| abstract |
Thin-gauge fire-resistant and weather-resistant steel plate/strip and its manufacturing method, its chemical composition weight percent is: C 0.02‑0.06%, Si 0.1‑0.55%, Mn 0.4‑1.7%, P≤0.03%, S≤0.007%, Cr 0.30‑ 0.80%, Mo 0.20‑0.60%, N 0.004‑0.010%, Als<0.001%, B: 0.001‑0.006%, total oxygen [O] T : 0.007‑0.020%, remaining Fe and other unavoidable impurities, and, containing One or two elements in Cu 0.10‑0.60% or Sn 0.005‑0.04%; Mn/S>250; Pcm≤0.27%. The present invention utilizes residual elements such as Sn and Cu in scrap steel for smelting, and selectively adds microalloying elements such as Mo/Cr and B elements; smelting controls the basicity of slag, type and melting point of inclusions in steel, and free oxygen in molten steel content, acid-soluble aluminum Als content; twin-roll strip continuous casting is adopted, the cast strip is hot-rolled on-line, and the cooling after rolling is cooled by gas atomization. |