What is Q345 steel?
A: Low-alloy high-strength structural steel, formerly known as 16Mn, national standard GB/T 1591-2008, the new national standard after 2019 corresponds to Q355.
2. What does "Q345" mean?
A: Q = Yield strength; 345 = Minimum yield strength ≥ 345MPa (thickness ≤ 16mm).
3. How many quality grades of Q345 are there?
A: 5: Q345A, B, C, D, E. The core difference lies in impact temperature and toughness.
4. What are the impact temperatures for each grade?
A: A: No impact test
B: +20℃ (room temperature)
C: 0℃
D: -20℃
E: -40℃
5. How to choose between Q345A/B/C/D/E? A: The lower the temperature and the greater the dynamic load, the higher the grade (D/E) should be selected; B can be used for static load at normal temperature.