What is Q355D steel?
A: Q355D is a low-alloy high-strength structural steel according to GB/T 1591-2018 standard. "Q" = yield strength, "355" = ≥355MPa (≤16mm), "D" = -20℃ impact toughness (≥34J).
What older grade does Q355D replace?
A: It replaces the original Q345D, with comprehensive improvements in strength, low-temperature toughness, and purity.
What are the core differences between Q355D and Q355B/C?
A: Different impact temperatures:
B: 20℃ impact; C: 0℃ impact; D: -20℃ impact.
Grade D has P and S ≤0.025% (purer), resulting in stronger resistance to brittle fracture at low temperatures.
What is the density of Q355D?
A: 7.85g/cm³, consistent with ordinary carbon steel.
What standards does Q355D adhere to?
A: GB/T 1591-2018 (Low-alloy high-strength structural steel).