Q: What do "Q" and "235" represent in Q235?
A: Q stands for "Yield Strength," and 235 refers to the minimum yield strength of 235 MPa for a thickness ≤16mm.
Q: What is the standard for Q235?
A: GB/T 700-2006 "Carbon Structural Steel."
Q: How many quality grades are there for Q235? What are the core differences?
A: There are four grades: A, B, C, and D. The differences lie in the S and P content and impact test requirements: A: No impact; B: Impact energy ≥27J at 20℃; C: 0℃; D: -20℃. The S and P content decreases progressively with each grade.
Q: What are the upper limits for S and P for Q235A/B/C/D?
A: A: S≤0.050%, P≤0.045%; B: S≤0.045%, P≤0.045%; C: S≤0.040%, P≤0.040%; D: S≤0.035%, P≤0.035%.
Q: What is the unified numerical designation rule for Q235?
A: It begins with "U", such as Q235B being U12352.