What is Q235 Coil?
A: Q235 Coil, or Q235 steel coil, is a low-carbon structural steel coil produced according to the GB/T 700 "Carbon Structural Steel" standard. "Q" represents yield strength, and "235" indicates a yield strength ≥ 235 MPa. It is the most commonly used economical steel in the construction industry.
What are the quality grades of Q235 steel coil? How to select it in construction?
A: It is divided into four grades: A, B, C, and D. The core difference lies in impact toughness:
Q235A: No impact test is performed. It is only suitable for simple, non-welded structures above 0℃ under static load (such as temporary fencing).
Q235B: 20℃ room temperature impact (≥27J). Most commonly used in construction, for welded structures at room temperature (beams, columns, embedded parts).
Q235C: 0℃ impact (≥27J). Used for winter construction and low-temperature welded structures in northern regions.
Q235D: -20℃ impact resistance (≥27J), used in extremely cold regions and important low-temperature load-bearing structures.
What are the core differences between Q235 and Q355 steel coils in construction?
Answer: Differences in strength, cost, and applicable scenarios:
Q235: Yield strength 235MPa, excellent plasticity/weldability, low cost, suitable for light loads and conventional buildings (factories, multi-story frames).
Q355: Yield strength 355MPa, high strength, allows for material reduction, suitable for heavy loads, large spans, and high-rise buildings (heavy-duty factories, bridges).
What is the carbon content range of Q235 steel coils? How does it affect construction applications?
Answer: Carbon content ≤0.22% (low-carbon steel), ensuring good plasticity, toughness, and weldability, making it an ideal base material for welded building structures.
What national standards apply to Q235 steel coils used in construction?
A: The core standard is GB/T 700-2006 "Carbon Structural Steel". Hot-rolled coils must also comply with GB/T 14977 "Dimensions, Shape, Weight and Permissible Deviations of Hot-rolled Steel Plates and Strips".