Marine hydrogen-induced-cracking-resistant X80-grade pipeline steel and manufacturing method thereof

Abstract

The invention discloses marine hydrogen-induced-cracking-resistant X80-grade pipeline steel and a manufacturing method of the marine hydrogen-induced-cracking-resistant X80-grade pipeline steel, and relates to the technical field of steel for ocean engineering. According to the chemical components, the marine hydrogen-induced-cracking-resistant X80-grade pipeline steel comprises, by mass percentage, 0.05%-0.07% of C, 0.24%-0.30% of Si, 1.75%-1.95% of Mn, smaller than or equal to 0.003% of S, smaller than or equal to 0.005% of P, 0.20%-0.30% of Cu, 0.25%-0.30% of Ni, 0.22%-0.27% of Mo, 0.03%-0.06% of Ta, 0.005%-0.01% of N and the balance Fe. A manufacturing technology of the pipeline steel comprises the steps of conducting burdening, smelting and casting to form a blank, reheating the casting blank, conducting rough rolling, conducting aerial fog cooling and slow cooling, conducting finish rolling and conducting curling. According to the method, a proper quantity of Ta elements are added, the Ta/N ratio is controlled, fog cooling and slow cooling technologies are adopted after rough rolling is accomplished, and therefore dispersed tantalum carbide precipitated phases can be formed in the steel, a granular bainite matrix is refined, the sigma 3 interface proportion is reduced, and the combination of high strength, high toughness and excellent hydrogen induced cracking resistance is achieved.

Description

technical field [0001] The invention relates to the technical field of steel for marine engineering, in particular to a hydrogen-induced cracking-resistant X80 grade pipeline steel 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. my country's development and production of submarine pipeline steel began in 2004. So far, Baosteel, Anshan Iron and Steel, Wuhan Iron and Steel, etc. have developed and produced special submarine pipeline steel of X70 and below grades, which have been applied in shallow sea environments, and X70 and higher grade pipeline steels for deep seas have been developed. still in its infancy; [0003] At present, the high hydrogen-induce...

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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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