Production process of microalloyed iron-nickel-based precision alloy strip

Abstract

The invention discloses a microalloyed iron-nickel-based precision alloy strip production process, and relates to the technical field of iron-nickel-based alloy preparation, and the process mainly comprises the steps of batching, vacuum induction melting, electroslag remelting, forging, hot rolling, cold rolling and heat treatment. On the basis of a traditional 4J42 alloy, a trace amount of ferrous sulfide is added, rare earth is added to serve as a nucleation center of manganese sulfide, MnS is controlled to be in a spherical shape, deformation is not likely to happen in the rolling process, transverse plasticity and toughness losses are reduced, and the material performance is more uniform; surface oxidation and defect inheritance in the heating process are inhibited through measures of coating the surface of the forging stock with an antioxidant, enhancing milling surface treatment and the like, the thermal expansion coefficient of spherical MnS is closer to that of a matrix, pitting sources are reduced, and corrosion resistance is improved; the rare earth is converted into high-melting-point rare earth oxysulfide, so that the corrosion resistance is enhanced; by controlling sulfur, the proportion of a shearing surface and a fracture surface of the strip in stamping and punching is increased, and the problems of peeling and cracking in the stamping and forming process are solved.

Description

Technical Field

[0001] This invention relates to the field of iron-nickel based alloy preparation technology, and in particular to a process for producing micro-alloyed iron-nickel based precision alloy strips. Background Technology

[0002] Nickel-iron based precision alloys, especially 4J42 alloy, are important sealing materials. Due to their stable coefficient of thermal expansion within a temperature range of 20–500°C, matching that of soft glass and ceramic packaging materials, they are widely used in integrated circuit lead frames, vacuum electronic devices, solar collectors, electric light sources, semiconductor packaging, and aerospace precision instruments. This alloy uses nickel and iron as its main matrix, and adds small amounts of silicon and manganese to adjust its thermal expansion behavior, ensuring the airtightness and reliability of the sealing structure during thermal cycling.

[0003] However, traditional 4J42 alloy strip still faces significant problems in actual industrial production and subsequent processing. On the one hand, due to lax control over smelting processes and insufficient control over impurity elements, most domestic manufacturers experience large fluctuations in strip product quality, specifically manifested as poor plasticity and low yield. Defects such as peeling and edge cracking are particularly prone to occur in precision forming processes like stamping and die-cutting, severely impacting product qualification rates and performance. On the other hand, the sulfur content in conventional 4J42 alloys is not actively controlled, leading to sulfur segregation at grain boundaries and the formation of chain-like MnS inclusions. This not only reduces the material's high-temperature plasticity but also causes anisotropy during cold working, further deteriorating stamping performance. Therefore, there is an urgent need to develop a novel iron-nickel-based precision alloy production process with a rationally designed composition, rigorous process flow, and the ability to significantly improve the stamping performance and surface quality of strip. Summary of the Invention

[0004] In view of the problems of quality fluctuation, insufficient plasticity, and stamping defects in the production and processing of existing iron-nickel based alloys, this invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to provide a production process for microalloyed iron-nickel-based precision alloy strip.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a process for producing micro-alloyed iron-nickel-based precision alloy strips, including: S1. Ingredients: The alloy composition selected by weight percentage includes: Ni 42.0%, C 0.02%, Si 0.15%, Mn 0.45%, Co 0.08%, Al 0.034%, S 0.0075%, Re 0.006%, with the balance being Fe and trace impurities; S2, Vacuum Induction Melting: The ingredients are melted, refined and cast into electrode rods in a vacuum induction furnace; S3. Electroslag remelting: Electroslag remelting is performed on the electrode rod to obtain an electroslag ingot; S4. Forging: The electroslag ingot is heated to 1100±10℃ and held for a period of time before forging. S5. Hot rolling: Forged billets are heated and rolled into hot-rolled plates after surface treatment; S6. Cold rolling and heat treatment: Hot-rolled plates are cold rolled, intermediate annealed, finished cold rolled, finished pre-annealed, cleaned, tension leveled and stress-relief annealed to obtain finished strip.

[0007] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process described in this invention, wherein: The Ni is nickel powder with a particle size ≤ 50 μm and a purity ≥ 99.95%; The C is graphite powder with a particle size ≤10μm that has undergone high-temperature purification. The Si is silicon blocks with a purity of ≥99.9% that are crushed before use; The Mn is manganese powder with a particle size ≤30μm; The Co is cobalt powder with a particle size ≤20μm; The Al is spherical aluminum powder with a particle size of 10–30 μm and an oxygen content of ≤0.1%; The S is iron sulfide powder with a particle size ≤ 5 μm, which is vacuum dried. The Re is a rare earth powder with a particle size ≤ 5 μm, and it is sealed to prevent oxidation; The Fe is iron powder with a particle size of 10–50 μm and a purity of ≥99.98%.

[0008] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, wherein: in step S2: the melting vacuum degree is <10Pa, the material processing power is 300–400kW, and the time is ≤2.5h; After adding all the main materials, increase the power to 500kw during the molten pool cleaning process to raise the molten pool temperature to 1600±10℃ and maintain it for 5~10min.

[0009] The refining stage is carried out at 1530–1570℃ and 5Pa for 45–60 minutes; when adding S, 4J42 strip is used for wrapping, electromagnetic stirring is performed for 5 minutes, and the vacuum degree is ≤2Pa; the casting temperature is 1520–1540℃, and the casting rate adopts a slow-to-fast-to-slow mode.

[0010] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, in step S3: the electroslag remelting uses CaF2+Al2O3+CaO+MgO pre-melted slag, with a slag amount of 40kg; the remelting stage current is 7000–8000A, voltage is 46±5V, and time is 100–120min; the crystallizer return water temperature is ≤40℃.

[0011] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, in step S4: the electroslag ingot is heated to 800℃ for 3 hours and held for 1 hour, and then heated to 1100±10℃ for 3–5 hours; the initial forging temperature is ≥1080℃ and the final forging temperature is ≥900℃.

[0012] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, in step S5: the forging billet is milled, ground, coated with an antioxidant, and then air-dried for 24 hours; heated to 1150±10℃ and held for 30–40 minutes, with an initial rolling temperature ≥1130℃ and a final rolling temperature ≥900℃; the deformation per pass is ≤30%, and the billet is rolled to a 5mm thick hot-rolled plate.

[0013] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, in step S6: the total cold rolling deformation rate is ≤70%, and the deformation rate per pass is controlled at ≤15% for the first pass, ≤20% for the intermediate pass, and ≤10% for the last pass; intermediate annealing is carried out in a pure hydrogen atmosphere at 980℃; the total cold rolling deformation rate of the finished product is 30–40%; the pre-annealing of the finished product is carried out in a pure hydrogen atmosphere at 950℃; the strip is degreased, tensioned, and stress-relieved annealed to obtain the finished product.

[0014] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, the S content in the alloy is controlled at 0.006–0.012%, and the Re content is controlled at 0.005–0.008%.

[0015] As a preferred embodiment of the microalloyed iron-nickel-based precision alloy strip production process of the present invention, the finished strip has a stamping and shearing surface ratio of ≥85%, an elongation after fracture of ≥30%, and a tensile strength of ≤570MPa.

[0016] A type of iron-nickel-based precision alloy strip prepared by the above-mentioned production process has uniform spherical MnS inclusions, high stamping performance and excellent surface quality.

[0017] The beneficial effects of this invention are as follows: By adding trace amounts of ferric sulfate and rare earth elements as nucleation centers for manganese sulfide, the morphology of manganese sulfide is controlled. After sulfur control, spherical MnS is formed in 4J42S, which is less prone to deformation during rolling, reducing the loss of transverse plasticity and toughness, and making the material properties more uniform. By coating the forging billet surface with antioxidants and enhancing milling treatment, surface oxidation and defect inheritance during heating are effectively suppressed. Furthermore, the thermal expansion coefficient of spherical MnS is closer to that of the matrix, reducing pitting corrosion sources and improving corrosion resistance. Rare earth treatment can transform MnS into high-melting-point rare earth oxysulfides, enhancing corrosion resistance. Through sulfur control, the shearing surface and fracture surface ratio of strip stamping and cutting can be increased, improving the problems of peeling and cracking during stamping. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0021] Example 1 This is the first embodiment of the present invention, which provides a process for producing micro-alloyed iron-nickel-based precision alloy strip, comprising the following steps: S1. Ingredients: Selected according to the weight percentage of alloy composition: Nickel (Ni) 42.0%, Carbon (C) 0.02%, Silicon (Si) 0.15%, Manganese (Mn) 0.45%, Cobalt (Co) 0.08%, Aluminum (Al) 0.034%, Sulfur (S) 0.0075%, Rare Earth (Re) 0.006%, with the balance being Iron (Fe) and unavoidable trace impurities (P<0.010%, O≤0.0020%, N≤0.0020%, H≤0.0002%). For example: The method for producing Ni is as follows: using electrolytic nickel plates as raw materials, after crushing and cleaning, vacuum melting is carried out under an argon protective atmosphere to produce high-purity nickel ingots, which are then mechanically crushed and ball-milled to obtain nickel powder with a particle size ≤50μm and a nickel content ≥99.95%; The method for producing C is as follows: high-purity graphite is selected, crushed, and sieved to obtain graphite powder with a particle size ≤10μm, and then purified at high temperature (≥2500℃, argon protection) to reduce ash and impurity content. The method for producing Si is as follows: metallurgical grade industrial silicon is crushed, acid-washed (HCl+H2SO4 mixed acid) to remove surface oxides, then washed with water and dried, and then refined and purified under vacuum conditions to obtain silicon blocks with a silicon content ≥99.9%, which are then crushed and used. The method for producing Mn is as follows: electrolytic manganese metal sheets are cleaned and dried, then remelted and refined in a vacuum induction furnace to form manganese ingots, which are then crushed and ball-milled to produce manganese powder with a particle size ≤30μm. The method for producing Co is as follows: a high-purity electrolytic cobalt plate is selected, and after acid washing, water washing, and drying, it is smelted into cobalt ingots in a vacuum electric arc furnace, and then mechanically crushed and air-flow milled into cobalt powder with a particle size ≤20μm. The method for producing Al is as follows: using high-purity aluminum ingots (≥99.99%), spherical aluminum powder is produced through vacuum melting and powder spraying, with the particle size controlled at 10–30 μm and the oxygen content ≤0.1%; The method for producing S is as follows: high-purity iron sulfide (FeS) is crushed and sieved to obtain iron sulfide powder with a particle size ≤5μm, and then dried under vacuum conditions to prevent oxidation; The method for producing Re is as follows: a mixture of rare earth metals (Ce, La, etc.) is selected, and alloy ingots are produced by vacuum melting and rapid cooling. The ingots are then hydrogen-crushed and ball-milled to produce rare earth powder with a particle size ≤5μm, which is then sealed and stored to prevent oxidation. The Fe is prepared by using carbonyl iron powder or electrolytic iron powder, which is then vacuum annealed to remove impurities such as carbon and oxygen, resulting in an iron content ≥99.98% and a particle size controlled between 10 and 50 μm.

[0022] S2. Vacuum Induction Melting: The prepared raw materials are loaded into a 1T vacuum induction melting furnace. After loading, the furnace is evacuated to <10Pa, and then powered on for melting (power 300~400kW, melting time ≤2.5h). After melting, the power is increased to 500kW, and impurities are removed at 1600±10℃ for 5~10min. Then, the power is adjusted to 150~200kW, and refining is carried out at 1530~1570℃ under a 5Pa vacuum for 45~60min. After refining, the power is reduced to 1... 00kW, purging with argon to 3~5kPa, adding small alloy materials such as Mn, Si, and C; then increasing the power to 450kW to raise the temperature to 1540~1560℃, then reducing to 120kW for refining for 10~20min; then slowly adding ferrous sulfate wrapped with 4J42 strip, turning on electromagnetic stirring for 5 minutes, and controlling the vacuum degree at ≤2Pa; finally purging with argon to 3~5kPa, adjusting the temperature to 1520~1540℃, and casting into Φ295mm electrode rods at a slow→fast→slow rate.

[0023] S3. Electroslag Remelting: After grinding and cleaning the oxide scale on the surface of the electrode rod, it is welded to the dummy electrode and baked at 550℃ for more than 6 hours. A Φ400 / Φ420mm crystallizer is selected, with a slag plate and three arc-starting blocks distributed at 120° at the bottom. The slag material is a pre-melted slag of CaF2+Al2O3+CaO+MgO, with a slag quantity of 40kg, and baked at 700℃ for ≥4 hours.

[0024] The remelting process is as follows: Arc initiation and slag formation stage: current 1800~5000A, voltage 36~48V, time 15~20min; Power increase stage: current 5000~7000A, voltage 50~51V, time 15~20min, with argon purging to control oxygen content; Remelting stage: current 7000~8000A, voltage 46±5V, time 100~120min, crystallizer return water temperature ≤40℃; Hot sealing stage: current 8000~4500A, voltage 44~41V, time 20min. After remelting, the electroslag ingot is cooled in the crystallizer for at least 60min, and the ingot guide plate is removed.

[0025] S4. Forging: The electroslag ingot is loaded into a Class IV natural gas heating furnace, slowly heated to 800℃ for 3 hours and held for 1 hour, then heated to 1100±10℃ for another hour and held for 3~5 hours. After exiting the furnace, it is forged using a 4T electro-hydraulic hammer with an initial forging temperature ≥1080℃ and a final forging temperature ≥900℃.

[0026] S5. Hot Rolling: After milling (1mm on one side) and grinding with an angle grinder to remove surface defects, the forged billet is coated with an antioxidant and air-dried for 24 hours. It is then heated in a furnace: at temperatures <700℃, the heating rate is ≤100℃ / h, and the temperature is held at 1150±10℃ for 30~40 minutes. After exiting the furnace, it is rolled with an initial rolling temperature ≥1130℃, a final rolling temperature ≥900℃, and a deformation per pass ≤30%. It is rolled into a 5mm thick hot-rolled plate in 7~11 passes and air-cooled. Afterwards, it undergoes cold acid pickling to remove oxide scale, followed by double-sided water grinding, welding, and coiling.

[0027] S6. Cold rolling and heat treatment: Hot-rolled coils are cold rolled on a 650 rolling mill (AGC). The total deformation of a single rolling pass is ≤70%, and the deformation of each pass is controlled as follows: first pass ≤15%, intermediate passes ≤20%, and last 1-2 passes ≤10%.

[0028] Intermediate annealing: Annealing is performed at 980℃ under a pure hydrogen protective atmosphere.

[0029] Finished product cold rolling: Control the total deformation rate of the finished product to 30~40% and roll to the target thickness (e.g., 0.5mm).

[0030] Pre-annealing of finished product: Annealing at 950℃ under a pure hydrogen protective atmosphere.

[0031] Cleaning and degreasing: Degreasing and cleaning are carried out at a belt speed of 10~15m / min (strips with a thickness ≤0.07mm are not cleaned).

[0032] Straightening: Straightening finished strips to control their shape.

[0033] Stress-relief annealing: Stress-relief annealing of finished products is carried out at 500~600℃.

[0034] Example 2 In the second embodiment of the present invention, unlike embodiment 1, in step S1, the alloy composition by weight percentage is: nickel (Ni) 42.0%, carbon (C) 0.012%, silicon (Si) 0.13%, manganese (Mn) 0.40%, cobalt (Co) 0.06%, aluminum (Al) 0.030%, sulfur (S) 0.0070%, rare earth (Re) 0.007%, with the balance being iron (Fe).

[0035] In step S2, the vacuum melting and refining time is adjusted to 50 minutes.

[0036] In step S3, the electroslag remelting current is controlled at 7500A during the remelting stage.

[0037] Example 3 In the third embodiment of the present invention, unlike embodiment 1, the alloy composition by weight percentage in step S1 is as follows: nickel (Ni) 42.0%, carbon (C) 0.016%, silicon (Si) 0.16%, manganese (Mn) 0.44%, cobalt (Co) 0.06%, aluminum (Al) 0.033%, sulfur (S) 0.0078%, rare earth (Re) 0.007%, with the balance being iron (Fe).

[0038] In step S4, the forging holding time is adjusted to 4 hours.

[0039] In step S5, the final hot rolling temperature is controlled at 910°C.

[0040] Comparative Example 1: This comparative example differs from Example 1 in that it uses a conventional 4J42 alloy composition: 42.0% nickel (Ni), 0.02% carbon (C), 0.15% silicon (Si), 0.45% manganese (Mn), with the balance being iron (Fe). No sulfur (S) or remanganese (Re) elements are added, and the content of co and al is controlled at conventional upper limits. The vacuum melting process for sulfur control and rare earth element addition is omitted. After electroslag remelting, the product is directly forged and hot rolled. During cold rolling, intermediate annealing is performed in a conventional atmosphere instead of pure hydrogen protection. The tensile straightening and stress-relief annealing processes are omitted from the finished product.

[0041] Comparative Example 2: This comparative example differs from Example 1 in that the sulfur content was excessively added during the vacuum melting process, reaching 0.025%, far exceeding the 0.006~0.012% range required by this invention, and no rare earth element Re was added for modification. The remaining process steps are the same as in Example 1.

[0042] Performance testing methods The finished strips (0.5mm specification) obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests, and the test methods are as follows: Room temperature tensile properties: Standard tensile specimens were prepared according to GB / T228.1 "Metallic materials - Tensile testing - Part 1: Test method at room temperature", and the test was performed using a universal testing machine. The tensile rate was controlled at 2 mm / min, and the tensile strength and elongation after fracture were recorded.

[0043] Vickers hardness: The test was conducted according to GB / T4340.1 "Metallic materials Vickers hardness test - Part 1: Test method". The test force was 98.07 N (10 kgf) and the holding time was 15 s. Five points were tested for each sample and the average value was taken.

[0044] Average linear expansion coefficient: A Φ6mm × 50mm cylindrical sample was prepared according to GB / T4339 "Determination of thermal expansion characteristic parameters of metallic materials". A thermal expansion apparatus was used to heat the sample at a rate of 5℃ / min within the temperature ranges of 20–300℃ and 20–450℃, and the average linear expansion coefficient (×10) was recorded. -6 / ℃).

[0045] Stamping section quality: The strip was punched using a stamping die to prepare 10 stamping samples. The cross-sectional morphology was observed using a metallographic microscope. The percentage of the sheared surface to the total cross-sectional area was calculated and the average value was taken.

[0046] The finished strips prepared by the production processes of Examples 1-3 and Comparative Examples 1-2 were subjected to corresponding performance tests, and the test results are shown in Table 1 below.

[0047] Table 1

[0048] From Table 1, we can conclude that: Conclusion: Comparison of the test results of Examples 1-3 and Comparative Examples 1-2 shows that the composition design provided by this invention, which involves micro-alloying by adding trace amounts of S and Re, combined with strict vacuum sulfur-controlled melting, electroslag remelting, protective atmosphere heat treatment, and fine cold rolling processes, can significantly improve the stamping performance of iron-nickel-based precision alloy strips. The stamping shear surface ratio is increased from the conventional 65-75% to over 85%, while ensuring that its mechanical properties and coefficient of thermal expansion stably meet standard requirements. Comparative Example 1 (traditional composition and process) exhibits poor stamping performance; Comparative Example 2 (excessive S and no Re modification) suffers from severe peeling defects and decreased plasticity due to the deterioration of sulfide morphology. This indicates that the composition design combined with sulfur control and rare earth treatment processes of this invention is key to obtaining strips with high formability and high surface quality.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and not restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A process for producing micro-alloyed iron-nickel-based precision alloy strip, characterized in that, include: S1. Ingredients: The alloy composition selected by weight percentage includes: Ni 42.0%, C 0.02%, Si 0.15%, Mn 0.45%, Co 0.08%, Al 0.034%, S 0.0075%, Re 0.006%, with the balance being Fe and trace impurities; S2, Vacuum Induction Melting: The ingredients are melted, refined and cast into electrode rods in a vacuum induction furnace; S3. Electroslag remelting: Electroslag remelting is performed on the electrode rod to obtain an electroslag ingot; S4. Forging: The electroslag ingot is heated to 1100±10℃ and held for a period of time before forging. S5. Hot rolling: Forged billets are heated and rolled into hot-rolled plates after surface treatment; S6. Cold rolling and heat treatment: Hot-rolled plates are cold rolled, intermediate annealed, finished cold rolled, finished pre-annealed, cleaned, tension leveled and stress-relief annealed to obtain finished strip.

2. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that, In step S1: The Ni is nickel powder with a particle size ≤ 50 μm and a purity ≥ 99.95%; The C is graphite powder with a particle size ≤10μm that has undergone high-temperature purification. The Si is silicon blocks with a purity of ≥99.9% that are crushed before use; The Mn is manganese powder with a particle size ≤30μm; The Co is cobalt powder with a particle size ≤20μm; The Al is spherical aluminum powder with a particle size of 10–30 μm and an oxygen content of ≤0.1%; The S is iron sulfide powder with a particle size ≤ 5 μm, which is vacuum dried. The Re is a rare earth powder with a particle size ≤ 5 μm, and it is sealed to prevent oxidation; The Fe is iron powder with a particle size of 10–50 μm and a purity of ≥99.98%.

3. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that, In step S2: the melting vacuum degree is <10Pa, the material processing power is 300–400kW, and the time is ≤2.5h; After adding all the main materials, increase the power to 500kw during the molten pool cleaning process to raise the molten pool temperature to 1600±10℃ and maintain it for 5~10min; The refining stage is carried out at 1530–1570℃ and 5Pa for 45–60 minutes; when adding S, 4J42 strip is used for wrapping, electromagnetic stirring is performed for 5 minutes, and the vacuum degree is ≤2Pa; the casting temperature is 1520–1540℃, and the casting rate adopts a slow-to-fast-to-slow mode.

4. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that, In step S3: the electroslag remelting uses CaF2+Al2O3+CaO+MgO pre-melted slag, with a slag quantity of 40kg; the remelting stage current is 7000–8000A, voltage is 46±5V, and time is 100–120min; the crystallizer return water temperature is ≤40℃.

5. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that, In step S4: the electroslag ingot is heated to 800℃ for 3 hours and held for 1 hour, then heated to 1100±10℃ for another hour and held for 3–5 hours; the initial forging temperature is ≥1080℃ and the final forging temperature is ≥900℃.

6. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that, In step S5: the forging billet is milled, polished, coated with antioxidant and then air-dried for 24 hours; heated to 1150±10℃ and held for 30–40 minutes, with an initial rolling temperature ≥1130℃ and a final rolling temperature ≥900℃; the deformation per pass is ≤30%, and it is rolled to a 5mm thick hot-rolled plate.

7. The microalloyed iron-nickel-based precision alloy strip production process as described in claim 1, characterized in that: In step S6: the total cold rolling deformation rate is ≤70%, and the deformation rate per pass is controlled at ≤15% for the first pass, ≤20% for the intermediate pass, and ≤10% for the last pass; intermediate annealing is carried out in a pure hydrogen atmosphere at 980℃; the total cold rolling deformation rate of the finished product is 30–40%; the pre-annealing of the finished product is carried out in a pure hydrogen atmosphere at 950℃; the strip is degreased, tensioned, and stress-relieved annealed to obtain the finished product.

8. The manufacturing process for microalloyed iron-nickel-based precision alloy strip as described in claim 1, characterized in that: The S content in the alloy is controlled at 0.006–0.012%, and the Re content is controlled at 0.005–0.008%.

9. The manufacturing process for microalloyed iron-nickel-based precision alloy strip as described in claim 1, characterized in that: The finished strip has a stamping and shearing surface ratio of ≥85%, an elongation after fracture of ≥30%, and a tensile strength of ≤570MPa.

10. A type of iron-nickel-based precision alloy strip prepared by the production process described in any one of claims 1–9, characterized in that, It has uniform spherical MnS inclusions, high stamping performance and excellent surface quality.

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