Q：What are the sub-grades of Q355 steel plate?
A：According to the impact test temperature, it is divided into 5 sub-grades: Q355A, Q355B, Q355C, Q355D, Q355E. The impact test temperatures are: no requirement for A, +20℃ for B, 0℃ for C, -20℃ for D, -40℃ for E.
Q：Why is the sub-grade of Q355 important for selection?
A：Sub-grades determine the low-temperature toughness of the steel plate. For projects in cold regions (such as northern China, Russia, Canada), Q355D or Q355E must be selected to avoid brittle fracture at low temperatures.
Q：What is the yield strength of Q355 plate?
A：The minimum yield strength is 355 MPa for plates with thickness ≤ 16mm. For thicker plates, the yield strength decreases slightly: 345 MPa (16-40mm), 335 MPa (40-63mm), 325 MPa (63-80mm), 315 MPa (80-100mm).
Q：What is the tensile strength range of Q355 plate?
A：The tensile strength is 470-630 MPa, which is suitable for most structural engineering requirements.
Q：What is the elongation rate of Q355 plate?
A：The minimum elongation rate is 21% (for plates with thickness ≤ 16mm), which ensures good ductility and processing performance.