460MPa anti-seismic and fire-resistant building steel and preparation method thereof

Abstract

The invention relates to a 460MPa anti-seismic and fire-resistant building steel and a preparation method thereof, and belongs to the field of building steels. The 460MPa anti-seismic and fire-resistant building steel is prepared from the following components of 0.03 to 0.08% of C (carbon), 1.0 to 1.8% of Mn (manganese), 0.1 to 0.5% of Si (silicon), 0.2 to 0.7% of Cr (chromium), 0.1 to 0.3% of Mo(molybdenum), 0.05 to 0.12% of Ti (titanium), 0.04 to 0.12% of V (vanadium), 0.01 to 0.06% of Nb (niobium), 0.01 to 0.05% of Al (aluminum), 0.008% or less of P (phosphor), 0.002% or less of S (sulfur), and the balance of iron and unavoidable trace chemical elements. The preparation method comprises the following steps of performing conventional vacuum smelting, and casting into a blank; heating acasting blank, and performing conventional warming; coarsely rolling, and controlling temperature; finely rolling, and controlling finishing temperature; naturally cooling to certain temperature; performing water cooling until the temperature reaches room temperature; controlling the rolling and cooling, so as to obtain a martensite / bainite and ferrite double-phase tissue with fine crystal grains.The 460MPa anti-seismic and fire-resistant building steel and the preparation method have the advantages that by delivering in a TMCP (thermal mechanical control process) way, the complicated heat treatment technology is not needed; a process window is wider, the yield strength is greater than or equal to 460MPa, the tensile strength is 670 to 800MPa, the elongation rate at break is greater thanor equal to 26%, the KV2 at temperature of -40 DEG C is greater than or equal to 250J, and the yield ratio is smaller than 0.75; the 460MPa anti-seismic and fire-resistant building steel can be widelyapplied to high-rise and ultrahigh-rise buildings with high-strength, anti-seismic and fire-resistant steel requirements.

Description

technical field [0001] The invention belongs to the field of structural steel for construction, and particularly designs a 460MPa-grade anti-seismic fire-resistant construction steel and a preparation method thereof, which is especially suitable for TMCP production. Background technique [0002] At present, domestic and international earthquake-resistant steel plates for building structures with a yield strength below 460MPa are gradually being popularized and applied in large-scale buildings. , Refractory properties put forward higher requirements. [0003] For the sake of seismic performance, the yield ratio of most 460MPa construction steels is required to be less than 0.8, and the development of construction steels with lower yield ratios is of key significance for the improvement of seismic performance. [0004] At present, the improvement of the fire resistance of steel structures is mainly to protect the steel structure by spraying a thick fireproof coating, and spra...

AI Technical Summary

Problems solved by technology

This type of steel uses Nb, V, Ti to replace Mo, and mainly uses MC-type precipitates to precipitate in ferrite or bainite. Through the precipitation strengthening effect of the precipitates, the matrix is ​​strengthened to ensure good corrosion resistance at high temperatures. strength, but MC-type carbides are prone to coarsening with the prolongation of the holding time. In addition, the method of intelligent precipitation in case of fire is difficult to achieve while saving costs, and it only guarantees the high-temperature strength under the condition of holding for 3 hours. If If it continues to prolong the time, its strengthening effect will drop a lot, and its safety for buildings needs to be further verified

[0007] None of the above-mentioned documents propose that the yield ratio is lower than 0.75, or that the purpose of fire resistance is achieved by combining interphase precipitation with high-temperature precipitation of MC-type carbides.

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