Preparation method of ultrafine-grained HRB500E aseismic reinforcement with high strength and toughness

Abstract

The invention discloses an ultrafine-grained HRB500E aseismic reinforcement with high strength and toughness and a preparation method of the ultrafine-grained HRB500E aseismic reinforcement. The reinforcement is prepared from chemical components in percentage by weight as follows: 0.21wt%-0.25wt% of C, 0.32wt%-0.45wt% of Si, 1.30wt%-1.48wt% of Mn, 0.20wt%-0.25wt% of Cr, 0.015wt%-0.020wt% of Nb, 0.050wt%-0.060wt% of V, smaller than or equal to 0.040wt% of S, smaller than or equal to 0.043wt% of P, smaller than or equal to 0.0070wt% of O, 0.0140wt%-0.0180wt% of N and the balance Fe and inevitable impurities. The preparation method of the ultrafine-grained HRB500E aseismic reinforcement with high strength and toughness comprises processes of molten steel smelting, deoxidizing alloying, moltensteel refining in an argon station, molten steel casting, billet steel heating and controlled rolling and controlled cooling of billet steel; a small amount of nitrogen-silicon alloy is added in a deoxidizing alloying process of steelmaking, the nitrogen content of the molten steel is increased, ratio values of V / N and Nb / N in steel are reduced, transfer of V and Nb from a solid solution state toa carbo-nitride precipitated phase in a rolling process is promoted, a large quantity of finely dispersed V(C,N) and Nb(C,N) precipitated phases are formed and precipitated, the phase-transition temperature is reduced, and a precipitation strengthening effect of steel is obviously improved; and according to the preparation method, the production cost is reduced, the anti-seismic property is improved, and market competitiveness of products is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to an ultra-fine-grained high-strength and toughness HRB500E anti-seismic steel bar and a preparation method thereof. Background technique [0002] Hot-rolled ribbed steel bar is the main reinforcement material of reinforced concrete building structure, and it carries the stress and strain of loads such as tensile and compressive stress and strain in the structure. At present, the annual output of hot-rolled ribbed steel bars in my country is about 200 million tons, which is the most widely used steel material in the construction of national economic construction projects. With the continuous development of my country's buildings towards high-rise, long-span and earthquake-resistant structures, the development of fine-grained anti-seismic steel bars with high strength, toughness and excellent comprehensive performance has become one of the important tasks for the iron...

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Problems solved by technology

[0004] At present, there have been domestic research reports on the production technology of HRB500E straight anti-seismic steel bars after the implementation of the GB / T 1499.2-2018 standard. The process obtains HRB500E steel bars whose macroscopic metallography, cross-sectional Vickers hardness, and microstructure meet the GB / T 1499.2-2018 standard. The grain size of the steel bar microstructure is mostly controlled at 9.0-10.5 grades. Due to the high price of vanadium alloys, the production cost is relatively high. High, which is not conducive to the reduction of production cost of steel bar enterprises and the improvement of product market competitiveness; at present, there is no research report on the preparation method of ultra-fine-grained high-strength and toughness HRB500E seismic steel bars in China

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