Higher-strength structural steel — same weldability as S275 with ~30% more yield.
| Property | Typical value |
|---|---|
| Density | 7850 kg/m³ |
| Yield (≤16mm) | 355 MPa |
| Tensile | 470–630 MPa |
| Elongation | 22 % |
| Young's E | 210 GPa |
| Hardness | ~150 HB |
| CTE | ~12 µm/m·K |
| Thermal cond. | ~50 W/m·K |
| Max service | ~350 °C |
| Poisson ν | ~0.29 |
| Shear modulus G | ~81 GPa (derived) |
| Shear strength | ≈0.6 × UTS (design convention — not test data) |
| Specific heat | ~460–480 J/kg·K |
| Elec. resistivity | ~0.15–0.20 µΩ·m |
| Melting range | ~1450–1520 °C |
| Fatigue (indicative) | ~210–310 MPa (≈0.45–0.5 × UTS) — rotating-bend, polished specimen; indicative only, surface/size/loading factors apply |
~60%. Slightly harder than S275.
Weldable all processes; check CEV on thick/J2+K2 grades, preheat heavy sections.
| System | Designation |
|---|---|
| EN | S355JR / 1.0045; S355J2 / 1.0577 |
| DIN | St 52-3 / 1.0570 |
| ASTM | ≈A572 Gr 50 |
| JIS | ≈SM490 (SM490YA/YB) / SS490 |
| BS | BS 4360 50B/50D |
Equivalents & alternatives: S355JR/J2/K2 (1.0045/1.0577); old BS 50B; ASTM A572 Gr50. Alt: S275 (lower cost).
General structural mild steel — sections, plate, weldments. The default for fabrication.
Carbon steelFree-cutting bright mild steel — first choice for high-volume machined parts, studs, fittings.
Carbon steelGeneral bright mild steel bar — weldable, case-hardenable, good all-rounder for machined parts.
Carbon steelMedium-carbon steel — shafts, studs, gears, keys. Through-hardenable to moderate strength.
