Ni-based corrosion resistant alloy for high-acidity oil-gas field and manufacturing method of oil casing of Ni-based corrosion resistant alloy for high-acidity oil-gas field

Abstract

The invention relates to Ni-based corrosion resistant alloy for a high-acidity oil-gas field and a manufacturing method of an oil casing of the Ni-based corrosion resistant alloy for the high-acidity oil-gas field. The Ni-based corrosion resistant alloy comprises the following chemical components by weight percent: smaller than or equal to 0.03% of C, 21.0-24.0% of Cr, 18.0-20.0% of Fe, 7.0-9.0% of Mo, 1.5-2.0% of Cu, smaller than or equal to 3.0% of Co, smaller than or equal to 3.0% of W, smaller than or equal to 0.50% of Nb and Ta, smaller than or equal to 0.50% of Ti, smaller than or equal to 0.5% of Si, smaller than or equal to 0.5% of Mn, smaller than or equal to 0.003% of S, smaller than or equal to 0.005% of P, and smaller than or equal to 0.012% of N, wherein the total amount of (Mo+0.5*W) is 7.0-10.0%, and the numerical value of (Ti/6+(Nb+Ta)/8)/(C+N) is greater than or equal to 1 and smaller than or equal to 2. The manufacturing method comprises the following steps: I smelting, to be specific, smelting electroslag refining ingots; II tube blank processing; III tube making including hot-extrusion, reaming and solution treatment, wherein the grain size of a crude tube is 4-7 grade, the hot-extruded crude pipe is cold-rolled into a finished seamless tube, the total cold-rolling pass deformation amount is 30-61%, the cold-rolling speed is 25-35 times/min. The Ni-based corrosion resistant alloy and the oil casing manufactured are excellent in corrosion resistance.

Description

technical field [0001] The invention relates to a nickel-based corrosion-resistant alloy for oil and gas development, in particular to a nickel-based corrosion-resistant alloy for high-acid oil and gas fields. [0002] The invention also relates to a method for manufacturing an oil casing, in particular to a method for manufacturing a nickel-based corrosion-resistant alloy oil casing suitable for high-acid oil and gas fields. Background technique [0003] With the rapid development of oil and natural gas industry and the continuous reduction of exploited oil and gas resources, the exploitation of oil and gas resources has to turn to complex areas, deep wells and ultra-deep wells facing deep highly acidic and corrosive environments. Such sour oil and gas wells have a large depth, high pressure and temperature in the well, and the presence of CO 2 、H 2 S and chloride ion salt, and the concentration is relatively high, which makes the service conditions of the oil casing extr...

AI Technical Summary

Problems solved by technology

However, the alloy has a high degree of alloying, high temperature rheological resistance, high dynamic recrystallization temperature, narrow processing temperature range, and easy cracking in extrusion molding; complex precipitated phases of the alloy, improper chemical composition, and improper production process control lead to harmful phases ( For example, the precipitation of σ phase, μ phase, nitride phase and carbide, etc.) affects the corrosion resistance of the alloy; the alloy needs to be strengthened by cold deformation, due to high cold deformation resistance, low ductility, and unreasonable cold deformation process control, It is very easy to cause defects such as cracks and wrinkles on the inner and outer surfaces of the pipe, and at the same time, the microstructure and properties are difficult to meet the standard requirements