A corrosion-resistant nickel-iron-based alloy and a method for preparing the alloy plate

Abstract

The present invention discloses a corrosion-resistant nickel-iron-based alloy characterized by including Cr in its chemical composition, with Cr accounting for 0.1% to 0.3% by mass. The corrosion-resistant nickel-iron-based alloy improves its oxidation resistance and corrosion resistance in humid environments. Successfully produced plates can reach a thickness of 30 mm, a width of 1500 mm, and a length of 8000 mm, with no surface or internal cracks.

Description

Technical Field

[0001] The present invention relates to the technical field of nickel-iron based alloys, and in particular to a corrosion-resistant nickel-iron based alloy and a method for preparing the alloy plate. Background Art

[0002] Nickel-iron alloy is an alloy whose main components are nickel and iron, and also contains impurity elements such as Cr, Si, S, P, and C. Nickel-iron alloy has excellent comprehensive performance and is widely used. In addition, the advantage of nickel-iron alloy in reducing the cost of stainless steel smelting has gradually been reflected, and it occupies an important position in stainless steel raw materials. At present, the research on nickel-iron alloy is further deepened, and corresponding performance requirements are put forward for iron-nickel alloy in response to various special working environments. Nickel-iron alloys in the prior art (such as 4J36 nickel alloy) are generally corrosion-resistant in dry air at room temperature, but in harsh environments such as humid air, rust spots will appear on the plate after milling. The present invention is to develop an iron-nickel alloy with an ultra-low expansion coefficient and a plate that is not easy to rust in a humid environment. Summary of the Invention

[0003] In order to solve the above problems, the present invention aims to provide a corrosion-resistant nickel-iron-based alloy with an ultra-low expansion coefficient and a plate that is not easy to rust in a humid environment, and a method for preparing the alloy plate.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0005] The present invention provides a corrosion-resistant nickel-iron based alloy, characterized in that its chemical composition includes Cr, and the mass percentage of Cr is 0.1%-0.3%.

[0006] Furthermore, in the corrosion-resistant nickel-iron-based alloy provided by the present invention, it is characterized in that its chemical composition includes, in terms of mass percentage: C: 0.01%-0.05%, Cr: 0.1%-0.3%, Mn≤0.5%, Si≤0.015%, S≤0.007%, P≤0.010%, Cu≤0.03%, Al≤0.10%, Ti≤0.1%, Mo≤0.08, and the remainder is Fe and Ni, with Ni accounting for 20%-60% of the total.

[0007] The present invention also provides a method for preparing a corrosion-resistant nickel-iron-based alloy plate, characterized in that the method comprises the following steps:

[0008] 1) Melting: The alloy raw materials are melted in a vacuum induction furnace, cast into electrode rods, and then electroslag remelted to obtain alloy ingots;

[0009] 2) Forging: Forging the alloy ingot into a slab;

[0010] 3) Stress relief annealing treatment: The hot-rolled plate is subjected to solution annealing heat treatment.

[0011] Furthermore, the preparation method provided by the present invention may also have the following characteristics: wherein, the chemical composition of the electroslag slag system in the electroslag remelting process in the smelting step includes, by weight percentage, 22% CaO, 20% Al2O3, 6% NaF, 6% MgO, 0.5% TiO2, 0.4% SiO2, and the remainder CaF2.

[0012] Furthermore, the preparation method provided by the present invention may also have the following feature: during the smelting stage of the electroslag remelting process, 0.30-0.33 atm of 99.999 high-purity argon gas is introduced for protection.

[0013] Furthermore, the preparation method provided by the present invention may also have the following characteristics: wherein, after the slag-forming stage of the electroslag remelting process is completed, calcium particles are added in batches for antioxidant protection and deoxidation, each time at a rate of 1.0 g of calcium particles per kilogram of nickel-iron alloy, for a total of 2 additions, each time with an interval of 9 to 12 minutes.

[0014] Furthermore, the preparation method provided by the present invention may also have the following characteristics: wherein, in the forging step, the initial forging temperature is 1180℃±10℃, the final forging temperature is controlled above 750℃, the number of upsetting and drawing is more than 3 times, and the grain size of the slab is controlled between 10-40μm.

[0015] Furthermore, the preparation method provided by the present invention may also have the following characteristics: wherein, in the stress relief annealing step, the solution heat treatment temperature is 810-850° C., and the holding time is 15-25 minutes.

[0016] Furthermore, the preparation method provided by the present invention may also have the following characteristics: wherein, after the stress relief annealing treatment, the thickness of the plate reaches 30 mm or more, the width reaches 1500 mm or more, and the length reaches 8000 mm.

[0017] Beneficial effects of the present invention:

[0018] The corrosion-resistant nickel-iron-based alloy of the present invention has good oxidation resistance and corrosion resistance in a humid environment, and the plate thickness can reach a relatively thick thickness of more than 30 mm, the length and width are also large, and there are no cracks on the surface and inside. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the microstructure of the corrosion-resistant nickel-iron-based alloy in an embodiment of the present invention;

[0020] Figure 21 is a schematic diagram showing the comparison of Comparative Example 1 before and after the antioxidant test;

[0021] Figure 3 3 is a comparative diagram of Example 3 before and after the antioxidant test. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the following embodiments are combined with the accompanying drawings to specifically illustrate the technical solutions of the present invention.

[0023] The corrosion-resistant nickel-iron-based alloy of the present invention comprises, in terms of mass percentage, the following chemical components: C: 0.01%-0.05%, Cr: 0.1%-0.3%, Mn≤0.5%, Si≤0.015%, S≤0.007%, P≤0.010%, Cu≤0.03%, Al≤0.10%, Ti≤0.1%, Mo≤0.08%, and the balance being Fe and Ni, with Ni accounting for 20%-60% of the total.

[0024] <Example 1>

[0025] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.03%, Cr: 0.1%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 36%, and the balance Fe.

[0026] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is carried out according to the following steps:

[0027] 1) Melting: Use vacuum induction furnace to melt the alloy raw materials and cast them into The electrode rods are then electroslag remelted to obtain alloy ingots.

[0028] The electroslag remelting process in the smelting step contains, by weight, 22% CaO, 20% Al2O3, 6% NaF, 6% MgO, 0.5% TiO2, 0.4% SiO2, and the balance CaF2. During the smelting phase, 99.999% high-purity argon gas at a pressure of 0.30-0.33 atm is introduced for shielding. After the slagging phase, calcium granules are added in batches for antioxidant protection and deoxidation. 1.0g of calcium granules per kilogram of nickel-iron alloy is added twice, with 9-12 minutes between each addition.

[0029] 2) Forging: Forging the alloy ingot into a slab.

[0030] The initial forging temperature is 1180℃±10℃, the final forging temperature is controlled above 750℃, the upsetting and drawing times are more than 3 times, and the grain size of the slab is controlled between 10-40μm.

[0031] 3) Stress relief annealing treatment: The hot-rolled plate is subjected to solution annealing heat treatment.

[0032] The hot-rolled plate is subjected to solution annealing heat treatment, the solution heat treatment temperature is 810-850°C, and the holding time is 15-25 minutes.

[0033] <Example 2>

[0034] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.03%, Cr: 0.2%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 36%, and the balance Fe.

[0035] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is the same as that of Example 1 and will not be repeated here.

[0036] <Example 3>

[0037] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.03%, Cr: 0.3%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 36%, and the balance Fe.

[0038] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is the same as that of Example 1 and will not be repeated here.

[0039] <Example 4>

[0040] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.01%, Cr: 0.3%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 60%, and the balance Fe.

[0041] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is the same as that of Example 1 and will not be repeated here.

[0042] <Example 5>

[0043] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.05%, Cr: 0.3%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 20%, and the balance is Fe.

[0044] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is the same as that of Example 1 and will not be repeated here.

[0045] <Example 6>

[0046] The corrosion-resistant nickel-iron-based alloy of this embodiment has the following chemical compositions in mass percentage: C: 0.02%, Cr: 0.3%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo0.08%, Ni 45%, and the balance Fe.

[0047] The preparation method of the corrosion-resistant nickel-iron-based alloy plate is the same as that of Example 1 and will not be repeated here.

[0048] <Comparative Example 1>

[0049] The nickel-iron-based alloy of Comparative Example 1 does not contain Cr compared to Example 1, and its chemical composition is as follows in terms of mass percentage: C: 0.03%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti0.1%, Mo 0.08%, Ni36%, and the balance is Fe.

[0050] The preparation method of the nickel-iron based alloy plate is the same as that of Example 1 and will not be described in detail.

[0051] <Comparative Example 2>

[0052] The nickel-iron-based alloy of Comparative Example 2 has the same component elements as those of Example 1, wherein the Cr content is not within the numerical range of 0.1 to 0.3% defined in the present invention, and its chemical composition is as follows by mass percentage: C: 0.03%, Cr: 0.4%, Mn 0.5%, Si 0.015%, S 0.007%, P 0.010%, Cu 0.03%, Al 0.10%, Ti 0.1%, Mo 0.08, Ni 36%, and the balance is Fe.

[0053] The preparation method of the nickel-iron based alloy plate is the same as that of Example 1 and will not be described in detail.

[0054] <Comparative Example 3>

[0055] The nickel-iron-based alloy of Comparative Example 2 is the prior art 4J36 nickel alloy, and its chemical composition by mass percentage is: C: 0.05%, Mn: 0.40%, Si: 0.30%, S: 0.02%, P: 0.02%, Ni: 36.0%, and the balance is Fe.

[0056] The preparation method of the nickel-iron based alloy plate is the same as that of Example 1 and will not be described in detail.

[0057] <Performance Test>

[0058] 1. Metallographic (grain size) test

[0059] Metallographic (grain size) tests were performed on the plates prepared in Comparative Example 1, Example 1, Example 2, Example 3, and Comparative Example 2. Figure 1 In the schematic diagram of the microstructure of the corrosion-resistant nickel-iron-based alloy, (a) is Comparative Example 1, (b) is Example 1, (c) is Example 2, (d) is Example 3, and (e) is Comparative Example 2.

[0060] Table 1 Grain size

[0061] Sample name Comparative Example 1 Example 1 Example 2 Example 3 Comparative Example 2 Grain size (μm) 78.5 60.4 55.3 45.0 40.5

[0062] From Table 1 and Appendix Figure 1 It can be seen that with the increase of Cr content, the grain size of the alloy gradually decreases and shows a trend of uniform distribution. The addition of Cr refines the grain size, and it can be seen from the microscopic point of view that it has the ability to produce thick plates.

[0063] 2. Linear expansion coefficient test

[0064] According to the YB / T5341-1993 test method, the linear expansion coefficient of the plates prepared in Comparative Example 1, Example 1, Example 2, Example 3, Comparative Example 2, and Comparative Example 3 was tested.

[0065] Table 2 Average linear expansion coefficient at different temperatures

[0066]

[0067] As shown in Table 2, Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2, the average linear expansion coefficient of the alloy gradually increases with increasing Cr content at the same temperature. However, when the Cr content reaches 0.4%, the average linear expansion coefficient exceeds the standard requirement (i.e., cracks will occur). 4J36 nickel alloy does not contain Cr, but its linear expansion coefficient is greater than that of Comparative Example 1, Examples 1, 2, and 3 at the same temperature. This shows that Cr content is not the only factor that determines the average linear expansion coefficient. However, when the formula components are basically determined, the average linear expansion coefficient of the plate can be adjusted by adjusting the Cr content.

[0068] 3. Antioxidant test

[0069] According to the test method of GB / T 13303-91, the antioxidant test was conducted by improving the test furnace, introducing high-temperature water vapor, and adjusting the relative humidity of the test environment to 51%-60%. The oxidation rates of Comparative Example 1, Example 1, Example 2, Example 3, and Comparative Example 2 are shown in Table 3 below.

[0070] Table 3 Oxidation rate K of alloys with different Cr contents

[0071] Sample name Comparative Example 1 Example 1 Example 2 Example 3 Comparative Example 2 <![CDATA[K(g / m 2 .h)]]> 0.0546 0.0038 0.0020 0.0005 0.0004

[0072] It can be seen from Table 3 that with the increase of Cr content, the oxidation rate K value gradually decreases. When the Cr content is 0.3%, the K value is only 1 / 100 of that without Cr addition.

[0073] Also, see Figure 2 and Figure 3 Comparing the two, we can see that Example 3 has almost no surface rust, while Comparative Example 1 is already covered in rust after the test. The present invention incorporates a small amount of Cr in its formulation, allowing the metal surface to form a dense passivation film of Cr2O3 when the plate comes into contact with humid air. This effectively prevents the combination of Fe and O on the metal surface, achieving an anti-oxidation effect and preventing the appearance of rust on the metal surface.

[0074] 4. Plate size test

[0075] The thickness of the plates produced in Examples 1, 2, 3, and 2, respectively, was measured, and all were found to be 30 mm thick, 1500 mm wide, and 8000 mm long. However, Examples 1, 2, and 3 exhibited no surface or internal cracks, while Comparative Example 2 exhibited cracks. Furthermore, Example 3 successfully produced large-size plates with a thickness of 37 mm, a width of 2500 mm, and a length of 8000 mm, all without surface or internal cracks.

[0076] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A corrosion-resistant nickel-iron based alloy, characterized in that: Its chemical composition includes, by mass percentage: C: 0.01%-0.05%, Cr: 0.1%-0.3%, Mn: 0.5%, Si≤0.015%, S≤0.007%, P≤0.010%, Cu≤0.03%, Al≤0.10%, Ti≤0.1%, Mo≤0.08%, and the balance is Fe and Ni; The method for preparing the corrosion-resistant nickel-iron-based alloy plate comprises the following steps: 1) Melting: The alloy raw materials are melted in a vacuum induction furnace, cast into electrode rods, and then electroslag remelted to obtain alloy ingots; 2) Forging: Forging the alloy ingot into a slab; 3) Stress relief annealing treatment: solution annealing heat treatment is performed on the hot-rolled plate; The chemical composition of the electroslag slag system in the electroslag remelting process in the smelting step includes, by weight percentage, 22% CaO, 20% Al2O3, 6% NaF, 6% MgO, 0.5% TiO2, 0.4% SiO2, and the balance CaF2; In the forging step, the initial forging temperature is 1180°C ± 10°C, the final forging temperature is controlled above 750°C, the upsetting and drawing times are more than 3 times, and the grain size of the slab is controlled between 10-40 μm; In the stress relief annealing step, the solution heat treatment temperature is 810-850° C. and the holding time is 15-25 minutes; After the slagging stage of the electroslag remelting process is completed, calcium particles are added in batches for antioxidant protection and deoxidation. Each time, 1.0 g of calcium particles are added per kilogram of nickel-iron alloy, and the addition is performed twice, with an interval of 9 to 12 minutes between each addition.

2. A method for preparing a corrosion-resistant nickel-iron based alloy plate according to claim 1, characterized in that: The method comprises the following steps: 1) Melting: The alloy raw materials are melted in a vacuum induction furnace, cast into electrode rods, and then electroslag remelted to obtain alloy ingots; 2) Forging: Forging the alloy ingot into a slab; 3) Stress relief annealing treatment: solution annealing heat treatment is performed on the hot-rolled plate; The chemical composition of the electroslag slag system in the electroslag remelting process in the smelting step includes, by weight percentage, 22% CaO, 20% Al2O3, 6% NaF, 6% MgO, 0.5% TiO2, 0.4% SiO2, and the balance CaF2; In the forging step, the initial forging temperature is 1180°C ± 10°C, the final forging temperature is controlled above 750°C, the upsetting and drawing times are more than 3 times, and the grain size of the slab is controlled between 10-40 μm; In the stress relief annealing step, the solution heat treatment temperature is 810-850° C. and the holding time is 15-25 minutes; After the slagging stage of the electroslag remelting process is completed, calcium particles are added in batches for antioxidant protection and deoxidation. Each time, 1.0 g of calcium particles are added per kilogram of nickel-iron alloy, and the addition is performed twice, with an interval of 9 to 12 minutes between each addition.

3. The method for preparing a corrosion-resistant nickel-iron based alloy plate according to claim 2, wherein: in, During the smelting stage of the electroslag remelting process, 99.999% high-purity argon gas at 0.30-0.33 atm is introduced for protection.

4. The method for preparing a corrosion-resistant nickel-iron based alloy plate according to claim 2, wherein: in, After the stress relief annealing treatment, the plate thickness reaches 30 mm or more, the width reaches 1500 mm or more, and the length reaches 8000 mm.

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