S280GD steel (1.0244): properties, composition, equivalents
S280GD (1.0244): 280 MPa yield, 360 MPa tensile, 18 % elongation, EN 10346 galvanized structural sheet — the standard European purlin and framing grade. Chemistry, coating codes, A653 SS Grade 40 and SGC400 equivalents.
What is S280GD?
S280GD is the grade most European purlin and light-gauge framing lines run on: a hot-dip galvanized structural sheet with a guaranteed 280 MPa yield and 360 MPa tensile that still bends and roll-forms cleanly at 18 % elongation. Werkstoff number 1.0244; ordered as S280GD+Z275 for enclosed buildings, +Z350 or +ZM120 where the frame is exposed or in humid climates, and as the substrate under pre-painted purlins.
Within EN 10346 it sits between S250GD (light purlins, cable trays) and S320GD/S350GD (deck, long spans, racking). Compared with the forming grade DX51D there is no formability loss that matters for open profiles, but the guaranteed yield lets the designer use EN 1993-1-3 section tables instead of a conservative assumption.
ASTM A653 SS Grade 40 and JIS SGC400 are the working equivalents; span tables published by purlin manufacturers in the Gulf and Africa are commonly based on S280GD or S350GD.
S280GD chemical composition
| Element | Mass % | Note |
|---|---|---|
| C | ≤ 0.2 | |
| Si | ≤ 0.6 | |
| Mn | ≤ 1.7 | |
| P | ≤ 0.1 | |
| S | ≤ 0.045 |
EN 10346:2015 Table 2, common to S220GD–S350GD. Mills reach 280 MPa with C 0.06–0.12 and Mn 0.40–0.80 plus temper rolling; no Nb/V in this class.
S280GD mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| S280GD, all thicknesses (longitudinal) | 280 (40.6) | 360 (52.2) | 18 | ≈ 70–85 HRB (typ.) |
| S250GD (for comparison) | 250 (36.3) | 330 (47.9) | 19 | — |
| S320GD | 320 (46.4) | 390 (56.6) | 17 | — |
| S350GD | 350 (50.8) | 420 (60.9) | 16 | — |
EN 10346 Table 5, minimum values, A80 longitudinal; minus 2 points below 0.7 mm. Typical S280GD coil tests 300–340 MPa yield.
S280GD equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| S280GD+Z | GB/T (China) | Identical | GB/T 2518 adopts the EN designation. |
| SS Grade 40 (A653) | ASTM / ASME | Near | ASTM A653 Structural Steel Grade 40 [275]: 275 MPa yield, 380 MPa tensile — the US purlin and deck grade. |
| S250GD | EN (European) | Near | One class lower; interchangeable for light purlins if the span table allows. |
| S350GD | EN (European) | Near | One class higher; chosen for deck and long-span purlins. |
| IS 277 Grade 275 | IS (India) | Near | Indian galvanized sheet, 275 MPa yield. |
| SGC400 | JIS (Japan) | Near | JIS G3302 SGC400: yield ≥ 295 MPa, tensile ≥ 400 MPa, A ≥ 18 %; slightly stronger. |
| S275JR | EN (European) | Functional | Uncoated hot-rolled equivalent by yield for members that will be hot-dip galvanized after fabrication. |
Identical = same composition and mechanical limits within rounding. Near = one limit differs (e.g. carbon max or impact temperature). Functional = interchangeable for most uses after an engineering check. Full cross-reference for S280GD →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| FeE280G | EN 10147:1992 | Pre-2000 designation. |
| StE280-2Z | DIN 17162 (withdrawn) | German structural galvanized grade. |
| Z28 | BS 2989 | British structural galvanized quality, 28 kgf/mm² ≈ 275 MPa. |
Product forms and tolerance standards
Product forms: hot-dip galvanized coil and sheet 0.50–4.0 mm (+Z, +ZM, +AZ), slit strip for C/Z purlin, sigma and deck lines, pre-painted (EN 10169) base for visible purlins and trays.
Dimensional tolerances: thickness/width/flatness: EN 10143; coating mass per EN 10346 (Z275 standard for structural use; Z350/Z450 for exposed frames); surface A or B, finish N or M.
Key property values
S280GD yield strength
≥ 280 MPa (41 ksi), longitudinal. Typical 300–340 MPa.
S280GD tensile strength
≥ 360 MPa (52 ksi); typical 380–430 MPa.
S280GD elongation
≥ 18 % (A80, longitudinal); 16 % below 0.7 mm.
Design values
EN 1993-1-3: fyb = 280 MPa, fu = 360 MPa; average yield fya may be increased for cold-forming in fully effective sections. E = 210 GPa.
Coating and corrosion life
Z275 (≈ 20 µm/face) — 10–20 years in urban C3, 20–40 in rural C2; Z450 or ZM140 for coastal or agricultural exposure. Cut edges under 2 mm are protected by the zinc's sacrificial action.
Weldability
Weldable as DX51D+Z with fume extraction and zinc-rich repair; purlin systems normally use bolted cleats, sleeves and self-drilling screws so the coating stays intact. Spot welding needs 10–20 % more current and electrode dressing.
Machining, forming and heat treatment
Roll forming, punching (bolt holes on the line), swaging and slitting are routine; inside bend radius ≥ 1 t transverse recommended, EN 10346 T-bend test guaranteed. Not intended for drawing.
Typical applications
- C, Z and sigma purlins and girts (the reference grade)
- Light-gauge steel framing (LSF) studs, tracks and joists
- Composite and roof deck (with S350GD)
- Cable trays, ladders, strut channels
- Solar mounting rails and trackers (+ZM)
- Shelving and light racking
- Highway and agricultural fencing posts
Frequently asked questions
What is S280GD used for?
Mainly C/Z purlins, girts, light-gauge framing and deck: any roll-formed galvanized profile that carries load and is designed with a 280 MPa yield to EN 1993-1-3.
S280GD or S350GD for purlins?
S280GD is the standard; S350GD gives about 20 % more moment capacity from the same section and is chosen for long spans, deck and heavy racking. Ductility drops from 18 % to 16 %, which is irrelevant for open profiles.
What is the ASTM equivalent of S280GD?
ASTM A653 SS Grade 40 [275] — 275 MPa yield, 380 MPa tensile. JIS SGC400 (295 MPa) is slightly stronger.
What coating should I specify for purlins?
Z275 for enclosed buildings in dry inland climates; Z350–Z450 or ZM120–ZM140 for exposed frames, coastal sites and agricultural buildings; pre-painted on S280GD where purlins remain visible.
Is S280GD available thicker than 3 mm?
Yes, to about 4.0 mm from continuous galvanizing lines; heavier purlins (4–6 mm) are usually hot-rolled S275JR/S355JR profiles hot-dip galvanized after forming.
Related grades
Verified against EN 10346:2015; EN 10346:2015 Tables 2 and 5; EN 10143:2006; EN 1993-1-3; ASTM A653/A653M-22; JIS G3302:2019. Last checked: September 2026.