Current Welding Definition: What AWS and ISO Say Today

A fabricator once told a shop foreman he had “welded” a cracked plastic housing with epoxy, and the argument that followed ended with a rejected work order and a re-do. The truth is, whether something counts as welding is not a matter of opinion — it is written down in a current, living standard, and knowing exactly where that line sits is what keeps specs, inspections, and repairs from falling apart.

Why Welding Needs a Formal Definition (and the Short Answer)

Picture a Saturday morning in a two-car garage. A DIYer has a cracked aluminum motorcycle housing and a tube of high-strength epoxy. He clamps the halves together, bonds them, drills and taps the repair, and tells his buddy he “welded it back together.” His buddy runs a fabrication shop, laughs, and says no he didn’t. The argument escalates: does welding require a torch? An arc? Melted metal? The buddy grabs his phone, pulls up a standard, and reads it aloud. Five minutes later there is no argument left, because the definition was never a matter of opinion.

That scene plays out in real shops, repair bids, inspection disputes, and classrooms, and it happens because most people learn the word “welding” from experience or a decades-old textbook rather than from the standard that governs contracts, procedures, and inspections. This article fixes that, starting with the answer you came for.

So What Does Welding Currently Mean?

Under the glossary that carries the most weight in the United States, welding is a materials joining process that produces coalescence of materials by heating them to suitable temperatures, with or without the application of pressure, or by the application of pressure alone, with or without the use of filler material.

That sentence is deliberately broad, and we will unpack every clause later. For now, notice what it permits: heat alone, pressure alone, or both, with filler metal optional. That flexibility is not a loophole. It is what lets one definition cover arc welding, gas welding, forge welding, ultrasonic welding, and dozens of modern processes that look nothing alike on the shop floor.

If you want the shorter, lay-friendly phrasing, TWI puts it plainly: welding is a fabrication process whereby two or more parts are fused together by means of heat, pressure, or both, forming a join as the parts cool. Same idea, fewer syllables, and a good mental model to carry when you are not reading a spec.

Why Does Anyone Need a Formal Definition at All?

Because welding sits at the intersection of contracts, engineering drawings, safety standards, inspection criteria, and national building codes, and all of those documents have to agree with each other. If a purchase order says “weld the bracket” and the shop reads that as brazing while the engineer intended fusion welding, the weld does not meet the procedure, the inspector rejects it, and the money argument starts. If a welding procedure specification (WPS) and an inspection report use different words for the same joint, traceability collapses.

That is exactly why the American Welding Society maintains a formal glossary, and why ANSI describes AWS A3.0 as a glossary that establishes standard terms to aid communication of information related to welding and allied processes. Notice the emphasis: communication. The glossary exists so a drafter in one state, a welder in another, and an inspector in a third are all describing the same physical event with the same words.

The American Welding Society has been doing this work since its founding in 1919, and in the century since it has authored more than 350 standards covering welding practices, procedures, safety, and terminology. When you cite “AWS” on a document, you are tapping into that accumulated body of work rather than anyone’s personal vocabulary.

What This Article Will Cover

The short answer above is the doorway. What follows is the full room:

• The current AWS standard itself — AWS A3.0M/A3.0:2025: its scope, who maintains it, and what changed in the newest edition.
• How the definition got here — a lineage running from 1940 to today, and why older shop manuals word it differently.
• The international view — how the ISO vocabulary series phrases welding, and how it differs from the AWS approach.
• Inside the sentence — coalescence, suitable temperatures, pressure, and filler metal, explained word by word.
• The boundaries — where welding ends and brazing, soldering, adhesive bonding, thermal spraying, and thermal cutting begin.
• The neighboring terms — weld, weldment, weld metal, faying surfaces, and the qualified-versus-certified confusion.
• Why it matters at work — contracts, WPS paperwork, code compliance, inspection acceptance, and safety planning.
• Mistakes to avoid — and a practical routine for looking terms up and applying them correctly.

That last point deserves emphasis, because the stakes are bigger than a garage argument. Thousands of new welders enter the field each year, learning vocabulary from a mix of YouTube channels, trade school handouts, decades-old textbooks, and employer shorthand. Some of that material is excellent. Some of it is quietly outdated. A definition that “feels right” because it came from a 1990 textbook can still fail a modern audit, and the difference usually comes down to which edition of which standard someone was holding.

The good news is that the current definition has not changed nearly as much as you might fear. Its core idea has held steady for generations, and the newest edition mostly refines rather than replaces what came before. If anything, the current wording is more useful, because it now covers additive manufacturing and nondestructive examination vocabulary alongside classic processes like stick welding and the aluminum work you see in shops every day.

From here, we will start with the authoritative U.S. source behind that definition, edition by edition, so that the next time someone tells you they welded a plastic housing with epoxy, you will know exactly what to say — and where to point them.

The Current AWS Definition of Welding: AWS A3.0M/A3.0:2025

If you ask three welders what welding is, you will get three slightly different answers. If you ask the American Welding Society, you get one answer, and it comes with a document number. The current U.S. authority behind the definition is AWS A3.0M/A3.0, Standard Welding Terms and Definitions, published in its 2025 edition.

That edition is not a minor reprint. It is the 14th edition of the standard, approved by ANSI on July 30, 2024, and it formally revises AWS A3.0M/A3.0:2020. You can confirm the designation through the ANSI webstore listing for A3.0M/A3.0:2025, and AWS publishes a preview of the document through its own publications preview PDF. If your WPS, contract, or training manual still points at 2020 or earlier, that citation is now superseded.

What the standard actually covers

The title itself has grown, and that growth tells you where the industry has gone. Earlier editions focused on welding, cutting, brazing, soldering, thermal spraying, and adhesive bonding. The 2025 scope explicitly adds two new domains: Additive Manufacturing and Nondestructive Examination. So the full scope now reads across adhesive bonding, brazing, soldering, thermal cutting, thermal spraying, additive manufacturing, and nondestructive examination, alongside welding itself.

That matters practically. Terms used by an inspector running ultrasonic testing and terms used by an operator running a wire-arc additive cell now live in the same reference as the welder laying a fillet. When an Aluminum MIG Welding: The Complete Practical Guide procedure references penetration or a welder running Aluminum Flux Core Welding: What Actually Works in 2026 reads a procedure sheet, both are drawing vocabulary from the same glossary.

In sheer volume, the 2025 edition defines more than 1,500 terms, supported by numerous illustrations, classification charts, and corollary information. Every entry is flagged as either standard or nonstandard, and the whole list is arranged in word-by-word alphabetical sequence so you can look up a term the way you would look up a word in a dictionary.

Who maintains it

The standard is prepared and maintained by the AWS A2 Committee on Definitions and Symbols, a technical committee formed specifically to establish standard terms for communicating welding information. That mandate is the whole point: the glossary exists so that a drawing produced in one shop, inspected by a third party, and fabricated again in another shop means the same thing at every step.

What changed in 2025

The 14th edition is not just new additive manufacturing and NDE vocabulary bolted onto an old core. Several familiar definitions were reworked:

• Hybrid welding — clearer boundaries on what qualifies when two heat sources operate in one process.
• Plastic welding — refined wording for polymer joining, which behaves differently from metal joining.
• Waveform-controlled welding — updated language for programmable current and voltage profiles.
• GMAW transfer modes — sharpened distinctions between short-circuit, globular, spray, and pulsed transfer.
• SAW multi-electrode variations — refined terms for tandem and series electrode setups.
• Temper bead welding — tightened wording around bead placement and heat input control.
• Welding test positions — updated terminology for the positions used in performance qualification.

None of these are cosmetic. A refined term for a GMAW transfer mode changes how a Aluminum Cleaner for Welding: How to Prep Aluminum Right procedure is written, how an Aerospace Welding: Processes, Standards, and Careers Guide spec reads, and how a test coupon is oriented on the qualification plate. If the wording shifts, the acceptance criteria can shift with it.

For older documents, the same caution applies in reverse. A procedure qualified against AWS A3.0M/A3.0:2020 is not automatically wrong, but any term defined differently in 2025 should be reconciled before the next audit, contract renewal, or procedure revision.

The practical habit worth building: whenever a term in a specification seems ambiguous, open the current edition, read the exact wording, and mirror it verbatim. That single habit prevents more scope arguments than any amount of shop experience.

How the Definition of Welding Has Evolved Since 1940

If you’ve ever flipped through an old shop manual and noticed its definition of welding reads just a little different from one you’d find today, there’s a good reason for it. The language has been slowly shaped over the course of nearly nine decades to keep up with the trade. While the exact words may have shifted, the backbone of it all has stayed the same: coalescence produced by heat, pressure, or both.

The Push For a Universal Language

Before the 1940s, welders, inspectors, and engineers often used their own terminology to describe the same process. To fix this confusion, the work that would become AWS A3.0 began under the efforts of what is now the AWS A2 Committee on Definitions and Symbols. The very first milestone came on January 18, 1940 with the publication of the ‘Tentative Definitions of Welding Terms and Master Chart of Welding Processes’.

From there, the glossary grew steadily. The 1942 edition built upon that tentative release, followed by A3.0-49, A3.0-61, and A3.0-69. It wasn’t until A3.0-76 that the document saw one of its largest expansions, bringing brazing and thermal spraying into the same family of joining and cutting terms. This trend continued with A3.0-80 and later ANSI/AWS A3.0-85 and A3.0-94, slowly widening the scope to reflect an ever growing industry.

From Inches to a Global Standard

The turn of the millennium marked a massive shift in accessibility. AWS A3.0:2001 served the trade for many years until it was superseded by AWS A3.0M/A3.0:2010, the 12th edition. Approved by ANSI on July 1, 2009, this metric dual-designation edition made it far easier for international projects to reference the same definitions. You can find more information about the current series through the AWS A3.0M/A3.0 standard page.

This push for harmonization would only continue. AWS A3.0M/A3.0:2020 was approved by ANSI on October 22, 2019 and superseded the 2010 edition. Now, the most up to date release, AWS A3.0M/A3.0:2025 (the 14th edition), has taken that a step further by adding and refining terms to cover modern fabrication. The ANSI webstore listing and the published 2025 PDF reflect these additions, specifically for surfacing weld test positions, procedure and performance qualification, GMAW transfer modes, and multi-electrode SAW variations.

Why The Wording Keeps Changing

These updates aren’t done for the sake of rewriting history. They’re driven by three major forces. First, new processes. With the growth of alpha laser welding, hybrid welding, and additive manufacturing, the glossary needs the vocabulary to accurately describe them. Second, inspection technology. As nondestructive examination becomes more advanced, it requires its own defined terms to keep pass/fail decisions consistent. Third, global harmonization. With fabricators working across borders now more than ever, aligning with an internationally recognizable vocabulary prevents costly miscommunication between clients, inspectors, and contractors.

These advancements have even begun to touch the more specialized side of the trade, from the selection of alloy steel welding electrodes, all the way down to choosing the correct all-position welding rod for a code qualified joint. All of these rely on the correct, agreed upon terminology to be specified properly.

With all of that said, it’s incredibly important to remember this: despite nearly 85 years of revisions, the core idea of coalescence by heat, pressure, or both has remained remarkably stable. A definition pulled from a 1990 textbook may still feel correct, however, for compliance with a modern code, citing an outdated edition can be flat out incorrect.

The International View: How ISO Currently Defines Welding Terms

AWS A3.0M/A3.0:2025 is the authoritative answer inside the United States, but welding specifications rarely stop at a border. If your fabrication package comes out of Europe, Asia, or an international project spec, the governing vocabulary is ISO’s, not AWS’s. Two shops can weld identical joints and follow identical physics yet still talk past each other if one is quoting the American glossary and the other is quoting the ISO vocabulary series. Here is how the international side currently words it.

The ISO/TR 25901 Vocabulary Series

ISO’s current answer lives in ISO/TR 25901, “Welding and allied processes — Vocabulary”, which is not a single book but a family of parts, each covering a slice of the trade:

• Part 1 (2016) — general terms for fusion welding
• Part 2 (2022) — health and safety terms
• Part 3 (2016) — welding processes
• Part 4 — arc welding

The heavy lifter for anyone asking “what is welding, by ISO’s rules” is ISO/TR 25901-3:2016. That document cancels and replaces both ISO 857-1:1998 and the earlier ISO/TR 25901:2007, which is why older shop manuals and legacy international specs often word things differently from what you see today. It is not a stale document either: its status has been reviewed and confirmed as recently as 2022, so a citation to ISO/TR 25901-3 is current rather than legacy. Part 4, the arc welding volume, is also under revision, so anyone drafting a long-lived specification should re-check that part’s status before the document is issued.

How ISO Organizes Its Definitions

This is where the two systems feel visibly different. AWS A3.0 is an alphabetical glossary you flip through; ISO/TR 25901-3 is built as a systematic classification. It contains terms and definitions for welding processes organized by their physical characteristics and the relevant energy carrier — meaning processes group together by what physically happens at the joint and by the energy that drives it, whether that is an electric arc, a gas flame, a laser beam, friction, or something else. Read it top to bottom and it behaves more like a taxonomy than a dictionary.

Within that structure sit basic entries that do a surprising amount of work. “Metal welding” anchors the family, and “welding with pressure” is defined by the behavior of the joint itself: sufficient external force causes plastic deformation of the faying surfaces, generally without filler metal. That single sentence is why forge welding, friction welding, and resistance pressure welding all count as welding even when nobody ever pointed a torch at the parts. Nothing about puddles or arcs is required — deformation under force is enough.

Related ISO Standards That Are Still Current

ISO 857-1:1998 is withdrawn, but several neighbouring documents remain live references on real projects:

• ISO 857-2:2005 — the current vocabulary reference for soldering and brazing, which keeps the “base metal does not melt” boundary clearly drawn on the international side.
• ISO 6947:2019 — welding positions, the designations that appear on drawings and procedure documents worldwide. Anyone working through an aluminium welding course for international work will meet these early.
• ISO/TR 581:2005 — weldability, covering the general terms and definitions used when a material’s suitability for welding is discussed.

AWS vs. ISO: Two Philosophies, One Physical Reality

Neither system is “more correct.” They describe the same metallurgy with different organizing instincts, and the differences show up in how each is built:

Aspect	AWS A3.0M/A3.0:2025	ISO/TR 25901 series
Structure	Single glossary, alphabetical, terms marked standard vs. nonstandard	Multi-part vocabulary, systematic by physical characteristics and energy carrier
Orientation	Code- and contract-oriented, feeding documents like AWS D1.1 and ANSI Z49.1	Process-classification oriented, built for international technical work
Lookup access	Purchased standard	Free term lookup on the ISO Online Browsing Platform
Recent direction	Expanded into additive manufacturing and NDE vocabulary	Added a health and safety part (2022); arc welding part in revision

The practical takeaway is simple: when someone asks for the current welding definition on an international package, ISO/TR 25901 is the reference to reach for, and its free Online Browsing Platform makes verification quick enough that there is no excuse for guessing. Confirm which part and edition you are standing on — and remember that both ISO and AWS ultimately point at the same physical idea of coalescence, only through different vocabulary architecture.

Inside the Definition: Coalescence, Heat, Pressure, and Filler Metal

The current AWS definition fits on an index card: welding is coalescence produced by heating to suitable temperatures, with or without pressure and/or with or without filler material, plus the related surfacing operations. That looks almost too casual for something a $55,600-a-year career and a multi-million-dollar contract rest on. Yet every clause is doing work: understand what each one includes and excludes, and you can classify any joining process in about ten seconds.

Coalescence: The Word Carrying the Whole Definition

Coalescence means merging into a single mass. In welding, the atoms of two separate pieces form a continuous bond, so the boundary between them effectively disappears. The pieces stop being two objects touching and become one body. TWI’s plain-language FAQ puts the same idea in layman’s terms: joining materials so they act as one.

That word is the gatekeeper. Adhesive holds two faces together; coalescence makes them one. Glue lines peel and the parts underneath are unchanged; a coalesced joint cannot be split without breaking metal. That is why the fabricator in our opening story lost the argument: epoxy produces adhesion, not coalescence, no matter how strong the bond feels.

Heating to Suitable Temperatures: Not Always a Molten Puddle

Notice the definition says suitable temperatures, not melting temperatures. Suitable means whatever temperature produces coalescence for the process. For arc welding, that is above the metal’s melting point. For solid-state processes, it is often several hundred degrees below it, where the metal becomes soft and plastic but never liquid.

With or Without Pressure

This two-word clause is the most underappreciated part of the definition, because it explicitly allows welding by pressure alone. Forge welding, rotary friction welding, diffusion bonding, and cold pressure welding are all welding under AWS’s rules even though a heat source plays no starring role. Heat plus pressure gives resistance welding; heat alone gives oxyfuel or arc fusion welding. All three combinations qualify, and the definition was written to hold them.

The international vocabulary reaches a compatible place from a different direction. ISO/TR 25901-3 notes that a filler metal with a melting temperature of the same order as the parent metal can be used, and that the result of welding is the weld. The emphasis is on materials behaving alike under heat, not on a single melting requirement.

With or Without Filler Material

Filler is optional too. Autogenous welding, such as GTAW run without a rod, fuses base metal to base metal and nothing else. AWS captures this inside its definition of fusion: the melting together of filler metal and base metal (the substrate), or of base metal only, which results in coalescence of the materials. The “base metal only” phrase keeps autogenous processes legally inside the welding family, while the requirement that the base melt keeps brazing outside it.

Fusion Welding vs. Solid-State Welding

Split the process universe by that one question and you get two clean families. As Lincoln Electric’s resource explains, fusion means melting together; penetration is a separate measure of how deep that fusion reaches.

Aspect	Fusion welding	Solid-state welding
Base metal melts?	Yes	No
What produces coalescence	A molten weld pool solidifying	Heat, plastic flow, and/or pressure
Filler metal	Common, but optional	Rarely used
Typical examples	GMAW, GTAW, SMAW, SAW	Friction stir, friction, diffusion, forge
Tell-tale sign	Visible puddle and ripple pattern	No arc, no puddle, often a flash or tool path

Surfacing Counts as Welding Too

AWS gets this right: the standard’s scope states that the welding definition also includes surfacing. Hardfacing and overlay work deposit weld metal onto a surface to change its properties, and that deposited filler coalesces with the base metal just as it would in a joint. Nothing is being assembled, yet welding has occurred. The parent part remains the workpiece; the deposit is the weld. Alloy wheel repair leans on this principle when a damaged rim is built back up with overlay passes.

The Master Chart: Where the Process Names Come From

None of this classification lives only in prose. AWS A3.0 includes a Master Chart of Welding and Joining Processes, a Joining Method Chart, and the letter designations that let one document name processes unambiguously. That is why a WPS says SMAW, GMAW, GTAW, or SAW instead of “stick,” “MIG,” “TIG,” or “sub-arc.” You can preview the standard’s structure through AWS’s own publication page, and the full catalog entry sits on the AWS A3.0M/A3.0 page. To see those designations at work, our guide to why SMAW still wins, the aluminum GMAW guide, and the aerospace GTAW overview all walk through real applications process by process.

Read the definition that way and it stops being abstract. Heat, pressure, or both; filler if you need it; melting if the process melts. That flexibility is what lets a society founded in 1919 keep one vocabulary standing across a century of new technology.

Where the Line Is Drawn: Welding vs. Brazing, Soldering, and Other Joining

Most arguments about “what counts as welding” are really arguments about neighboring processes. The current standard does not leave those boundaries to opinion, and its own title is the first clue: AWS A3.0M/A3.0:2025 is formally designated as the standard welding terms and definitions covering additive manufacturing, adhesive bonding, brazing, soldering, thermal cutting, thermal spraying, and nondestructive examination in addition to welding. It defines all of those families precisely so it can separate them. A term that appears in the glossary is not automatically a welding term, and that distinction decides specifications, invoices, and repair acceptance every day.

Why Brazing and Soldering Are Not Welding

Brazing and soldering share welding’s appearance: heat, filler metal, a finished joint. What they do not share is melted base metal. Under AWS terminology, brazing produces coalescence using a filler metal whose liquidus is above 450 °C but below the solidus of the base materials, so the filler flows while the parts being joined stay solid. Soldering follows the same logic with a filler metal whose liquidus falls below 450 °C. Welding, by contrast, is defined around coalescence of the base materials themselves, by heat, pressure, or both.

That single threshold explains why a braze joint can look like a weld, pass a visual check, and still be the wrong answer to a specification that calls for welding. Torch work makes the confusion worse, which is why process guides such as Air Acetylene Welding: Torch Basics, Brazing & Safety treat brazing as a distinct skill with distinct qualification requirements rather than a variant of fusion welding.

Adhesive Bonding, Spraying, Cutting, and Fastening

The other excluded categories fail for different reasons. Adhesive bonding is defined in A3.0 around the attractive forces of a polymeric material placed at the faying surfaces, not coalescence produced by heat or pressure — an epoxy repair can be strong, but no amount of clamping makes it welding. Thermal spraying builds a coating on a surface rather than joining two parts. Thermal cutting removes material rather than combining it. Mechanical fastening holds parts together through interference, friction, or bolting, with no coalescence anywhere in the process.

Two categories deserve special mention because the 2025 edition refined them: plastic welding and hybrid welding. Polymer welding — solvent, hot-tool, spin, or ultrasonic joining of thermoplastics — is a recognized, legitimate form of welding, but it is a distinct family with its own vocabulary, and the 2025 edition sharpened its terminology alongside new terms for hybrid processes and waveform-controlled welding. Hybrid welding, typically laser-plus-arc, is the case that trips people up: two heat sources, one weld, still welding.

Friction and stir processes complete the picture. Friction stir welding joins solid material without melting it, which is the clearest possible proof that fusion is not mandatory. The definition requires coalescence, not a puddle.

Method	What triggers the definition	Base metal melts?	Filler needed?	Typical example
Welding (fusion)	Coalescence from heat, pressure, or both	Yes	Optional	GTA W fillet weld on steel plate
Welding (solid state)	Coalescence without reaching melting point	No	Usually no	Friction stir weld on aluminum
Brazing	Filler liquidus above 450 °C, below base solidus	No	Yes	Copper pipe brazing
Soldering	Filler liquidus below 450 °C	No	Yes	Tin-lead solder on copper trace
Adhesive bonding	Attractive forces at faying surfaces	No	Adhesive instead of filler	Epoxy-bonded composite panel
Thermal spraying	Coating deposition	No (feedstock only)	Feedstock instead of filler	Spray zinc on structural steel
Thermal cutting	Material removal	Melts or oxidizes locally	No	Plasma severing of plate
Mechanical fastening	Interference or bolted grip	No	No	Riveted lap joint

Getting the line right also keeps terminology aligned with the processes you actually run. The same discipline applies on the shop floor: whether you are running Aluminum MIG Welding: The Complete Practical Guide or specifying a repair procedure, naming the process correctly is what makes the definition useful instead of decorative.

Weld, Joint, Weldment, and Related Terms Around the Core Definition

The current welding definition only makes sense beside the terms around it. Inspectors, engineers, and shop crews need that shared vocabulary for procedure documents, inspection reports, and everyday shop talk, and AWS A3.0M/A3.0 defines each term precisely.

The Building Blocks: Weld, Fusion Weld, and How They Are Produced

A weld is the localized coalescence of metals or nonmetals produced by heating to suitable temperatures, with or without pressure, and with or without filler material. A fusion weld melts the base metal and the filler metal (if used) so they flow together and solidify into a single mass — the type produced by arc processes like SMAW, GMAW, and GTAW.

These definitions anchor how standards describe quality. Whether you compare shop-floor approaches such as Advantages of Stick Welding: Why SMAW Still Wins or study process-specific work like Aerospace TIG Welding: Standards, Techniques, and Training, you are dealing with fusion welds made by controlled heat sources: the weld is the result, the process is the method.

Joints, Faying Surfaces, and the Distinction Between ‘Weld’ and ‘Welded Joint’

A weld joint is the arrangement of two or more workpieces in a manner that permits welding. The faying surfaces are the mating faces in contact or near contact where the weld forms. Think of the joint as geometry — butt, lap, tee — and the faying surfaces as the interfaces.

The weld is the junction produced by coalescence; the welded joint is the assembly that results from welding those parts together. One is material, the other is configuration, so an inspector evaluates both: joint design and preparation on one side, weld quality on the other. Codes such as AWS A3.0M/A3.0 keep that wording strict.

A weldment is the finished product or assembly made up of welded parts — the base metal components plus all welds. A structural frame is a weldment; the individual fillet inside it is a weld.

Base Metal, Filler Metal, Weld Metal, Arc, and Bead/Ripple

To describe what is joined and what is added, AWS uses precise terms:

• Base metal: the metal or alloy to be welded, brazed, or cut.
• Filler metal: metal added in making a weld (optional in many processes).
• Weld metal: metal that solidified in the weld, from melted base metal and/or filler.
• Arc: a sustained luminous discharge across a gap in a circuit; the heat source in many processes.
• Weld bead: the deposit of weld metal from a single pass.
• Ripple: the weld surface pattern left by solidification.

Preparation and filler selection turn on these terms, as in Alloy 20 Welding: Procedures, Filler Metals, and Best Practices and Alloy Steel Welding Electrodes: Selection, Use & Safety. Telling weld metal from base metal also sharpens fusion-versus-penetration talk — see Lincoln Electric’s fusion vs. penetration explanation.

2025 Expansion: Nondestructive Examination and Additive Manufacturing Vocabulary

The 2025 edition of AWS A3.0M/A3.0 reached well beyond traditional welding terms, adding expanded definitions for nondestructive examination (NDE) methods alongside additive manufacturing (AM) vocabulary. Inspection and 3D-printing terms now sit in the same reference standard as welding and joining processes.

That harmonization matters wherever inspection is built into production. Whether you are studying inspection workflows or a broader training path like Aluminium Welding Course: What You Learn, Costs & Careers, one shared vocabulary cuts miscommunication between design, production, and QA. Verify the changes in the AWS A3.0M/A3.0:2025 preview and compare the 2020 edition.

Welder Performance Qualification vs. Welder Certification

One of the most common points of confusion is the difference between welder performance qualification and welder certification. AWS A3.0 defines them precisely:

• Welder performance qualification: demonstration of an individual’s ability to produce a weld meeting prescribed standards.
• Welder certification: written verification that a welder has produced welds meeting a prescribed standard of welder performance.

Qualification is the demonstration — the test; certification is the written verification — the credential. AWS D1.1, Structural Welding Code – Steel, Clause 3 carries parallel definitions. The stakes are practical: AWS Welding Workforce Data shows a large, aging workforce with strong demand for qualified welders, which is why consistent terminology matters across employers and training programs (see AWS Welding Workforce Data and AWS Welding Digest on qualification vs. certification).

The vocabulary follows you onto real jobs, from marine repairs like Aluminum Boat Welding: The Complete Guide for Strong Hull Joints to specialized services such as Alamo Welding & Boiler Works: Services & Boiler Expertise. The right term can change what a job requires.

Together these terms frame the core definition: weld and fusion weld, joint geometry and faying surfaces, the metals involved, and the credentials that prove capability.

Why the Current Definition Matters in Real Work

For most welders, the argument over what counts as “welding” starts small. It could be an inspector rejecting a repair, a customer insisting their cracked part was “welded” with epoxy, or a shop foreman debating whether a brazed joint can be labeled as a weld on an invoice. While these debates may seem trivial at first, they can quickly spiral into lost money, failed inspections, or even unsafe repairs. This is exactly why the current definition of welding matters, and why using an outdated or loose definition can break work in the real world.

Contracts, WPSs, and Code Compliance

One of the first places a loose definition falls apart is in contracts and compliance. When a repair is quoted, the line between welding and brazing or soldering can change the scope of work, the filler metal required, and the acceptance criteria. For jobs following structural codes such as AWS D1.1, the welding procedure specification (WPS) and its procedure qualification records must reference standard terminology that matches the code’s edition of AWS A3.0M/A3.0:2025. If an older edition is cited, or if nonstandard terms are used, an inspector can rightfully reject the procedure. These standards allow for a wide range of processes, from the precision required for Alpha Laser Welding, all the way to tried and true methods like SMAW. No matter the process, the terminology must stay consistent.

Inspection, NDE, and Safety

Precise vocabulary also plays a massive role in inspection and nondestructive examination (NDE) acceptance criteria. For example, the difference between a “weld” and a “surfacing deposit” can determine which flaws are rejectable. This extends to safety planning as well, as terms defined within the current standards are used throughout documents like ANSI Z49.1 to communicate hazards. These safety measures are crucial for high risk work, such as Aluminum Boat Welding, Alloy Wheel Welding, or even large scale repairs from shops like Alamo Welding & Boiler Works. A single misused term can lead to incorrect testing, missed defects, or unsafe work conditions.

The Workforce Behind It All

The scale of the welding trade only adds to these stakes. According to AWS Welding Workforce Data, there are an estimated 771,000 U.S. welding professionals as of 2025. More than 157,000 of these professionals are approaching retirement, and roughly 320,500 new welding professionals are projected to be needed in the U.S. by 2029. On average, about 80,000 welding jobs are expected to be filled between 2025 and 2029. Per Bureau of Labor Statistics data cited by AWS, 61% of welders work in manufacturing, with a national median salary of $55,600 and average hourly earnings of $26.76. With robotic and automated welding systems becoming standard, welders are increasingly stepping into hybrid roles that combine hands-on skill with programming and calibration. This new generation is learning definitions from mixed sources, making a shared, current vocabulary more vital than ever.

When Definitions Impact Everyday Projects

These consequences aren’t reserved for massive structural jobs. They trickle down to smaller projects as well. For students learning through an Aluminium Welding Course, quoting the correct terminology can be the difference between passing a qualification, or failing it. Those sourcing supplies from Airgas Welding Supplies or AllGas Welding Supply need to know exactly what process they’re ordering for. Even specialized repairs, such as Alloy 20 Welding, require strict adherence to standard terms to prevent corrosion and failure.

The table below shows just a few real-world scenarios and what can break when an outdated or loose definition is used:

Scenario	Risk of a Loose Definition	Why Current Terms Prevent It
Contract Dispute (Repair Quote)	Brazing mislabeled as welding, inflating or voiding the quoted price.	Sets a clear boundary between joining processes under the current AWS A3.0:2025 scope.
WPS & Qualification	Rejection from an inspector due to obsolete terminology.	Ensures alignment with code required references, such as ISO vocabulary or AWS D1.1.
Safety & NDE	Incorrect testing or hazards due to misclassified joints.	Allows accurate acceptance criteria for flaws under current inspection standards.

At the end of the day, the current definition isn’t about splitting hairs. It’s about protecting workers, upholding contracts, and ensuring that the knowledge being passed to the next wave of welders is correct. With hundreds of thousands of jobs on the line, a few precise words go a very long way.

Common Misunderstandings and Mistakes About Welding Definitions

Ask ten people on a shop floor what welding is and you will get ten slightly different answers, most of them reasonable and a few of them dangerous. Definitions drift through apprenticeships, old textbooks, supplier catalogs, and marketing copy until the word means whatever the speaker needs it to mean. On a DIY project that is an annoyance. On a contract, a work order, or an inspection report it is a dispute waiting to happen. Here are the errors readers actually run into, and the correct move for each.

1. Calling Adhesive or Epoxy Repairs “Welding”

The plastic-housing argument from the start of this article is the classic case. An adhesive joins two surfaces through physical attraction and curing, not through coalescence produced by heat, pressure, or both, so it does not meet the current AWS A3.0M/A3.0:2025 definition. Correct move: name the actual process on the work order, “bonded” or “adhesively joined,” and reserve “welded” for work that satisfies the definition.

2. Treating Plastic-Bag Rubbing or “Cold Weld” Products as the Standard Definition

The playground trick of rubbing two pieces of film together is not welding, and neither is any product marketed as a “cold weld” compound. The standard’s trigger is heat to a suitable temperature, pressure, or both, producing coalescence. AWS does list informal terms in its glossary, but it explicitly flags them as nonstandard, which means they appear for recognition, not for use in documents. Solid-state “cold pressure welding” of clean soft metals under vacuum is a real process, and it is a different thing entirely from the colloquial phrase. Correct move: check whether the term is marked standard or nonstandard before quoting it.

3. Confusing Welding with Brazing or Soldering on Quotes and Invoices

Brazing uses filler metal above 450 °C (840 °F) while the base metals never melt; soldering is the same idea below that threshold. Welding requires coalescence of the base metal itself. This is exactly where a job priced as a “weld repair” turns into an argument, and aluminum wheel work is a frequent flashpoint, so it pays to read a detailed alloy wheel welding guide before quoting the job. Correct move: identify the filler liquidus and whether the base metal melted, then use the matching term consistently in the quote, the invoice, and the inspection record.

4. Assuming Every Welding Process Melts Metal

Fusion welding does, but solid-state and pressure processes such as friction stir welding, diffusion welding, and forge welding reach coalescence without a molten pool. The definition deliberately says heat, pressure, or both, which is why these processes sit inside it. Correct move: before writing “molten” anywhere, confirm the process family you are describing.

5. Using “Certified Welder” and “Qualified Welder” Interchangeably

AWS itself acknowledges the common shop-floor habit of calling anyone who passed a qualification test a “certified welder,” while the codes keep the two words apart: qualification is a demonstration of an individual’s ability to produce a weld meeting prescribed standards, and certification is a written verification of that fact. Under AWS D1.1, qualification also requires the welder to follow a Welding Procedure Specification carrying all essential variables and limitations. Correct move: write “performance-qualified” unless a certifying body actually issued a certificate. If you are still building your vocabulary, a structured aluminium welding course outline is a useful map of which terms to learn first.

6. Citing an Obsolete Edition

AWS A3.0:2001 and every earlier printing are historical products. The current lineage runs A3.0M/A3.0:2010, the 2020 thirteenth edition, and the 2025 fourteenth edition. On the international side, ISO 857-1:1998 and ISO/TR 25901:2007 are both withdrawn, so a document citing them is referencing superseded vocabulary. Correct move: verify the edition year in the citation itself, not just in your notes.

7. Mixing ISO and AWS Term Sets in One Document

Both systems are authoritative, but they organize differently, and blending them produces hybrids no inspector recognizes. Correct move: choose one standard, state which one in the document header, and hold every term to it.

8. Assuming the Definition Covers Cutting and Spraying

A3.0’s scope title lists thermal cutting, thermal spraying, brazing, soldering, adhesive bonding, additive manufacturing, and nondestructive examination alongside welding, as separate subject areas. Gouging and cutting remove material rather than join it, which is why a process like air arc gouging is its own discipline with its own terminology. Correct move: look the term up instead of inferring it from the word “welding” in the standard’s title.

The Four-Step Correction Routine

1. Look the term up in AWS A3.0M/A3.0:2025, or in the current vocabulary references for international work.
2. Confirm the edition year on the document you are quoting.
3. Keep the terminology consistent from the quotation through the WPS to the final report.
4. Loop in the inspector or engineer the moment a term choice could shift an acceptance criterion.

How to Use the Current Welding Definition: Practical Tips and Takeaways

A definition earns its keep under pressure: a customer questions a quote, an inspector flags a report, or a procedure cites a term nobody on the crew can find. Treat the current welding definition as a working tool and run it through the same short routine instead of rebuilding it from memory.

A Five-Step Lookup Routine

1. Name the term precisely. Write down the exact word in dispute. “Weld,” “welded joint,” “fusion,” “surfacing,” and “welder performance qualification” are separate entries with separate meanings, and the right headword saves a second trip to the glossary.
2. Open the authoritative source. For U.S. work that is AWS A3.0M/A3.0:2025, available as an American National Standard through the ANSI webstore and the AWS bookstore in print and PDF. For international work, all terms and definitions in the ISO/TR 25901 series are free on the ISO Online Browsing Platform.
3. Confirm the edition year. Note it in your record before you quote anything. Wording that looks familiar may have shifted between the 2001, 2020, and 2025 editions, and an unattributed quote is unverifiable.
4. Check whether the term is marked standard or nonstandard. A3.0 flags standard terms as the preferred vocabulary; nonstandard terms are tolerated but should not appear in new specifications when a standard term exists.
5. Mirror the wording exactly. Copy the definition into your WPS, quotation, inspection report, or article word for word, then cite the standard and edition beneath it. Paraphrasing is where drift begins.

Because A3.0 is prepared under ANSI consensus rules, its definitions carry recognized standing beyond a single company. That is why the A2 Committee exists: its stated purpose is to establish standard terms and definitions to aid the communication of welding information. Copy it exactly; that is what makes a document defensible when two parties read it differently.

Legacy Document Update Checklist

If your quality manual, WPS, or shop SOP cites an older edition, walk this list once and log the results:

• Search every document for “A3.0” and record each edition year that appears.
• Compare each quoted definition against the 2025 wording and highlight differences.
• Flag terms the 2025 edition revised or added: hybrid welding, plastic welding, waveform-controlled welding, GMAW transfer modes, SAW multi-electrode variations, temper bead welding, test positions, and the new additive manufacturing and NDE vocabulary.
• Replace nonstandard terms that have a standard equivalent.
• Confirm downstream documents, including quotations, drawings, and inspection reports, carry the corrected wording.
• Route any change affecting acceptance criteria through the engineer or inspector before reissuing.
• Date the revision in your document control log so the next reader knows which edition was in force.

What Students and Newcomers Should Learn First

You will not memorize more than 1,500 terms, and you do not need to. Learn in three practical layers:

1. The core nouns: weld, base metal, filler metal, weld metal, faying surfaces, fusion, workpiece, bead.
2. The process designations: SMAW, GMAW, GTAW, SAW, FCAW, and what each abbreviation actually stands for.
3. The qualification pair: welder performance qualification versus welder certification, plus the difference between a WPS and a PQR.

This vocabulary is not academic. The occupational categories published through AWS Welding Workforce Data and careersinwelding.com rest on Bureau of Labor Statistics definitions for six welding-related occupations, so you learn the same words used to describe the jobs you chase.

Cross-Border Projects: Choose One Standard and Say So

Mixed standards cause mixed results. On any project that crosses a border, pick AWS or ISO as the governing vocabulary, state that choice in the contract and specification, and never switch mid-document. If a client requires both, publish a short reconciliation table mapping each AWS term to its ISO counterpart so inspectors and bidders read the same words the same way. Remember that only English, French, and Russian terms are official ISO terms, so translations carry no normative weight.

The Definition in One Sentence

Welding is the joining of materials by producing coalescence through heat, through pressure, or through both, with or without filler metal. Everything else in this article exists to keep that one sentence meaning the same thing in every shop, contract, and inspection report. From here, go deeper with our process tutorials, keep your safety fundamentals current, and build your qualification path through our career and training resources.

Frequently Asked Questions

What is the current definition of welding?

Under AWS A3.0M/A3.0:2025, welding is a materials joining process that produces coalescence of materials by heating them to suitable temperatures, with or without the application of pressure, or by the application of pressure alone, and with or without the use of filler material. In everyday language, TWI summarizes it as fusing two or more parts with heat, pressure, or both so they join as they cool.

Which standard defines welding terminology today?

In the United States, AWS A3.0M/A3.0:2025, Standard Welding Terms and Definitions, approved by ANSI on July 30, 2024, is the current reference. Internationally, the ISO/TR 25901 vocabulary series covers welding and allied processes.

What changed in the 2025 welding definition update?

The 14th edition added terminology for additive manufacturing and nondestructive examination and refined definitions for hybrid welding, plastic welding, waveform-controlled welding, GMAW transfer modes, multi-electrode submerged arc welding, temper bead welding, and welding test positions. The core idea of coalescence through heat, pressure, or both remains intact.

Is brazing considered welding under the current definition?

No. Brazing produces coalescence with a filler metal whose liquidus is above 450 °C but below the solidus of the base materials, and the base metals do not melt. Welding, by contrast, can melt the base metal or rely on heat and pressure to create coalescence directly in the base materials.

Does welding always require melting the metal?

No. Because AWS’s definition allows welding by the application of pressure alone, solid-state processes such as friction-based welding qualify without creating a molten pool. Fusion welding is only one branch of the definition.

What is the difference between a weld and a welded joint?

A weld is the junction produced by the welding process where the materials coalesce, while a welded joint (or weld joint) is the arrangement or configuration of the parts being joined, such as a lap, tee, or butt joint. Confusing the two leads to ambiguous inspection and drawing callouts.

Why does the exact wording of the definition matter?

The wording decides whether a procedure, repair, or qualification falls under a welding code, affects acceptance criteria, and can determine contract disputes and inspection results. Documents must cite the current edition so all parties evaluate the work against the same vocabulary.

Where can I look up welding terms for free?

ISO makes its welding vocabulary available through the ISO Online Browsing Platform, and AWS publishes preview sections of A3.0 through its publications page and the ANSI store. Reputable industry references such as TWI also publish clear definitions of core welding concepts.