Low-alloy high-strength corrosion-resistant steel bar and preparation method thereof

Abstract

The invention relates to a low-alloy high-strength corrosion-resistant steel bar composed of Al, Ti, Cr and other elements and a preparation method of the low-alloy high-strength corrosion-resistant steel bar, and belongs to the technical field of steel preparation. The low-alloy high-strength corrosion-resistant steel bar comprises the following components in percentage by weight: 0.05-0.2% of C,0.1-1.0% of Si, 0.8-1.5% of Mn, 0.5-1.5% of Cr, 0.005-0.15% of Ti, 0.005-0.60% of Al, 0.005-0.05% of V, 0.01-0.03% of Nb, less than or equal to 0.045% of S, less than or equal to 0.045% of P and thebalance of iron and inevitable impurity elements. The preparation method comprises the following steps that smelting is carried out in a converter to obtain crude molten steel, the crude molten steelenters an LF (ladle furnace) to be refined to obtain refined molten steel, the refined molten steel is continuously cast into small square billets, the small square billets are heated and soaked in aheating furnace, and rolled into steel bars with target specifications on a bar rolling mill, and the structure of the obtained corrosion-resistant steel bar is ferrite and pearlite. Compared with other corrosion-resistant steel bars, the production process is simple, and the obtained corrosion-resistant steel bars are high in yield strength and tensile strength and good in corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of steel preparation, and particularly relates to a low-alloy high-strength corrosion-resistant steel bar composed of Al, Ti, Cr and other elements and a preparation method thereof. Background technique [0002] Corrosion of steel bars is one of the main reasons for the failure of reinforced concrete structures. The marine environment is extremely complex. Sea-crossing bridges, wharves, and coastal civil buildings are very susceptible to chloride ion erosion, resulting in premature failure of steel bars, which seriously affects reinforced concrete structures. life, resulting in huge economic losses. To this end, researchers have done a lot of research work and proposed many effective protective measures and technologies, including: improving the corrosion resistance of the steel bar itself, cathodic protection, surface modification treatment, coating layer protection, etc. The types of corrosion-resistant s...

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Problems solved by technology

Jinan Iron and Steel Company has studied a kind of composition and is by mass fraction: C=0.10-0.12%, Cr=0-0.78%, Ni=0.32-0.67%, Mo=0-0.52%, V=0-0.06%, Cu= 0.3-0.36% low-carbon high-strength corrosion-resistant steel bars ("Special Steel" 2004 No. 6), this steel contains high-cost alloy elements such as Ni, Mo, and Cu, and also increases the difficulty of production

Such as the patent No. CN101144137 "a kind of niobium-containing high-strength corrosion-resistant steel and its rolling process", its alloy elements are: C=0.17-0.24%, Si=0.55-0.75%, Mn= 1.35-1.50%, Nb=0.02-0.04%, Re=0.04-0.10%, and the rest are Fe and impurity elements. Because of the high Re element, most of the rare earths are particularly easy to oxidize into rare earth oxide inclusions with high melting point and high viscosity after adding molten steel It is difficult for the oxidized inclusions to float up in the molten steel, and the continuous casting process is very easy to block the nozzle. At present, there is no domestic precedent that the continuous casting can be poured smoothly after the rare earth reaches 0.04-0.10%

The patent No. CN104846287 of the patent "HRB400 anti-seismic and corrosion-resistant steel bar" has alloy elements according to weight percentage: C=0.01-0.10%, Si=0.10-0.30%, Mn=0.20-0.80%, Ni=0.01-0.05% , Cr=0.01-0.05%, Nb=0.02-0.03%, Mo=0.02%, and the rest are Fe and unavoidable impurity elements. Due to the low content of alloy elements, the mechanical properties and corrosion resistance of the steel bars produced by this patent cannot be achieved. Requirements for industrial production applications

[0006] Low-alloy corrosion-resistant steel has been widely used because of its excellent mechanical properties and corrosion resistance. However, some studies have focused on Cr, Ni, Mo, V, Cu and rare earth elements. In order to ensure the corresponding corrosion resistance, more High content, in addition to the relatively high cost of the alloy, it is extremely difficult to obtain a P+F structure (ferrite + pearlite) that meets the national standard GB / T33953-017 (corrosion-resistant steel bars for reinforced concrete) during the production process, and the elongation rate cannot be guaranteed

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