-20℃ Impact Energy Requirements?
Answer: ≥34J (KV2), Class D core indicator.
What is the carbon equivalent (Ceq)?
Answer: ≤0.45%, good weldability.
Q355D Chemical Composition (Upper Limit)?
Answer: C≤0.20%, Si≤0.55%, Mn≤1.60%
P≤0.025%, S≤0.025%
Contains Nb/V/Ti microalloying
Thickness Direction Properties (Z-direction)?
Answer: Can be reinforced with Z15/Z25/Z35. For thick plates ≥40mm, Q355DZ15/Z25 is commonly used for full penetration welding to prevent lamellar tearing.
When is Q355D mandatory in construction?
Answer: Operating temperature ≤-20℃ (extremely cold regions)
Low temperature + dynamic load + fatigue components
Mandatory Standard: GB 50017-2017