FlowMarket
Where to find welded assembly suppliers: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the assembly — material, size, welding standard, post-weld tolerances, finish and volume — and the agent matches you with fabricators holding the right certification and equipped for that work, then requests quotes and lead times so you can compare them in one place.
Sourcing welded assemblies
A weldment is where a set of parts becomes one part, and it is where the accumulated tolerance of everything upstream arrives at once. That is why a welded assembly rarely fails on the weld itself: it fails on distortion, on a hole that moved, on a frame that will not sit flat. The welding is the easy bit. Controlling what heat does to the assembly is the skill you are buying.
It follows that the enquiry has to describe the finished assembly, not the welds. The dimensions that must survive welding, whether anything is machined afterwards, how flat is flat enough — these decide the fixturing, the weld sequence and half the price. A drawing that specifies weld sizes in detail and says nothing about post-weld tolerance is describing the wrong half of the job.
Certification is the first filter
- EN 1090 — mandatory for structural steel and aluminium components in the EU, with execution classes EXC1 to EXC4 setting the rigour. Name your class; it changes who may quote at all.
- ISO 3834 — quality requirements for fusion welding, in three levels. Often required alongside EN 1090 and increasingly asked for on machinery weldments.
- Welder qualification — individual welders qualified to ISO 9606 for the process, material group and position. A certified company still needs qualified people on your joint type.
- Welding procedure specifications — qualified WPS/WPQR for the joints in your part. Ask whether they already hold one covering your material and thickness, or have to qualify a new one, which takes weeks.
Process, and what it implies
MAG welding is the workhorse for steel: fast, tolerant, well suited to robot cells at volume. TIG is slower, cleaner and the usual answer for stainless and aluminium where appearance and purity matter. Spot and projection welding suit thin sheet at high volume. Robot welding pays back above a few thousand assemblies a year or on long repetitive seams, and needs consistent, well-fixtured input parts — a robot amplifies upstream variation rather than absorbing it.
Material matters more than process choice, though. Aluminium conducts heat away fast and distorts differently from steel; stainless moves more and needs the heat tint removed or the corrosion resistance is compromised. Say what the material actually is and what the assembly has to look like afterwards.
Distortion, fixturing and tolerance
Every weld shrinks as it cools, and a large assembly can pull itself several millimetres out of true. Experienced fabricators manage this with weld sequence, balanced welding, fixtures and sometimes deliberate pre-set. All of that is engineering time before the first arc, and it is the difference between a frame that arrives square and one that arrives approximately square.
For anything with real dimensional requirements, expect and budget for a fixture, and expect the first article to take longer than you would like. Where tolerances are genuinely tight, machining after welding is the honest answer — say so in the enquiry, because it changes which suppliers can do the whole job in-house.
Inspection and what it costs
Visual inspection is standard. Beyond it, dye penetrant, magnetic particle, ultrasonic and radiographic testing each cost real money per joint, and the extent of testing is set by the execution class or by your customer — not by the fabricator. Specify what proportion of welds must be tested and by which method, because a quote assuming visual inspection and one assuming 10% ultrasonic are not the same quote.
The rest of the price is material, fit-up time, welding time and post-weld work: grinding, straightening, blasting, painting or passivation. Fit-up is often the largest labour block on a complex assembly, and it is driven by how well the upstream parts were cut and bent, which is an argument for sourcing the whole assembly from one supplier rather than three.
How the AI agent matches suppliers
The agent reads your requirement rather than your keywords. It searches the FlowMarket network and connected industrial directories together, scores every candidate on how well it answers what you described — material, size, certification, process, volume, geography — and drops anything that does not clear the bar. Each match comes back with a plain-language reason, which is the fastest way to tell whether a fabricator holds the certification your part requires.