Corrosion-resistant and anti-fatigue pipeline steel for underwater oil and gas production and transportation and production method thereof

Abstract

The invention provides corrosion-resistant and anti-fatigue pipeline steel for underwater oil and gas production and transportation and a production method thereof. The steel is prepared from the components including, by weight, 0.030%-0.055% of C, 0.26%-0.40% of Si, 1.10%-1.29% of Mn, less than or equal to 0.010% of P, less than or equal to 0.0015% of S, 0.035%-0.060% of Nb, 0.012%-0.025% of Ti, 0.01%-0.04% of V, 0.10%-0.19% of Ni, 0.16%-0.25% of Cu, 0.10%-0.19% of Mo, less than 0.25% of Cr, 0.010%-0.025% of Al, 0.0015%-0.0050% of Ca, 0.0010%-0.0040% of N, less than or equal to 0.00015% of H, less than or equal to 0.0020% of O and the balance Fe and inevitable impurities; the ratio of Ni / Cu is larger than or equal to 0.7, and the ratio of Ca / S is larger than or equal to 1.6. A pipeline steel plate contains 0.03%-0.09% by mass of carbonitride precipitates, and fine carbonitride precipitates with the particle size being 10 nm or below account for more than or equal to 30% of the total carbonitride precipitates. The steel plate produced from the steel has the comprehensive technical characteristics of thick wall, high strength, high toughness, low yield ratio, high uniform deformation rate, high stress ratio, excellent corrosion resistance, high fatigue strength and the like, and meets the requirements of manufacturing longitudinal submerged arc welded pipes for oil and gas production and transportation in underwater complex environments.

Description

technical field [0001] The invention belongs to the field of low-carbon and low-alloy steels, and in particular relates to a thick-walled, corrosion-resistant, high-fatigue strength and high-plasticity pipeline steel plate with a thickness ≥ 21 mm and a production method thereof; it is suitable for making oil and gas production in complex underwater environments. Longitudinal submerged arc welded pipes are used for transportation, especially steel pipes for H and S-rich oil and gas media. Background technique [0002] With the development of economy and society, the demand and consumption of oil and gas energy continue to increase. Offshore oil and gas resources have become an important part of oil and gas resources and an important direction for future oil and gas resource exploitation; the ability to exploit underwater, especially deep-sea oil and gas, is an important foundation for developing the marine economy and realizing the dream of a powerful ocean country. In the ...

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Problems solved by technology

[0011] The object of the present invention is to overcome the above-mentioned problems and deficiencies and provide a steel plate for underwater oil and gas production and transportation with thick wall, high strength, high toughness, low yield ratio, high uniform deformation rate, and high stress ratio. Corrosion resistance, high fatigue strength and other technical indicators matching problems, corrosion-resistant and fatigue-resistant underwater oil and gas production and transportation pipeline steel with thickness ≥ 21mm and its production method

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