High-strength martensite ferrite two-phase stainless steel anti-corrosion oil casing pipe and manufacturing method thereof

Abstract

The invention provides a high-strength martensite and ferrite two-phase stainless steel anti-corrosion oil casing pipe and a manufacturing method of the high-strength martensite ferrite two-phase stainless steel anti-corrosion oil casing pipe. The high-strength martensite ferrite two-phase stainless steel anti-corrosion oil casing pipe comprises, by weight, 0.05% to 0.10% of C, 0.1% to 0.4% of Si, 0.20% to 1.0 % of Mn, less than 0.03% of P, less than 0.01% of S, 13.5% to 15.0% of Cr, 0.5% to 1.5% of Ni, 0.2% to 1.0% of Mo, 0.005% to 0.02% of Nb, 0.01% to 0.10% of N and less than 0.004% of O, wherein the compositions satisfies the inequality that Cr+1.5Mo+2Ni+16N>=17 and the inequality that Ni+30(C+N)+8Nb>=3.5, Cr, Ni, Mo, Si, Nb, Mn, C and N stand for the weight relative content of the elements, and the rest of the oil casing pipe comprises Fe and inevitable impurities. The oil casing pipe has good corrosion resistance performance, and the yield strength is more than 110ksi. The oil casing pipe is quenched and tempered, a martensite phase is used as the main body of a metallographic structure, and the metallographic structure contains 2% to 10% of ferrite phases. The steel pipe has good carbon dioxide corrosion resistance performance and low temperature impact toughness.

Description

technical field [0001] The invention relates to an oil casing for crude oil or natural gas oil wells and gas wells, in particular to a high-strength martensitic ferritic duplex stainless steel corrosion-resistant oil casing and a manufacturing method thereof, suitable for containing carbon dioxide gas (CO 2 ), chloride ion (Cl - ) and other oil wells and gas wells in very severe corrosive environments, with excellent corrosion resistance and impact toughness. Background technique [0002] With the intensification of my country's oil and gas development, oil well casings and tubing for collecting oil and gas are facing high temperature, high pressure, and high CO content. 2 , Cl - Coexisting strong corrosive environment. In addition, since many oil and gas resources are located in relatively cold regions, the temperature can reach minus 20 degrees or even lower during winter operations. For such an environment, high-alloy products are generally required to meet the corros...

AI Technical Summary

Problems solved by technology

[0011] This patent improves corrosion resistance by low carbon and adding a large amount of alloy elements, but due to the high content of alloys such as Ni and Mo, the cost is high

In addition, due to the austenite structure, the strength of the steel pipe reaches 95ksi, which is difficult to meet the requirements of deep wells

Images