Welded steel
Welded Steel Machine Bases, Sourced from Vietnam
Plate and section, cut, jigged, welded, stress relieved and machined. No pattern, so it is the fastest route to a first unit and the easiest construction to change. We match your drawing to up to three fabricators in Vietnam that already weld and machine structures of that size.
We are a sourcing service, not a foundry or a fabrication shop. You pay the fabricator you choose, nothing to us. Reply within 24 business hours.
What it is
A welded base is a steel structure cut from plate, tube and section and joined to a qualified welding procedure. Because the only tooling is fixtures, the first unit is the fastest of any construction, and a rib, pad or bolt pattern can still move after the first quote. Cost per unit stays roughly flat across quantities, which is why welded steel is the default for prototypes, low volume and large envelopes.
Its weak point is damping. Bare steel rings unless ribbing, mass or a filled core is added, and the stress locked in by welding has to be released before the datum faces are machined or the base will move afterwards. Most of what separates a good welded base from a poor one is therefore in the process: weld sequence, stress relief method and how many setups the machining takes.
Where it fits
- Prototypes, low volume and designs that are still moving
- Large envelopes, roughly 6 x 2.5 x 2 m in one piece, larger structures split and bolted
- Presses, gantries, columns and frames where stiffness per unit volume matters most
- Anything where the pattern lead time of a casting would delay the first machine
Where it does not
- A repeat model in steady annual volume where damping decides accuracy: a casting gets cheaper per unit
- Grinders and fine finishing machines that need the damping of iron or mineral cast without a filled core
- Designs with no stress relief budget and a tight flatness callout on large machined pads
Process
How it is made
- Plate and section cut to size, typically by laser, plasma or waterjet
- Fit-up and tack welding to a jig or fixture
- Welding to a qualified procedure (WPS), by welders qualified to ISO 9606-1
- Stress relief, thermal or vibratory, to release welding residual stress
- Machining of datum faces, way mounting surfaces and bolt patterns
- Inspection against the drawing, shot blast, primer or paint, packing
Standards
What governs it
ISO 13920, ISO 5817, ISO 3834, ISO 15614-1, ISO 9606-1, EN 10025, EN 10204.
Each is explained in the standards index, including the one that is most often cited where a different one was meant. Themanufacturing technologies page shows the stages side by side with the other constructions.
Before you ask for a quote
What to put in the RFQ
Typical ranges for this construction, and what to state so two quotes can be compared. Ranges are not promises: they depend on the shop and the part.
| Item | Typical | Say in the RFQ |
|---|---|---|
| Envelope and weight | Weldments to roughly 6 x 2.5 x 2 m in one piece. From about 80 kg to the 12 - 20 t range, limited by the shop crane and machining table. | Overall length, width, height, target finished weight, and whether a bolted split is acceptable. |
| Material | S235 / S355 to EN 10025 and equivalents, 6 - 80 mm plate, hollow section, channel and heavy bar. | Grade and thickness if fixed, or the load case so the fabricator can size it. |
| Weld quality and tolerance | ISO 5817 quality level for the weld itself, ISO 13920 class for the weldment. Class B is the usual choice for machine frames. | Name both standards on the drawing. They are different requirements and are often confused. |
| Stress relief | Furnace thermal cycle or vibratory treatment, before rough machining and again before finish machining on critical work. | Which method you require, and whether you want the chart or certificate. |
| Machined geometry | Flatness commonly held in the 0.02 - 0.10 mm band over a metre on machined pads; ground or scraped work goes tighter. | Flatness, parallelism and squareness per surface, with the datum scheme. |
| Documents | Dimensional report, weld inspection (visual, MT, UT as specified), material certificates. | EN 10204 type 3.1 by name if you want traceable material. |
The full checklist is in the RFQ checklist guide, and the seven things that move the price are on the home page.
Questions
Can you send me a price for a welded base without a drawing?
A budget number, yes, from the envelope, the approximate weight, the machined faces and the flatness you expect. A firm price needs a drawing or a STEP model with the datums and machined features defined. Send what you have and we say which of the two you are getting.
Do I have to specify stress relief?
If you machine a flatness tighter than the welding distortion allows, yes. A weldment that is machined before the residual stress is released can move afterwards. Furnace treatment and vibratory treatment are different, and not every specification accepts vibratory. Say which you need before you compare quotes.
What drives the price of a welded base?
Weight and plate thickness, metres of weld and how awkward each joint is to reach, the stress relief method, the machined area and tolerance, the number of setups, the inspection paperwork and the crating. The home page lists all seven; pin them down in the RFQ and quotes become comparable.
Is welded steel or cast iron better for a machine base?
Neither. Welded steel is faster to a first unit, easier to change and flatter in cost across quantities. Cast iron damps better and gets cheaper per unit on a long run. The construction comparison table sets the two side by side.