A kind of anti-hydrogen-induced cracking X80 pipeline steel for marine use and its manufacturing method

Abstract

The invention discloses an X80 grade pipeline steel with resistance to hydrogen-induced cracking for marine use and a manufacturing method thereof, and relates to the technical field of steel for marine engineering. The pipeline steel of the invention includes C: 0.05-0.07%, Si: 0.24~0.30%, Mn: 1.75~1.95%, S: ≤0.003%, P: ≤0.005%, Cu: 0.20~0.30%, Ni: 0.25~0.30%, Mo: 0.22~0.27%, Ta: 0.03~0.06 %, N: 0.005-0.01%, the balance is Fe; the chemical composition mass percentages of Ta and N meet 6≤Ta / N≤9, and the manufacturing process of the present invention includes: batching, smelting and casting into a billet-casting billet and reheating- Rough rolling-aerosol cooling and slow cooling-finishing-coiling; the present invention forms dispersed tantalum carbide precipitation in the steel by adding an appropriate amount of Ta element, controlling the Ta / N ratio, and the process of mist cooling and slow cooling after rough rolling. , and refine the granular bainite matrix and reduce the Σ3 interface ratio to achieve both high strength, high toughness and excellent hydrogen-induced cracking resistance.

Description

technical field [0001] The invention relates to the technical field of steel for marine engineering, in particular to an X80 grade pipeline steel with resistance to hydrogen-induced cracking for marine use and a manufacturing method thereof. Background technique [0002] In recent years, my country's marine economy has developed rapidly. With the large-scale exploration and development of deep-water oil and gas fields in the South my country Sea, the application scale of high-strength pipeline steel for deep-sea oil and gas transportation will expand rapidly. The development and production of submarine pipeline steel in my country began in 2004. So far, Baosteel, Anshan Iron and Steel, Wuhan Iron and Steel have developed and produced X70 and below-grade submarine special pipeline steel, which has been applied in shallow sea environment, and deep-sea pipeline steel with X70 and higher grades has been developed. still in its infancy; [0003] At present, the high hydrogen-indu...

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Problems solved by technology

[0003] At present, the high hydrogen-induced cracking resistance marine pipeline steels involved in the existing technology are mainly low-grade pipeline steels with low strength, such as X70 and X65 steel grades, etc. There is no technology involving high-steel grade marine pipelines of X80 and above steel; while the X80 pipeline steel technology involving high strength and high toughness pipeline steel does not mention high hydrogen-induced cracking resistance and deep-sea applications

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