation it has.

Who Requires It, and Why

Anyone hiring you to put structural steel together will ask about it: bridge contractors, structural fabricators, steel erection and ironworker outfits, shipyards, and heavy equipment shops. State transportation departments are among the strictest, because bridge welds carry live loads and fatigue. Welding qualification is also an employer responsibility under D1.1 — the code does not hand out certificates; it tells an employer how to verify that a welder can produce sound work to a given procedure. That verification can happen in the employer’s own shop or at an AWS-accredited testing facility, where an inspector runs the whole process against the code’s Clause 6 performance qualification rules.

WPQ Record vs. AWS Certified Welder Card

These two get confused constantly. A Welder Performance Qualification (WPQ) record is the document your employer or test facility generates when you pass a qualification test under AWS D1.1 Clause 6 or AWS B2.1 Clause 5. It lists the processes, positions, thickness ranges, and essential variables you are qualified for, and it stays with the employer who qualified you. It is not a portable license.

An AWS Certified Welder card is different. That program, run through the American Welding Society, tests you against a standard welding procedure and issues a personal certification that you carry from job to job. Many welders hold both, but passing your 3G and 4G at a fab shop gives you a WPQ, not an AWS card.

Why “3G and 4G” Means All-Position

The shorthand exists because of what the qualification tables allow. A 3G test alone qualifies you for vertical and flat groove work; a 4G test alone qualifies you for overhead and flat. Weld both, and the combined coverage expands to every plate groove position (1G, 2G, 3G, 4G) and every plate fillet position (1F through 4F), plus groove welds on large-diameter pipe. That is why a foreman who says “I need a 3G/4G welder” really means “I need someone who can weld flat, horizontal, vertical, and overhead without supervision.”

It is also why the test is the natural next step after you have learned the fundamentals. If you are still building hours, a solid all-position welding rod and a stack of practice coupons will get you far closer to passing than any amount of reading alone. The next section breaks down the full position system so the 3G and 4G designations sit in context rather than floating as two mysterious letters.

Understanding Welding Positions: Groove vs. Fillet, Plate vs. Pipe

Before tackling a 3G or 4G test, it’s important to know the code behind it. Welding position designations are a shorthand that tells an inspector the weld type, the orientation of the joint, and how much gravity the welder will have to fight. These designations are standardized by AWS, and can be found referenced in both AWS B2.1, the Specification for Welding Procedure and Performance Qualification and the AWS Structural Welding Code.

The Number and Letter Code

Each position is made up of a number and a letter. The letter defines the weld type: G for a groove weld, and F for a fillet weld. The number defines the position, and for plate work it follows a set order based off of gravity:

• 1 = Flat – Welded from above with gravity assisting.
• 2 = Horizontal – Weld axis is horizontal.
• 3 = Vertical – Weld axis runs vertically along the plate.
• 4 = Overhead – Welded from underneath the joint against gravity.

Groove vs. Fillet: Different Joints, Different Qualifications

A groove weld requires the edges of the two pieces to be beveled or prepped, allowing the weld metal to fill the gap for full thickness fusion. This is the joint used for 3G and 4G plate tests, and it’s typically used where the weld must carry structural loads. A fillet weld, on the other hand, is placed in the corner of a perpendicular or overlapping joint, such as a T-joint, with little to no edge preparation.

These are not interchangeable. Passing a groove qualification does not automatically qualify a welder for fillet work, and vice versa. For all-position groove tests, low-hydrogen rods such as E7018 are commonly used due to their stability. For more specifics on rod selection, our all position welding rod guide goes into greater detail.

Gravity and the Difficulty of Vertical and Overhead

Position difficulty comes down to gravity. In flat welding, it pulls the puddle into the joint. In horizontal (2G), it pulls molten metal towards the bottom edge, requiring tight control to avoid buildup. Vertical welding requires an uphill approach for most tests, forcing the puddle to freeze fast enough to support itself as it’s built up. Overhead is the harshest of the four plate positions, as gravity is constantly trying to drip molten metal off of the joint.

The 4G Paradox and Plate vs. Pipe

The most common point of confusion is the 4G test. A 4G coupon is horizontal, with its single-V groove facing down. The welder must work underneath it, depositing overhead metal into a joint with a horizontal axis. This is what makes it vastly different from 2G, despite both plates often looking horizontal at a glance. As stated by AWS D1.1 performance qualification position summaries, the designation is based off of the position of the weld as deposited, not the plate’s orientation alone.

Pipe adds rotation into the equation. A 1G or 2G pipe test can be rolled on rollers, keeping the weld in flat or horizontal position for the welder. However, 5G fixes the pipe horizontally with no rotation, forcing the welder to move around the circumference through flat, vertical, and overhead. 6G takes this a step further, fixing the pipe at a 45° angle with no rotation. This combines every position into one continuous weld, making 6G the most widely recognized test of all-position pipe skill.

AWS D1.1 Qualification Rules: What Passing 3G and 4G Actually Qualifies You For

Passing a test is one thing. Knowing exactly what that test buys you is another. This is where most welders get confused, because AWS D1.1 does not hand you a magic “all-position” card the moment the bend specimens come back clean. The code ties your qualification to three specific things: the positions you welded, the thickness you welded, and whether backing was present. Get those three straight and you will never misread your own paperwork again.

The Position Table: 3G, 4G, and the Magic of 3G + 4G

AWS D1.1 welder performance qualification tables (listed as Table 6.10 and Table 6.11 in recent editions, with older editions numbering them differently) map each test coupon to a specific set of production positions. The pattern is consistent and easy to remember:

Test passed	Qualifies you for (groove)	Qualifies you for (fillet)
3G only	1G, 3G plate	1F, 2F, 3F
4G only	1G, 4G plate	1F, 2F, 4F
3G + 4G	All plate groove: 1G, 2G, 3G, 4G	All plate fillet: 1F, 2F, 3F, 4F

Notice what happens when you combine them. The 3G coupon covers flat and vertical, the 4G coupon covers flat and overhead, and together they fill every gap, including the horizontal (2G) position you never actually tested in. That is the whole reason shops ask for “3G and 4G” as a package: it is the shortest route to full plate qualification. The combined test also extends to groove welds on pipe with a nominal outside diameter of 24 in. (600 mm) and larger, which covers structural pipe and tube work but not small-bore piping.

Fillet qualifications ride along with the groove test automatically, since a groove test is the more demanding demonstration of skill. The full range of rod options you might run in those positions is covered in our All Position Welding Rod Guide: Types, Uses & Tips.

Thickness Qualification: The 3/8 In. vs. 1 In. Coupon Decision

Position is only one axis. The thickness of your test coupon sets the range of material you may weld in production, and this is where candidates sometimes pick the wrong coupon without realizing it.

• 3/8 in. (10 mm) coupon: qualifies you to weld production base metal from 1/8 in. (3 mm) up to 3/4 in. (20 mm), or 2T maximum, whichever is less.
• 1 in. (25 mm) coupon: qualifies you from 1/8 in. (3 mm) up to unlimited thickness.

The thinner coupon is faster and cheaper to run, but it caps you out at 3/4 in. material. If you are heading into heavy structural or bridge work where flange thickness regularly exceeds that, it pays to weld the 1 in. coupon once and be done. The base metal itself has to stay within the qualified range of your written procedure, and every test weld is performed against a specific WPS with defined preheat and interpass limits, such as the NCDOT 3G-4G Plate Certification WPS.

Backing and Essential Variables: What Can Void Your Qualification

Backing is its own qualifier. A test welded with a backing strip qualifies you for production welds with backing; it does not automatically qualify you for open-root, no-backing work. To weld without backing you must test in the no-backing condition, or your procedure must specifically permit it. The reverse also holds, and testing without backing typically covers both cases under D1.1, though the exact rule depends on your WPS and clause.

Then come the essential variables, the parameters that quietly invalidate a qualification when they change. The one that catches the most welders is vertical progression: switching from vertical uphill to vertical downhill (or vice versa) is an essential variable under AWS D1.1. Test uphill and your employer runs production downhill, and you are no longer qualified for that weld, even though the plate, process, and electrode are identical. Other common essential variables include process changes, transfer from one classification of electrode to a significantly different one, and removal of backing where it was qualified as present. AWS B2.1, the base specification behind these qualification rules, is published by the American Welding Society for reference alongside D1.1 (AWS B2.1/B2.1M specification).

Read your WPQ line by line when you receive it. It should state the positions, thickness range, backing condition, process, and essential variables you are qualified for. If any line surprises you, ask before you leave the shop, because that document, not your memory of the test, is what an inspector will read.

Test Coupon Setup: Joint Design, WPS, Materials, and Preparation

Before a welder strikes an arc on a 3G or 4G test, someone has already spent time building the coupon. The test plate is not a scrap piece you grab off the rack. It is a precisely fit-up joint built to a specific figure in the AWS D1.1 Structural Welding Code, and every dimension on it has a reason. Understanding that setup is half the battle, because most “test failures” start before the first bead is laid.

The Standard Unlimited-Thickness Coupon

For the standard plate qualification test, the coupon is a single-V groove butt joint made from two steel plates:

• 45° included angle total, split evenly so each bevel is cut at roughly 22.5°.
• 1/4 in. (6 mm) root opening between the two plate edges.
• Steel backing strip at least 3/8 in. × 1 in. (10 mm × 25 mm), seated in close, tight contact with the underside of both plates.

The backing bar matters more than it looks. If there is a gap between the backing strip and the test plates, the root pass can miss one side entirely, producing a lack-of-fusion reject on the root bend. Test facilities check that contact before you start. Plates are tacked on the outside edges and at the ends of the joint, and the tacks are blended and inspected like any other part of the weld.

Two common variants exist alongside the standard coupon. The 3/8 in. limited-thickness coupon is used when qualification is being restricted to thinner material rather than the full thickness range. The no-backing (open-root) variant removes the backing strip altogether and is used when the employer needs to qualify the welder for open-root joints; the technique and difficulty change significantly, since there is no bar to tie into on the root pass.

Cleaning and Fit-Up Before the Arc

Both plate edges and the backing strip must be cleaned of oil, rust, and mill scale within one inch of the weld area before fit-up. During the weld, all slag and spatter must be removed between passes with a wire brush or grinder, and the finished coupon is presented to the inspector in the as-welded condition — grinding, blending, or dressing the cover passes is a problem in itself. A ground cap hides undercut and reinforcement issues, and inspectors treat it as a rejectable condition.

The Written WPS: Your Rules for the Day

The coupon is meaningless without a Welding Procedure Specification. The WPS defines electrode classification, diameter ranges, polarity, amperage range, voltage, travel speed limits, preheat, interpass temperature, and joint details. You are tested to that procedure, not to your personal preferences. Dialing in your own amperage outside the qualified range technically puts the weld outside the procedure, and the inspector can flag it.

A concrete example: NCDOT’s published 3G-4G Plate Certification WPS covers 3/8 in. A36 plate and specifies:

Parameter	Specification
Process	SMAW (stick), DC electrode positive
Electrodes	E7018, 3/32 in. and 1/8 in.
Amperage	70–110 A (3/32 in.); 90–160 A (1/8 in.)
Preheat	50°F minimum
Interpass	450°F maximum

Notice the range is deliberately modest. An All Position Welding Rod Guide is useful background, but on test day the WPS electrode and range are the only ones that count. Low-hydrogen E7018 rods must be stored properly — damp electrodes introduce hydrogen and show up as porosity or, worse, cracking.

Preheat and interpass limits deserve the same respect. Cold plate sucks heat out of the puddle and promotes lack of fusion at the groove walls; exceeding 450°F interpass changes the metallurgy the procedure was qualified for. Both are checked with a temperature indicator during the test.

Take the time to confirm every dimension and every number before your first pass. The setup is fixed, the rules are written down, and once the root pass goes in, you are already being judged.

How the 3G/4G Test Is Administered: Visual Inspection, Bend Tests, and Paperwork

The welding itself is the shortest part of a 3G/4G test day. Most of it is administrative, and that catches first-time candidates off guard. Understanding the sequence in advance removes the surprises, because a test is run the same way almost everywhere: paperwork first, welding second, inspection third, destruction fourth.

Before the Arc: Verification and Signatures

Every test starts with a qualifier confirming who you are and what you are about to weld. AWS’s official welder testing routing sheet requires the qualifier to verify your PPE, confirm that your machine is calibrated, label the coupon for identification, confirm that the WPS is the correct one for the joint, and establish material traceability through mill test reports and certificates of conformance for filler metal and backing. Nothing about that is optional, and it exists for a simple reason: a weld test is worthless if the plates, rod, or settings can’t be documented later.

You will review the written WPS and sign that you understand it before striking an arc. AWS B2.1 is the standard that sets out the specification and qualification framework for these welding procedures, and the D1.1 guides published by WPS America walk through how Clause 6 applies to plate test coupons. Most facilities then let you run one or two practice beads on scrap of the same thickness and electrode classification, so you can check your machine settings before the coupon counts.

Welding Under Watch

Fit-up is verified against the WPS: root opening, bevel angle, backing contact, and cleanliness within about an inch of the joint. Once you start, the inspector or test administrator records your amps and volts as you weld, and the root pass may be visually checked before you continue. Between passes you clean with a brush or grinder on the root and hot passes as the WPS allows, but the final cover stays untouched. Electrode choice matters here too; the All Position Welding Rod Guide covers why a 7018 behaves so differently overhead than in flat, and why the WPS, not your preference, decides which rod goes in the stinger.

Visual Inspection Comes First

Before any specimen is cut, an AWS Certified Welding Inspector examines the coupon against the same codified visual acceptance criteria used for production structural work. If it fails visual inspection, the test stops there and no bend test is performed.

Rejection Trigger	What the Inspector Sees
Cracks	Any crack, of any length, in the weld or heat-affected zone. Never acceptable.
Lack of fusion	Unfused groove wall or toe; often visible at the root or face edges.
Porosity	Rounded indications beyond the code’s size and spacing limits.
Undercut	A groove melted into the base metal beyond the permitted depth at the toe.
Excess reinforcement, overlap, sag	Profile failures on the cover pass.
Grinding damage	A ground cover pass on a coupon that must be as-welded.

Guided Bend Testing

If the visual inspection passes, the coupon is sectioned into specimens and bent on a guided bend jig, typically side bends plus face and root bends, which is the standard destructive route under AWS D1.1 Clause 6. Bending stretches the outer surface of the weld, so any hidden lack of fusion, slag inclusion, or incomplete penetration opens up where the inspector can see it. As a working reference, D1.1 rejects face and root bend specimens with open discontinuities larger than 3/16 in. (5 mm) in any dimension; side bends are judged against tighter limits. Where the governing standard permits it, radiographic or ultrasonic testing can replace destructive bend testing, but most plate qualification still uses bends because they are fast, cheap, and hard to argue with.

If You Fail

A rejection is not a permanent mark. The usual path is targeted practice on the specific defect you produced, then a retest with a new coupon welded to the same WPS. What you should not do is retest blind. Ask which pass failed, request your bend specimens if they are available, and look at them yourself. Reading your own failure is the fastest education in welding inspection you will ever get.

WPQ Records and Continuity

Pass, and the qualifier issues a Welder Performance Qualification record: your identity (usually with a photograph), the process, positions, material group, thickness range, filler classification, backing condition, test date, and results. That card is what you hand to an employer. Keep it, and keep evidence of continuity, because AWS requires welders to demonstrate recent use of the qualified process within the specified period to maintain their qualification. This is different from AWS Certified Welder certification, which is a separate, accredited-facility program. Your qualification is tied to an employer; your certification travels with you.

3G Technique Guide: Welding Vertical Uphill on the Test Plate

The 3G coupon is where most candidates either prove their fundamentals or go home with a rejection. The plate stands vertical in the fixture, the groove runs up and down in front of you, and gravity wants that puddle on your arm instead of in the joint. This is the technique that gets welders through on the first try.

Why Vertical Uphill Is the Default

Downhill vertical welding has its place on thin sheet, where it limits burn-through. On structural plate, uphill progression produces a far more consolidated groove weld: the puddle freezes underneath you and supports the next increment of fill, giving better sidewall penetration, fewer cold laps, and a denser deposit. That is why structural codes default to uphill on thicker material, and travel direction is an essential variable under AWS D1.1 and the AWS B2.1 qualification standard. Check the WPS before you strike an arc, because running downhill when the procedure calls for uphill is an automatic rejection no matter how clean the bead looks. Position also changes how filler metal behaves, and our all position welding rod guide explains that shift in more depth.

Electrode, Amperage, and Travel Speed

E7018 low-hydrogen stick is the classic 3G filler, and there are solid reasons SMAW still dominates structural qualification, as we cover in our advantages of stick welding guide. If your shop runs FCAW, the WPS may instead specify a gas-shielded or self-shielded wire. Either way, weld the consumable named in the procedure, not your favorite rod.

Amperage is where candidates go wrong, running comfortable rather than correct. NCDOT’s published 3G-4G plate certification WPS allows 3/32 in. E7018 at 70–110 A and 1/8 in. E7018 at 90–160 A, with travel speed held at roughly 4–11 ipm. That single band covers root through cover passes. The practical rule: err slightly hot rather than cold, because a cold pass washes into the sidewalls without fusing them, and lack of fusion is the number one killer on bend tests.

E7018 diameter	Amperage range	Typical use
3/32 in.	70–110 A	Root pass and tie-ins
1/8 in.	90–160 A	Fill and cover passes

Arc Length, Weave, and Puddle Control

Hold the arc short, roughly the diameter of the core wire, and watch the puddle instead of the arc. Travel slow enough to fill the joint but fast enough that the puddle doesn’t sag. Two patterns work reliably: a tight side-to-side motion with a deliberate pause at each groove wall, or a shallow triangle weave that pushes the puddle into the leading edge. Pause at the sides; whipping out of the puddle invites trapped slag and fusion defects. Keep pass widths moderate, since most WPSs cap the weave at about two to two-and-a-half electrode diameters, and use stringers wherever the joint width allows them.

Root Pass on the Backing Bar

The root is where the backing strip earns its place: complete fusion into both sidewalls and a consistent tie-in to the bar beneath. Run a touch hotter, keep the arc short, and watch the puddle wet fully across the root face and onto the backing. A cold or rushed root will sit on the bar without bonding, and the root bend specimen will fold you out immediately.

Fill, Cover, and Heat Management

Once the root is in, fill passes come down to rhythm and cleaning. Weld while the previous pass is still warm, but watch interpass temperature: NCDOT caps it at 450°F, and excess heat is exactly what makes vertical cover passes sag. Feather each layer so the final bead has room to finish flat. On the cover pass, control reinforcement height. Undercut at the groove edges usually traces to too much heat, travel speed that is too fast, or a weave that terminates abruptly at the sides. Slow down, pause at the edges, and let the filler metal fill the crater.

Restarts and Interpass Cleaning

Every restart is a potential defect. Feather the leading edge of a stop with a grinder so the next arc ties in smoothly, and do the same when welding over tacks. Slag must come off completely between passes, and a power wire brush is permitted for that job on the test coupon. Power grinding on completed weld faces is not. Grind only leading edges and tie-ins: smoothing a finished bead thins and contaminates the weld, and many shops will fail the coupon on visual alone.

Three Drills That Actually Help

• Puddle control drill: stringer beads on a bare vertical plate with no joint, each bead uniform from start to finish.
• Restart drill: bead, stop, feather, restart, until tie-ins vanish under a thin fill pass.
• Full mock test: fit up a coupon as the WPS describes, weld it in the fixture, then have it cut and bent. A failed practice coupon costs an afternoon; a failed real one costs the job.

One last reminder: vertical stick welding puts fume right in your breathing zone, so review OSHA’s welding, cutting, and hot work guidance and ventilate properly before you start practicing.

4G Technique Guide: Welding Overhead on the Test Plate

Ask ten structural welders which coupon they dreaded more, and most will say 4G. Vertical uphill is physically awkward, but overhead puts gravity directly against you: the molten puddle hangs above your head and every amp you add is an amp trying to drip on your shoulder. In the 4G test the plate sits horizontally with the groove facing down, so you are welding from underneath with a restricted view of the joint. That single fact is why sagging and drip are the dominant defect modes on this coupon, and why the whole technique comes down to one principle: build small beads and freeze them fast.

Get Your Body Set Before You Strike the Arc

Overhead punishes shaky hands more than any other position. Set your feet, then brace your welding arm against your body or the fixture so the stinger moves from a pivot rather than from your shoulder. Keep the plate at a height where you can see the joint without craning your neck, and check that your hood is clean and sitting square so you are not tilting your head to see through the lens. A dry, comfortable welder makes fewer rushed corrections, and rushed corrections are what cause sag.

Short Arc, Low Heat, Slight Drag

Overhead calls for the shortest arc length and the lowest practical heat input of the four plate positions. Hold the arc at roughly one electrode diameter or less and keep it tight all the way through the pass. Your work angle should be close to perpendicular with a slight drag of about 15 to 20 degrees, adjusted to whatever the puddle tells you. As the rod burns, your stickout gets shorter on its own, so feed your hand forward continuously instead of letting the arc creep into the flux coating. If the puddle starts looking shiny, wide, and lazy, you are too hot or moving too slowly.

For a standard E7018 groove, start near the lower half of your WPS range rather than the top. The NCDOT 3G-4G plate certification procedure lists 90 to 160 A for 1/8 in. electrodes, and most overhead welders live near the bottom of numbers like those. If your procedure allows FCAW, our all position welding rod guide breaks down how root and fill wires behave differently overhead.

Pass Strategy: Root, Fill, Cap

Root pass. Tie firmly into the backing bar with small stringers or a tight, shallow weave. Keep the root thin: excess reinforcement up here becomes the ledge that catches and carries the fill passes.

Fill passes. Stack narrow beads, slightly staggered, letting each one solidify before you add the next. Watch the toes at the groove walls. Overhead lack of fusion usually comes from a bead that was too wide, too cold, or deposited too fast to wet the side wall.

Cap. Two or three small stringers beat one wide weave every time. A wide cap traps heat, sags in the middle, and undercuts the edges when you terminate. Aim for a slightly convex profile with clean, blended toes and no overlap.

Restarts, interpass cleaning, and puddle control are the same fundamentals you use in vertical work, which is why the case for stick welding as a training process still holds: SMAW forces you to feel the heat input rather than hide behind a wire feed dial.

Safety: Everything Falls Down

Overhead work exposes your face, neck, and chest to falling spatter, sparks, and hot slag, so full leathers, a properly shaded hood, a cap or beanie, and fire-resistant clothing are non-negotiable PPE for the position. Tuck in, close up, and keep bare skin out of the drop zone; the OSHA welding, cutting, and hot work guidance makes the same point about protective equipment and fire prevention. Position yourself so slag cannot fall inside your collar, and run ventilation so fumes do not pool at head height directly under the arc.

How to Practice 4G Safely

Do not start with the test coupon. Work up to it:

1. Lay overhead stringer beads on flat plate until they stay narrow and flat instead of balling up.
2. Move to a 4F fillet T-joint, which trains puddle control overhead with less at stake.
3. Run a full groove with backing, then have a qualified inspector or experienced welder review your cap for sag, undercut, and toe fusion.
4. Only then simulate test conditions: same fixture, same amperage, same electrode batch, no grinding allowed on the cover pass.

The payoff is worth the discomfort. Passing 4G alongside 3G is what unlocks all-position plate work, and it is the coupon that proves you can actually hold a puddle up where gravity wants it to fall.

Common Reasons Welders Fail the 3G/4G Test (And How to Fix Them)

Most welders who fail a plate groove qualification fail because of one repeatable defect on a coupon they thought looked fine, not because they “can’t weld.” Plate groove failures cluster into a short list of causes, and every one of them is fixable with deliberate practice rather than raw talent.

Lack of Fusion at the Groove Wall: The Number One Killer

Lack of fusion at the groove wall and weld toe is the single most common destructive-test failure on plate groove coupons. It never looks dramatic — the cap can be perfectly convex while the root never bonded to the land. Three causes account for nearly all of it:

• Too cold. Amperage at the bottom of the WPS range, or an electrode dragged too slowly to stay hot, leaves the puddle sitting on the wall instead of biting into it.
• Wrong work angle. Pointing the rod too far toward the center of the groove means the arc never reaches the side wall.
• Travel speed outrunning the puddle. Moving faster than the metal melts produces a cosmetic bead with cold gray sidewalls underneath.

The fix: push amperage toward the middle or upper part of the qualified range, keep a tight arc, aim the rod visibly into the wall, and slow down until the puddle washes into the joint. An all-position welding rod matching the WPS gives you the freeze characteristics you need, but angle and heat do the actual work.

Porosity, Undercut, Overlap, and Excessive Reinforcement

Visual defects have their own fingerprints:

Symptom	Typical cause	Fix
Pores or wormholes	Contaminated joint, damp electrodes, wrong gas or flow	Grind land clean 1 in. each side, oven low-hydrogen rods, verify gas
Undercut on the cap	Too hot, too fast, or a weave that stops against the edge	Lower amps, slow down, pause to build the edge each weave
Overlap / cold lap	Too cold, wrong angle, long arc	Raise heat, shorten arc, angle into the corner
Reinforcement over the code limit	Travel too slow, too many cover passes	Keep cap flat to slightly convex, single pass, steady travel
Burn-through at the root	Amps too high, weaving the root pass	Drop to the lower range, run stringers, watch the backing bar

Slag Inclusions and the Grinding Trap

Slag inclusions come from one source: inadequate interpass cleaning. Test rules require all slag and spatter removed between passes; a power wire brush is permitted, but power grinding of completed weld faces is not. Chipping lazily, running a bead over trapped slag, then trying to grind it out at the end fails twice over. Chisel, brush, and confirm each layer before the next bead.

Grinding or blending the cover pass is its own problem. The cap is the evidence of your technique, and most facilities treat removing it as automatic rejection under the AWS D1.1 qualification guides.

Sagging and Dripping in the 4G Position

Overhead failures are almost always heat and puddle-size failures. A wide weave, an arc that creeps out as the rod burns down, and slow travel let gravity pull the puddle off the joint. Keep a short arc, run small stringers, let the puddle freeze slightly ahead of progress, and brace yourself so your hand does not drift as the electrode shortens.

Reading Your Own Results

After the visual inspection and bend testing, look at the specimens yourself. A side bend with a line along the fusion face means lack of fusion — check angle and heat. A break with gray, sugary grain means porosity or contamination. A clean bend with a corner lifting away is lack of fusion at the toe, usually travel speed. Cracks mid-face point to undercut or a cold lap you missed. Ask the inspector where the defect sat; that location tells you which pass and which habit to change.

How to Practice Deliberately

Random bead-laying will not fix a failure. Reproduce the test: cut real coupons to WPS geometry, weld them in position in your own fixture, then have an AWS Certified Welding Inspector review the bead and, if possible, cut and bend it. Change one variable per coupon — angle, amperage, travel speed — so you know what moved the result. If you are still learning electrode behavior, an advantages-of-stick-welding comparison explains why SMAW punishes sloppy arc length more than any other process.

Fail once and you learn what the inspector sees. Fix the cause, not the symptom, and the second attempt is usually a formality.

3G/4G Plate vs. 6G Pipe: Which Certification Do You Need?

Once 3G and 4G are in your pocket, the next question is whether to stop there or chase the 6G. The honest answer depends on where you want to work. Structural shops rarely ask for 6G. Pipeline and pressure-piping employers almost never accept a plate card on its own. Knowing what each test actually covers saves you from paying for a qualification you don’t need, or showing up to an interview missing the one you do.

What the 6G and 6GR Tests Cover

The 6G test uses a fixed pipe coupon mounted at a 45-degree angle and welded in position without rotating the pipe. Because the welder moves through flat, horizontal, vertical, and overhead within a single sequence around the circumference, AWS treats 6G as an all-position qualification. Pass it and you are qualified for groove and fillet work on both pipe and plate in every position. That breadth is why 6G is the benchmark for pipeline, offshore, refinery, and power-piping work, and why it is the most requested pipe test in the industry.

One suffix is worth knowing: 6GR. The R stands for restricted. A 6GR coupon adds a restriction ring that simulates a tubular T-, Y-, or K-connection and blocks easy torch access. If offshore jacket structures or complex structural tubulars are your goal, ask specifically about 6GR, because a standard 6G does not cover those joints. Pipe qualification criteria come from the AWS B2.1 specification series (AWS B2.1 base metal and procedure qualification), which most test facilities work from alongside their written procedures.

What Your 3G/4G Plate Card Actually Buys You

Here is the part that catches people off guard. Passing both 3G and 4G plate groove tests gives you all-position plate qualification, all plate fillet positions from 1F through 4F, and a bonus that is often overlooked: it also qualifies you for groove welds on pipe with a nominal outside diameter of 24 inches (600 mm) and larger. Big structural pipe, piling, and large tubular towers all fall inside that range (AWS D1.1 Clause 6 position qualification).

What it does not do is qualify you for small-diameter pipe. A 6-inch, 8-inch, or 10-inch line sits outside the plate test scope, and an employer running that work will send you straight back for a 6G. Process matters too: most 3G, 4G, and 6G tests are run with stick electrodes, so brush up on your arc control and why SMAW still holds its ground before either test day.

Test	Mounting	Qualifies You For	Typical Employers
3G + 4G plate	Vertical and overhead groove coupons	All plate groove and fillet positions; pipe groove welds 24 in. OD and larger	Structural fabricators, bridge and building contractors, ironwork
6G pipe	Fixed 45° pipe, not rotated	All positions on both pipe and plate	Pipeline, offshore, refinery, pressure piping, power
6GR pipe	6G plus restriction ring	Everything 6G covers, plus tubular T-, Y-, and K-joints	Offshore and heavy tubular structure fabricators

Which Industries Ask for Which

• Structural steel, bridges, buildings: 3G + 4G plate under AWS D1.1, often with 2G and 5G added when the shop runs large pipe columns or handrails.
• Pipeline: 6G, matched to the specific process you will run, whether stick, flux-core, TIG, or MIG.
• Offshore: 6G or 6GR, frequently followed by an employer-specific performance test on production material.
• Pressure piping and refineries: 6G or the position set required by the applicable piping code, verified through an accredited facility.
• Small job shops: sometimes only a fillet demonstration, sometimes nothing on paper at all.

Continuity: Your Qualification Is Not Permanent

Both plate and pipe qualifications expire if you stop welding. AWS D1.1 continuity provisions require that a welder have been engaged in the qualified work within a defined period, generally the preceding six months, for the qualification to remain current. If continuity breaks, requalification is required, and the employer is responsible for documenting it. Keep a simple log of jobs, dates, and procedures to protect yourself when you change employers. Accredited facilities also standardize the paperwork, which is why the AWS welder application and routing sheet exists in the first place. Shop-level tracking typically follows the same framework (AWS D1.1 qualification guide).

Employer Qualification vs. Accredited Testing

There are two routes to a card. Under employer-based qualification, your company administers the test to its own WPS, and the resulting record is valid for work done under that employer. It is usually the cheapest path and often free, but the qualification walks out the door with the employer, not with you. An AWS-accredited test facility issues a portable record you can carry to any contractor, and union apprenticeship programs often run their tests the same way. Accredited testing costs more and takes longer, but if you plan to move between structural, marine, and industrial work, it is money well spent.

Planning a Sensible Certification Path

1. Start with basic fillet and groove plate work if you are entry-level.
2. Add 3G + 4G to become all-position qualified on plate, the standard gatekeeper for structural hiring.
3. Add 2G and 5G, or go straight to 6G, when you decide to target pipe industries.
4. Finish with 6GR if offshore tubular work is the long-term goal.

Run the same process logic through each step: get solid on stick first, then add flux-core or TIG as the jobs demand. And if your ambitions eventually lean toward aluminum or other non-ferrous work, the process fundamentals transfer, but the certification route looks different, which our aluminium welding course overview spells out.

Think of the two credentials as a ladder, not rivals. 3G and 4G open the structural door; 6G opens the industrial one. Whichever rung you are on, keep your continuity records current and your next qualification stays within reach.

Career Value, Training Paths, and Practical Tips to Pass First Try

Why Employers Value All-Position Qualification

Holding both a 3G and 4G plate qualification expands the kind of work a welder can be hired for. A ticket limited to flat and horizontal work will often keep you in a shop setting, while an all-position qualification proves you can put down sound metal against gravity on a documented procedure. For this reason, structural fabricators, bridge contractors, and ironworkers use it as a fast filter when hiring.

This distinction can pay off. Contractors bidding structural steel packages need crew members who can be assigned anywhere on a job without having to stop for retesting. As noted by the U.S. Bureau of Labor Statistics Occupational Outlook Handbook, welders, cutters, solderers, and brazers make up a large construction and extraction group. Those who can read drawings, follow qualified procedures, and work multiple positions are often considered first when work picks up.

Training Paths That Get You Ready

There is no single route to a 3G and 4G qualification, but most successful candidates come through one of the following paths:

• Trade schools and community colleges: These programs typically run a few months to a year and cover SMAW, GMAW, FCAW, and blueprint reading. Resources like Aluminium Welding Course: What You Learn, Costs & Careers can give a general idea of how these courses are structured.
• Apprenticeships: Earn while you learn by gaining supervised hours with a contractor, all while building skills for testing.
• Union programs: Boilermaker and ironworker apprenticeships often build directly towards performance qualification testing.
• AWS SENSE aligned training: Many schools follow AWS SENSE entry-level guidelines to better match employer expectations.

Regardless of which route you choose, your preparation will come down to deliberate practice on coupons that match your test joint. A resource such as the All Position Welding Rod Guide can help you narrow down which electrodes will be the most manageable for vertical and overhead work.

How to Prepare to Pass First Try

The best way to avoid surprises is to rehearse the test exactly as it will be run. Use plates with the same groove geometry, prop them in the vertical and overhead fixtures, and weld them in one attempt. Before your official test, have a Certified Welding Inspector (CWI) review at least one of your practice coupons for visual acceptance to catch issues like lack of fusion, undercut, or excessive reinforcement.

Take advantage of any allowed practice time at the testing facility. Verify your machine output with a calibrated meter, confirm your electrode matches the classification on the WPS, and run a small bead before committing to your test plates. Many facilities allow this, and it can be the difference between guessing and knowing your settings are correct.

What to Bring, Safety, and Paperwork

For test day, bring valid photo identification, your own PPE (helmet, leathers, gloves, safety glasses, and hearing protection), and any documentation the facility requests. Overhead welding is physically demanding, so arrive well rested and fed. During your practice, follow OSHA’s welding, cutting, and brazing guidance to mitigate electric shock, fire and explosion, fumes and gases, and radiation by ventilating your booth, having a fire watch and extinguisher nearby, and inspecting all leads and stingers.

Lastly, qualification isn’t permanent. AWS requires a demonstration of continuity within a defined period to maintain your welder performance qualification. From day one, keep your WPQ records, employer continuity statements, and welding hours organized so a new employer can verify them without delay.

Pre-Test Checklist

• Procedure: Read the WPS and confirm the electrode, amperage range, preheat, and interpass limits.
• Rehearse: Practice at least two 3G and two 4G coupons in test fixtures.
• Inspect: Have a CWI review one practice coupon for visual acceptance.
• Fit-up: Confirm root opening, fit-up, and backing contact on your plates.
• Verify: Use a meter to confirm machine output during any allowed practice session.
• Prep: Pack PPE, ID, and records the night before.
• Clarify: Ask about bend specimens, grinding rules, and the retake policy.

Two plates, one upright and one overhead, stand between practice and genuine all-position structural work. Prepare deliberately, respect the procedure, and keep your paperwork current. That is what will get you through your 3G and 4G test on the first try.

Frequently Asked Questions

What does the ‘G’ mean in 3G and 4G welding tests?

The ‘G’ stands for groove weld. The number indicates the position: 3 means vertical and 4 means overhead. So a 3G test is a groove weld on a vertical plate, and a 4G test is a groove weld performed overhead on a horizontally fixed plate.

Does passing both 3G and 4G qualify me for all-position welding?

Yes, on plate. Under AWS D1.1, a combined 3G + 4G plate groove test qualifies a welder for all groove positions (1G, 2G, 3G, 4G) and all fillet positions (1F through 4F), plus groove welds on pipe 24 inches in diameter and larger.

What thickness can I weld after passing a 3G/4G plate test?

It depends on the coupon. A 3/8 in. test coupon qualifies you for base metal from 1/8 in. up to 3/4 in. (2T maximum), while a 1 in. coupon qualifies you for 1/8 in. up to unlimited thickness.

How is the 3G/4G test graded?

The finished coupon is first visually inspected by a Certified Welding Inspector against code acceptance criteria. If it passes, specimens are cut and subjected to guided bend testing (or NDT where permitted) to check for fusion and soundness. Failing visual inspection ends the test.

Is 3G or 4G harder?

Most welders find 4G (overhead) harder because gravity pulls the puddle down, demanding a shorter arc, lower heat, and tighter bead control. 3G vertical uphill is challenging in a different way — controlling a climbing puddle against the plate edges — but overhead is usually where candidates struggle most.

What electrode is most commonly used for the 3G/4G test?

AWS A5.1 E7018 low-hydrogen stick electrodes are the standard choice, typically run DC electrode positive. Some test facilities qualify welders with FCAW or GMAW depending on the WPS, but E7018 dominates structural plate testing.

Can I grind my weld cap on the test coupon?

No. Test coupons must be presented in the as-welded condition. Grinders are only allowed for feathering tacks and weld tie-ins at starts and stops; final cleaning for presentation must be done by brushing only.

How long does a welder qualification stay valid?

Qualifications are maintained through continuity. AWS D1.1 requires the welder to have performed the qualified welding within a specified continuity period for the qualification to remain current, and the employer is responsible for documenting that continuity.