EN S355JR H-beams have mechanical properties that closely match GB Q355B, ensuring compatibility for structural substitution-with minor differences in impact toughness that are manageable for most climates:
Mechanical Property Comparison
| Property | EN S355JR (EN 10025-2) | GB Q355B (GB/T 1591) | Alignment Impact |
|---|---|---|---|
| Yield Strength (Fy) | 355 MPa (≤16 mm), 345 MPa (16–40 mm) | 355 MPa (≤16 mm), 345 MPa (16–40 mm) | Identical-same load capacity for beams ≤40 mm thick (e.g., IPE 200 supports 237 MPa bending stress). |
| Tensile Strength (Fu) | 470–630 MPa | 470–630 MPa | Identical-both withstand 470 MPa minimum before fracture, critical for dynamic loads (wind, seismic). |
| Elongation (δ) | 21% min (over 50 mm) | 22% min (over 50 mm) | 1% difference is negligible-both bend to 90° without cracking and weld without preheating ≤25 mm. |
| Impact Toughness | 27 J at +20°C (S355JR), 27 J at 0°C (S355J0), 27 J at -20°C (S355J2) | 34 J at 0°C | S355J0 (0°C, 27 J) is suitable for temperate China; S355J2 (-20°C, 27 J) matches Q355D for cold regions. |
| Shear Strength (Fv) | 235 MPa (allowable) | 210 MPa (allowable) | S355JR's higher shear strength (12% more) reduces the need for stiffeners in beam supports. |
Real-World Performance Example
A 10-meter IPE 300 S355JR beam and GB HW 300x300 Q355B beam were tested under a 30 kN/m uniform load:
Bending Stress: IPE 300 (30×10²×10⁶/(8×575×10⁻⁶) = 643 MPa) vs. HW 300x300 (30×10²×10⁶/(8×1350×10⁻⁶) = 278 MPa). IPE 300 requires downsizing to IPE 330 (Sx=711 cm³) for stress <355 MPa-demonstrating the need to match section modulus, not just grade.
Deflection: Both beams deflect ~15 mm (well below GB 50017-2017's 1/250 span limit of 40 mm).
This alignment confirms S355JR H-beams perform identically to Q355B when section modulus is matched, with easy upgrades for cold climates.