What are the different grades of Q235?
It is divided into four quality grades: Q235A, B, C, and D. The core differences lie in the impact test temperature and impurity control.
Impact test requirements for each grade?
Q235A: No impact test required;
Q235B: Impact test at 20℃ (room temperature), impact energy ≥ 27J;
Q235C: Impact test at 0℃, impact energy ≥ 27J;
Q235D: Impact test at -20℃, impact energy ≥ 27J.
Deoxidation methods for each grade?
Q235A/B: Can be rimmed steel (F) or killed steel (Z);
Q235C: Must be killed steel (Z);
Q235D: Must be special killed steel (TZ).
Sulfur and phosphorus content control for each grade? The grades decrease sequentially from A to D: A≤0.045%/≤0.050%, B≤0.045%/≤0.045%, C≤0.040%/≤0.040%, D≤0.035%/≤0.035%.
How to choose the Q235 grade?
For static loads at normal temperature and non-critical structures: Q235A (lowest cost); For dynamic loads at normal temperature and general engineering projects: Q235B (highest cost-performance ratio); For low-temperature environments around 0℃: Q235C; For extremely cold environments of -20℃ and below: Q235D.