CO2 corrosion resistant pipeline steel used for surface gathering and preparation method of same

Abstract

The invention relates to a kind of CO2 corrosion resistant pipeline steel used for surface gathering and a preparation method of the same. The pipeline steel consists of following components, in weight percentage, C 0.01 to 0.08%, Si 0.10 to 0.50%, Mn 0.50 to 1.50%, P not larger than 0.02%, S not larger than 0.006%, sum of Nb, V, Ti not larger than 0.1%, Cr 1.0 to 3.0%, Mo 0.10 to 0.30%, Cu 0.10 to 0.50%, Ni 0.10 to 0.50%, and the rest is Fe and inevitable impurities. The preparation method comprises the first step of smelting, casting, forging and pressing to produce steel billets, the second step of heating, the third step of rough rolling, the fourth step of finish rolling, and the fifth step of cooling. The CO2 corrosion resistant pipeline steel has a good anti-CO2 corrosion performance, and also has high strength and roughness performances and a good weldability. The pipeline steel is capable of being applied to a surface gathering pipeline project, and has a wide application prospect.

Description

technical field [0001] The present invention relates to a kind of CO resistant for ground gathering and transportation 2 Corrosion pipeline steel and preparation method thereof. Background technique [0002] In recent years, in the process of oil and gas exploitation, due to the use of carbon dioxide re-injection technology to improve oil recovery, the CO 2 content is greatly increased. Therefore, CO 2 Corrosion has become one of the main reasons for pipeline corrosion in the process of oil and gas collection and transportation in surface engineering. Generally dry CO 2 No corrosion to steel, but CO 2 It is extremely corrosive to steel when dissolved in water. At the same pH, CO 2 The total acidity is higher than that of hydrochloric acid, so CO 2 Corrosion to steel is more serious than that of hydrochloric acid. During oil and gas collection and transportation, CO 2 Corrosion causes frequent accidents in oil and gas pipelines. This is not only a serious and safe ...

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Problems solved by technology

[0004] After searching, it was found that the alloy steel disclosed in the Chinese invention patent application with application number 201110154407.6 (name: Cr-containing alloy steel and its manufacturing method) has carbon dioxide corrosion resistance, but its tensile strength, yield strength, and elongation are all lacking. Its scope of application is greatly limited; the Chinese invention patent with patent number 201010130911.8 (name: a high-strength, anti-CO 2 / H 2 S corroded seamless gathering and transportation line pipe) The disclosed line pipe has carbon dioxide corrosion resistance, but its yield strength is still slightly lacking. At the same time, the line pipe needs to be added with rare earth, which will undoubtedly increase the cost

[0005] In addition, there are existing reports on the resistance to CO 2 Most of the patents on steel for corrosion are used to manufacture oil well pipes and casings, etc. However, the use conditions and manufacturing methods of pipeline steel are quite different from oil casing pipes, especially the CO in the delivery pipe. 2 / H 2 S partial pressure, temperature, flow rate, etc. are very different from downhole oil and casing, and there are also great differences in the processing and forming process of oil and casing and pipeline steel: the manufacture of oil and casing requires quenching and tempering of steel pipes, and It is only suitable for oil well pipes with low strength grades, which limits its application in gathering pipeline steel

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