EN 10025 steel grades comparison — a Singapore fabrication reference
A technical supplement to the Ezzogenics Glass & Metal scope: how the four steel grades that dominate Singapore drawings — S275, S355, SS304 and SS316 — compare on yield, tensile, weldability and corrosion, with the downloadable 49-sheet workbook used in our shop.
Who this page is for
Architects, engineers, ID firms and main contractors specifying or quoting fabrication scopes under our Glass & Metal service — handrails, balustrades, cat ladders, gates, awning frames, skylight framing and similar carbon-steel and stainless-steel work. The figures here are drawn from BS EN 10025-2, BS EN 10088-2, ISO 1461 and ISO 9223 and are presented as a fabricator-friendly reference. Project-specific values must be confirmed by the appointed qualified person, professional engineer or supplier.
Inline grade comparison
The compact table below covers the four grades that show up on most Singapore tenders. The full 49-sheet workbook (linked in the sidebar) extends the same comparison across S235–S500, SS304L / SS316L / SS439 / SS201, aluminium 6063-T6 and weathering steel, with EN section catalogues and weight / cost calculators.
| Property | S275JR | S355JR | SS304 (1.4301) | SS316 (1.4401) |
|---|---|---|---|---|
| Standard | BS EN 10025-2 | BS EN 10025-2 | BS EN 10088-2 | BS EN 10088-2 |
| Family | Non-alloy structural | Non-alloy structural | Austenitic stainless | Austenitic stainless (Mo) |
| Yield, t ≤ 16 mm (MPa) | 275 | 355 | ≥ 210 | ≥ 220 |
| Tensile Rm (MPa) | 410–560 | 470–630 | 520–720 | 520–700 |
| Elongation (%, min) | 23 | 22 | 45 | 40 |
| Charpy V-notch (J, min) | 27 @ +20 °C | 27 @ +20 °C | Not specified | Not specified |
| Density (kg/m³) | 7850 | 7850 | 8000 | 8000 |
| Young’s modulus (GPa) | 210 | 210 | 200 | 200 |
| Weldability (CEV typ.) | ≤ 0.40 (good) | ≤ 0.45 (good) | Excellent — 308L filler | Excellent — 316L filler |
| Galvanising | Yes (HDG, ISO 1461) | Yes (HDG, ISO 1461) | Not applicable | Not applicable |
| PREN | — | — | ≈ 18–19 | ≈ 24–25 |
| Corrosion in SG | Rusts — paint or HDG required | Rusts — paint or HDG required | Good — indoor / sheltered | Strong — coastal / splash zones |
| Typical fabrication use | Brackets, secondary beams, walkways | Primary frame, trusses, long-span beams | Indoor handrails, balustrades, fittings | Coastal handrails, splash-zone hardware |
Values are the published minima or typical ranges from the standards above, assembled for a quick fabricator-side comparison. Project-specific section properties, thickness-banded yield, weld procedure and coating thickness are determined by the appointed engineer or supplier.
How to choose between them on a fabrication scope
On the workshop side, most decisions on a Singapore fabrication scope come down to four questions — and the answer to each one usually picks the grade for you.
- Where will the steel live? Indoor / sheltered → SS304 or painted MS. Outdoor inland → S355 with HDG or paint. Coastal or splash-zone → SS316 (or duplex / low-carbon variants for severe service).
- What is the design driver — strength, stiffness or geometry? If span and weight are critical, S355 is the default primary-frame grade. If the section is already thicker than yield-driven, S275 saves cost without changing the geometry.
- Is the surface part of the architecture? If the metal is the finish, stainless avoids the paint cycle and matches the architect’s expectation of a 25-year surface life. If the metal will be hidden or coated, the lower-cost coated MS route wins.
- What is the inspection / certification regime? Mill Test Certificates, weld procedure qualification and coating-thickness records are easier to assemble on EN 10025-2 / EN 10088-2 stock than on unspecified “mild” or “stainless” material. Ask for the MTC and the heat number with every delivery.
Coating choices for mild-steel work
Bare carbon steel exposed to Singapore air loses on the order of 25–80 µm per year (ISO 9223 C3–C4 inland and coastal respectively). Ezzogenics fabrication of S275 / S355 elements is specified with one of three coating systems:
- Hot-dip galvanising to BS EN ISO 1461 — sacrificial zinc, typically 70–85 µm on structural sections (e.g. Z600 grade-mass). Indicative service life of about 25–30 years inland and 15–20 years near the sea.
- Paint systems to ISO 12944 — a primer + intermediate + topcoat reaching a dry film thickness suited to the corrosivity category (typ. 200–320 µm for C3 long-durability). Easier to repair and re-coat than galvanising.
- Duplex (galvanise then paint) — used for high-corrosivity zones and infrastructure where re-coating access is expensive.
Stainless welding and finishing notes
SS304 and SS316 are excellent welders with austenitic 308L / 316L filler metals. The workshop discipline that protects the long-term corrosion performance is the same on both: isolate stainless lines from carbon-steel grinding, brushes and tools; pickle or passivate after welding; and avoid prolonged dwell in the 425–850 °C sensitisation range. Surface finish (brushed No. 4, satin, mirror) should be specified on the shop drawing — it changes the cost, the cleaning regime and the tolerable contact with chlorides over the service life.
What this page is not
This is a fabricator-side reference, not a structural-design or compliance document. The figures support tendering and shop-drawing review; they do not substitute for an Eurocode calculation, a Mill Test Certificate or a project specification. Where the design is governed by BCA, SCDF or a project consultant’s appendix, the appointed qualified person, professional engineer or supplier remains the source of truth for the grade, thickness, coating and inspection regime that apply to your job.
Reference photos
What the four grades look like in the workshop
Specifying steel for a fabrication scope?
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