High nickel steel for ultra-low temperature pressure vessel and manufacturing method thereof

A technology for pressure vessels and manufacturing methods, applied in the field of high-alloy steel manufacturing, can solve the problems of low impact toughness and not recommended

Active Publication Date: 2019-04-30
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its test data show that the quenching + critical quenching + tempering (QLT) heat treatment method is adopted, and the critical quenching temperature needs to be greater than 720°C before its strength can reach the standard, while the Ac3 temperature of 9Ni steel is below 720°C, and the Ac3 temperature after the Ni content is reduced Therefore, the QLT heat treatment method is not established, and the impact toughness is low when the QT heat treatment method is used, and the author does not recommend using

Method used

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  • High nickel steel for ultra-low temperature pressure vessel and manufacturing method thereof
  • High nickel steel for ultra-low temperature pressure vessel and manufacturing method thereof
  • High nickel steel for ultra-low temperature pressure vessel and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] 100 tons of oxygen top-blown converter is used for smelting, and the position of the gun is well controlled during the blowing process to achieve good slag in the process and coordinated carbon temperature;

[0053] The reduced slag made by LF furnace is desulfurized to reduce inclusions and adjust the composition. The holding time of VD furnace is 18min. Determination of H and O content, [H]=1.0ppm, [O]=15ppm, [N]=40ppm;

[0054] The whole process of continuous casting is protected and poured, and the billet size is 300mm;

[0055] The slab is slowly cooled in the slow cooling pit for 60 hours. After the slab is slowly cooled, the upper and lower surfaces of the slab are ground by 2mm each, and sprayed with anti-high temperature oxidation paint;

[0056] Two-stage controlled rolling, the first-stage rolling temperature is 1100°C, the second-stage rolling temperature is 850°C, the final rolling temperature is 750°C, air-cooled after rolling, and the steel plate thickn...

Embodiment 2

[0059] 100 tons of oxygen top-blown converter is used for smelting, and the position of the gun is well controlled during the blowing process to achieve good slag in the process and coordinated carbon temperature;

[0060] The reduced slag made by LF furnace is desulfurized to reduce inclusions and adjust the composition. The holding time of VD furnace is 18min. [H]=1.2ppm, [O]=16ppm, [N]=38ppm;

[0061] The whole process of continuous casting is protected and poured, and the billet size is 300mm;

[0062] The slab is slowly cooled in the slow cooling pit for 55 hours. After the slab is slowly cooled, the upper and lower surfaces of the slab are ground by 3mm respectively, and the anti-high temperature oxidation coating is sprayed;

[0063] Two-stage controlled rolling, the first-stage rolling temperature is 1080°C, the second-stage rolling temperature is 870°C, the final rolling temperature is 760°C, air-cooled after rolling, and the steel plate thickness is 35mm;

[0064]...

Embodiment 3

[0066] 100 tons of oxygen top-blown converter is used for smelting, and the position of the gun is well controlled during the blowing process to achieve good slag in the process and coordinated carbon temperature;

[0067] The reduced slag made by LF furnace is desulfurized to reduce inclusions and adjust the composition. The holding time of VD furnace is 18min. [H]=1.2ppm, [O]=15ppm, [N]=35ppm;

[0068] The whole process of continuous casting is protected and poured, and the billet size is 300mm;

[0069] The slab is slowly cooled in the slow cooling pit for 56 hours. After the slab is slowly cooled, the upper and lower surfaces of the slab are ground by 3mm each, and sprayed with anti-high temperature oxidation paint;

[0070] Two-stage controlled rolling, the first-stage rolling temperature is 1050°C, the second-stage rolling temperature is 870°C, the final rolling temperature is 760°C, air-cooled after rolling, and the steel plate thickness is 25mm;

[0071] Quenching +...

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Abstract

The invention provides high nickel steel for an ultra-low temperature pressure vessel and a manufacturing method thereof. The components of a steel plate include, by weight percentage, 0.01-0.10% of C, 0.01-0.10% of Si, 0.50-1.50% of Mn, 6.50-7.50% of Ni, 0.01-0.20% of RE, S which is less than or equal to 0.005%, and P which is less than or equal to 0.008%, with the balance being Fe and inevitableimpurities; and the manufacturing method includes converter smelting, external refining, continuous casting, slow cooling of slabs, rolling and heat treatment. The yield strength of the produced steel plate is greater than or equal to 585 MPa, the tensile strength is greater than or equal to 680 MPa, he elongation rate is greater than or equal to 18%, -196 DEG C V-type impact energy is greater than or equal to 100 J, and the lateral expansion is greater than or equal to 1.0; and therefore, manufacturing costs of the steel for LNG storage tanks can be reduced.

Description

technical field [0001] The invention belongs to the field of high-alloy steel manufacture, and in particular relates to the construction suitable for liquefied natural gas (LNG) storage tanks. Background technique [0002] With the increasing use of natural gas worldwide, the demand for 9% Ni steel for the construction of liquefied natural gas (LNG) storage tanks is also increasing rapidly. The cost of 9% Ni steel remains high due to its Ni content reaching 9%. Before the application of the present invention, there was no relevant patent application. [0003] For the report on 7% Ni steel, see "Development of 7% Ni-TMCP Steel Plate for LNG Storage tanks" in "Proceedings of Welding Society", Volume 28, No. 1, published in Japan in 2010. Its chemical composition is calculated by weight percentage: C: 0.05%, Si: 0.05%, Mn: 0.80%, Ni: 7.10%, Cr: 0.41%, Mo: 0.04%. In the article, the author did not give the composition range of 7% Ni steel, but only explained its manufacturing...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/08C21D1/18C21D8/02
CPCC21D1/18C21D8/0226C21D8/0247C22C38/001C22C38/005C22C38/02C22C38/04C22C38/08
Inventor 朱莹光侯家平吴铎王超王飞龙张宏亮
Owner ANGANG STEEL CO LTD
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