Corrosion-resistant high-strength low-alloy steel and preparation method thereof

A high-strength low-alloy steel and corrosion-resistant technology, applied in the field of deep-sea oil production equipment, can solve the problems of low-temperature impact resistance and poor corrosion resistance, low strength and toughness, etc.

Active Publication Date: 2021-04-09
TIANJIN HEAVY EQUIP ENG RES +1
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  • Application Information

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Problems solved by technology

[0005] In view of the above analysis, the present invention aims to provide a corrosion-resistant high-strength low-alloy steel and its preparation method, which solves the problem of low strength and toughness, low temperature impact resistance and poor corrosion resistance of subsea wellhead and oil production equipment materials in the prior art The problem

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  • Corrosion-resistant high-strength low-alloy steel and preparation method thereof
  • Corrosion-resistant high-strength low-alloy steel and preparation method thereof
  • Corrosion-resistant high-strength low-alloy steel and preparation method thereof

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preparation example Construction

[0049] The present invention also provides a method for preparing corrosion-resistant high-strength low-alloy steel, comprising the following steps:

[0050] Step S1: According to the composition of corrosion-resistant high-strength low-alloy steel, vacuum induction melting is used to smelt the raw materials to obtain ingots, which can ensure the smelting quality of ingots and reduce inclusions;

[0051] Step S2: performing thermal processing on the ingot to obtain a billet;

[0052] Step S3: normalizing the billet to obtain a billet with uniform structure;

[0053] Step S4: performing quenching treatment on the blank to obtain a blank with a martensitic structure;

[0054] Step S5: performing a tempering treatment on the billet to obtain a corrosion-resistant high-strength low-alloy steel with a tempered sorbite structure.

[0055] Compared with the prior art, the beneficial effect of the preparation method of the corrosion-resistant high-strength low-alloy steel provided b...

Embodiment 1

[0074] In a specific embodiment of the present invention, the composition of corrosion-resistant, high-strength and low-alloy steel for deep-sea oil recovery equipment is: C 0.35, Mn 0.95, Si 0.26, Cr 1.05, Mo 0.25, Ni 0.19, V 0.045, Cu 0.015 , P≤0.005, S≤0.003, the balance is Fe and unavoidable impurities.

[0075]Smelting 40kg recast ingots in a vacuum induction furnace;

[0076] The ingot is homogenized and then heated for forging to obtain a 80×80×550 mm forging billet with a total forging ratio of ≥6.

[0077] Normalizing the forging billet: normalizing temperature (T 1 ) is controlled at 880°C, and the holding time (t 1 ) for 2 hours, air-cooled to 675°C, then isothermal for 5 hours, and then air-cooled to room temperature; in the normalizing heating process, two-stage heating is adopted, namely "room temperature-700°C, 700-880°C", of which "room temperature-700°C stage" adopts Rapid heating, the heating rate is about 350°C / h; "700-880°C" adopts slow heating, and the ...

Embodiment 2

[0082] In a specific embodiment of the present invention, the composition of corrosion-resistant, high-strength and low-alloy steel for deep-sea oil production equipment is: C 0.34, Mn 0.96, Si 0.29, Cr 1.15, Mo 0.26, Ni 0.22, V 0.050, Cu 0.015 , P≤0.005, S≤0.003, the balance is Fe and unavoidable impurities.

[0083] Smelting 40kg recast ingots in a vacuum induction furnace;

[0084] The ingot is homogenized and then heated for forging to obtain a 80×80×550 mm forging billet with a total forging ratio of ≥6.

[0085] Normalizing the forging billet: normalizing temperature (T 1 ) is controlled at 920°C, and the holding time (t 1 ) for 2 hours, air-cooled to 690°C, then isothermal for 5 hours, and then air-cooled to room temperature; in the normalizing heating process, two-stage heating is adopted, namely "room temperature-700°C, 700-920°C", of which "room temperature-700°C stage" adopts Rapid heating, the heating rate is about 350°C / h; "700-920°C" adopts slow heating, and t...

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Abstract

The invention discloses corrosion-resistant high-strength low-alloy steel and a treatment process thereof, and belongs to the technical field of deep sea oil extraction equipment. The problems of low strength and toughness, poor low-temperature impact resistance and poor corrosion resistance of seabed wellhead and oil extraction equipment materials in the prior art are solved. The corrosion-resistant high-strength low alloy steel comprises the following components of, in percentage by mass, 0.33-0.38 of C, 0.90-1.00 of Mn, 0.26-0.35 of Si, 0.95-1.20 of Cr, 0.21-0.30 of Mo, 0.16-0.25 of Ni, 0.04-0.08 of V, 0.010-0.020 of Cu, less than or equal to 0.01 of P, less than or equal to 0.01 of S, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps of smelting raw materials to obtain a cast ingot; carrying out hot working on the cast ingot to obtain a blank; and sequentially carrying out normalizing treatment, quenching treatment and tempering treatment on the blank to obtain the corrosion-resistant high-strength low-alloy steel with a tempered sorbite structure.

Description

technical field [0001] The invention belongs to the technical field of deep-sea oil production equipment, and in particular relates to a corrosion-resistant high-strength low-alloy steel and a preparation method thereof. Background technique [0002] The subsea wellhead and oil production equipment in offshore engineering are important unit equipment for the development of offshore oil and gas fields, and are also key equipment for the subsea oil production system. Due to the harsh working conditions of subsea high pressure, low temperature, seawater and oil gas corrosion, the performance and quality of subsea equipment play a vital role in the safety of oil wells. [0003] Materials for forgings such as blowout preventers, connector housings and wellhead heads of key subsea equipment must meet the requirements of API 6A / 17D, ISO 10423 / 13628, NACE MR01-75 and other standards. Although these standards do not specify the specific composition of forging materials for subsea eq...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/46C22C38/42C21D1/28C21D1/18
CPCC22C38/02C22C38/04C22C38/44C22C38/46C22C38/42C21D1/28C21D1/18C21D2211/008C21D2211/001
Inventor 朱琳张心金段修刚
Owner TIANJIN HEAVY EQUIP ENG RES
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