80ksi anti-h for shale gas 2 s-corrosion casing steel and manufacturing method thereof

Abstract

The invention discloses H2S corrosion-resistant 80-ksi casing steel for shale gas. The casing steel is prepared from, by weight, 0.25%-0.29% of C, 0.20%-0.35% of Si, 0.90%-1.10% of Mn, 0.95%-1.15% of Cr and the balance Fe, residual elements and unavoidable impurities. The invention further discloses a preparation method of the H2S corrosion-resistant 80-ksi casing steel for the shale gas. The preparation method comprises the steps of steelmaking, wherein pig iron and waste plain carbon steel are adopted as raw materials in the steelmaking process, a deoxidizing agent is added in the steel tapping process, static blowing treatment is performed in a VD vacuum chamber, and argon blowing and sealing gasket adding for protection are performed during pouring; pipe manufacturing, wherein the temperature of a heating zone ranges from 1210 DEG C to 1270 DEG C, and the temperature of a soaking zone ranges from 1240 DEG C to 1260 DEG C; heat treating, wherein the heat treatment technologies of spraying and inner axial flow water cooling quenching, air cooling tempering and straightening under the temperature are adopted. According to the casing steel, the yield strength is 552-655 MPa, the tensile strength is larger than or equal to 655 MPa, the transverse 10*10-mm V-shaped impact energy at 0 DEG C is larger than or equal to 40 J, the elongation is larger than or equal to 19%, and the allowed hardness change delta HRC is smaller than or equal to 3.0.

Description

technical field

[0001] The invention relates to the technical field of steel manufacturing, in particular to an 80ksi anti-H 2 A manufacturing method of S corroded casing steel, and a casing steel obtained by the manufacturing method. Background technique

[0002] As the world's main energy and high-quality chemical raw materials, oil and natural gas are one of the important production factors in today's social and economic development. Oil casing is a steel pipe used in oil exploration and production, and plays an important role in my country's oil industry. As the world's energy consumption continues to rise, a large number of oil and gas fields with harsh corrosive environments and other harsh conditions have been put into development one after another, and the development of unconventional energy including shale gas has received more and more attention.

[0003] At present, the exploration and development of shale gas in my country has just started, mainly concentrated...

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