A good weld looks simple. Two pieces become one, the bead is clean, and the part moves on to paint. In practice, the quality behind that seam rests on years of training, disciplined procedures, and third‑party verification. Certifications are the way a welding company proves all of that to you before the first spark. If you build industrial machinery, order custom metal fabrication, or run a machine shop that relies on contract manufacturing, understanding certifications helps you pick the right partner and price risk correctly.
This guide unpacks the most common welding credentials, how they tie into procedure control, what inspectors actually check, and which ones matter for your industry. I’ll also share what tends to go wrong when paperwork becomes a box‑check rather than a living quality system. The goal is not to drown you in acronyms. It’s to help you read a cert and know what it really buys you on the shop floor.
The role of certifications in the real world
Certifications do three things. First, they create a shared language. When a steel fabricator says a weld is qualified to AWS D1.1, the customer and the inspector know the joint details, base metals, and acceptance criteria without reinventing the wheel. Second, they force repeatability. A certified procedure locks in parameters like amperage, travel speed, preheat, and filler metal class, which helps a metal fabrication shop deliver consistent strength and appearance across shifts and locations. Third, they put accountability on paper. If a weld fails, there is a trail of who qualified what, when, and how.
This matters in industrial machinery manufacturing and custom industrial equipment manufacturing, where fatigue and vibration punish welds for years. It matters in structural steel holding up platforms and catwalks, where code compliance and public safety are front and center. It matters in pressure boundaries on tanks and piping, where a poor root pass can set you up for leaks and costly downtime. Certifications don’t make a weld perfect, but they make quality measurable and enforceable.
The basic building blocks: WPS, PQR, and welder performance
Before the alphabet soup of standards, learn three documents that show whether a welding company runs a disciplined process.
- Welding Procedure Specification (WPS): Think of this as the recipe. The WPS lists the process (GMAW, GTAW, FCAW, SMAW), joint design, base material, filler metal, shielding gas, preheat, interpass temp, heat input limits, position, and other variables. A practical WPS saves headaches. When I audit a shop, I look for WPS documents posted at each booth with settings that match the power sources on the floor, not a binder that no one reads. Procedure Qualification Record (PQR): This is the proof the recipe works. The shop welds a test coupon to the WPS, then a lab performs bend tests, tensile tests, and sometimes impact tests or macroetch examinations. The PQR lists actual ranges used during the test. If your project has thick sections, check that the PQR qualifies those thicknesses and joint types, not just a thin plate in the flat position. Welder Performance Qualification (WPQ or Welder Cert): This certifies a person can deposit a sound weld using a qualified WPS, in a specific process, position, and range of thicknesses and diameters. Passing a single horizontal fillet test does not qualify someone to run a 6G pipe weld. The best shops track continuity every six months so qualifications don’t lapse.
In a tight‑run machine shop with a small welding cell, these three documents do more to assure quality than any logo on a website. They are also the foundation of every major code.
The big standards and what they control
Different industries lean on different standards bodies. Here are the ones you will most often see and what they cover in practical terms.
AWS D1.1 and structural codes
AWS D1.1 is the backbone for structural steel in buildings, platforms, and some industrial frames. It governs design, qualification, fabrication, and inspection. If your steel fabrication package calls out D1.1, the fabricator needs qualified WPS/PQRs for the specific base materials and processes, and their welders need position‑appropriate performance qualifications. The code sets acceptance criteria for visual inspection and for NDT methods like ultrasonic testing or radiography when specified.
For aluminum structures, D1.2 applies. For stainless in structural contexts, D1.6. For sheet metal under 3/16 inch, D1.3 is the guide. A custom metal fabrication project may pull in multiple sections if the assembly blends thick plate with thin guard panels.
What this means for your project: D1.1 compliance tells you the fabricator has a system to manage essential variables and inspection, but it does not automatically cover fatigue life under high‑cycle machinery. If you are mounting a gearbox with a 1,200 pound out‑of‑balance load, add your own fatigue requirements or request a higher category weld detail and additional NDT beyond the minimum.
ASME Section IX and pressure equipment
ASME Boiler and Pressure Vessel Code, particularly Section IX, controls welding qualifications for pressure vessels and piping. Section IX covers procedure and performance qualification, and it cross‑references construction codes like Section VIII Div. 1 for vessels and B31.1/B31.3 for power and process piping.
A shop that holds a National Board “R” stamp or ASME “U” stamp has gone beyond certifying welders. They have a quality program audited to ensure material traceability, calibrated gauges, certified inspectors, and document control. If your industrial design company is delivering a skid with pressure piping, ask whether the piping will be built per ASME B31.3 and whether impact‑tested materials and low heat input procedures are required for cold service.
What this means for your project: Stamped shops cost more but close risk on liability and inspections. For non‑code spools or low‑pressure jackets, you can work with a qualified welding company without a stamp, as long as their WPS/PQRs and NDT plan meet the service conditions. Be explicit in your purchase order about code applicability to avoid expensive surprises during customer or jurisdictional inspections.
ISO 3834 and EN standards
If you export equipment to Europe or serve global OEMs, ISO 3834 sets requirements for quality requirements in fusion welding of metallic materials. It comes in parts (Basic, Standard, Comprehensive), paired with EN 1090 for structural components in CE‑marked construction products. These frameworks look holistically at the welding management system: coordination roles, supplier control, consumable storage, traceability, and NDT.
What this means for your project: ISO 3834 certification is less about one weld and more about consistent execution across the contract manufacturing lifecycle, from order review to final documentation. If you run a cnc metal fabrication program with repeat part families, ISO 3834 can reduce requalification churn and audit friction across borders.
API, AAR, and sector‑specific standards
The American Petroleum Institute (API 1104) covers welding of pipelines and related facilities, with heavy emphasis on radiography, fracture toughness, and field conditions. Rail projects may call AAR standards, which add fatigue and impact considerations. These are specialized. If your machinery parts manufacturer builds frames that ride on rails or rigs, expect a different set of test coupons, positions, and acceptance criteria than a typical shop sees.
Process competence matters as much as the code
Codes tell you what to test and accept. Process expertise determines how cleanly a shop hits those marks. A few examples from the floor:
- GMAW spray versus pulse: For thick carbon steel, spray transfer gives efficient deposition but can sacrifice control on out‑of‑position welds. Pulse adds control and reduces spatter but requires tuned waveforms and distinct parameter windows. The right choice affects bead profile and heat input on your cnc metal cutting skeletons and tabs. GTAW root with GMAW fill: On stainless or thin pressure parts, a TIG root with a backing gas controls oxide and ensures full fusion in corners. Fill and cap with MIG save time. Make sure the WPS defines purge gas quality and damming methods, so your custom industrial equipment manufacturing does not suffer from sugar on the ID. FCAW in the yard: Structural frames that exceed fixture envelopes often require flux‑cored wire outdoors. A shop trained on gas‑shielded flux‑cored processes will have different slag control and interpass cleaning routines than a team that only runs solid wire indoors. Your schedule and weather drive real trade‑offs.
A Machining manufacturer with in‑house welding can qualify to the same code as a pure steel fabricator, yet produce different weld outcomes because of fixturing capability, preheat control, and how they sequence assemblies to manage distortion. Ask how they plan to hold perpendicularity on a 2‑meter mast after multi‑pass welding, and you’ll learn more than any certificate reveals.
Reading a certificate without getting snowed
Marketing decks love badge walls. Slow down and read the scope lines. Most certificates carry annexes that list processes, materials, and limitations. A few items to check:
- Process coverage: If your part requires GTAW on aluminum and FCAW on heavy carbon steel, look for both in the scope. A shop might be certified for GMAW only, which is fine for many parts but not for thin crack‑sensitive sections or critical roots. Material groups and thickness: AWS and ASME group materials into families. Make sure your base metal grade falls within the qualified groups, and that thick plates are covered. I’ve seen 2‑inch base rings welded with WPSs qualified only to 1‑inch because someone grabbed the wrong PQR. Position and joint type: All‑position qualification is not a given. If the job demands overhead fillets or 6G pipe, the welder and procedure must be qualified accordingly. NDT level and acceptance: If the spec demands 100 percent ultrasonic testing to a specific class, confirm the code edition and criteria. Not all “UT passed” stamps mean the same thing. API 1104 acceptance for lack of fusion is different from AWS D1.1, which differs again from ASME B31.3. Continuity and expiration: Welder performance qualifications require continuity. If more than six months have passed without documented welding in the qualified process, the qualification lapses. Ask for continuity logs if the schedule slipped and a crew rotated off.
A five‑minute desk review can prevent days of rework. You don’t have to become a code expert. You just need to match what’s printed to what your welds demand.
How certifications affect cost, schedule, and risk
Certifications change the way a welding company plans, quotes, and executes. That ripple shows up in your project.
Cost: Qualifying a new WPS and PQR can run from a few thousand dollars to tens of thousands when you include lab time, destructive testing, and engineer oversight. If your design uses an odd alloy or joint design outside common prequalified ranges, expect a setup charge and a longer lead to qualify. Per‑part cost may rise for increased NDT or slower processes like GTAW on thin sections.
Schedule: New qualifications add weeks. Even with existing procedures, higher NDT percentages and inspector availability can stretch delivery. On one skid line, we budgeted 7 to 10 days just for radiography review cycles on a set of critical welds. Build that into your milestones, not as a hidden buffer at the end.
Risk: Certifications lower technical risk when used correctly. They also create a paper trail that auditors and insurance adjusters will follow. If a failure happens and the PQRs don’t match the welding done, liability grows. The safest course is alignment up front: specification, cert scope, and actual practice on the floor.
When a prequalified procedure is your friend
Not every job needs a fresh PQR. AWS D1.1 includes prequalified procedures that allow a fabricator to write a WPS without destructive testing, provided they follow strict joint details, base metal groupings, processes, and parameter ranges. For standard A36 or A572 structural parts, prequalified WPSs save time and money.
Here’s the catch. Prequalified does not mean anything goes. A switch from ER70S‑6 to a metal‑core wire, or a change in joint root opening beyond code limits, can void the prequalification. Good shops lock down consumables, protect wire from moisture, and measure actual heat input. If your metal fabrication shop leans on prequalified procedures, ask to see the joint detail sketches and confirm they match your drawings.
Inspectors and NDT: how verification actually happens
A certification system without inspection is a wish. Third‑party verification comes in two forms: visual inspection by certified welding inspectors, and non‑destructive testing.
Visual inspection: Certified Industrial manufacturer Welding Inspectors (CWIs) look for weld size, contour, undercut, porosity, overlap, and discontinuities. Good CWIs catch upstream issues too, like improper fit‑up, paint or mill scale in the bevel, or lack of preheat. If your project has tight flatness needs, coordinate acceptance criteria for weld reinforcement and grinding. A proud cap may be allowed by code yet cause interference on a machined feature.
NDT methods: Radiography (RT) and ultrasonic testing (UT) reveal subsurface flaws. Dye penetrant (PT) and magnetic particle (MT) expose surface cracks. Each has limitations. RT struggles with planar lack of fusion if oriented unfavorably to the beam. UT depends on geometry and operator skill. For complex CNC metal fabrication with varied thickness, a blended NDT plan often works best: PT on first pass of stainless to catch hot cracking, UT on thick butt joints, and MT for carbon steel fillets in fatigue‑sensitive areas.
When NDT finds something, a good partner doesn’t just grind and patch. They run a root cause. Was it heat input too low? Gap too tight? Contamination in the joint? The fix goes back into the WPS or the work instruction, not just into a one‑off rework.
Certifications across the supply chain
Large assemblies rarely live under one roof. A Manufacturer might outsource tube lasering, bring burnouts from a cnc metal cutting service, and send weldments to a Machine shop for machining. Traceability gets messy. Certifications help, but only if the prime contractor enforces flow down requirements. A few habits make a difference:
- Assign a single WPS for each weld symbol on the drawing and keep that callout through subassemblies. Require consumable certificates and heat lot traceability when service conditions demand it, then check the paperwork against what arrives on the dock. Lock down who is allowed to tack. If the tacker is not qualified to the same process and position, you can trap defects into the joint before the certified welder starts. Align drawing weld symbols to the governing code. Hybrid symbols or “shop standard” notes create ambiguity that inspectors will resolve against the builder, usually with more NDT.
In contract manufacturing, the lowest quote sometimes comes from a shop without the right system for documentation. That can be fine for guards and stands. It is a gamble for load‑bearing weldments that run near the public or hold pressure. Match supplier capability to risk.
Common pitfalls and what they signal
Paper compliance feels safe until the welds distort a machined surface or a simple corner cracks in service. Watch for these red flags during vendor qualification or first article builds.
- WPSs that don’t match the machines: If the spec lists a spray transfer window that the power source cannot deliver, expect inconsistency. I once found a shop with WPSs from a sister plant running different equipment. The beads told the story before the paperwork did. No control over interpass temperature: Preheat and interpass limits matter, especially for higher strength steels. If no one measures with temp sticks or IR guns, hydrogen cracking risk rises. On thick frames, this shows up days later as toe cracks. Polished welds with no record: Grinding every fillet for appearance can mask undercut and overlap. If cosmetics drive modification, document it. Excessive grinding can reduce throat size below code. Specify finish in the drawing if needed, and ensure inspectors measure effective throat after blending. Drifting NDT subcontractors: If different UT providers get different results week to week, the joint design may be hard to interrogate, or the acceptance class is unclear. Lock the technique and acceptance in a brief ITP (inspection and test plan) before production. Lapsed welder continuity: It happens during slow seasons. A quick continuity check before release to production prevents a scramble when the auditor arrives.
None of these issues are terminal. They point to gaps in the quality loop. The right welding company surfaces them during kickoff and proposes practical controls.
Tying certifications to design decisions
Design engineers have more influence over weld success than any inspector. A few practical examples from industrial equipment:
- Joint access: A beautifully qualified procedure can’t fix a joint a torch cannot reach. Leave access for torches and NDT probes. If a rib or gusset blocks approach, change the order of operations or the part geometry. Your cnc metal fabrication vendor can suggest alternative tabbing to hold alignment without boxing in the welder. Heat input and machining order: On precision frames, plan machining after welding and stress relief. If tolerances force pre‑machining, reduce weld size where possible and control sequence. Overwelding adds heat, which adds distortion. A certified WPS with calculated heat input limits helps. Material selection: Higher strength steels like A572 Gr. 65 or quenched and tempered plate save weight, but they demand tighter control on preheat and interpass. If your Machine shop wants those grades for strength, make sure the welding company has procedures specifically qualified for them, not just for A36. Fillet sizes: A common habit is to oversize fillets “for safety.” That is money and distortion with little benefit once you clear code minimums and calculated loads. If a 6 mm fillet meets demand, calling out 10 mm across the board adds cost and cycle time. Your steel fabricator will follow the print. Be intentional.
The best outcomes happen when the Industrial design company, the Machinery parts manufacturer, and the welding company collaborate early. Certifications provide the framework, and design tweaks make them efficient.
When ISO 9001 and welding codes intersect
ISO 9001 is a management system standard, not a welding standard. It won’t tell you how to weld a joint, but it requires the organization to plan, control, and verify processes. In shops that blend machining and Waycon Manufacturing Ltd. underground mining equipment welding, ISO 9001 closes the gaps between disciplines: document control, calibration, nonconforming product handling, and corrective action. Pair ISO 9001 with AWS D1.1 or ASME Section IX, and you get both the technical backbone and the management discipline to keep the system running under production pressure.
A cnc metal fabrication supplier with ISO 9001 often handles revision control better, which keeps the right WPS tied to the right drawing and BOM. That reduces the risk of welding to an obsolete spec, a surprisingly common failure mode.
What to ask a prospective welding partner
A short, focused conversation reveals whether a shop lives its certifications or just holds them.
- Show me the WPS and PQR that cover this assembly, and tell me where on the floor they live during production. Which welds are you planning to inspect with NDT, and to which acceptance class? How do you control preheat and interpass? Where do you record those values? If we need to change a fillet size or joint detail after the first build, what requalification, if any, will that trigger? Who signs off welder performance continuity, and how do you onboard new welders onto our project?
You will hear either crisp answers with examples, or a generic “we can do anything” pitch. Choose the former. It’s the same advice I give when vetting a Machine shop or a Machining manufacturer. Specifics equal competence.
Certifications and automation: robots still need recipes
Robotic welding amplifies both good and bad processes. A robot repeats what it is taught. If the WPS is sound and the fixture locates parts consistently, automated cells deliver beads with tight variation, less spatter, and higher throughput. If gap variation is high or heat input isn’t managed, a robot will calmly produce the same defect hundreds of times.
For shops running robotic GMAW in contract manufacturing, look for WPSs tuned for the specific wire, contact tip‑to‑work distance, and waveform. Ask about gap‑handling strategies. Are they using seam tracking, touch sensing, or laser scanning? Certified procedures still govern, and the robot program is an extension of the WPS. The same inspector will apply the same acceptance criteria to a robot’s bead as to a human’s.
A practical path for owners and buyers
You don’t need to memorize the codes to buy well. You need a clear spec, a credible partner, and a modest verification plan. Here is a compact approach that works for most industrial projects:
- Define the governing code on the drawing and PO. If none applies, state the acceptance criteria you care about: visual standards, NDT percentage, and any fatigue or corrosion considerations. Ask for the specific WPS/PQR set and welder qualifications that will be used, and review them for process, material, position, and thickness match. Agree on an inspection and test plan that lists hold points, NDT methods, and documentation deliverables. Keep it to a page if you can. Witness the first article welds or review photos with gauges in frame. Small misreads early prevent delays later. Keep the paperwork tied to the part number and revision, so repeat orders don’t trigger unnecessary requalification or, worse, accidental scope creep.
This is the same discipline you apply when selecting a cnc metal fabrication vendor or a Machine shop for precision bores. Welding deserves that rigor because the consequences of failure are harder to machine away.
Final thought: certification as a promise kept
A certification is a promise. It says the welding company has proven it can produce sound joints with specified materials and processes, and that it keeps people and paperwork aligned to that promise. In the best shops, you see that promise in small details: clean wire liners, rods kept dry, preheat measured, beads consistent across shifts, WPS sheets smudged with gloved fingerprints because they’re actually used. In weaker shops, you see certificates on the wall and improvisation in the booth.
If your business depends on reliable welds, make certifications part of your supplier selection, not the whole story. Tie them to the realities of your parts, your loads, and your schedule. Ask a few pointed questions, stay close during first builds, and choose partners who treat the code as a guide rather than a hurdle. That’s how frames stay straight, tanks stay tight, and equipment runs for years without drama.
Waycon Manufacturing Ltd
275 Waterloo Ave, Penticton, BC V2A 7N1
(250) 492-7718
FCM3+36 Penticton, British Columbia
Manufacturer, Industrial design company, Machine shop, Machinery parts manufacturer, Machining manufacturer, Steel fabricator
Since 1987, Waycon Manufacturing has been a trusted Canadian partner in OEM manufacturing and custom metal fabrication. Proudly Canadian-owned and operated, we specialize in delivering high-performance, Canadian-made solutions for industrial clients. Our turnkey approach includes engineering support, CNC machining, fabrication, finishing, and assembly—all handled in-house. This full-service model allows us to deliver seamless, start-to-finish manufacturing experiences for every project.