Q: What are the minimum mechanical properties of Q355 steel plate?
A: For plates with thickness ≤16mm: yield strength ≥355MPa, tensile strength 470-630MPa, elongation after fracture ≥21%. For plates with thicker thickness, the yield strength will be appropriately reduced (e.g., 345MPa for 16-40mm, 335MPa for 40-63mm).
Q: What is the impact test requirement of Q355 steel plate grades?
A: - Q355A: No impact test required;
Q355B: Impact test at +20℃, absorbed energy ≥34J;
Q355C: Impact test at 0℃, absorbed energy ≥34J;
Q355D: Impact test at -20℃, absorbed energy ≥34J;
Q355E: Impact test at -40℃, absorbed energy ≥34J.
Q: What is the hardness range of Q355 steel plate?
A: The typical Brinell hardness (HB) of Q355 steel plate is 120-180. It can be adjusted according to the heat treatment process (e.g., normalized treatment can make the hardness more uniform).
Q: How does the thickness of Q355 steel plate affect its mechanical properties?
A: With the increase of plate thickness, the cooling rate during rolling decreases, the grain structure becomes coarser, and the mechanical properties decrease. Therefore, the national standard stipulates that the yield strength of Q355 steel plate with thickness >16mm will be gradually reduced, while the tensile strength and elongation requirements remain basically unchanged.
Q: Does Q355 steel plate have good ductility?
A: Yes. Q355 steel plate has excellent ductility, with elongation after fracture ≥21% (for thin plates). It can withstand cold forming processes such as bending, stamping and rolling without cracking, which is suitable for the manufacturing of various structural parts.