What is Q345 steel?
It is a low-alloy high-strength structural steel, with a carbon content ≤ 0.20% and a yield strength ≥ 345 MPa (thickness ≤ 16 mm). The old national standard was GB/T 1591-2008, now replaced by Q345 (GB/T 1591-2018).
2. What does "Q345" mean?
Q: Yield strength (Qu); 345: Standard yield strength value of 345 MPa.
3. How many quality grades of Q345 are there?
5 grades: A/B/C/D/E, the core difference being the low-temperature impact temperature.
4. What are the impact temperatures for each grade?
A: No impact; B: +20℃; C: 0℃; D: -20℃; E: -40℃.
5. What is the effect of thickness on yield strength? The yield strength decreases with increasing thickness: ≤16mm: ≥345MPa; 16–35mm: ≥335MPa; 35–50mm: ≥325MPa; 50–100mm: ≥315MPa.