Chemical composition: usually contains carbon (C) ≤ 0.12%, silicon (Si) 0.20%-0.75%, manganese (Mn) ≤ 1.00%, phosphorus (P) 0.07%-0.15%, sulfur (S) ≤ 0.020%, copper (Cu) 0.25-0.55%, chromium (Cr) 0.30-1.25%, nickel (Ni) ≤ 0.65% and other elements. In order to improve the performance of steel, trace alloying elements may also be added, such as niobium (Nb) 0.015%-0.060%, vanadium (V) 0.02%-0.12%, titanium (Ti) 0.02%-0.10%, etc., and aluminum (Alt) ≥ 0.020%. Molybdenum (Mo) ≤ 0.30%, zirconium (Zr) ≤ 0.15% and other alloying elements may also be added.
Mechanical properties: yield strength ≥355MPa, tensile strength 490-630MPa, elongation after fracture ≥22% (when thickness is not more than 16mm). In terms of impact performance, the requirements of V-notch impact test are different according to different quality grades. For example, grade D requires impact absorption energy ≥34J at -20℃.
Performance characteristics: Excellent atmospheric corrosion resistance: Through the reasonable ratio of alloy elements, a stable rust layer is formed on the surface to effectively resist the erosion of the atmospheric environment.
Good comprehensive mechanical properties: It has high strength and certain toughness, which can meet the load-bearing and deformation requirements of related structural parts.
Application areas: Mainly used for steel structures such as railway vehicles, bridges, towers, containers, etc. that are exposed to the atmosphere for a long time, as well as facilities such as oil derricks, seaport buildings, and oil production platforms. It can also be used to manufacture structural parts such as containers containing hydrogen sulfide corrosive media in chemical petroleum equipment.