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CN-122013035-A - Sulfur-resistant alloy steel for wellhead equipment pressure bearing piece and preparation method thereof

CN122013035ACN 122013035 ACN122013035 ACN 122013035ACN-122013035-A

Abstract

The invention relates to the technical field of alloy steel, in particular to sulfur-resistant alloy steel for a wellhead equipment pressure bearing piece and a preparation method thereof. The sulfur-resistant alloy steel comprises the following raw material components in percentage by mass: 0.28 % to 0.33%, si:0.15 % to 0.35%, mn:0.60 0 to 80 percent, less than or equal to 0.015 percent of P, less than or equal to 0.010 percent of S and less than or equal to Cr:1.20 31.39%, ni:0.025 % to 0.060%, mo:0.50 % to 0.90%, nb:0.020 % to 0.050%, V:0.030 % to 0.10%, ti:0.010 % to 0.10%, al:0.020 0.050%, and the balance of Fe and unavoidable impurities. The tensile strength of the sulfur-resistant alloy steel prepared by the method is more than or equal to 655MPa, the yield strength is more than or equal to 586MPa, and the impact energy at-46 ℃ is more than or equal to 27J; the elongation percentage is more than or equal to 17 percent, the hardness is less than or equal to 22HRC.

Inventors

  • LONG YAN
  • KUANG XIANREN
  • WEI JUNHUI
  • LUO JINHENG
  • ZHAO JIQING
  • HE XIKOU
  • JI NAN
  • WANG JINZHI
  • ZHU WENFENG

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团工程材料研究院有限公司
  • 钢铁研究总院有限公司

Dates

Publication Date
20260512
Application Date
20251225

Claims (10)

  1. 1. The sulfur-resistant alloy steel for the wellhead equipment pressure bearing piece is characterized by comprising the following raw material components in percentage by mass: C：0.28 %~0.33 %、Si：0.15 %~0.35 %、Mn：0.60 %~0.80 %、P≤0.015 %、S≤0.010 %、Cr：1.20 %~1.39 %、Ni：0.025 %~0.060 %、Mo：0.50 %~0.90 %、Nb：0.020 %~0.050 %、V：0.030 %~0.10 %、Ti：0.010 %~0.10 %、Al：0.020 %~0.050 %, The balance of Fe and unavoidable impurities.
  2. 2. The sulfur-resistant alloy steel for wellhead equipment pressure bearing pieces as claimed in claim 1, wherein the raw material components of the sulfur-resistant alloy steel, in mass percent, comprise: C：0.28 %~0.33 %、Si：0.15 %~0.35 %、Mn：0.60 %~0.80 %、P≤0.015 %、S≤0.010 %、Cr：1.30 %~1.39 %、Ni：0.035 %~0.055 %、Mo：0.50 %~0.90 %、Nb：0.020 %~0.050 %、V：0.030 %~0.10 %、Ti：0.010 %~0.10 %、Al：0.020 %~0.050 %, The balance of Fe and unavoidable impurities.
  3. 3. The sulfur-resistant alloy steel for wellhead equipment pressure bearing piece according to claim 1, wherein the sum of mass percentages of Nb, V and Ti is 0.09% -0.25%.
  4. 4. The sulfur-resistant alloy steel for wellhead equipment pressure bearing members according to claim 1, wherein the surface and 1/4 diameter microstructure of the sulfur-resistant alloy steel is a bainitic matrix and a dispersed carbide precipitated phase.
  5. 5. The sulfur-resistant alloy steel for wellhead equipment pressure bearing piece according to claim 1, wherein the tensile strength of the sulfur-resistant alloy steel is equal to or more than 655MPa, the yield strength is equal to or more than 586 MPa, the impact energy at-46 ℃ is equal to or more than 27J, the elongation is equal to or more than 17%, and the hardness is equal to or less than 22 HRC.
  6. 6. The preparation method of the sulfur-resistant alloy steel for the wellhead equipment pressure bearing piece is characterized by comprising the following steps of: smelting a raw material of sulfur-resistant alloy steel for wellhead equipment pressure-bearing pieces according to any one of claims 1 to 5 to obtain cast ingots; carrying out hot working on the cast ingot to obtain a blank; and carrying out normalizing treatment, quenching treatment, primary tempering treatment and secondary tempering treatment on the blank in sequence to obtain the sulfur-resistant alloy steel for the wellhead equipment pressure bearing piece.
  7. 7. The method for producing sulfur-resistant alloy steel for wellhead equipment pressure bearing members as claimed in claim 6, wherein, In the normalizing treatment process, the temperature is raised to 630-660 ℃ along with the furnace, the temperature is kept for 1.5-3 h, the temperature is raised to 900-950 ℃, the temperature is kept for 4-10 h, and the air cooling is carried out to the room temperature.
  8. 8. The method for producing sulfur-resistant alloy steel for wellhead equipment pressure bearing members as claimed in claim 6, wherein, In the quenching treatment process, the temperature is raised to 630-660 ℃ along with the furnace, the temperature is kept for 1.5-3 h, then the temperature is raised to 890-940 ℃, the temperature is kept for 4-7 h, and the water is cooled to room temperature.
  9. 9. The method for producing sulfur-resistant alloy steel for wellhead equipment pressure bearing members as claimed in claim 6, wherein, And (3) performing primary tempering treatment, namely performing heat preservation for 5-10 hours at the temperature of 670-690 ℃, and performing air cooling to room temperature.
  10. 10. The method for producing sulfur-resistant alloy steel for wellhead equipment pressure bearing members as claimed in claim 6, wherein, And (3) tempering for the second time, namely, preserving heat for 5-10 hours at the temperature of 670-690 ℃, and then cooling to room temperature in an air way.

Description

Sulfur-resistant alloy steel for wellhead equipment pressure bearing piece and preparation method thereof Technical Field The invention relates to the technical field of alloy steel, in particular to sulfur-resistant alloy steel for a wellhead equipment pressure bearing piece and a preparation method thereof. Background The development of ultra-deep oil and gas exploration faces the challenges of 'ultra-high pressure and ultra-high temperature' severe working conditions, and the current demands for ultra-high pressure wellhead equipment with higher pressure levels are increasingly urgent. However, the highest strength grade of wellhead equipment materials currently specified by the API Spec 6A standard is only 75 ksi (yield strength > 517 MPa). Considering the light design and manufacturing requirements of extra-high voltage wellhead equipment, the research and development strength reaches the requirement of 85 ksi steel grade, and meanwhile, the forging material which can be applied to the environment with high content of hydrogen sulfide is an engineering technical problem to be solved in the research and development of the extra-high voltage wellhead equipment. The current high-pressure wellhead equipment pressure bearing part material mainly adopts a low-alloy Cr-Mo steel forging piece with better hydrogen sulfide stress corrosion resistance, typical materials are such as standard 4130 steel (Cr 0.80% -1.10% and Mo 0.15% -0.25%), the strength grade is generally 75 ksi, but the hardenability is poor, and the wellhead equipment pressure bearing part material with the strength grade of 85 ksi steel grade is selected by adopting 4130 modified steel (Ni and Mn elements with higher content are added on the basis of 4130 steel) or F22 modified steel (Cr 2.00% -2.50% and Mo 0.87% -1.13% and Ni elements are added) so as to improve the hardenability and enable the strength grade to be improved to be close to 85 ksi steel grade. However, the strength is improved, the environmental fracture sensitivity limit is improved, and the sulfide stress cracking resistance (SSC) is reduced due to the increase of Ni and Mn elements, so that the sulfur resistance of the materials is regulated by a hardness index (the Rockwell hardness of SSC 3-area service carbon steel and alloy steel regulated by GB/T20972.2 standard is less than or equal to 22 HRC), and the SSC laboratory assessment requirement is not regulated. For the forge piece material for the acid environment service wellhead equipment, the strength grade of the material is improved, meanwhile, the excellent SSC resistance is ensured, and meanwhile, the hardness level of the material is strictly controlled, so that the long-term service safety of the high-sulfur environment is ensured. Chinese patent CN 110284062A discloses a large diameter round steel with high strength and high toughness, which adopts higher C content and increases alloy element V, reduces noble metal Mo and Ni content, ensures hardenability and strength, adopts micro alloying element Nb, refines crystal grains of rolled material and final quenched and tempered bar, compensates for the reduction of plastic toughness caused by C, V improvement, but the material is noticed to increase strength level, and the C content is too high, which is easy to cause the reduction of overall corrosion resistance and sulfur resistance. Therefore, in order to improve the service performance of the Cr-Mo steel large-section member in an acidic environment, the bottleneck of process regulation and control of the conventional Cr-Mo steel large-forging (poor hardenability and uneven performance) is broken through, and a pressure-bearing member material with high strength (more than or equal to 85 ksi) and high sulfur resistance (the hardness is less than or equal to 22HRC and is evaluated by SSC test) is developed, so that the cost is prevented from being greatly improved due to the addition of a large amount of alloy elements. Disclosure of Invention In order to solve the problems, the invention provides sulfur-resistant alloy steel for a wellhead equipment pressure bearing piece and a preparation method thereof, and the invention provides the following technical scheme: The invention provides sulfur-resistant alloy steel for a wellhead equipment pressure bearing piece, which comprises the following raw material components in percentage by mass: C：0.28 %~0.33 %、Si：0.15 %~0.35 %、Mn：0.60 %~0.80 %、P≤0.015 %、S≤0.010 %、Cr：1.20 %~1.39 %、Ni：0.025 %~0.060 %、Mo：0.50 %~0.90 %、Nb：0.020 %~0.050 %、V：0.030 %~0.10 %、Ti：0.010 %~0.10 %、Al：0.020 %~0.050 %, The balance of Fe and unavoidable impurities. Further, the raw material components of the sulfur-resistant alloy steel comprise, by mass: C：0.28 %~0.33 %、Si：0.15 %~0.35 %、Mn：0.60 %~0.80 %、P≤0.015 %、S≤0.010 %、Cr：1.30 %~1.39 %、Ni：0.035 %~0.055 %、Mo：0.50 %~0.90 %、Nb：0.020 %~0.050 %、V：0.030 %~0.10 %、Ti：0.010 %~0.10 %、Al：0.020 %~0.050 %, The balance of Fe and unavoidable impurities. Further,