Ultrahigh-strength high-plasticity nickel-based corrosion-resistant alloy, bar and preparation method of ultrahigh-strength high-plasticity nickel-based corrosion-resistant alloy

Abstract

The alloy bar comprises the following components in percentage by weight: 50.0-57.0% of Ni, 20.0-22.0% of Cr, 6.0-7.5% of Nb, 2.0-3.0% of Mo, 0.8-1.2% of Ti, 0.4-0.9% of Al, less than or equal to 0.03% of C, less than or equal to 0.1% of V, less than or equal to 0.003% of B, less than or equal to 0.1% of Zr, less than or equal to 0.03% of Mg and the balance of Fe and impurities existing in common metal smelting, and the content of the impurities is controlled in percentage by mass as follows: less than or equal to 0.030% of P, less than or equal to 0.035% of S, less than or equal to 0.005% of O and less than or equal to 0.012% of N. The nickel-based corrosion-resistant alloy bar is prepared through the steps of vacuum induction melting (VIM) and electroslag remelting (ESR) duplex smelting, homogenizing diffusion annealing, forging, heat treatment and the like. The content and distribution of strengthening phases in the alloy are controlled through multiple means such as component regulation and control, thermal deformation and thermal treatment, it is guaranteed that the yield strength of a bar can reach 1,300 MPa or above, the tensile strength can reach 1,450 MPa or above, the elongation can reach 18% or above, the percentage reduction of area can reach 40% or above, and technical improvement of ultrahigh strength and high plasticity of the nickel-based corrosion-resistant alloy is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials and processing, and particularly to a nickel-based corrosion-resistant alloy with ultra-high strength and high plasticity, a bar, and a preparation method thereof. Background Art

[0002] In recent years, China's dependence on foreign oil and gas resources has been increasing year by year. It has become an urgent task to build an oil and gas security guarantee system under the condition of all-round opening up. Vigorously developing the exploitation of deep and unconventional oil and gas resources represented by deep water (1500 - 3000 m) and deep earth (>10000 m) has become an inevitable strategic choice for China's oil and gas industry. The rotary steerable system is a bright pearl in the directional drilling technology and an important technical means to achieve the low-cost and high-efficiency development of oil and gas resources. Among them, a certain type of rotary steerable instrument is applied to the final landing section of the directional well operation. The drilling depth is large, and the loads received are complex, and the requirements for the material strength index are very harsh.

[0003] For traditional age-hardening precipitation-strengthened nickel-based corrosion-resistant alloys, according to the latest technical specification of API 6ACRA, their yield strengths are roughly distributed in grades of 758 - 965 MPa (N09925), 1034 - 1207 MPa (N07718), 1103 - 1241 MPa (N09946), and the highest tensile strength reaches 1241 MPa (N09946). Under high-strength conditions, the elongation rate of the alloy is 18%, and the reduction of area is only 25% (N09946), making it difficult to meet the requirements of the ultra-high strength and high plasticity of nickel-based corrosion-resistant alloys during offshore oil and gas drilling and production.

[0004] At present, generally, the strength grade of nickel-based corrosion-resistant alloys is improved by adjusting the alloy composition or adopting cold deformation methods. However, the addition of a large number of strengthening elements not only aggravates the element segregation tendency during the melting and solidification process but also increases the deformation resistance, resulting in difficulties in the forming of bars; while under the cold deformation method, the bar specifications of the alloy are small, making it difficult to meet the size limitations of the rotary steerable instrument.

[0005] Therefore, those skilled in the art are committed to developing a nickel-based corrosion-resistant alloy, a bar, and a preparation method thereof that can effectively solve the problem of ultra-high strength and high plasticity that cannot be achieved by existing precipitation-strengthened nickel-based corrosion-resistant alloys. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a nickel-based corrosion-resistant alloy, a bar, and a preparation method thereof that can effectively solve the problem of ultra-high strength and high plasticity that cannot be achieved by existing precipitation-strengthened nickel-based corrosion-resistant alloys.

[0007] To achieve the aforementioned invention object, the present invention provides a nickel-based corrosion-resistant alloy with ultra-high strength and high plasticity. By weight percentage, the alloy comprises 50.0 - 57.0% Ni, 20.0 - 22.0% Cr, 6.0 - 7.5% Nb, 2.0 - 3.0% Mo, 0.8 - 1.2% Ti, 0.4 - 0.9% Al, and trace elements C ≤ 0.03%, V ≤ 0.1%, B ≤ 0.003%, Zr ≤ 0.1%, and Mg ≤ 0.03%, with the balance being Fe and unavoidable impurities.

[0008] Further, by weight percentage, it comprises 55.9 - 56.1% Ni, 20.52 - 20.98% Cr, 6.18 - 7.32% Nb, 2.80 - 2.96% Mo, 0.93 - 1.07% Ti, 0.48 - 0.86% Al, and trace elements 0.019 - 0.023% C, 0.075 - 0.096% V, 0.0022 - 0.003% B, 0.028 - 0.054% Zr, and 0.027 - 0.031% Mg, with unavoidable impurities ≤ 0.082%, and the balance being Fe.

[0009] Further, by weight percentage, the impurities are P ≤ 0.030%, S ≤ 0.035%, O ≤ 0.005%, and N ≤ 0.012%.

[0010] The present invention also provides a manufacturing method of the above nickel-based corrosion-resistant alloy with ultra-high strength and high plasticity, comprising the following steps:

[0011] S1. Material preparation: Weigh raw materials according to the alloy element ingredient table, where V, B, and Mg are weighed in the form of master alloys Fe-V, Fe-B, and Mg-Ni respectively, and other elements are weighed in the form of single substances;

[0012] S2. Vacuum induction melting: Use a vacuum induction melting furnace for melting. First, melt Ni, Cr, Fe, Nb, and Mo. After melting, first add C, Ti, and Al. After melting, then add Fe-V, Fe-B, and Zr. After melting, finally add Mg-Ni;

[0013] S3. Electroslag remelting: Grind the surface of the vacuum ingot, select a slag suitable for this alloy for electroslag remelting to obtain a nickel-based alloy ingot;

[0014] S4. Annealing: Anneal the nickel-based alloy ingot to obtain the nickel-based corrosion-resistant alloy with ultra-high strength and high plasticity.

[0015] Further, in step S2, the vacuum melting is carried out with high temperature of 1500 - 1550 °C and high vacuum of 1 - 3 Pa for enhanced refining, and fully stirred and shaken to ensure the uniformity of composition.

[0016] Further, in step S3, the slag material is CaO-Al 2 O 3 -MgO-CaF 2 quaternary slag system, where the weight percentages of each component are 55-75% CaO, 10-20% Al 2 O 3 , 0.5-5% MgO and 10-20% CaF 2 , effectively controlling the burning loss of Ti and Al and the problem of double skin on the surface of the electroslag ingot.

[0017] Further, in step S4, the annealing is carried out by a two-stage homogenization diffusion annealing process. In the first stage, it is kept at 1160 °C to eliminate brittle phases, and in the second stage, it is kept at 1190 °C to eliminate elemental segregation.

[0018] The present invention also provides a super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar, which is made of the above-mentioned super-high-strength and high-plasticity nickel-based corrosion-resistant alloy.

[0019] The present invention also provides a preparation method of the above-mentioned super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar, including the following steps:

[0020] S5. Forging and forming: Forging the super-high-strength and high-plasticity nickel-based corrosion-resistant alloy into a forged bar;

[0021] S6. Heat treatment: Heat-treating the forged bar by a solution aging treatment process to obtain a super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar.

[0022] Further, in step S5, it is kept at a temperature range of 1100-1170 °C for 90 min for cogging and drawing out type of bloom forging, with a deformation amount ≥ 30%; then multi-pass straight drawing is carried out in the temperature range of 1050-1150 °C, and finally it is rolled round to obtain a forged bar.

[0023] Further, in step S6, the solution aging treatment process is: solution at 1010-1080 °C for 0.5-2 h and then water-quenched to room temperature, kept at 700-780 °C for 8-10 h and then furnace-cooled to 600-650 °C and kept for 8-12 h for double-stage aging and then air-cooled to obtain a super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar.

[0024] The main functions of various elements in the super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar of the present invention:

[0025] Nickel: The matrix element, a high nickel content can ensure stress corrosion resistance.

[0026] Chromium: Solid solution strengthening; in high-temperature environments, it forms a dense oxide film to improve oxidation resistance; in corrosive environments, it forms a dense passivation film to improve corrosion resistance and pitting resistance in strongly oxidizing acidic environments.

[0027] Iron: Reduces the tendency of carburization at high temperatures and lowers the alloy cost.

[0028] Carbon: Deoxidizes during vacuum smelting; forms highly stable carbides such as titanium carbide and niobium carbide, which hinder grain growth at high temperatures, pin the grain boundaries, and increase strength; however, when the carbon content is too high, the carbides will cause chromium-depleted regions and reduce corrosion resistance, so the carbon content needs to be controlled within a reasonable range.

[0029] Aluminum and titanium: During aging, Ni 3 Al, Ni 3 Ti, Ni 3 Dispersed strengthening phases such as (Ti, Al) are distributed to increase strength; deoxidize and denitrify to improve the purity of the alloy; fix carbon to improve intergranular corrosion resistance.

[0030] Niobium: During aging, dispersed Ni 3 Nb is precipitated to increase strength; adding a higher content of niobium forms Ni 3 (Ti, Al, Nb) to enhance the strengthening effect; fix carbon to improve intergranular corrosion resistance.

[0031] Vanadium: Forms fine and dispersed VC and VN, which become the nucleation cores during solidification, dynamic recrystallization, recrystallization, etc., reduce segregation, and refine the microstructure; during high-temperature heating, the fine and dispersed VC and VN pin the grain boundaries and hinder grain growth; forms vanadium carbide, consumes carbon and nitrogen in the alloy, reduces Ti(C, N) and Nb(C, N), and improves intergranular corrosion resistance.

[0032] Boron, zirconium, and magnesium: Purify the grain boundaries; improve high-temperature mechanical properties; reduce low-melting-point phases and improve processability.

[0033] Compared with the prior art, the advantages of the present invention include:

[0034] (1) The alloy of the present invention adds a large amount of strengthening elements Nb, Ti, and Al to increase the content of strengthening phases, which can effectively improve the strength of the alloy. At the same time, beneficial trace elements such as V, B, Zr, and Mg are added to pin and purify the grain boundaries to ensure the plasticity of the alloy.

[0035] (2) During the smelting of the alloy of the present invention, by adding intermediate alloys such as Fe-B, Fe-V, and Mg-Ni, the burn-off of beneficial trace elements V, B, and Mg in the alloy can be effectively controlled.

[0036] (3) The ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar of the present invention controls the content and distribution of strengthening phases in the alloy through multiple means such as composition regulation, hot deformation, and heat treatment. The yield strength can reach above 1300 MPa, the tensile strength can reach above 1450 MPa, the elongation can reach above 18%, and the reduction of area can reach 40% and above, meeting the index requirements for ultra-high strength and high plasticity of nickel-based corrosion-resistant alloys during offshore oil and gas drilling and production, and achieving the technical improvement of ultra-high strength and high plasticity of nickel-based corrosion-resistant alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flowchart of the preparation method of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy of the present invention;

[0038] Figure 2 It is a flowchart of the preparation method of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar of the present invention;

[0039] Figure 3 It is the macrostructure of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar in Example 1 of the present invention;

[0040] Figure 4 It is the microstructure morphology of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar in Example 1 of the present invention;

[0041] Figure 5 It is the tensile stress-strain curve of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To enable those skilled in the art to understand the features and effects of the present application, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art for the present application. In case of conflict, the definition in this specification shall prevail.

[0043] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present application in any way, that is, the content of the present application can be implemented without being limited by any specific theory or mechanism.

[0044] In this article, "the present application" is the same as "the present invention" and "the present disclosure".

[0045] In this article, "a", "an", "one", or similar expressions are used to describe the components and technical features of the present application. Such descriptions are merely for convenience of expression and give a general meaning to the scope of the present application. Therefore, such descriptions should be understood to include one or at least one, and the singular also includes the plural, unless clearly referring to something else.

[0046] In this text, "or a combination thereof" means "or any combination thereof", and "any", "any one kind", "any one" means "any arbitrary one", "any arbitrary kind", "any arbitrary one".

[0047] In this text, terms such as "comprising", "including", "having", "containing" or any other similar terms are all open-ended transitional phrases, which are intended to cover non-exclusive inclusions. For example, a composition or an article thereof containing multiple elements is not limited to only the elements listed herein, but may also include other elements that are not explicitly listed but are usually inherent in the composition or the article thereof. In addition, unless otherwise clearly stated to the contrary, the term "or" means an inclusive "or", rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), A and B are both true (or exist). Furthermore, in this text, the interpretations of the terms "comprising", "including", "having", "containing" should be regarded as having specifically disclosed and simultaneously covered closed transitional phrases such as "consisting of", "composed of", "the balance is", etc., as well as connecting words such as "substantially consisting of", "mainly consisting of", "mainly composed of", "basically containing", "basically consisting of", "basically composed of", "essentially containing", etc.

[0048] In this text, all features or conditions defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or a percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions), especially integer numerical values. For example, a range description such as "1.0 to 8.0" or "between 1.0 and 8.0" or "between 1.0 and 8.0" should be regarded as having specifically disclosed all sub-ranges such as 1.0 to 8.0, 1.0 to 7.0, 2.0 to 8.0, 2.0 to 6.0, 3.0 to 6.0, 4.0 to 8.0, 3.0 to 8.0, etc., and should be regarded as covering the endpoint values, especially sub-ranges defined by integer numerical values, and should be regarded as having specifically disclosed individual numerical values within the range such as 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, etc. Unless otherwise specified, the foregoing interpretation method applies to all contents of this application throughout the text, regardless of the scope being broad or narrow.

[0049] If a quantity, concentration, or other numerical value or parameter is expressed as a range, a preferred range (or a better range), or a series of upper and lower limits, it should be understood that all ranges formed by any pair of the upper limit or preferred value (or better value) of the range and the lower limit or preferred value (or better value) of the range have been specifically disclosed herein, regardless of whether these ranges are separately disclosed. In addition, when a range of numerical values is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0050] In this document, on the premise that the purpose of the invention can be achieved, a numerical value should be understood to have the precision of the significant digits of that numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0051] It should be understood that the features disclosed in each embodiment herein can be arbitrarily combined to form the technical solutions of this application, as long as there is no contradiction in the combination of these features.

[0052] The following will describe this application in specific implementation manners and examples. It should be understood that these specific implementation manners and examples are merely illustrative and are not intended to limit the scope and use of this application.

[0053] Unless otherwise specified, the methods, reagents, and conditions used in the preparation examples, comparative examples, and examples below are conventional methods, reagents, and conditions in this field.

[0054] The following illustrates the technical solutions of the present invention through three examples and two comparative examples.

[0055] Example 1

[0056] A super-high-strength and high-plasticity nickel-based corrosion-resistant alloy bar, as Figure 1 , Figure 2 shown, is prepared as follows:

[0057] S1. Material preparation: Weigh the raw materials according to the alloy element ingredient table. Among them, V, B, and Mg are weighed in the form of master alloys Fe-V, Fe-B, and Mg-Ni respectively, and other elements are weighed in the form of simple substances. The weight percentages of its chemical components are shown in Table 1.

[0058] S2. Vacuum induction melting: Use a vacuum induction melting furnace for melting. First, melt Ni, Cr, Fe, Nb, and Mo. After melting, first add C, Ti, and Al. After melting, then add Fe-V, Fe-B, and Zr. After melting, finally add Mg-Ni; Vacuum melting uses a high temperature of 1500~1550°C and a high vacuum of 1~3 Pa for enhanced refining, and fully uses electromagnetic and / or mechanical means for stirring and oscillation (electromagnetic and / or mechanical means for stirring and oscillation are common technical means in the metallurgical field and will not be elaborated here) to ensure the uniformity of composition.

[0059] S3. Electro-slag remelting: Grind the surface of the vacuum ingot, select the slag material suitable for this alloy for electro-slag remelting to obtain a nickel-based alloy ingot; in this step, the slag material is CaO-Al 2 O 3 -MgO-CaF 2 quaternary slag system, where the weight percentages of each component are 55-75% CaO, 10-20% Al 2 O 3 , 0.5-5% MgO and 10-20% CaF 2 , effectively control the burning loss of Ti and Al and the problem of double skin on the surface of the electro-slag ingot. Drill chip materials at the top and bottom of the cooled electro-slag ingot for chemical composition analysis to ensure that the alloy composition is uniformly controllable.

[0060] S4. Annealing: Anneal the nickel-based alloy ingot to obtain the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy. Use a two-stage homogenization and diffusion annealing process for the annealing. Insulate at 1160 °C in the first stage to eliminate brittle phases, and insulate at 1190 °C in the second stage to eliminate elemental segregation.

[0061] S5. Forging and forming: Forge the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy into a forged bar. Insulate for 90 min in the temperature range of 1100-1170 °C for cogging and drawing out type blank forging, with a deformation amount ≥ 30%; then perform multi-pass straight drawing in the temperature range of 1050-1150 °C, and finally roll round to obtain a forged bar.

[0062] S6. Heat treatment: Heat-treat the forged bar using a solution aging treatment process to obtain an ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar. The solution aging treatment process is: solution at 1010-1080 °C for 0.5-2 h and then water quench to room temperature, insulate at 700-780 °C for 8-10 h and then furnace cool to 600-650 °C, insulate for 8-12 h for double-stage aging and then air cool to obtain an ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar.

[0063] Example 2

[0064] Except that the ingredient list of the raw materials is different from that of Example 1, the remaining steps are the same, and the weight percentages of its chemical components are shown in Table 1.

[0065] Example 3

[0066] Except that the ingredient list of the raw materials is different from that of Example 1, the remaining steps are the same, and the weight percentages of its chemical components are shown in Table 1.

[0067] Example 4

[0068] Except for the ingredient list of raw materials being different from that of Example 1, the remaining steps are the same, and the weight percentages of its chemical components are shown in Table 1.

[0069] Example 5

[0070] Except for the ingredient list of raw materials being different from that of Example 1, the remaining steps are the same, and the weight percentages of its chemical components are shown in Table 1.

[0071] Comparative Example 1

[0072] The raw material formula of this comparative example is shown in Table 1. The preparation method steps of Comparative Example 1 are obtained by omitting step S6 from Example 1.

[0073] Comparative Example 2

[0074] Zr and Mg are removed from the raw material formula of this comparative example. The raw material formula of this comparative example is shown in Table 1, and its preparation method is the same as that of the example.

[0075] Table 1 Chemical composition table of ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bars for different examples (wt.%)

[0076] Element Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Ni 56.10 56.10 55.90 50.00 57.00 56.10 52.10 Cr 20.98 20.98 20.52 22.00 20.00 20.98 19.07 Nb 6.28 6.18 7.32 6.00 7.50 6.18 5.03 Mo 2.85 2.96 2.80 2.00 3.00 2.96 2.92 Ti 1.07 0.96 0.93 1.20 0.80 0.96 0.95 Al 0.86 0.72 0.48 0.40 0.90 0.72 0.47 C 0.021 0.019 0.023 0.019 0.020 0.019 0.020 V 0.095 0.096 0.075 0.080 0.100 0.095 0.047 B 0.0028 0.0022 0.0030 0.0028 0.0030 0.0028 0.0011 Zr 0.054 0.046 0.028 0.062 0.100 0.054 / Mg 0.027 0.028 0.031 0.028 0.030 0.027 / P 0.026 0.024 0.019 0.030 0.023 0.026 0.006 S 0.032 0.031 0.023 0.035 0.030 0.032 0.001 O 0.0034 0.0044 0.0032 0.0041 0.0035 0.0034 / N 0.0120 0.0100 0.0087 0.0120 0.0091 0.0120 / Fe The balance The balance The balance The balance The balance The balance The balance

[0077] To further illustrate the unexpected positive technical effects achieved by the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar products involved in each embodiment of the present invention, the mechanical properties of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bars made from Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 2. The mechanical property test method is based on the tensile test standard ASTM A370 formulated by the American Society for Testing and Materials Standards and Specifications Committee; the macrostructure of Example 1 is processed according to the macro test standard ASTM A604 as Figure 3 shown, the microstructure of Example 1 is according to ASTM E2 as Figure 4 shown, and the tensile stress-strain curve is as Figure 5 shown.

[0078] Table 2 Mechanical properties of ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bars for different examples

[0079] <![CDATA[R m / MPa]]> <![CDATA[R p0.2 / MPa]]> A / % Z / % Example 1 1454 1321 18.5 41.0 Example 2 1510 1380 18.5 40.0 Example 3 1560 1410 22.0 40.0 Example 4 1540 1390 21.0 40.0 Example 5 1520 1400 20.0 40.0 Comparative Example 1 1357 1133 25.0 45.0 Comparative Example 2 1310 1150 27.5 51.0

[0080] From Table 2 and Figure 3 it can be seen that the tensile properties of Examples 1 to 5 are better than those of the comparative examples, and the yield strength can reach above 1300 MPa, the tensile strength can reach above 1450 MPa, the elongation rate can reach above 18%, and the reduction of area can reach 40% and above, meeting the index requirements for the ultra-high strength and high plasticity of nickel-based corrosion-resistant alloys during offshore oil and gas drilling and production, and realizing the technical improvement of the ultra-high strength and high plasticity of nickel-based corrosion-resistant alloys.

[0081] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can also be made. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An ultra-high strength and high plasticity nickel-based corrosion-resistant alloy, characterized in that: The alloy comprises, by weight percentage, 50.0-57.0% Ni, 20.0-22.0% Cr, 6.0-7.5% Nb, 2.0-3.0% Mo, 0.8-1.2% Ti, 0.4-0.9% Al and trace elements C≤0.03%, V≤0.1%, B≤0.003%, Zr≤0.1% and Mg≤0.03%, and the balance is Fe and unavoidable impurities.

2. The ultra-high strength and high plasticity nickel-based corrosion-resistant alloy according to claim 1, characterized in that: By weight percentage, it includes 55.9~56.1% Ni, 20.52~20.98% Cr, 6.18~7.32% Nb, 2.80~2.96% Mo, 0.93~1.07% Ti, 0.48~0.86% Al and trace elements 0.019~0.023% C, 0.075~0.096% V, 0.0022~0.003% B, 0.028~0.054% Zr and 0.027~0.031% Mg, unavoidable impurities ≤0.082%, and the balance is Fe.

3. A method for manufacturing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy according to claim 1 or 2, characterized in that: The following steps are involved: S1. Material preparation: weigh the raw materials according to the alloy element ingredient list, wherein V, B and Mg are weighed in the form of master alloys Fe-V, Fe-B and Mg-Ni, respectively, and other elements are weighed in the form of single substances; S2. Vacuum induction melting: A vacuum induction melting furnace is used for melting. Ni, Cr, Fe, Nb and Mo are first melted. After melting, C, Ti and Al are first added. After melting, Fe-V, Fe-B and Zr are added. After melting, Mg-Ni is finally added. S3. Electroslag remelting: The surface of the vacuum ingot is sanded, and a slag suitable for the alloy is selected for electroslag remelting to obtain a nickel-based alloy ingot; S4. Annealing: Annealing the nickel-based alloy ingot to obtain the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy.

4. The method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy according to claim 3, characterized in that: In step S2, vacuum melting is performed by means of high temperature 1500-1550°C and high vacuum 1-3Pa to strengthen refining, and sufficient stirring and shaking are performed.

5. The method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy according to claim 3, characterized in that: In step S3, the slag material is a quaternary slag system of CaO-Al2O3-MgO-CaF2, wherein the weight percentage of each component is 55-75% CaO, 10-20% Al2O3, 0.5-5% MgO and 10-20% CaF2.

6. The method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy according to claim 3, characterized in that: In step S4, the annealing is performed using a two-stage homogenization diffusion annealing process, with the temperature being kept at 1160° C. in the first stage and at 1190° C. in the second stage.

7. An ultra-high strength and high plasticity nickel-based corrosion-resistant alloy bar, characterized in that: Made of the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy described in claim 1 or 2.

8. A method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy rod according to claim 7, characterized in that: The following steps are involved: S5. Forging: Forging the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy into a forged rod; S6. Heat treatment: The forged rod is heat treated by a solid solution aging treatment process to obtain an ultra-high strength and high plasticity nickel-based corrosion-resistant alloy rod.

9. The method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy rod according to claim 8, characterized in that: In step S5, the billet is forged by upsetting and drawing in a temperature range of 1100-1170°C for 90 minutes, with a deformation of ≥30%; then, straight drawing is performed in a temperature range of 1050-1150°C for multiple times, and finally, the forged rod is rounded.

10. The method for preparing the ultra-high strength and high plasticity nickel-based corrosion-resistant alloy rod according to claim 8, characterized in that: In step S6, the solution aging treatment process is: solution treatment at 1010-1080°C for 0.5-2h, followed by water quenching to room temperature, heat preservation at 700-780°C for 8-10h, furnace cooling to 600-650°C, heat preservation for 8-12h, double-stage aging, and air cooling to obtain ultra-high strength and high plasticity nickel-based corrosion-resistant alloy rods.

Images