Here's a more detailed explanation of the impact energy requirements for S355J2WP at -20°C, including relevant standards and practical implications:
Impact Toughness of S355J2WP at -20°C
According to EN 10025-5 (European standard for weathering steels), the minimum Charpy V-notch (KV) impact energy for S355J2WP at -20°C is:
Longitudinal (L) test direction: ≥27 Joules
Transverse (T) test direction: Typically lower (~20 J), but the standard specifies longitudinal values unless otherwise agreed.
Key Factors Affecting Impact Toughness
Material Thickness:
The 27J requirement applies to thicknesses ≤50 mm. For thicker plates (e.g., 50–100 mm), impact values may decrease, and additional testing or stricter criteria might apply.
Production Process:
Normalized rolling (thermomechanical treatment) improves low-temperature toughness.
Weathering Steel vs. Ordinary S355:
While S355J2 (non-weathering) has the same 27J requirement at -20°C, S355J2WP offers additional corrosion resistance due to its alloying elements (Cu, Cr, P).
Practical Implications
Bridges & Offshore Structures: Ensures ductility in cold climates, preventing brittle fracture.
Welding Considerations: Preheating (100–150°C) may be needed for thick sections to maintain toughness.
Certification: Always verify via Mill Test Certificates (MTCs), as actual values can vary.
