EN S355JR and GB Q355B channels have identical tensile strength ranges, ensuring no difference in maximum load resistance-critical for structural safety in applications like bridge bracing, industrial cranes, and high-rise columns:
Tensile Strength Comparison
| Grade | Tensile Strength Range | Minimum Tensile Strength | Practical Impact |
|---|---|---|---|
| EN S355JR | 470–630 MPa | 470 MPa | Identical to Q355B-both withstand 470 MPa minimum before fracture. |
| GB Q355B | 470–630 MPa | 470 MPa | No difference in maximum load capacity (e.g., a UPE 300 channel supports ~500 kN tensile load for both grades). |
Implications for Structural Design
Allowable Tensile Stress: Both grades use an allowable tensile stress of ~290 MPa (per Eurocode 3 and GB 50017-2017), based on a load factor of 1.25. This means a 100 cm² cross-sectional area channel can safely carry 290 kN tensile load-no design adjustments needed.
Seismic Performance: Tensile strength directly impacts a channel's ability to absorb seismic energy. During a magnitude 6 earthquake, a S355JR UPE 200 channel and Q355B C200x75x7 channel both deform ductilely, reaching 550 MPa (well below their 630 MPa maximum) without fracture.
Welded Joints: Tensile strength of welded joints is identical (470 MPa minimum) when using E5015 electrodes. A welded UPE 300 joint fails at the base metal (550 MPa) rather than the weld (500 MPa) for both grades-confirming joint reliability.
Edge Case: Ultra-High Tensile Loads
For applications requiring tensile strength above 630 MPa (e.g., offshore platforms), specify EN S460JR (460 MPa yield, 570–770 MPa tensile) or GB Q460C (460 MPa yield, 550–720 MPa tensile)-both of which align in tensile range.
In summary, the tensile strength of S355JR and Q355B is identical, making them fully interchangeable for structural design.