Large-section aluminum-containing hot-rolled H-shaped steel and manufacturing method thereof

Abstract

The invention discloses large-section aluminum-containing hot-rolled H-shaped steel and a manufacturing method thereof. Chemical components of the hot-rolled H-shaped steel comprise, by weight percent, 0.11-0.14% of C, 0.18-0.25% of Si, 1.40-1.50% of Mn, smaller than or equal to 0.025% of P, smaller than or equal to 0.008% of S, 0.040-0.050% of V, 0.012-0.02% of Ti, 0.040-0.050% of Al and the balance iron and trace impurity. The manufacturing method of the steel comprises the steps of molten iron pre-desulfuration, converter smelting, LF refining, near-net-shape beam bank continuous casting and rolling. According to the steel and the method, by means of vanadium-titanium composite microalloying, meanwhile, an aluminum element is used in cooperation, the refined crystalline strengthening and dispersion strengthening effect is achieved, and the comprehensive mechanical performance of the large-section H-shaped steel is improved. In the production process, the beam blank single-point flange non-equilibrium full-protection continuous casting technology is adopted, the cleanness degree of the molten steel is controlled strictly, scaffolding of a water opening is reduced, the inclusion content is low, the low-temperature impact performance of rolled materials is stable, and the yield is high.

Description

technical field [0001] The invention relates to metallurgical technology, in particular, the invention relates to a large-section aluminum-containing hot-rolled H-shaped steel and a preparation method thereof. Background technique [0002] The section shape of H-shaped steel is economical and reasonable, with good mechanical properties. It has the advantages of large section modulus, light weight, and metal saving. It can reduce the steel structure by 30-40%. Because the inside and outside of the legs are parallel, and the legs are at right angles, they can be assembled and combined. It can save up to 25% of welding and riveting workload, so it is an important steel for steel structure. With the high-rise and large-span steel structures, the demand for large-section low-alloy high-strength H-beams is increasing. Due to the continuous expansion of steel structure application fields, special steel structure application fields such as high-altitude regions, high-latitude regio...

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Problems solved by technology

[0004] Chinese patent CN103589951B "Production method of large-section H-shaped steel" discloses a production method of large-section H-shaped steel, including converter smelting, LF refining, continuous casting of special-shaped billets, surface cleaning of billets, rolling H-shaped steel and straightening. The feature is that the comprehensive performance of large-section H-shaped steel is improved by adding alloying element V, but the amount of V added is 0.10% to 0.20%, and the alloy cost is high; the impact at 0°C is >98J, and the impact at -20°C is >44J, and its low temperature resistance performance lower

Chinese patent CN107829031A "A Large-Section H-Shaped Steel and Its Production Method" discloses a large-section H-shaped steel and its production method, which adds microalloying elements vanadium 0.10%-0.20%, niobium 0.03-0.05%, and thallium 0.03-0.05% %, polonium 0.03-0.05%, terbium 0.02-0.04%, nickel 0.01-0.02%, the cooling process parameters are that the rolled piece is cooled to 700 ℃ at a cooling rate of 110 ℃ / s, and then returned to 780 ℃, and finally H The section steel is naturally cooled to room temperature, and there are many alloy elements added, the cost of the alloy is high, and the cooling process after rolling is complicated

Chinese patent CN109576570A "A Large Section Boron Containing Low Yield Strength Ratio 355MPa Hot-Rolled H-Shaped Steel and Its Production Method" discloses a large section boron-containing low yield strength ratio 355MPa hot-rolled H-shaped steel. In converter smelting, the initial slag basicity is 1.5-2.0, and the final slag basicity is 2.5-3.0. The strength of H-shaped steel is enhanced by adding alloy element boron. When boron is added to the steel as an alloy element, high-temperature boron is extremely active and can C, N, O, S, P in the steel and the iron matrix form various types of compounds, which can easily lead to unstable boron recovery rate and difficult smelting control

Chinese patent CN102618782B "A large-scale Z-direction H-shaped steel and its preparation method" discloses a large-scale Z-direction H-shaped steel and its preparation method. The weight percentage of the chemical composition of the large-scale Z-direction H-shaped steel is: C 0.12 ~0.22%, Si 0.10~0.40%, Mn 1.1~1.50%, P≤0.020%, S<0.008%, V 0.02~0.05%, the rest is iron and trace impurities. Protective casting does not use aluminum deoxidation. Since the shape of the nozzle is flat, the degree of erosion of each part during the pouring process is different, resulting in a large difference in the service life of the nozzle, which affects the production rhythm.

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