Corrosion-resistance iron-based austenite oil well pipe and manufacturing method thereof

Abstract

The invention discloses a corrosion-resistance iron-based austenite oil well pipe and a manufacturing method thereof. The main chemical components of the oil well pipe include C larger than 0 and smaller than or equal to 0.03%, Si larger than 0 and smaller than or equal to 1.00%, Mn larger than 0 and smaller than or equal to 2.50%, P smaller than or equal to 0.03%, S smaller than or equal to 0.03%, 20.0%-28.0% of Cr, 20.0%-38.0% of Ni, 3.0%-5.0% of Mo and 0.50%-2.00% of Cu. The manufacturing method includes the first step of smelting; the second step of billet pouring; the third step of electroslag remelting; the fourth step of homogenizing annealing; the fifth step of billet forging; the sixth step of pipe billet preparing; the seventhly step of hot extruding, wherein a seamless steel pipe is formed through pipe billet preheating, power frequency induction furnace heating, pipe billet broaching, secondary induction heating and extruding; the eighth step of solid solution treating; and the ninth step of conducting of a deformation strengthening mode in cold drawing, wherein the percentage reduction of area is controlled within 20-40%, and the oil well pipe is manufactured. According to the corrosion-resistance iron-based austenite oil well pipe and the manufacturing method thereof, the wall thickness of the manufactured oil well pipe ranges from 15 mm to 40 mm, the yield strength is 760 MPa or higher, the tensile strength is 793 MPa or higher, the impact energy is 100 J or higher, the corrosion resistance is good, and the requirement for strictest and slow-strain tests is met.

Description

technical field [0001] The invention relates to an iron-based austenitic oil well pipe and a manufacturing method thereof, and mainly relates to a high-strength, corrosion-resistant iron-based austenitic seamless steel pipe and a manufacturing method thereof. Background technique [0002] As the environment for oil and gas exploitation is getting worse, the "three high" (high temperature, high pressure, high corrosion) oil and gas wells are gradually increasing. The depth of oil and gas wells in some areas of the country has exceeded 7,000 meters, and the temperature in the well is above 150 ° C. At the same time, there are high concentrations of H 2 S and CO 2 gas, and H 2 The partial pressure of S gas has reached above 8MPa. For such downhole conditions, iron-based and nickel-based corrosion-resistant alloys must be used to meet the application requirements. [0003] The structure of the iron-based austenitic corrosion-resistant alloy is austenite, and due to the addit...

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Problems solved by technology

[0009] However, there are many specifications of oil well pipes. For Fe-based corrosion-resistant alloy oil well pipes with large wall thickness (the wall thickness is generally more than 15mm), conventional cold working strengthening cannot meet the strengthening requirements (the surface is deformed, but the core is not deformed). If Increase the amount of cold deformation, but can not achieve industrial production