Q: Can Q355 plate be heat-treated to improve performance?
A: Q355 plate is usually supplied in hot-rolled or normalized state, and its performance can meet most structural requirements. If higher strength or toughness is needed, it can be subjected to heat treatment such as normalizing, tempering, or quenching and tempering. However, heat treatment will increase the production cost, so it is not commonly used in actual projects.
Q: What is the corrosion resistance of Q355 plate?
A: Q355 plate is low-alloy steel, and its natural corrosion resistance is slightly better than that of Q235 carbon steel, but it is still not suitable for use in strong corrosive environments. For projects with corrosion resistance requirements, surface anti-corrosion treatment such as painting, galvanizing, or cladding with corrosion-resistant steel plates is required.
Q: What is the fatigue performance of Q355 plate?
A: Q355 plate has good fatigue performance, and its fatigue limit is about 1/2 of the tensile strength (about 235-315 MPa) under the condition of symmetrical cyclic loading (stress ratio R=-1). It is suitable for structures subjected to cyclic loading, such as bridges, cranes, and machine frames.
Q: What is the hardness range of Q355 plate?
A: The hardness of Q355 plate is usually between 120-180 HB (Brinell hardness). The specific value is related to the grade, thickness, and delivery state. Hardness testing is a non-destructive testing method, which can quickly evaluate the mechanical properties of the plate.
Q: What is the difference between Q355B and Q355C plates in terms of performance?
A: The main differences are:
Impact test temperature: Q355B is 20℃, Q355C is 0℃.
P and S content: Q355C has lower P and S content (≤0.030%), better purity, and higher toughness.
Application scenario: Q355B is suitable for general structural parts; Q355C is suitable for structural parts used in cold regions or with higher toughness requirements.**