High-toughness corrosion-resistant steel and manufacturing method thereof

Abstract

The invention relates to high-toughness corrosion-resistant steel. The high-toughness corrosion-resistant steel comprises the following chemical components in percentage by weight: 0.03 to 0.10 percent of C, 0.2 to 0.6 percent of Si, 0.35 to 0.75 percent of Mn, 12 to 14 percent of Cr, 0.5 to 1.5 percent of Ni, 0.01 to 0.04 percent of Al, 0.1 to 0.3 percent of Mo, less than or equal to 0.015 percent of P, less than or equal to 0.006 percent of S and less than or equal to 0.01 percent of N, wherein the Al/N is greater than 2, and the balance is Fe and unavoidable impurities. The manufacturing method of the high-toughness corrosion-resistant steel comprises the following steps of: smelting the chemical components by refining in and out of an electric arc furnace and performing vacuum refining treatment, or refining in and out of an oxygen converter and performing vacuum refining treatment or adopting an electroslag remelting method, and casting into ingots; making hot ingots enter the furnace before forging, wherein the surface temperature of ingots entering the furnace is less than 600 DEG C, the forging heating temperature is 1,200 to 1,250 DEG C, the finish forging temperature is greater than 1,000 DEG C, the forging ratio is greater than 6, and the grain fineness number at 1/2 of the thickness of the wall of a forged piece is not less than level 6. The high-toughness corrosion-resistant steel obtained by the method has the yield strength of greater than 517 MPa, and the ballistic work at -46 DEG C is greater than 27 J; and the high-toughness corrosion-resistant steel is suitable for FF-grade 105 MPa production tree body in oil and gas industry.

Description

technical field [0001] The invention relates to a high-toughness corrosion-resistant steel for low-temperature use in the oil and gas industry, in particular to a high-strength, high-toughness corrosion-resistant steel with a service temperature of -46°C and a manufacturing method thereof. Background technique [0002] The Christmas tree is an oil and gas well head device that provides access to the production tubing string and is an assembly of valves and fittings for fluid control. The Christmas tree hangs the tubing string running into the well, seals the annular space of the oil casing, controls and regulates the production of the oil well, ensures operation, construction, records oil and casing pressure data, tests and removes wax and other daily production management. [0003] According to different functions, the Christmas tree is divided into oil recovery (self-injection, artificial lift), gas recovery (natural gas and various acid gases), water injection, thermal re...

AI Technical Summary

Problems solved by technology

Use UNS42400 (C≤0.06%, Si: 0.3-0.6%, Mn: 0.5-1.00%, P≤0.03%, S≤0.03%, Cr: 12-14%, Ni: 3.5-4.5%, Mo: 0.3- 0.7%) material can better solve the problem of impact instability, but because more expensive alloy elements such as Ni and Mo are added to the material, the cost of the alloy is too high

[0004] CN101096744A discloses a high steel grade and high resistance to carbon dioxide and chloride ion corrosion oil casing steel and its manufacturing method, C: 0.15-0.25%, Si: 0.2-1.0%, Mn: 0.2-1.0%, Cr: 12/14% , Ni: 0.5-1.5%

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