Cu-Fe-Ni-Cr austenite alloy for oil bushing

Abstract

The invention relates to an austenite alloy which comprises the following chemical constituents by weight percent: 0 to 0.03% of C, 0 to 0.015% of P, 0 to 0.01% of S, 0 to 0.5% of Si, 0.5 to 2.0% of Mn, 25 to 27% of Ni, 24 to 26% of Cr, 3 to 4% of Mo, 3 to 5% of Cu, 0.1 to 0.3% of Al, 0.001 to 0.2% of V, and Fe in balancing amount. A manufacturing method of an oil bushing comprises the steps as follows: smelting is conducted in an electric arc furnace and an argon-oxygen decarburization furnace; a steel ingot is formed by casting and then is subjected to electroslag remelting and forging to obtain a hot extrusion ingot blank; the preheating temperature of the hot extrusion ingot blank ranges from 850 to 1100 DEG C; the ingot blank heat preservation time is 1 to 5 minutes per one-centimetre-thick piece of the ingot blank; and extruded tube blank is immersed in water to be cooled to below 50 DEG C and is cooled to below 100 DEG C with one minute; solution treatment is conducted at 1000 to 1120 DEG C, the heat preservation time is 1 to 5 minutes per one-millimeter-thick piece of the tube blank; then the tube blank is immersed in water and is cooled to below 100 DEG C within one minute; and finally cold rolling deformation is conducted, the cross section reduction deformation is controlled within 25 to 45 percent according to the grade requirements of steel. The alloy has excellent pitting corrosion resistance and stress corrosion resistance.

Description

technical field [0001] The present invention relates to an iron-nickel-chromium alloy, in particular to a copper-containing iron-nickel-chromium alloy with high strength and corrosion resistance, which is especially suitable for manufacturing stress corrosion cracking-resistant oil casings for acid wells containing elemental sulfur . Background technique [0002] With the continuous increase of energy demand and the continuous reduction of exploitable oil and gas resources, the exploitation of oil and gas resources has to turn to deep wells, ultra-deep wells and highly corrosive wells. This type of oil and gas well is characterized by high temperature, high pressure, and high CO 2 、H 2 S partial pressure, containing elemental sulfur and high salinity. In order to meet the production and development needs of such oil and gas wells, more and more ultra-high alloy oil casing products have been developed, especially iron-nickel-based alloy and nickel-based alloy oil casing. ...

AI Technical Summary

Problems solved by technology

These alloys can be used in high temperature, high pressure, high CO 2 、H 2 Production of S partial pressure and high salinity oil and gas wells, but the Ni content in it is more than 30%, the alloy cost is high, resulting in high oil field production costs

[0004] US4840768 discloses an iron-nickel-chromium alloy that can be used as oil well pipe fittings, which has good corrosion resistance, but cannot meet the requirements of corrosion resistance in the presence of elemental sulfur

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