Double Bevel Weld Symbol: How to Read, Draw, and Apply It (AWS A2.4 & ISO 2553)

What a Double Bevel Weld Symbol Actually Tells You

You’re standing at the layout table with a set of heavy structural prints in front of you. The foreman points to a groove symbol with a triangle on both sides of the reference line and asks, “Which side do we bevel, and how deep?” For a moment, the whole crew goes quiet. This is the moment that many welders first run into the double bevel weld symbol, and once you know how to read it, the answer becomes clear in an instant.

A Groove Weld, Defined Simply

Before breaking down the “double bevel” part, it helps to understand the family it belongs to. According to the AWS A3.0M/A3.0 Standard Welding Terms and Definitions, a groove weld is a weld made in a weld groove between workpiece edges, surfaces, or a combination of the two. Groove welds are designed to allow filler metal to reach deeper into the joint, creating a strong bond for thicker materials.

With that said, not all groove welds are created equal. AWS A3.0 lists nine (9) types of single-groove welds and seven (7) types of double-groove welds. Each of these designs has its own symbol, and each tells the shop a specific set of instructions. For welders looking to build a solid foundation in print reading, resources like Welding Practice: The Complete Guide to Building Real Welding Skills can be incredibly useful when putting these symbols into action.

What Does “Double Bevel” Actually Mean?

The word “double” is the most important part of this symbol. A double bevel groove weld means that weld metal is deposited from both sides of the joint, and only one of the two members is beveled on each side. This is different from a single bevel, where the preparation and welding only take place on one side of the joint.

For example, imagine two plates of one-inch steel being joined for a structural column. Beveling just one side would require an extremely large root opening or excessive filler metal to reach full penetration. By beveling one member on the top side and the opposing member on the bottom side, the joint can be welded from both sides with far less filler, better balance, and less distortion. This is why the double bevel weld symbol is so common on heavy structural, pressure vessel, and pipe drawings.

Why This Symbol Carries So Much Weight

A single double bevel weld symbol has a ripple effect throughout the entire fabrication process. It can drive the bevel angle, depth of groove, root face, root opening, the need for backgouging, and even the inspection methods used. These decisions directly impact everything from metal rolling and fit-up to the safety measures outlined in Welding Facilities: How to Plan & Set Up a Safe Shop.

With thicker materials, the cost savings can be immense. Welding from both sides allows for more efficient heat distribution, which helps prevent warping and reduces the total volume of filler metal needed. For large-scale operations utilizing processes like Robotic Submerged Arc Welding, these savings are multiplied tenfold.

Looking Ahead

The double bevel weld symbol may look small on a print, but it holds a massive amount of information. From its roots in the AWS A2.4:2020 Standard Symbols for Welding, Brazing, and Nondestructive Examination to its international counterpart, ISO 2553, this symbol is a universal language for fabricators.

Short Note: As we move through this article, we will dissect its anatomy, dimensions, comparisons, penetration requirements, and common mistakes. However, before any of that, the key takeaway is simple: “double” means both sides, and only one member is beveled per side. That alone is enough to prevent the awkward silence at the layout table.

Anatomy of the Welding Symbol: Reference Line, Arrow, and Tail

Think of a welding symbol as a sentence. The reference line is the sentence itself, the arrow is the subject, and the tail is the footnote. Once you can read the individual parts, you can read any groove weld — including a double bevel — without hesitation.

The Reference Line: The Backbone of Every Symbol

Everything hangs off the horizontal reference line. Per AWS A2.4, weld symbols shall be drawn in contact with the reference line, so there are no floating triangles and no guesswork. The reference line is also a divider: what sits below it and what sits above it tell you which side of the joint gets welded. A groove-weld symbol placed below the reference line specifies a weld on the arrow side only, while the same symbol placed above the line specifies a weld on the other side only. That vertical position is not decoration — it is instruction. The trainer’s reference material used in many welding programs reinforces this arrow-side/other-side placement rule.

The Arrow and Arrow Line: Pointing at the Truth

The arrow line springs from one end of the reference line and ends in an arrowhead that points at the joint. In AWS notation, the arrow side is the side of the joint the arrow points to; the other side is the face opposite the arrow (AWS A2.4). This matters enormously for a double bevel, because the arrow identifies the joint member that receives the near-side bevel. Slide the arrowhead to the other plate and you have flipped the joint’s meaning — the bevel belongs to a different member and the fit-up changes. Don’t assume the arrow marks the deeper side; it marks the near side.

Space Above and Below: Reading the Two Sides

Here’s a shop-floor analogy that sticks. Picture the reference line as the edge of a workbench, and the arrow side as the face of the part you can reach without spinning it around. Symbols written “under the bench” (below the line) apply to that reachable face. Symbols written “on top of the bench” (above the line) apply to the hidden face. So before you cut anything, check both faces — an arrow-side callout and an other-side callout mean work on both. Building that habit is part of the muscle memory covered in our guide to welding practice.

The Tail: Where the Details Live

The tail, the forked section at the far end of the reference line, carries the process, specification, or other reference data. That could be “GTAW,” “FCAW,” a WPS number, or a drawing note. It’s where you confirm which process is required — and by extension which polarity or filler you’ll set up, whether that’s TIG polarity or a flux-cored setup like the one in our gasless MIG welding guide. When the tail is blank, the process is typically specified in the drawing notes instead.

All-Around and Field Weld Marks: Small Marks, Big Meaning

A circle at the junction where the arrow line meets the reference line means weld all around the joint. A small flag at that same elbow means a field weld — the joint is welded on site, not in the shop. Both marks change planning, access, and safety, including how you organize a welding facility and stage equipment.

Reading a Double Bevel Groove Weld Symbol Step by Step

A double bevel groove weld symbol tells you the groove exists on both faces of the joint before you read a single number. As AWS A2.4 puts it, when a weld is applied to both sides of the joint it is called a double groove weld — and the double bevel is the specific case where both sides carry the bevel groove triangle. Reading one is really a three-step habit: position, orientation, then dimension.

Step 1: A Triangle Below and Above the Reference Line

By AWS convention, the symbol beneath the reference line describes the arrow side; the symbol above describes the other side. A double bevel groove weld therefore shows a bevel triangle below the line and a matching triangle above it. Both triangles must be the same weld symbol when the callout denotes one continuous double weld. Mix a bevel on one side with a V on the other and you have described a different joint entirely.

Step 2: Orientation Tells You Which Member Is Beveled

The direction the bevel symbol faces indicates which joint member carries the beveled face. The triangle’s vertical leg sits against the member that stays square, while the sloped leg faces the member that gets machined. On a single bevel groove the arrow generally points to the member being beveled; on a double bevel, that relationship simply repeats on each side of the reference line. Check it twice — flipping the orientation in your head is the single most common misread on the shop floor.

Step 3: Follow the Arrow to the Member

The arrow line points from the reference line to one side of the joint, and that side is the arrow side. When the arrow touches a specific member, the symbol nearest the arrow governs that member’s bevel. On a double bevel, the tail holds the process or reference, and the leader’s direction keeps you honest about which face gets machined. Get the arrow attachment wrong and you will cut the bevel on the wrong part.

Double Bevel vs Double V and Single Bevel

A double V-groove uses two V triangles, so both faces are chamfered symmetrically into a double-V profile. A single bevel groove bevels only one member and leaves the other square, producing an asymmetric joint. The double bevel sits between them: two beveled faces, machined on both sides of the joint. The distinction matters most on thick plate, where picking the wrong one changes prep time and weld volume. The open Oregon weld-symbols course diagrams make this contrast easy to see side by side.

Worked Reading Exercise

Picture a butt joint in 3/4 in. plate. Below the reference line sits a 45° bevel triangle with a groove depth of 3/8 in., a 3/16 in. root face, and a 1/8 in. root opening. Above the line, the same triangle repeats. Read it aloud as: “Bevel both members 45°, each groove 3/8 in. deep, 3/16 in. root face, 1/8 in. root opening, weld both sides.” The total beveled depth across the joint is 3/4 in., so with a 1/8 in. root opening you are filling roughly 7/8 in. of joint thickness per side. Good fit-up is everything here — sloppy gaps force extra passes and distortion, which is exactly where a solid welding practice guide pays off. A tidy root also sets up multi-pass fills that resist defects like overlap.

Same Symbol, Different Joint

On a T-joint, the two bevels are cut into opposite faces of the vertical stem, opening toward the base plate. On a butt joint, both plate edges are beveled so the groove opens on both faces. The symbol is identical; the geometry is not. That’s why fit-up on tube and pipe work deserves extra care — see our weld tube fittings fit-up guide. Designers may also reach for a double bevel when plate is thick enough to warrant beveling on both sides, a decision the CWB Group ties directly to thickness.

Dimensions and Callouts: Bevel Angle, Depth of Groove, Root Face, and Root Opening

A double bevel symbol without dimensions is just a shape. The numbers around it turn a sketch into a work instruction — they tell the fitter how to prepare each edge and the welder how much metal to deposit. Get them wrong and a perfectly good joint becomes a rework ticket. Reading these callouts correctly is as basic as matching a contact tip to your wire, yet it trips up experienced hands.

Every dimension has a fixed home. Sizes sit to the left of the weld symbol, and when both sides of the reference line carry a symbol, each side gets its own size. That single layout rule resolves most “which number is which” arguments on the shop floor.

The Four Core Dimensions

• Bevel angle: the angle between the beveled edge of one member and a plane perpendicular to its surface — defined exactly that way in AWS A3.0. Each member on a double bevel usually carries its own bevel angle, commonly 30°.
• Groove angle (included angle): the total angle between the two members once fitted. Two 30° bevels meeting produce a 60° included groove angle. The bevel is half the story; the groove angle is what the arc actually sees.
• Depth of groove: how far the bevel cuts into the member. This replaced the older, inconsistently used term “depth of bevel.”
• Root opening (R) and root face (f): R is the gap between members at the root; f, also called the land, is the flat unbeveled face at the bottom of the groove.

What Changed in AWS A2.4:2012

If you trained on older prints, the letters may look wrong. AWS A2.4:2012 replaced the groove placeholder “S” with “D” and swapped the groove weld size “(E)” for “(S)” throughout the standard. The same edition standardized “Depth of Bevel” into “Depth of Groove.” So a callout that once read S and E now reads D and S — same joint, updated grammar.

Reading a Double Bevel With Different Depths

Because a double bevel is cut from both sides, the symbol shows two triangles — one above and one below the reference line. Each triangle gets its own depth value to its left. A callout like (D) 12 / (D) 8 tells the fitter the top side is cut 12 mm deep and the bottom 8 mm. That asymmetry is common when only one side is accessible, when a heavier plate needs more bevel on the thick side, or when a robotic submerged arc cell was programmed around a specific joint prep.

Length goes to the right of the symbol. If the weld runs the full joint, no length is shown; a number or an “all around” flag changes that.

You will also see a size in parentheses below the symbol — the groove weld size or effective throat, now labeled “S.” That is the strength dimension inspectors verify, not the groove depth. Confusing the two is one of the most frequent misreads, and it matters on everything from pressure piping to weld tube fittings.

Why the WPS Matters More Than the Drawing

The symbol defines the shape; the WPS defines the numbers behind it. Root opening and root face are both recorded in the ASME QW-482 WPS format because they directly drive penetration and burn-through. A drawing might show “(D) 10” and nothing more, but the WPS still holds the qualified R and f values your procedure was tested with — so verify those before you fit up. Building habits like this pays off the same way structured welding practice sharpens technique over time.

Note: Remember the reading order on a double bevel: depth on the left, size below, length on the right. Read it in that sequence every time and the callout decodes itself.

Double Bevel vs Other Groove Symbols: A Side-by-Side Comparison

When reading a fabrication drawing, groove weld symbols can look nearly identical at first glance. However, the small differences between them determine how much material is removed, how much weld metal is deposited, and how efficiently a joint can be completed. For this reason, it is important to compare the double bevel weld symbol to the other common groove types that fabricators will encounter.

According to AWS A3.0, there are nine single-groove weld types and seven double-groove weld types, with double-V, double-bevel, double-U, and double-J among the most specified. These classifications are further standardized in AWS A2.4, which is the primary reference for welding symbols in North America.

Key Differences at a Glance

While every groove weld aims to achieve proper fusion, their prep, access, and efficiency vary drastically. The table below breaks down the most common types that a shop will run into when comparing them to a double bevel groove weld.

When to Choose Double Bevel Over Double V

The biggest distinction is simple: a double V-groove places a V on each side, while a double bevel groove bevels one member on each side, conserving weld metal on thicker joints. This is especially impactful for T-joints and corner joints, where only one plate can be practically beveled due to the geometry of the joint. By prepping a single member from each accessible side, fabricators can still achieve complete joint penetration while drastically reducing the amount of filler metal required.

This efficiency not only saves on consumables, but it also helps to balance heat input, limiting distortion across larger assemblies. These savings can be further optimized when paired with high-deposition processes, such as robotic submerged arc welding, or when shops focus on their welding practice to maximize travel speeds.

Prequalified Details and Practical Considerations

Before cutting any bevels, it is always worth verifying that your joint configuration matches a prequalified joint detail. Codes such as those referenced in AWS prequalified groove details dictate allowable angles, root openings, and land dimensions for each groove type. These parameters ensure repeatability, whether you are working with TIG on steel or MIG in a high-production shop.

Ultimately, the choice between groove types comes down to one question: how can we achieve the required penetration with the least amount of prep, heat, and weld metal? For many thick T and corner joints, the double bevel groove is the answer that strikes that balance with precision.

AWS A2.4 vs ISO 2553: The Same Joint, Two Different Languages

Here’s where even seasoned fabricators get tripped up. A double bevel weld on a European drawing and one on an American drawing describe the same joint geometry, yet they don’t speak the same language. If you read an ISO 2553 drawing with AWS eyes, you can bevel the wrong face, size the wrong dimension, and scrap a part before anyone catches it. Learning both notations is like learning to weld to two codes — the same discipline you’d build through deliberate welding practice.

One Reference Line vs. Two

AWS A2.4 keeps things lean: a single solid reference line, with the arrow side below and the other side above. ISO 2553, which defines the rules for symbolic representation of welded joints, works differently. It recognizes two approaches for designating arrow side and other side, including a dual reference line system (its clauses are tagged with the suffix “A”). That system uses both a solid line and a dashed line. The solid line carries information for the arrow side, while a dashed line signals information that applies to the side opposite the solid reference line — the other side.

That distinction is the single biggest source of confusion. ISO also layers in auxiliary symbols — field weld, all-around, and the like — that follow their own conventions, so a flag or circle doesn’t always mean what an AWS-trained eye expects.

Dimensions: Leg vs. Throat, and ‘a’ vs ‘z’

Groove dimensions like bevel angle, depth, root face, and root opening transfer reasonably well between the two, but fillet notation diverges sharply. ISO uses a for the theoretical throat thickness and z for the leg length, and you’ll see these letters printed right on the symbol. AWS traditionally shows fillet size as leg length and leaves throat to calculation or a note. Reading a small “z10” above a fillet on an ISO drawing and treating it as an AWS inch value is a classic, expensive error.

Reading drawings well pairs with reading your process well. Just as you’d dial in TIG welding polarity or check a worn contact tip before blaming the machine, you verify which notation standard governs the print before you cut metal. And for the technicians actually running the arc, process choices like gasless MIG welding don’t change the symbol — only how you execute it.

Drawing a Double Bevel in Each System

In AWS, a double bevel groove weld is drawn with two triangles, both pointing at the reference line, one on each side of it. The bevel angle and depth sit on each side as needed, and the arrow defines which member is the arrow side. In ISO, you place one triangle on the solid line and one on the dashed line, with the dashed line potentially appearing on either side of the solid line to indicate the viewing direction. The dimensions follow ISO’s sequence, and any throat-based sizing uses the letter notation above.

So how do you avoid the trap? Check the drawing’s title block and general notes for the governing standard first. If it says ISO 2553, stop reading with AWS eyes — recompute the sides, translate ‘a’ and ‘z’, and confirm every auxiliary symbol against ISO’s rules. When in doubt, ask the engineer rather than “interpret.”

Think of the two systems as dialects of the same craft. Fluency in both keeps a double bevel weld from becoming a double misunderstanding.

CJP, PJP, and Backgouging: What a Double Bevel Implies About Penetration

A double bevel symbol tells you the shape of the groove. What it doesn’t say is how far through the plate the weld must travel — and that gap between “what the joint looks like” and “how much of it we fill” is where drawings get misread. Penetration is the real specification, and the symbol carries it in a few compact conventions.

CJP vs. PJP: The Line an Inspector Draws

A complete joint penetration (CJP) groove weld extends completely through the thickness of the joined components, while a partial joint penetration (PJP) groove weld does not — it fuses to a defined depth and stops, leaving unfused base metal below the root (Caltrans Bridge Design Details 11.3). That single distinction drives fatigue life, deposited volume, cost, and how much NDT the joint attracts.

For a double bevel, the drafting convention in ANSI/AWS A2.4 is refreshingly simple:

• No dimensions on the symbol — the groove symbol specifies complete joint penetration.
• Weld size in parentheses — a PJP groove weld, limited to that size.
• A backing weld symbol opposite the groove, with no depth or size given — complete joint penetration.

So the same two triangles can mean “weld all the way through” or “weld two-thirds of the way,” depending entirely on whether a parenthetical number sits beside them. Bare double-bevel triangles mean CJP — confirm against the notes — while a size tucked in parentheses signals a sized partial joint.

Why Two Sides Makes Full Penetration Achievable

Fusing the root of a thick joint is the hard part. Weld from one side only and the root stays cold, often with lack of fusion hiding under the bevel. Welding both sides — and removing the flawed root material between passes, as a double bevel invites — is what makes CJP realistic on heavy plate. That removal is back gouging: grinding or arc-cutting a groove into the previously deposited weld from the opposite side until sound metal is reached, then welding over it.

The effective throat follows the same logic: each side contributes to the load-carrying section, and the gouged, rewelded root ties both halves into one continuous piece of metal.

Reading It in the Field

Double-sided access also dictates process choice. On heavy fabrication, the second side is where high-deposition methods earn their keep — automated setups such as robotic submerged arc welding thrive on exactly this rhythm: heavy passes, gouge and clean, then reload the joint from the other side.

Whichever process you choose, penetration shifts with polarity, wire, and transfer mode. If a root simply won’t fuse, review TIG welding polarity: DCEN, DCEP, and AC explained — arc direction changes the penetration profile more than most beginners expect. Before blaming the symbol, rule out heat input, travel speed, and a dirty joint with our side-by-side look at good and bad MIG welds. And when penetration keeps surprising you, deliberate welding practice with logged settings beats symbol-staring.

A double bevel symbol is a penetration strategy waiting to be read. Bare triangles, a parenthetical size, or a backing symbol opposite the groove each point to a different joint requirement — and the back gouging recorded in your WPS is what turns a CJP promise into a weld that actually reaches the bottom of the joint.

Why Designers Specify Double Bevel Welds: Thickness, Distortion, and Access

When a structural engineer puts a double bevel symbol on a drawing, it isn’t decorative. It answers a specific set of problems: a thick plate that can’t be penetrated from one side, a weldment that will warp if the heat isn’t balanced, and a joint the welder can’t reach from the far side. Understanding why the symbol is specified makes reading it easier — and stops you questioning a detail that was carefully chosen.

Facilitating Penetration and Arc Access

A weld preparation has two jobs. As the AISC Engineering Journal puts it, its main function is to facilitate the required weld metal penetration and provide access so the arc can be directed against the base metal. A flat butt joint on 40 mm plate gives the arc nowhere to go — the electrode sits on the surface while the root stays cold and unfused. Beveling both sides opens a channel, lets the welder point heat at the root, and guarantees fusion.

That’s also why thickness drives the decision. The CWB Group notes that for plates over roughly 20 mm thick, beveling from both sides is chosen depending on whether the joint needs partial joint penetration (PJP) or complete joint penetration (CJP). Under about 20 mm, a single bevel or even a square groove may suffice; beyond it, the double bevel becomes the economical, practical choice.

Balancing Heat to Control Distortion

Weld shrinkage is unavoidable — molten metal contracts as it cools, and that contraction pulls. Fill a single-sided V on a wide flange and the flange rotates toward the weld. The AISC Engineering Journal highlights that reducing weld metal volume can also reduce flange rotations from shrinkage. A double bevel needs less groove volume than a full double-V of the same depth, and balancing passes on both sides manages angular distortion and residual stress.

In practice, this means alternating sides — root and hot passes on one face, flip, matching passes on the other. Shrinkage from side two counteracts side one instead of doubling the pull. On girder fabrication, that balance separates a beam that comes off the fixture straight from one that needs thermal straightening.

Where the Symbol Shows Up in Real Work

• Heavy structural steel and bridge girders: Thick flange-to-web connections often demand CJP groove welds; Caltrans details define CJP and PJP groove configurations for exactly this reason (Caltrans).
• Pressure vessels and pipe: Shell seams and nozzle attachments rely on full penetration for fatigue and pressure integrity, per National Board and ASME Section IX.
• Machine bases and heavy equipment: Thick weldments where access is limited to one side — until it’s flipped.
• High-deposition automated work: Robotic submerged arc welding on plate builds, where both faces are beveled and welded in a controlled sequence.

The Tradeoffs Nobody Reads on the Drawing

Nothing is free. A double bevel means double the fit-up: two bevels to cut and verify, two sides to clean, and the risk that misalignment or a mismatched root opening creeps in when the piece is flipped. It also means back-gouging labor — chipping or air-arc gouging the root from the second side to sound metal — adding time, consumables, and a grinding/gouging PPE requirement (see our protective eyewear for welding guide for the basics).

Note: Thick sections also bring preheat and interpass temperature into play. Cold plate plus multi-pass welding risks hydrogen cracking; the procedure specification will call out preheat and a maximum interpass temperature. Follow it — even a perfectly drawn symbol can’t save a weld from a cracking procedure. Building foundational skills first? Our welding practice guide covers what makes these procedures work in the field.

In short, designers pick the double bevel when thickness, distortion, access, and strength all push in the same direction — and the tradeoffs are worth the handling.

Common Mistakes: Misreading, Misdimensioning, and Misapplying the Symbol

The double bevel is one of the most consequential marks on a fabrication drawing — and one of the most frequently misread. The errors below keep showing up in shops, and most slip past a quick visual check, surfacing only later when a part won’t fit or a weld fails under load. Here’s how to catch each one before metal is cut.

Swapping the Arrow Side and the Other Side

In AWS notation, a symbol placed below the reference line applies to the arrow side, and a symbol above the line applies to the other side. Reversing them is a common and costly error: the welder bevels the wrong plate, or preps both edges when only one was called for, and the joint no longer fits up. Build a simple habit — trace the arrow to the joint, check which side of the line the triangle sits on, then confirm against the assembly sketch. AWS A2.4 spells the convention out in full.

Note: On ISO 2553 drawings, the dashed identification line flips that logic — a symbol shown on the dashed side refers to the other side, so don’t assume AWS conventions on an ISO print. If the print style is unfamiliar, review how the identification line changes the reading before interpreting a single triangle, and keep the AWS weld symbol chart posted at the workstation.

Confusing Single and Double Bevel

A single bevel shows one triangle; a double bevel puts triangles on both sides of the reference line. Fabricators sometimes see a bevel symbol, prep one edge, and discover at fit-up that the other side was also supposed to be beveled. Edge prep mistakes are expensive to undo — check twice before cutting.

Reading Depth of Groove as Weld Size

Groove dimensions carry different meanings: bevel angle, depth of groove, root face, root opening. A frequent mistake is treating the depth of groove as the total weld size, or overlooking a size in parentheses. In AWS practice, a weld size in parentheses on a groove symbol signals partial joint penetration rather than CJP; treating it as full penetration is a specification mistake that looks fine on the surface and fails under load. Caltrans states that CJP welds typically require a specific edge preparation, and that the effective throat — the shortest distance from the joint root to the weld surface — governs strength, not the leg length you can measure with a gauge.

If the drawing doesn’t say CJP, don’t assume it. Symbol-reading drills in Welding Practice build the habit of checking before you strike an arc.

Forgetting Backgouging on CJP Double Welds

When both sides of a double bevel are welded to CJP, the root of the first side is usually gouged back to sound metal before the second side goes down. Skip the backgouge and slag or lack of fusion can hide at the centerline — precisely where stress concentrates. A backgouge requirement should be written into the WPS, and inspectors will look for it.

Assuming a Double Bevel Is Always Full Penetration

The symbol describes geometry, not depth of fusion. No CJP note, no weld size, no backing detail? Treat it as PJP and ask the engineer.

Fabricating the Wrong Edge Prep

Wrong bevel angle, missing root face, root opening too wide or too tight — none of it matches the qualified WPS. Poor fit-up also breeds surface problems, from overlap welding defects to the profile differences visible in good and bad MIG welds. A five-minute fit-up check is cheap insurance; rework never is.

Practical Tips, Inspection, and Final Takeaways

You’ve made it through the whole symbol. Now comes the part that pays the bills: turning what you read on paper into a joint that passes inspection the first time. Here’s a field-tested routine for double bevel work.

The Five-Second Read

When a new drawing lands on your bench, run this quick sequence before you touch a torch:

1. Find the arrow. Which member gets beveled? The arrow side member is prepped; the other side is not.
2. Check both sides of the reference line. Triangles on both sides mean a double bevel — two separate bevels, one per member.
3. Read the numbers. Bevel angle, depth of groove, root opening, and root face (the land) all belong to specific positions around the symbol. Jot them on your fit-up sheet.
4. Look for the tail. A WPS or process reference (like “SMAW” or “GTAW”) tells you which procedure governs. If you’re running TIG, brush up on TIG welding polarity so your settings match the specification.

Fit-Up: Where Joints Are Won or Lost

Before the arc strikes, verify four things against the drawing:

• Cleanliness. Bevel faces and the root face must be free of oil, rust, paint, corrosion, and burrs so the weld fuses to sound base metal (Weiler/ASME weld preparation guidance).
• Bevel angle. Check it with a bevel gauge, not by eye. A 45° bevel cut at 40° changes both penetration and fill volume.
• Root opening. Keep it consistent along the entire joint length — a consistent root opening is what produces uniform penetration (Weiler/ASME weld preparation guidance).
• Root face (land). Too thick and you won’t fuse through; too thin and you’ll blow it away on the root pass.

Preheat is part of fit-up too. Requirements rise with thickness — thicker sections call for higher minimum preheat and interpass temperatures, a core principle in AISC and AWS D1.1 practice. Verify with a temp stick or infrared thermometer and log it per the WPS.

Welding Sequence and Distortion Control

The first bead in a groove joint is the stringer, or root pass, followed by a hot pass and then fill passes to the cap. On a double bevel, alternate sides between passes rather than finishing one face completely — that balances shrinkage forces and keeps the assembly from pulling out of alignment. If your shop runs mechanized or automated fill, resources like robotic submerged arc welding show how pass sequencing scales up. Back-gouge the root to sound metal before the second side is welded; that step is what makes full penetration real rather than assumed.

Inspection Points

Visually confirm the bevel angle, root opening, and land match the drawing, the joint is clean and dry, and the finished weld shows no overlap or lack of fusion — see overlap welding defects and good and bad welds for reference photos. When the drawing calls for CJP or the application is structural or pressure-related, NDT — typically UT or RT per AWS A2.4 and the applicable code — follows visual acceptance. Grinding and back-gouging throw sparks and sharp particles, so eye protection rated for the task is non-negotiable; our protective eyewear guide covers ratings and lens selection.

Finally, treat every drawing as practice. Pull real fabrication prints and read them cold, then check yourself against the symbol chart in the AWS weld symbol reference. If you’re still building fundamentals, work through Welding Practice: The Complete Guide, and make sure your shop layout supports clean, repeatable work — our Welding Facilities setup guide walks through that end to end. Read it right, fit it tight, weld it per procedure, and document it: that’s the whole game.

Frequently Asked Questions

What is a double bevel weld symbol?

It is a welding symbol showing a bevel groove weld symbol on both sides of the reference line, meaning the joint is beveled and welded from both faces. The arrow side symbol sits below the reference line and the other side symbol above it. Together they tell the welder to prepare two beveled grooves and deposit weld metal from each side.

How is a double bevel weld different from a double V-groove weld?

A double V-groove bevels both edges on each side, forming V shapes on both faces of the joint. A double bevel groove typically bevels only one member on each side, leaving a land and root face, which can reduce weld metal and simplify preparation on some T-joints and corner joints.

Does a double bevel weld symbol mean complete joint penetration?

Not automatically. In AWS notation, a groove symbol without any size dimensions specifies complete joint penetration, while a parenthetical weld size indicates partial joint penetration. Double-sided welding and backgouging are common ways to achieve CJP, but the dimensioning on the symbol and the drawing notes define the requirement.

How do I tell which side is the arrow side?

The arrow side is the side of the joint the arrow physically points to, and its symbol goes below the reference line. The other side is opposite the arrow, and its symbol goes above the reference line. On ISO drawings, a dashed line is used instead to indicate the side opposite the solid reference line.

Where do the bevel angle and depth dimensions go on the symbol?

Dimensions are placed to the left of the groove symbol. The groove or included angle is written inside the symbol opening, the depth of groove precedes the symbol, and the root opening and root face may also appear. Each side of a double groove weld can carry its own dimensions when the depths differ.

Why would an engineer choose a double bevel instead of a single bevel?

Double bevels are chosen on thick sections when welding from one side cannot reach the root, and when balanced welding from both sides helps control distortion. They are also used on T-joints and corner joints where access or geometry limits a full V preparation. The tradeoff is extra handling and back-gouging labor.

Is backgouging always required for a double bevel groove weld?

Backgouging is required when the joint must achieve complete joint penetration and the root pass cannot guarantee sound metal through the thickness. It removes the unsound root from the first side so the second side can be welded to sound metal. The WPS should specify the backgouging method and sequence.

What is the biggest mistake when reading a double bevel symbol?

The most common mistake is swapping arrow side and other side, which leads a fabricator to bevel the wrong plate or the wrong face. The second most common is treating a PJP symbol with a parenthetical size as a full-penetration weld. Always verify against the drawing notes and the WPS before cutting or welding.

Authoritative Sources & Further Reading

• https://pubs.aws.org/Download_PDFS/2__A2_4_2020_PV.pdf
• https://pubs.aws.org/Download_PDFS/A2.4-2012PV.pdf
• https://pubs.aws.org/Download_PDFS/A2.4_2007PV.pdf
• https://dl.gasplus.ir/standard-ha/Standard-AWS/AWS%20A3.0%202020.pdf
• https://app.aws.org/mwf/attachments/64/225364/AWSWeldSymbolchart.pdf
• https://www.nationalboard.org/index.aspx?pageID=164&ID=217
• https://committee.iso.org/cms/live/live/en/sites/isoorg/contents/data/standard/07/27/72740.html
• https://openoregon.pressbooks.pub/weldsymbols/chapter/chapter-6
• https://www.cwbgroup.org/resources/articles/which-plate-thickness-needs-to-be-beveled-for-welding
• https://dot.ca.gov/-/media/dot-media/programs/engineering/documents/bridgedesigndetails/chapter-11/2019june113-complete-joint-penetration-partial-joint-penetration-groove-weldsa11y.pdf
• https://www.mtm-inc.com/understanding-weld-symbols-the-groove-weld.html
• https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/bpvc%20resources/section_ix/bpvc_ix_qw-482.pdf