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Heat treatment method for improving sulfur resistance of welding area of high-steel-grade sulfur-resistant drill rod

A heat treatment method and steel grade technology, applied in the field of petroleum drill pipes, can solve problems such as uneven distribution, large differences in hardness values, poor resistance to sulfide stress corrosion, etc., and achieve excellent toughness and plasticity, increased diffusion coefficient, and good Effect of hydrogen sulfide stress corrosion resistance

Active Publication Date: 2021-11-19
HILONG GROUP OF +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The conventional heat treatment method, that is, high-temperature quenching + tempering (often called quenching and tempering treatment) is used to heat-treat the weld. The hardness value of the heat-affected zone of the weld varies greatly and the distribution is uneven, especially the metallographic structure of the weld line is tempered. Fire sorbite, often very high hardness, poor resistance to sulfide stress corrosion

Method used

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  • Heat treatment method for improving sulfur resistance of welding area of high-steel-grade sulfur-resistant drill rod
  • Heat treatment method for improving sulfur resistance of welding area of high-steel-grade sulfur-resistant drill rod
  • Heat treatment method for improving sulfur resistance of welding area of high-steel-grade sulfur-resistant drill rod

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Effect test

Embodiment 1

[0040]After the 120S steel grade sulfur-resistant drill pipe body and the 120S steel grade drill pipe joint are friction welded and annealed in the weld zone, the technical process of the present invention is used to carry out heat treatment in the weld zone:

[0041] Step 1, the first quenching specifically includes: (1) select a quenching heating coil with a width of 45mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the center of the quenching heating coil with the weld line; The temperature in the zone is raised to 830°C and kept warm for 100s; (3) Quenching and cooling uses water-soluble PAG medium with a concentration of 12.5% ​​for external spraying and compressed air for internal spraying.

[0042] Step 2, the second quenching specifically includes: (1) select a quenching heating coil with a width of 30mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the center of...

Embodiment 2

[0046] After the 120S steel grade sulfur-resistant drill pipe body and the 120S steel grade drill pipe joint are friction welded and annealed in the weld zone, the technical process of the present invention is used to carry out heat treatment in the weld zone:

[0047] Step 1, the first quenching specifically includes: (1) select a quenching heating coil with a width of 45 mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the center of the quenching heating coil with the weld line; The temperature in the zone is raised to 860°C and kept warm for 120s; (3) Quenching and cooling uses water-soluble PAG medium with a concentration of 12.5% ​​for external spraying and compressed air for internal spraying.

[0048] Step 2, the second quenching specifically includes: (1) select a quenching heating coil with a width of 30mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the center ...

Embodiment 3

[0052] After the 120S steel grade sulfur-resistant drill pipe body and the 120S steel grade drill pipe joint are friction welded and annealed in the weld zone, the technical process of the present invention is used to carry out heat treatment in the weld zone:

[0053] Step 1, the first quenching specifically includes: (1) select a quenching heating coil with a width of 45mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the center of the quenching heating coil with the weld seam line; The temperature in the zone is raised to 845°C and kept warm for 110s; (3) Quenching and cooling uses water-soluble PAG medium with a concentration of 12.5% ​​for external spraying and compressed air for internal spraying.

[0054] Step 2, the second quenching specifically includes: (1) select a quenching heating coil with a width of 30mm, send the welding area of ​​the drill pipe to the position of the quenching heating coil, and align the cen...

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Abstract

The invention discloses a heat treatment method for improving sulfur resistance of a welding area of a high-steel-grade sulfur-resistant drill pipe. The welding area of the drill pipe is formed by inertia friction welding of a 120S-steel-grade or 125S-steel-grade sulfur-resistant pipe body and a 120S-steel-grade sulfur-resistant drill pipe joint. The heat treatment of the welding area of the drill pipe comprises four steps of first quenching, second quenching, third quenching and tempering. During the first quenching, the quenching heating temperature is 830-860 DEG C, and the heat affecting range is 55-65 mm. During the second quenching, the quenching heating temperature is 800-830 DEG C, and the heat affecting range is 35-55 mm. During the third quenching, the quenching heating temperature is 750-800 DEG C, and the heat affecting range is 10-35 mm. During tempering, the tempering heating temperature is 670-710 DEG C, and the tempering heat affected zone range is 75-95 mm. After heat treatment, tempered sorbite and ferrite which are uniformly dispersed can be obtained in the welding area of the drill rod, and the proportion of the ferrite is not lower than 25%. The hydrogen sulfide stress corrosion resistance of the welding area of the 120S or 125S high-steel-grade sulfur-resistant drill rod can be remarkably improved, and the hydrogen sulfide corrosion resistance test passing rate is improved from 30% to 95% or above.

Description

technical field [0001] The invention belongs to the technical field of petroleum drill pipes, and relates to a heat treatment method for improving the anti-sulfur performance of the welding zone of high-grade sulfur-resistant drill pipes. Background technique [0002] In the process of exploration and production of sulfur-bearing oil and gas resources, hydrogen sulfide stress corrosion cracking (SSC) is likely to occur with conventional drill pipes. Relevant standards require the use of drill pipes with excellent resistance to hydrogen sulfide stress corrosion to reduce the risk of SSC. At present, 105SS sulfur-resistant drill pipes are commonly used in the market, but this kind of drill pipes face the disadvantages of insufficient bearing capacity and low safety factor in deep wells (such as well depths exceeding 6,000 meters). In recent years, high steel grades such as 120S and 125S Sulfur drill pipe products have become the market demand. [0003] The drill pipe is forme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/10C21D1/18C21D6/00C21D9/50C22C38/04C22C38/06C22C38/20C22C38/22C22C38/24C22C38/26
CPCC21D1/18C21D1/10C21D9/50C21D6/002C21D6/005C22C38/04C22C38/22C22C38/24C22C38/26C22C38/20C22C38/06C21D2211/009C21D2211/005Y02P10/25
Inventor 欧阳志英舒志强余世杰陈猛朱威
Owner HILONG GROUP OF