What is the maximum service temperature?
A: ≤350℃; above this, strength drops significantly.
What is the low-temperature limit for each grade?
A:
A: ≥+20℃ (no impact)
B: ≥0℃
C: ≥-10℃
D: ≥-20℃
What are the main applications of Q235?
A:
Construction: beams, columns, steel structures
Machinery: base frames, brackets, non-critical parts
General: tanks, pipes, shipbuilding, bridges (Q235q)
What's the difference between Q235 and Q345?
A:
Q235: 235 MPa yield; low cost; general use
Q345: 345 MPa yield; higher strength; heavy structures
2What's the difference between Q235 and 45# steel?
A:
Q235: low carbon; good weldability; low strength
45#: medium carbon; poor weldability; higher strength (quenched)