Manufacturing method of high nickel steel used for cryogenic storage tank

Abstract

The invention provides a manufacturing method of high nickel steel used for a cryogenic storage tank. In a converter smelting process, the carbon temperature is coordinated, and LF-VD compound refining ensures accurate control of the steel components and gas content. Compared with common plate billets, a slow cooling process is added, the gas content in a casting blank is reduced to the utmost, and the internal quality of the casting blank is improved. Plate billet shot blasting and iron sheet packaging treatment are carried out to improve the surface quality of the casting blank, thus ensuring the casting blank a smooth and defect-free surface before rolling, and further improving the surface quality of a steel plate. Controlled rolling and heat treatment processes aim to control the grain size and microstructure of a high nickel steel plate, and guarantee the strength and low temperature toughness of the steel plate. The high nickel steel manufactured by the method provided by the invention has yield strength of greater than or equal to 390MPa, tensile strength of greater than or equal to 530MPa, elongation of greater than or equal to 20%, a section shrinkage rate of greater than or equal to 50%, V type impact energy of greater than or equal to 150J at -120DEG C, and side expansion of greater than or equal to 2.0.

Description

technical field [0001] The invention belongs to the field of high-alloy steel manufacturing, and in particular relates to a method for manufacturing high-nickel steel used for building liquefied ethylene gas (LEG) storage tanks. Background technique [0002] With the increasing use of ethylene worldwide, the demand for high-nickel steel for the construction of liquefied ethylene gas (LEG) storage tanks is becoming increasingly urgent. High-nickel steel must not only meet the requirements for use in a low-temperature environment of -120°C, but also It is also required to have high strength. The addition of high content of nickel affects the fluidity of molten steel, which is not conducive to the homogenization of components and the floating of impurities and gases in the process of smelting and continuous casting. During the heating process, the surface of high-nickel steel slabs is prone to produce iron oxide scales that are difficult to remove, which in turn affects the su...

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Problems solved by technology

[0004] There are very few papers on 5Ni steel. Only Hu Sukun of Luoyang Ship Materials Research Institute published two articles on the microstructure and heat treatment process of 5Ni steel in "Material Science Progress" and "Material Development and Application" in 1988 and 1989. But the chemical composition of test steel is not listed in the article, and its steel plate strength far exceeds the regulation in the current 5Ni steel international standard, therefore, the 5Ni steel mentioned in the above-mentioned article does not match the present invention

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