T/HBJN 0006-2023 Rare earth carbon steel and low alloy structural steel hot-rolled steel plate and steel strip

Scope

Main technical content: 1. Smelting method: Steel can be smelted using oxygen converters or electric furnaces, with no further restrictions, to meet the flexibility requirements of steel mills production processes. 2. Grade and chemical composition: The steel grades adopt naming methods similar to GB/T700, GB/T1591, GB/T19879, GB/T16270, and T/CSM 12-2020, namely the yield strength-based naming method. The suffix RE indicates economical weathering steel with rare earth additives, and the quality grades still follow the common A–E grades. For example, the rare earth weathering steel with a yield strength of 355 MPa meeting the impact performance requirements at -20°C is denoted as Q355RED. The chemical composition range maximally reflects the principle of flexibility. Type I rare earth weathering structural steel defines the Q235RE and Q355RE grades, while Type II rare earth weathering structural steel defines the Q235NHRE, Q355NHRE, Q390NHRE, Q420NHRE, Q460NHRE, Q500NHRE, and Q550NHRE grades, where C, Si, Mn, P, S, Cu, Cr, and Ni are only set with upper limits. It emphasizes that rare earth weathering structural steel must contain one or more of the rare earth elements La, Ce, and Y, and appropriately reduce the content of other corrosion-resistant elements while meeting corrosion resistance requirements. Regarding corrosion resistance evaluation, in addition to referring to the corrosion resistance index in the appendix of GB/T4171, greater emphasis is placed on actual corrosion resistance effects, using the corrosion resistance of 09CuPCrNiA (GB/T4171's Q355GNH, US Corten A, and Japan's SPA-H) steel as a benchmark. Laboratory accelerated corrosion test results are used as the basis for evaluation, and electrochemical methods are encouraged for testing to meet the requirements of scientific experimental data accumulation and innovation. 3. Mechanical and process performance: The tensile properties of materials primarily comply with the requirements of GB50017

Development Information

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