Normalized acid resistant hot-rolled steel plate and preparation method thereof

Abstract

The invention discloses a normalized acid resistant hot-rolled steel plate and a preparation method thereof, belonging to the technical field of low-alloy steel production. The steel plate comprises the following chemical compositions in mass percentage: 0.061-0.151% of C, 0.10-0.45% of Si, 0.50-0.99% of Mn, less than or equal to 0.009% of P, less than or equal to 0.0015% of S, 0.02-0.06% of A1t,0.045-0.085% of V, 0.005-0.04% of Ti, 0.05-0.35% of Cr, 0.00-0.15% of Mo and the rest of Fe and unavoidable impurity elements. The preparation method comprises the processes of molten iron desulfurization, converter smelting, external refining, continuous casting, heating, rolling, normalization and the like. The normalized acid resistant hot-rolled steel plate has the advantages that fine ferrolites and globular pearlites are obtained at the surface layer, the 1 / 4 part and the center and the banded structure rating is less than or equal to 2.0. The yield strength of the steel plate can be upto 300-440MPa and the tensile strength can be up to 420-525MPa. The acid resistance satisfies that the crack length ratio CLR is less than or equal to 15%, the crack thickness ratio CTR is less than or equal to 5% and the crack sensitivity ratio CSR is less than or equal to 2% under the solution condition of NACE TM0284-96 standard A.

Description

technical field [0001] The invention belongs to the technical field of low-alloy steel production, and in particular relates to a normalized acid-resistant hot-rolled steel plate and a preparation method thereof, which are used for the exploitation, transportation and storage of high-sulfur and high-acid oil and gas. Background technique [0002] In recent years, the Middle East and my country's domestic petrochemical industry have seen an increasing demand for series steels resistant to hydrogen sulfide stress corrosion, such as container plates A516Gr65N, ERW oil well pipes, and pipeline steels BNS and X52NS. [0003] Hydrogen sulfide is one of the most corrosive and harmful media in oil and natural gas, which seriously affects the service life of oil and gas extraction, transportation and storage materials, and restricts the development of materials used in high-sulfur oil and gas environments. In the environment of hydrogen sulfide-containing oil and gas, the material wi...

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Problems solved by technology

[0006] But so far, there are very few relevant materials in the literature or patents about the normalized acid-resistant hot-rolled steel plate in the world. , the alloy formula adopts C: 0.02~0.04%, Mn: 1.4~1.6%, V: 0.02~0.04%, Mo: 0.2~0.4%, which is characterized by low carbon, high manganese, and adding a large amount of precious alloy Mo elements. If C in the alloy formula is too low, the smelting cost will increase, if Mn is too high, it will be detrimental to the HIC performance, and the Mo alloy is expensive, and the production cost is high; another example is the Chinese patent CN100359035C authorized announcement "X65 pipeline steel for acidic environment and its manufacturing method" , the alloy formula adopts C: 0.02~0.05%, Mn: 1.2~1.5%, Nb: 0.05~0.07%, Mo: 0.050~0.195%, and the coiling temperature is controlled at 500~580℃. The patent adopts low C, Add Mn, Nb and Mo alloys, use lower coiling temperature to improve the performance of the product, the cost of the alloy is higher, and the steel plate has thermal stress and structural stress

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