High-strength hydrogen embrittlement resistant wellbore material containing rare earth microalloy and preparation method thereof

Abstract

The present application relates to a high-strength hydrogen embrittlement resistant wellbore material containing rare earth microalloying and a preparation method thereof. The chemical composition at least includes C, Si, Mn, Cr, Ni, Mo, V, Nb, Ti, Y, B, Ta and Fe. The preparation process includes the following steps: S1: vacuum induction melting + electroslag remelting double smelting of molten steel; S2: after forging breakdown, adopting controlled rolling and controlled cooling process; S3: solid solution treatment: 1100 DEG C heat preservation 1-1.5 h, water cooling; S4: intermediate annealing treatment: 650 DEG C heat preservation 2 h, air cooling; S5: cryogenic treatment: -140 DEG C heat preservation 5-7 h, then heating to room temperature at ≤3 DEG C / min; S6: aging treatment: 480-500 DEG C heat preservation 3-4 h, air cooling; S7: ultrasonic shot peening strengthening treatment, introducing residual compressive stress layer with a depth of 0.5-1.0 mm. The hydrogen diffusion coefficient of the present application is low, the hydrogen-induced cracking sensitivity is significantly reduced, the service life can reach 30 years, and the long-term service requirement of 90 MPa hydrogen storage well is met.

Description

Technical Field

[0001] This invention relates to the field of high-pressure hydrogen storage equipment materials technology, specifically to high-strength, hydrogen-embrittlement-resistant wellbore materials containing rare earth microalloying and their preparation methods. Background Technology

[0002] Existing underground hydrogen storage wellbore materials are prone to hydrogen-induced cracking under 90 MPa high-pressure hydrogen environments, and traditional materials such as 4130 steel and 316L stainless steel lack sufficient resistance to hydrogen embrittlement. Although some patents involve rare earth microalloying or cryogenic treatment, they suffer from problems such as imperfect composition systems, unreasonable process combinations, and poor long-term stability. For example, patent CN119956239A discloses a Cr-Al-Mo-Nb resistant stainless steel, which does not contain the Y, B, and Ta combination; patent CN116970775A discloses a method for manufacturing hydrogen embrittlement resistant components for hydrogen energy equipment; and CN118028701B discloses a hydrogen embrittlement resistant austenitic stainless steel and its preparation method, which uses Y and Nb composite microalloying to form irreversible hydrogen traps at the inner interface of the hydrogen embrittlement resistant austenitic stainless steel. The underground hydrogen storage well casings produced by the corresponding material combinations and production processes failed to solve the hydrogen embrittlement problem under the 90MPa high-pressure hydrogen environment. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength, hydrogen-embrittlement-resistant wellbore material containing rare earth microalloying and its preparation method, so as to solve the problem that existing underground hydrogen storage wellbores cannot solve the hydrogen embrittlement problem under a high-pressure hydrogen environment of 90 MPa.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] The high-strength, hydrogen-embrittlement-resistant wellbore material containing rare earth microalloying has a chemical composition that includes at least C, Si, Mn, Cr, Ni, Mo, V, Nb, Ti, Y, B, Ta, and Fe.

[0006] Preferably, its chemical composition, calculated by mass percentage, meets the following requirements: C: 0.065-0.075%, Si: 0.15-0.35%, Mn: 0.30-0.60%, Cr: 12.5-13.5%, Ni: 8.5-9.5%, Mo: 2.3-2.7%, V: 0.12-0.18%, Nb: 0.03-0.04%, Ti: 0.015-0.025%, Y: 0.035-0.045%, B: 0.0015-0.0025%, Ta: 0.05-0.15%, P≤0.010%, S≤0.003%, with the balance being Fe and unavoidable impurities.

[0007] Preferably, its microstructure is ultrafine austenite with a grain size ≥11 and nanoscale (Nb, V) (C, N) precipitates distributed at the grain boundaries, with a size of 10-30 nm.

[0008] A method for preparing a high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying includes the following steps:

[0009] S1: The steel liquid is smelted by vacuum induction melting and electroslag remelting in a dual process, and the oxygen content is controlled to be ≤10ppm.

[0010] S2: After forging, a controlled rolling and cooling process is adopted, with a final rolling temperature of 860-880℃;

[0011] S3: Solution treatment: Hold at 1080-1100℃ for 1-1.5 hours, then water cool;

[0012] S4: Intermediate annealing treatment: Hold at 650℃ for 2 hours, then air cool;

[0013] S5: Cryogenic treatment: Hold at -140℃ for 5-7 hours, then heat to room temperature at ≤3℃ / min;

[0014] S6: Aging treatment: Hold at 480-500℃ for 3-4 hours, then air cool;

[0015] S7: Ultrasonic shot peening treatment to introduce a residual compressive stress layer with a depth of 0.5-1.0 mm.

[0016] Preferably, in step S2, the controlled rolling and cooling process includes: roughing temperature of 1050-1100℃, finishing temperature of 900-950℃, final rolling temperature of 860-880℃, and cooling to room temperature at 15-20℃ / s after rolling.

[0017] Preferably, in step S5, the cryogenic treatment is carried out in liquid nitrogen or a cryogenic chamber, with a holding time of 5-7 hours and a heating rate of ≤3 ℃ / min.

[0018] Preferably, in step S7, the process parameters for ultrasonic shot peening are: shot peening intensity 0.3-0.5 mmA, coverage 200-300%, and shot peening time 10-15 min.

[0019] Compared with existing technologies, the present invention can produce at least one of the following beneficial effects: the synergistic effect of rare earth elements Y, B, and Ta significantly improves the resistance to hydrogen embrittlement; the present invention has excellent yield strength and impact toughness; the present invention has a low hydrogen diffusion coefficient and significantly reduces the sensitivity to hydrogen-induced cracking; the present invention has an innovative preparation process, and the composite process of cryogenic treatment + intermediate annealing + aging treatment obtains an ultrafine crystalline structure; the present invention has a service life of up to 30 years, meeting the long-term service requirements of 90 MPa hydrogen storage wells. Attached Figure Description

[0020] Figure 1 This is a metallographic photograph of the material of the present invention.

[0022] Figure 2 This is the hydrogen embrittlement sensitivity test curve (SSRT curve).

[0023] Figure 3 This is the hydrogen diffusion coefficient test curve. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] The following examples are illustrated:

[0026] High-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying comprises the following chemical components, and meets the corresponding requirements by mass percentage:

[0027]

[0028] The materials with the chemical composition of Examples 1 to 5 were prepared by the following process:

[0029] S1: The steel liquid is smelted by vacuum induction melting and electroslag remelting in a dual process, and the oxygen content is controlled to be ≤10ppm.

[0030] S2: After forging, a controlled rolling and cooling process is adopted, with a final rolling temperature of 860-880℃;

[0031] S3: Solution treatment: Hold at 1100℃ for 1-1.5 hours, then water cool;

[0032] S4: Intermediate annealing treatment: Hold at 650℃ for 2 hours, then air cool;

[0033] S5: Cryogenic treatment: Hold at -140℃ for 5-7 hours, then heat to room temperature at ≤3℃ / min;

[0034] S6: Aging treatment: Hold at 480-500℃ for 3-4 hours, then air cool;

[0035] S7: Ultrasonic shot peening treatment to introduce a residual compressive stress layer with a depth of 0.5-1.0 mm.

[0036] In step S2, the controlled rolling and cooling process includes: rough rolling temperature of 1050-1100℃, finishing rolling temperature of 900-950℃, final rolling temperature of 860-880℃, and cooling to room temperature at 15-20℃ / s after rolling.

[0037] In step S5, the cryogenic treatment is carried out in liquid nitrogen or a cryogenic chamber, with a holding time of 5-7 hours and a heating rate of ≤3 ℃ / min.

[0038] In step S7, the process parameters for ultrasonic shot peening are: shot peening intensity 0.3-0.5 mmA, coverage 200-300%, and shot peening time 10-15 min.

[0039] Tests showed that Examples 1 to 5 all achieved a yield strength ≥ 870 MPa, room temperature impact toughness ≥ 100 J, and -40 ℃ impact toughness ≥ 80 J; the hydrogen embrittlement resistance coefficient KIH / KIC in a 90 MPa hydrogen environment was ≥ 0.95, and the hydrogen diffusion coefficient was ≤ 8×10-11 m2 / s; when applied in a 90 MPa underground hydrogen storage well, the characteristics are that the operating temperature can reach -40 ℃ to 85 ℃, and the design life is not less than 30 years. When applied in a 90 MPa underground hydrogen storage well, the well safety factor is ≥ 2.5, and the hydrogen leakage rate is less than 1×10-6 Pa·m3 / s.

[0040] Comparative experimental data: Compared with conventional 316L stainless steel, the yield strength of Examples 1 to 5 of the present invention is increased by at least 320%, the KIH / KIC ratio is increased by at least 72%, and the hydrogen diffusion coefficient is reduced by at least 68%.

[0041] The various illustrative embodiments mentioned in this specification refer to specific structures or methods described in connection with those embodiments, which are included in at least one embodiment of the general description in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a structure is described in connection with any embodiment, it is intended to suggest that implementing such a structure or method in conjunction with other embodiments falls within the scope of this invention.

Claims

1. A high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying, characterized in that: Its chemical composition includes at least C, Si, Mn, Cr, Ni, Mo, V, Nb, Ti, Y, B, Ta, and Fe.

2. The high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying according to claim 1, characterized in that: Its chemical composition, calculated by mass percentage, meets the following requirements: C: 0.065-0.075%, Si: 0.15-0.35%, Mn: 0.30-0.60%, Cr: 12.5-13.5%, Ni: 8.5-9.5%, Mo: 2.3-2.7%, V: 0.12-0.18%, Nb: 0.03-0.04%, Ti: 0.015-0.025%, Y: 0.035-0.045%, B: 0.0015-0.0025%, Ta: 0.05-0.15%, P≤0.010%, S≤0.003%, with the balance being Fe and unavoidable impurities.

3. The high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying according to claim 1, characterized in that: Its microstructure is ultrafine austenite with a grain size ≥11 and nanoscale (Nb, V) (C, N) precipitates distributed at the grain boundaries, with a size of 10-30 nm.

4. The method for preparing the high-strength, hydrogen-embrittlement-resistant wellbore material containing rare earth microalloying according to any one of claims 1 to 3, characterized in that: Includes the following steps: S1: The steel liquid is smelted by vacuum induction melting and electroslag remelting in a dual process, and the oxygen content is controlled to be ≤10ppm. S2: After forging, a controlled rolling and cooling process is adopted, with a final rolling temperature of 860-880℃; S3: Solution treatment: Hold at 1100℃ for 1-1.5 hours, then water-cooled; S4: Intermediate annealing treatment: Hold at 650℃ for 2 hours, then air cool; S5: Cryogenic treatment: Hold at -140℃ for 5-7 hours, then heat to room temperature at ≤3℃ / min; S6: Aging treatment: Hold at 480-500℃ for 3-4 hours, then air cool; S7: Ultrasonic shot peening treatment to introduce a residual compressive stress layer with a depth of 0.5-1.0 mm.

5. The method for preparing the high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying according to claim 4, characterized in that: In step S2, the controlled rolling and cooling process includes: rough rolling temperature of 1050-1100℃, finishing rolling temperature of 900-950℃, final rolling temperature of 860-880℃, and cooling to room temperature at 15-20℃ / s after rolling.

6. The method for preparing the high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying according to claim 4, characterized in that: In step S5, the cryogenic treatment is carried out in liquid nitrogen or a cryogenic chamber, with a holding time of 5-7 hours and a heating rate of ≤3℃ / min.

7. The method for preparing the high-strength, hydrogen-embrittlement-resistant wellbore material containing rare-earth microalloying according to claim 4, characterized in that: In step S7, the process parameters for ultrasonic shot peening are: shot peening intensity 0.3-0.5 mmA, coverage 200-300%, and shot peening time 10-15 min.

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