High-performance special alloy plate strip under high-Nb alloying design and preparation method of high-performance special alloy plate strip

Abstract

The invention belongs to the field of metal materials, and relates to a high-performance special alloy plate strip under high Nb alloying design and a preparation method thereof, and the preparation method is carried out according to the following steps: metal particles are proportioned according to set components, and the metal particles comprise the following components in percentage by mass: 52-55% of Ni, 18-21% of Cr, 2.9-3.4% of Mo, 6.0-7.0% of Nb, 0.2-0.8% of Al, 0.55-1.05% of Ti, less than or equal to 1% of Co, less than or equal to 0.7% of C, less than or equal to 0.38% of Si, less than or equal to 0.013% of P, less than or equal to 0.005% of B and the balance of Fe and inevitable impurities; putting the metal particles into an air-cooled copper crucible for vacuum arc melting, and carrying out vacuum arc melting; after vacuum arc melting is completed, alloy liquid is subjected to suction casting to form a suction casting plate strip with the thickness being 2-2.5 mm; carrying out primary cold rolling treatment on the suction casting plate strip; the cold deformation plate strip is subjected to solution treatment, and a solution plate strip is obtained; secondary cold rolling treatment is conducted on the solid solution plate strip, and the thickness ranges from 0.4 mm to 0.75 mm; s6, recrystallization annealing is conducted on the secondary cold-rolled alloy, and air cooling is conducted to the room temperature after heat preservation; and the recrystallized sample is subjected to heat preservation for 1-3 h at 720 DEG C, short-time aging treatment is conducted, air cooling is conducted to the room temperature after heat preservation, and the high-performance special alloy plate strip is obtained.

Description

Technical Field

[0001] The invention belongs to the field of metal materials and relates to a high-performance special alloy plate and strip with a high Nb alloying design and a preparation method thereof. Background Art

[0002] Special alloy plates and strips occupy a pivotal position in modern industry, with a wide range of applications. They are indispensable materials for the production of key components such as seals, heating stack grids, and welding strips. Among the numerous special alloys, most use niobium (Nb) as the primary strengthening element. During long-term aging treatment, a large amount of γ"-Ni3Nb strengthening phase precipitates in the alloy. The formation of this strengthening phase is a key factor in improving alloy strength and directly determines the performance and quality of special alloy plates and strips.

[0003] Existing patents CN202111604538 and CN202411239178 disclose a method for controlling the microstructure and shape of high-temperature alloy plates for aviation and a method for controlling the banded microstructure of GH4169 nickel-based high-temperature alloy, respectively. The three-way or double-way melting process is combined with forging and blanking, and multiple hot rolling to improve the comprehensive mechanical properties. However, both processes require forging and blanking, and the cooling rate is usually 0.01-0.33°C / s, which increases the length of the production line and leads to excessively high production costs. The existing paper "Basic Research on Solidification and Segregation Behavior of Large IN718 Nickel-Based Alloy Ingots by Electroslag Remelting" is by Shi Xiao, a doctoral dissertation from the University of Science and Technology Beijing. , 2019》The performance and quality of special alloy plates and strips have been improved to a certain extent through homogenization process and aging treatment, but the time required for homogenization and aging treatment is as long as dozens of hours, which not only leads to high production costs, but also makes production efficiency low; the existing patent CN202411626269 discloses a heat treatment method for improving the uniformity of the microstructure of the additive GH4169 alloy, and the additive nickel-based special alloy is treated with pre-aging combined with a two-stage aging process to improve the uniformity of the microstructure. The precipitation state of the γ"-Ni3Nb strengthening phase has a maximum elongation of 17.2%, but the strength is low, only 1179MPa; and the existing paper "Effect of Nb addition on the microstructure and mechanical properties of Inconel 718fabricated by laser directed energydeposition, Huaqiang Liu, Materials Characterization 183(2022)111601》The tensile strength of the high-temperature alloy was increased from 1149MPa to 1598.3MPa by increasing the Nb content, but the corresponding elongation was greatly reduced from 16% to 2.6%.

[0004] Clearly, the current conventional production process for specialty alloy sheet and strip presents numerous challenges. Conventional production processes are extremely complex, requiring multiple, lengthy deformation and heat treatment steps. Homogenization and aging treatments, among other processes, can take dozens of hours. This not only leads to high production costs but also low production efficiency. Furthermore, due to the lengthy process flow and numerous influencing factors, product quality is difficult to maintain, presenting significant operational risks and market challenges for companies. Therefore, streamlining the production process for specialty alloy sheet and strip, while simultaneously improving its comprehensive mechanical properties, is crucial for promoting the development of modern industry. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a high-performance special alloy plate and strip with a high Nb alloying design and a preparation method thereof, so as to solve the problems raised in the background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing high-performance special alloy plates and strips with a high Nb alloying design is carried out in the following steps:

[0008] S1: Metal particles with a set composition ratio, the mass percentage range of the components is as follows: Ni 52-55%, Cr 18-21%, Mo 2.9-3.4%, Nb 6.0-7.0%, Al 0.2-0.8%, Ti 0.55-1.05%, Co ≤ 1%, C ≤ 0.7%, Si ≤ 0.38%, P ≤ 0.013%, B ≤ 0.005%, the balance being Fe and unavoidable impurities;

[0009] S2: placing the metal particles into an air-cooled copper crucible for vacuum arc melting and performing vacuum arc melting to obtain a liquid alloy;

[0010] After vacuum arc melting, the alloy liquid is suction-cast into a suction-cast strip with a thickness of 2 to 2.5 mm;

[0011] S3: performing a cold rolling process on the suction cast strip to obtain a cold deformed strip;

[0012] S4: performing solid solution treatment on the cold deformed plate and strip to obtain a solid solution plate and strip;

[0013] S5: performing secondary cold rolling on the solid solution plate and strip to obtain a secondary cold rolled alloy with a thickness of 0.4 to 0.75 mm;

[0014] S6: performing recrystallization annealing on the secondary cold rolled alloy, keeping the alloy warm and then air cooling it to room temperature to obtain a recrystallized sample;

[0015] S7: The recrystallized sample is kept at 720°C for 1 to 3 hours for short-time aging treatment, and then air-cooled to room temperature to obtain high-performance special alloy plates and strips.

[0016] Furthermore, in step S2, the metal particles are subjected to vacuum arc melting for more than 5 times to ensure uniformity of alloy composition;

[0017] When the alloy liquid is suction-casted, an air-cooled copper mold is used as the suction-casting mold, and cooling water is passed through to prevent the suction-casting mold from overheating and to increase the cooling rate.

[0018] Furthermore, in step S2, the vacuum degree is controlled to be 5.5×10 -3 Pa, and filled with high-purity argon as a protective atmosphere.

[0019] Furthermore, in step S3, the cold rolling reduction ratio of the primary cold rolling process is 20 to 30%.

[0020] Furthermore, in step S4, the solution treatment is carried out by keeping the temperature at 1050-1100° C. for 1 hour, and then air-cooling to room temperature.

[0021] Furthermore, in step S5, the total reduction ratio of the secondary cold rolling process is 70-80%.

[0022] Furthermore, in step S6, the recrystallization annealing is carried out at a temperature of 1010-1030° C. for 1 hour.

[0023] The present invention also provides a high-performance special alloy plate and strip with a high Nb alloying design. The high-performance special alloy plate and strip with a high Nb alloying design is prepared by the preparation method.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention adopts vacuum arc melting technology to prepare special alloy plates and strips with high Nb content, and uses vacuum arc melting in combination with air-cooled copper mold suction casting to achieve rapid solidification, with a cooling rate of up to 300°C / s or more, far exceeding the 0.01-0.33°C / s of traditional melting methods. This high-speed cooling allows the alloy matrix to "capture" more solute atoms, greatly improving the solid solubility, effectively reducing the uneven distribution of elements (segregation), and shortening the time for subsequent homogenization treatment, while widening the adjustment window of the alloy element content. Compared with traditional processes (such as the existing patent CN202111604538), the present invention directly produces plates and strips with a thickness of only 2 to 2.5 mm, without the need for forging or multiple hot rolling, which simplifies the production process, shortens the production line length, and reduces costs.

[0026] 2. This invention uses a rapid solidification process called suction casting to reduce the Laves phase particles in the alloy to smaller sizes. After a single cold rolling step, a one-hour hold at 1050-1100°C removes most of the harmful Laves phase, retaining a small amount of granular Laves phase. This simplifies and improves the homogenization process. Furthermore, the invention combines a two-stage cold rolling and recrystallization annealing process to optimize the microstructure, refine grains to below 5μm, and regulate the precipitation of δ phase.

[0027] Secondly, the present invention increases the Nb content to above 6.0%, which accelerates the formation of the γ"-Ni3Nb strengthening phase during the aging process. The traditional two-stage aging process is shortened to a single-stage aging process of only 1 to 3 hours to achieve the peak aging effect. The production cycle is greatly shortened, making it possible to efficiently prepare high-performance alloy plates and strips.

[0028] 3. Through the above-mentioned technological innovations, the comprehensive performance of the alloy plates and strips prepared by the present invention is significantly improved, with the room temperature tensile strength exceeding 1550MPa and the elongation maintained at above 14.5%. In comparison, the existing patent CN202411626269 adopts a pre-aging plus double-stage aging process, with a strength of only 1179MPa and an elongation of 17.2%. While increasing the Nb content in the existing papers mentioned in the background technology increases the strength to 1598.3MPa, the elongation drops to 2.6%. The present invention maintains good toughness while ensuring high strength, achieving an optimal balance between strength and toughness, and demonstrating excellent practical value.

[0029] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0031] Figure 1 This is a schematic flow chart of a method for preparing a high-performance special alloy plate and strip with a high Nb alloying design in Example 1:

[0032] Figure 2 The metallographic structure of the alloy suction casting strip in Example 1;

[0033] Figure 3 is the metallographic structure of the solid solution sample in Example 1;

[0034] Figure 4 This is the engineering stress-strain curve of the sample after single-stage aging treatment in Example 1. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0037] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a method for preparing a high-performance special alloy plate and strip with a high Nb alloying design, which specifically includes the following steps:

[0040] S1: Ingredients

[0041] The metal particles are mixed according to the following mass percentages: Ni 52%, Cr 19%, Mo 3.1%, Nb 6.4%, Al 0.5%, Ti 0.59%, Co 0.5%, C 0.6%, Si 0.35%, P 0.012%, B 0.004%, and the balance is Fe and unavoidable impurities.

[0042] S2: Vacuum arc melting and suction casting

[0043] The prepared metal particles were placed in the air-cooled copper crucible of the vacuum arc melting equipment. The vacuum chamber was pumped to 5.0×10 -3 Pa below, and then filled with high-purity argon as a protective atmosphere. Five vacuum arc meltings were performed to ensure uniform composition. After the melting was completed, the alloy liquid was suction-cast into a 2mm thick suction casting strip. An air-cooled copper mold was used as the suction casting mold, and cooling water was continuously passed to increase the cooling rate. The metallographic structure of the obtained suction casting strip is as follows Figure 2 As shown, a uniform microstructure is displayed.

[0044] S3: primary cold rolling

[0045] The suction cast strip is placed in a cold rolling mill for a cold rolling treatment with a cold rolling reduction rate of 25% to obtain a cold deformed strip.

[0046] S4: Solution treatment

[0047] The cold-deformed strip was placed in a heating furnace and kept at 1100°C for 1 hour for solution treatment. After the insulation was completed, it was quickly taken out and air-cooled to room temperature to obtain a solution strip. Figure 3 The metallographic structure of the solid solution sample is shown, with refined grains and reduced Laves phase.

[0048] S5: Secondary cold rolling

[0049] The solid solution plate and strip were subjected to secondary cold rolling treatment, with a total cold rolling reduction of 80% and a final thickness of 0.4 mm, to obtain a secondary cold rolled alloy.

[0050] S6: Recrystallization annealing

[0051] The secondary cold-rolled alloy was placed in a heating furnace and kept at 1020°C for 1 hour for recrystallization annealing. After the holding period, it was air-cooled to room temperature to obtain a recrystallized sample.

[0052] S7: Short-term aging treatment

[0053] The recrystallized sample was kept at 720°C for 3 hours for short-time aging treatment, and then air-cooled to room temperature after the end of the holding period to obtain high-performance special alloy plates and strips. Figure 4 The engineering stress-strain curve after aging treatment is shown, and its yield strength reaches 1354MPa, tensile strength reaches 1645MPa, and elongation is 14.9%.

[0054] Example 2

[0055] S1: Ingredients

[0056] The metal particles are mixed according to the following mass percentages: Ni 54%, Cr 20%, Mo 3.2%, Nb 6.0%, Al 0.4%, Ti 0.69%, Co 0.4%, C 0.5%, Si 0.34%, P 0.009%, B 0.002%, and the balance is Fe and unavoidable impurities.

[0057] S2: Vacuum arc melting and suction casting

[0058] The prepared metal particles were placed in an air-cooled copper crucible and vacuumed to 5.0×10 -3 Pa, filled with high-purity argon as a protective atmosphere. Five vacuum arc melting cycles were performed. During suction casting, an air-cooled copper mold was used, and cooling water was passed through to produce a 2.5mm thick suction-cast strip.

[0059] S3: primary cold rolling

[0060] The suction cast strip is subjected to a cold rolling treatment with a cold rolling reduction rate of 30% to obtain a cold deformed strip.

[0061] S4: Solution treatment

[0062] The cold-deformed strip was kept at 1080°C for 1 hour for solution treatment, and then air-cooled to room temperature to obtain a solution strip.

[0063] S5: Secondary cold rolling

[0064] The solid solution plate and strip were subjected to secondary cold rolling with a total reduction of 75% and a final thickness of 0.625 mm to obtain a secondary cold rolled alloy.

[0065] S6: Recrystallization annealing

[0066] The secondary cold rolled alloy was kept at 1010°C for 1 hour for recrystallization annealing, and then air-cooled to room temperature to obtain a recrystallized sample.

[0067] S7: Short-term aging treatment

[0068] The recrystallized sample was subjected to a short-term aging treatment at 720°C for 2 hours and then air-cooled to room temperature. The resulting sheet and strip exhibited a yield strength of 1306 MPa, a tensile strength of 1560 MPa, and an elongation of 16.1%.

[0069] Example 3

[0070] S1: Ingredients

[0071] The metal particles are mixed according to the following mass percentages: Ni 53%, Cr 21%, Mo 3.0%, Nb 7.0%, Al 0.6%, Ti 0.67%, Co 0.7%, C 0.4%, Si 0.29%, P 0.010%, B 0.003%, and the balance is Fe and unavoidable impurities.

[0072] S2: Vacuum arc melting and suction casting: Place the prepared metal particles into an air-cooled copper crucible and evacuate to 5.0×10 -3 Pa, filled with high-purity argon as a protective atmosphere. Five vacuum arc melting processes were performed, and suction casting was performed to form a 2.2 mm thick suction casting strip. An air-cooled copper mold was used and cooling water was passed through.

[0073] S3: One-time cold rolling The suction cast strip is subjected to one-time cold rolling treatment with a cold rolling reduction rate of 20% to obtain a cold deformed strip.

[0074] S4: Solution treatment

[0075] The cold-deformed strip was kept at 1050°C for 1 hour for solution treatment, and then air-cooled to room temperature to obtain a solution strip.

[0076] S5: Secondary cold rolling

[0077] The solid solution plate and strip were subjected to secondary cold rolling with a total reduction of 70% and a final thickness of 0.66 mm to obtain a secondary cold rolled alloy.

[0078] S6: Recrystallization annealing

[0079] The secondary cold rolled alloy was kept at 1030°C for 1 hour for recrystallization annealing, and then air-cooled to room temperature to obtain a recrystallized sample.

[0080] S7: Short-term aging treatment

[0081] The recrystallized sample was subjected to a short-term aging treatment at 720°C for 2.5 hours and then air-cooled to room temperature. The resulting sheet and strip exhibited a yield strength of 1332 MPa, a tensile strength of 1570 MPa, and an elongation of 15.5%.

[0082] Table 1 Tensile strength and elongation of samples after single-stage aging treatment in different embodiments of the present invention

[0083] serial number Yield strength / MPa Tensile strength / MPa Elongation / % Example 1 1354 1645 14.9 Example 2 1306 1560 16.1 Example 3 1332 1570 15.5

[0084] The above three embodiments all successfully prepared high-performance special alloy plates and strips through different component ratios and process parameters, verifying the effectiveness and applicability of the preparation method of the present invention.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing high-performance special alloy plates and strips with high Nb alloying design, characterized in that: Follow these steps: S1: Metal particles with a set composition ratio, the mass percentage range of the components is as follows: Ni 52-55%, Cr 18-21%, Mo 2.9-3.4%, Nb 6.0-7.0%, Al 0.2-0.8%, Ti 0.55-1.05%, Co ≤ 1%, C ≤ 0.7%, Si ≤ 0.38%, P ≤ 0.013%, B ≤ 0.005%, the balance being Fe and unavoidable impurities; S2: placing the metal particles into an air-cooled copper crucible for vacuum arc melting and performing vacuum arc melting to obtain a liquid alloy; After vacuum arc melting, the alloy liquid is suction-cast into a suction-cast strip with a thickness of 2 to 2.5 mm; S3: performing a cold rolling process on the suction cast strip to obtain a cold deformed strip; S4: performing solid solution treatment on the cold deformed plate and strip to obtain a solid solution plate and strip; S5: performing secondary cold rolling on the solid solution plate and strip to obtain a secondary cold rolled alloy with a thickness of 0.4 to 0.75 mm; S6: performing recrystallization annealing on the secondary cold rolled alloy, keeping the alloy warm and then air cooling it to room temperature to obtain a recrystallized sample; S7: The recrystallized sample is kept at 720°C for 1 to 3 hours for short-time aging treatment, and then air-cooled to room temperature to obtain high-performance special alloy plates and strips.

2. The preparation method according to claim 1, characterized in that In step S2, the metal particles are subjected to vacuum arc melting for more than 5 times to ensure the uniformity of the alloy composition; When the alloy liquid is suction-casted, an air-cooled copper mold is used as the suction-casting mold, and cooling water is passed through to prevent the suction-casting mold from overheating and to increase the cooling rate.

3. The preparation method according to claim 1, characterized in that In step S2, the vacuum degree is controlled to be 5.5×10 -3 Pa, and filled with high-purity argon as a protective atmosphere.

4. The preparation method according to claim 1, characterized in that In step S3, the cold rolling reduction ratio of the primary cold rolling process is 20 to 30%.

5. The preparation method according to claim 1, characterized in that In step S4, the solution treatment is carried out at 1050-1100° C. for 1 hour, followed by air cooling to room temperature.

6. The preparation method according to claim 1, characterized in that In step S5, the total reduction ratio of the secondary cold rolling process is 70 to 80%.

7. The preparation method according to claim 1, characterized in that In step S6, the recrystallization annealing is carried out at a temperature of 1010-1030° C. for 1 hour.

8. A high-performance special alloy plate and strip with high Nb alloying design, characterized in that: The high-performance special alloy plate and strip with high Nb alloying design is prepared by the preparation method described in any one of claims 1 to 7.

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