Corrosion-resistant alloy and preparation method of plate made of corrosion-resistant alloy

Abstract

The invention relates to a corrosion-resistant alloy, in particular to a corrosion-resistant alloy and a preparation method of a plate made of the corrosion-resistant alloy. The corrosion-resistant alloy comprises the following chemical components in percentage by mass: 22 to 23 percent of Cr, 41 to 42 percent of Ni, 2.8 to 3.3 percent of Mo, 2.0 to 2.5 percent of Cu, 0.8 to 1.0 percent of Ti, 0.003 to 0.005 percent of Mg, less than or equal to 0.15 percent of Al, less than or equal to 0.05 percent of C, less than or equal to 0.3 percent of S i, less than or equal to 1.0 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.02 percent of S and the balance of Fe. The preparation method of the corrosion-resistant alloy plate comprises the steps of intermediate frequency furnace smelting, electrode bar die casting, electroslag remelting, forging, hot rolling and water cooling, coping, solid solution pickling and cold rolling. According to the method, pollution generated in the smelting process can be reduced, the alloy return scraps are fully utilized, the yield of alloy elements is increased, the production cost is reduced, the corrosion resistance, strength and plasticity of corrosion-resistant metal are improved, and burning loss of metal elements in the smelting process is reduced.

Description

Technical Field

[0001] The invention relates to a corrosion-resistant alloy, and in particular to a method for preparing a corrosion-resistant alloy and a plate thereof. Background Art

[0002] Corrosion-resistant alloy (UNS N08825) is a nickel-iron-chromium based solid solution strengthened nickel-iron based alloy, which has the ability to resist chloride ion stress corrosion cracking, intergranular corrosion, pitting corrosion, crevice corrosion, and has good corrosion resistance. Therefore, corrosion-resistant alloy can be widely used in mechanical chemical industry, electronics, environmental protection, aviation, instrumentation and other fields.

[0003] As the production progresses, the returned materials of corrosion-resistant alloys and returned materials rich in Cr, Mo, Ni, and Ti gradually increase. In order to reduce production costs, the returned materials of corrosion-resistant alloys and returned materials rich in Cr, Mo, Ni, and Ti are usually used as raw materials to re-produce corrosion-resistant alloys; currently, the commonly used processes in the production of corrosion-resistant alloys are: electric arc furnace → LF → VOD → die-cast electrode rods → electroslag remelting → forging → hot rolling → solutionizing → cold rolling.

[0004] When using an electric arc furnace to smelt corrosion-resistant alloys, it is easy to cause oxidation or burning of elements such as Cr, Mo, Ni, and Ti; and since returned materials are used to smelt corrosion-resistant alloys, the contents of oxygen, sulfur, and inclusions in the obtained corrosion-resistant alloys are relatively high; therefore, it is urgent to provide a method for preparing corrosion-resistant alloys and their plates to solve the above problems. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing a corrosion-resistant alloy and a plate thereof, by introducing 0.003-0.005% Mg to reduce the contents of oxygen, sulfur and inclusions in the corrosion-resistant alloy, thereby improving the strength, plasticity, corrosion resistance and impact toughness of the corrosion-resistant alloy.

[0006] To solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0007] A corrosion resistant alloy, the chemical composition of which, in terms of mass percentage, comprises:

[0008] Cr: 22-23%, Ni: 41-42%, Mo: 2.8-3.3%, Cu: 2.0-2.5%, Ti: 0.8-1.0%, Mg: 0.003-0.005%, Al≤0.15%, C≤0.05%, Si≤0.3%, Mn≤1.0%, P≤0.03%, S≤0.02%, and the balance is Fe.

[0009] A method for preparing a corrosion-resistant alloy plate comprises the following steps:

[0010] 1) Prepare the charge and place it into the medium frequency furnace for smelting under a protective atmosphere;

[0011] After the charge is melted and the temperature exceeds 1600℃, double slag smelting is carried out. After the slag is whitened, the slag in the medium frequency furnace is removed to obtain molten steel with the chemical composition.

[0012] 2) pouring the molten steel obtained in step 1) under a protective atmosphere, and obtaining an electrode rod after the molten steel is cooled;

[0013] 3) using the electrode rod obtained in step 2) as a consumable electrode of an electroslag remelting furnace; applying a voltage of 30 to 50 V and a current of 4500 to 11000 A to the consumable electrode, and melting the electrode rod at a melting rate of 5.3 to 8.0 kg / min;

[0014] The molten droplets of the electrode rods gather in the crystallizer of the electroslag remelting furnace and form steel ingots after cooling;

[0015] 4) heating the steel ingot obtained in step 3) to 1100° C. and then forging it, with the starting forging temperature being 1080° C. and the final forging temperature being 800° C.;

[0016] 5) The steel ingot forged in step 4) is heated again to 1100° C. and then hot rolled, with the starting rolling temperature being 1080° C. and the final rolling temperature being 820° C. After the hot rolling is completed, it is immediately cooled in water to obtain a steel billet;

[0017] 6) Grinding the surface of the steel billet obtained in step 5) to preliminarily remove defects on the surface of the steel billet;

[0018] 7) heating the steel billet after grinding in step 6) to 1080° C. and keeping the temperature for 20 minutes; after the heat preservation is completed, immediately cooling in water, and pickling the steel billet surface to a 2B surface;

[0019] 8) cold rolling the steel billet after pickling in step 7) to obtain a corrosion-resistant alloy plate.

[0020] Furthermore, in step 1) and step 2), the protective atmosphere is argon.

[0021] Further, step 2) is specifically as follows:

[0022] The molten steel obtained in step 1) is transferred to a tundish, and poured into an ingot mold under argon protection. After the pouring is completed, a heating agent and an ignition agent are added to the ingot mold; and the electrode rod is obtained after the molten steel is cooled.

[0023] Furthermore, in step 2), before transferring the molten steel obtained in step 1) to the tundish and before pouring the molten steel into the ingot mold, the tundish and the ingot mold are baked at a temperature exceeding 100°C.

[0024] Furthermore, in step 3), the electroslag slag material used in the electroslag remelting furnace is a pentaneous slag material;

[0025] In terms of mass percentage, the quinary slag includes 30-33% CaO, 30-33% Al 2 O 3 , 6-12% TiO 2 20-30% CaF 2 , and 1-5% MgO.

[0026] Furthermore, in step 5), the steel billet is immediately cooled in water after hot rolling, and the water temperature of the steel billet after hot rolling is ≥800°C.

[0027] Furthermore, step 8) is specifically: the steel billet after pickling in step 7) is subjected to two cold rolling passes in one rolling process to obtain a corrosion-resistant alloy plate.

[0028] Furthermore, the charge in step 1) is one or more of return material, ferrochrome, ferromolybdenum, nickel plate, copper plate, titanium bar, metal manganese, and nickel-magnesium; the charge is baked at a temperature exceeding 200° C. before being placed in the medium frequency furnace;

[0029] The returned material is scrap steel returned material.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The corrosion-resistant alloy provided by the present invention reduces the contents of oxygen, sulfur and inclusions in the corrosion-resistant alloy by introducing 0.003-0.005% Mg. Moreover, the Mg atoms are small in size and easily segregate at the grain boundaries, thereby hindering the growth of grains, refining grains and hindering grain dislocation movement. At the same time, the strength and plasticity of the corrosion-resistant alloy can be improved. Moreover, the Mg segregated at the grain boundaries can occupy the vacancies at the grain boundaries, reducing the M 23 C 6 The precipitation at the grain boundary promotes the movement of Cr atoms and Mo atoms into the grain, greatly reducing the generation of Cr-poor areas, improving the corrosiveness of the alloy, and making the carbides finer, reducing the precipitation of carbides at the grain boundary, improving the impact toughness, facilitating subsequent deformation processes such as forging, hot rolling, and cold rolling, and facilitating the crushing and refinement of grains.

[0032] 2. The preparation method of the corrosion-resistant alloy plate provided by the present invention uses a medium frequency furnace to melt the charge under a protective atmosphere, which has less pollution than an electric arc furnace, and the medium frequency furnace has lower power consumption per ton of steel than the electric arc furnace, saving energy and cost. The medium frequency furnace adopts induction coil heating, and the electromagnetic stirring effect is obvious during the heating process, so that the alloy elements are evenly distributed and the chemical composition of the smelted steel ingot is more uniform.

[0033] 3. The preparation method of the corrosion-resistant alloy plate provided by the present invention comprises the following steps: in the electroslag remelting process, a voltage of 30 to 50 V and a current of 4500 to 11000 A are applied to the consumable electrode, and the electrode rod is melted at a melting rate of 5.3 to 8.0 kg / min. By reducing the voltage and increasing the current, the insertion depth of the consumable electrode can be reduced, and the burning loss of Ti element in the charge can be reduced; the final forging temperature of forging is 800°C, which can avoid the problem that the σ phase precipitates when the ingot temperature is lower than 800°C, causing the ingot to become brittle and hard, and causing the plasticity of the ingot to decrease; the water entry temperature of the billet after hot rolling is ≥800°C, which can make the σ phase and M 23 C 6 The intermediate harmful phases have no time to precipitate, which is conducive to the subsequent cold rolling and prevents deformation and cracking during cold rolling. The ground steel ingot is kept at 1080℃ for 20 minutes, and the precipitated σ phase and M 23 C 6 The intermediate phase dissolves back into austenite and forms a supersaturated solid solution after water cooling, which reduces the precipitation of the intermediate phase at the grain boundary and improves the corrosion resistance, strength and plasticity of the matrix.

[0034] 4. The preparation method of the corrosion-resistant alloy plate provided by the present invention, the electroslag slag used in the electroslag remelting furnace is a five-element slag material containing 6-12% TiO 2 , can reduce the burning loss of Ti element, that is, reduce the burning Ti reaction (3Ti+2Al 2 O 3 =4A l+3T iO 2 ) is carried out; moreover, since the electroslag slag contains 1-5% MgO, the oxygen in the air can be reduced from entering the molten droplet, which can further reduce the burning loss of the Ti element and the head-tail segregation of the Ti element in the ingot.

[0035] 5. The preparation method of the corrosion-resistant alloy plate provided by the present invention can further remove defects on the surface of the steel billet by pickling to form a slightly rough 2B surface, which is beneficial to the subsequent composite processing of the customer. DETAILED DESCRIPTION

[0036] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] A corrosion-resistant alloy, the chemical composition of which, in mass percentage, includes: Cr: 22-23%, Ni: 41-42%, Mo: 2.8-3.3%, Cu: 2.0-2.5%, Ti: 0.8-1.0%, Mg: 0.003-0.005%, Al≤0.15%, C≤0.05%, Si≤0.3%, Mn≤1.0%, P≤0.03%, S≤0.02%, and the balance is Fe.

[0038] The present invention also provides a method for preparing a corrosion-resistant alloy plate, and the specific method is as follows:

[0039] 1) Prepare the charge according to the chemical composition. The charge is one or more of return material, ferrochrome, ferromolybdenum, nickel plate, copper plate, titanium bar, metallic manganese, nickel magnesium and fluorite. The charge is baked at a temperature exceeding 200°C before being placed in the medium frequency furnace. The return material is scrap steel return material, i.e., corrosion-resistant alloy return material or return material rich in Cr, Mo, Ni, Ti.

[0040] The charge is placed in a medium frequency furnace for melting under an argon protective atmosphere;

[0041] After the charge is melted and the temperature exceeds 1600℃, double slag smelting is carried out to achieve deoxidation, desulfurization, dephosphorization and inclusion removal of the charge; after slag whitening, the slag in the medium frequency furnace is removed to obtain molten steel;

[0042] 2) Baking the tundish and ingot mold at a temperature exceeding 100°C;

[0043] The molten steel obtained in step 1) is transferred to a tundish, and the molten steel is poured into a steel ingot mold under the protection of argon gas, and a heating agent and an igniter are added into the steel ingot mold after the pouring is completed; and an electrode rod is obtained after the molten steel is cooled;

[0044] 3) using the electrode rod obtained in step 2) as a consumable electrode of an electroslag remelting furnace; applying a voltage of 30 to 50 V and a current of 4500 to 11000 A to the consumable electrode, and melting the electrode rod at a melting rate of 5.3 to 8.0 kg / min;

[0045] The molten droplets of the electrode rods gather in the crystallizer of the electroslag remelting furnace and form steel ingots after cooling;

[0046] The electroslag slag used in the electroslag remelting furnace is a five-element slag material; in terms of mass percentage, the five-element slag material includes 30-33% CaO, 30-33% Al 2 O 3 , 6-12% TiO 2 20-30% CaF 2 , and 1-5% MgO;

[0047] 4) heating the steel ingot obtained in step 3) to 1100° C. and then forging it, with the starting forging temperature being 1080° C. and the final forging temperature being 800° C.;

[0048] 5) The steel ingot forged in step 4) is heated again to 1100° C. and then hot rolled, with the starting rolling temperature being 1080° C. and the final rolling temperature being 820° C.; immediately cooling the steel ingot in water after the hot rolling is completed, with the water temperature of the steel ingot after the hot rolling being ≥800° C., and obtaining a steel billet after cooling;

[0049] 6) Grinding the surface of the steel billet obtained in step 5) to preliminarily remove defects on the surface of the steel billet, that is, removing oxide scale, cracks, pits or scars on the surface of the steel billet;

[0050] 7) heating the steel billet after grinding in step 6) to 1080°C and keeping the temperature for 20 minutes; after the heat preservation is completed, immediately cooling in water, and further removing the defects on the surface of the steel billet by pickling, so that the surface of the steel billet becomes a 2B surface; the pickling adopts hydrofluoric acid;

[0051] 8) The steel billet after pickling in step 7) is subjected to two cold rolling passes in one rolling process to obtain a corrosion-resistant alloy plate.

[0052] Specific examples are given below.

[0053] Embodiment 1:

[0054] A method for preparing a corrosion-resistant alloy plate, the specific method is as follows:

[0055] 1) Prepare the charge;

[0056] Among them, the chemical composition, in mass percentage, includes: Cr: 22-23%, Ni: 41-42%, Mo: 2.8-3.3%, Cu: 2.0-2.5%, Ti: 0.8-1.0%, Mg: 0.003-0.005%, Al≤0.15%, C≤0.05%, Si≤0.3%, Mn≤1.0%, P≤0.03%, S≤0.02%, and the balance is Fe.

[0057] The charge is: corrosion-resistant alloy return material, ferrochrome, ferromolybdenum, nickel plate, copper plate, titanium bar, metal manganese, nickel magnesium and fluorite; the charge is baked at a temperature of 200°C before being placed in the medium frequency furnace;

[0058] The charge is placed in a medium frequency furnace for melting under an argon protective atmosphere;

[0059] After the charge is melted and the temperature reaches 1610℃, double slag smelting is carried out to achieve deoxidation, desulfurization, dephosphorization and inclusion removal of the charge; after slag whitening, the slag in the medium frequency furnace is removed to obtain molten steel with chemical composition, weighing 2.7t;

[0060] 2) baking the tundish and ingot mold at 100°C;

[0061] The molten steel obtained in step 1) is transferred to a tundish, wherein the temperature of the molten steel in the tundish is 1580° C.; the molten steel is poured into an ingot mold under argon protection, and a heating agent and an igniter are added to the ingot mold after the pouring is completed; and an electrode rod with a diameter of 440 mm is obtained after the molten steel is cooled;

[0062] 3) using the electrode rod obtained in step 2) as a consumable electrode of an electroslag remelting furnace; applying a voltage of 40V and a current of 7000A to the consumable electrode, and melting the electrode rod at a melting rate of 5.3kg / min;

[0063] The molten droplets of the electrode rods gather in the crystallizer of the electroslag remelting furnace and form steel ingots after cooling;

[0064] 4) heating the steel ingot obtained in step 3) to 1100° C. and then forging it, with the starting forging temperature being 1080° C. and the final forging temperature being 800° C.;

[0065] 5) The steel ingot forged in step 4) is heated again to 1100° C. and then hot rolled, with the starting rolling temperature being 1080° C. and the final rolling temperature being 820° C.; immediately after the hot rolling is completed, the steel ingot is cooled in water, and the water temperature of the steel ingot after the hot rolling is 820° C. After cooling, a steel billet is obtained;

[0066] 6) Grinding the surface of the steel billet obtained in step 5) to preliminarily remove defects on the surface of the steel billet, that is, removing oxide scale, cracks, pits or scars on the surface of the steel billet;

[0067] 7) heating the steel billet after grinding in step 6) to 1080° C. and keeping the temperature for 20 minutes; after the heat preservation is completed, immediately cooling it in water, and further removing the defects on the surface of the steel billet by pickling, so that the surface of the steel billet becomes a 2B surface;

[0068] 8) The steel billet after pickling in step 7) is subjected to two cold rolling passes in one rolling process to obtain a δ3.0*650 corrosion-resistant alloy plate.

[0069] Example 2

[0070] A method for preparing a corrosion-resistant alloy plate, the specific method is as follows:

[0071] 1) Prepare the charge;

[0072] Among them, the chemical composition, in mass percentage, includes: Cr: 22-23%, Ni: 41-42%, Mo: 2.8-3.3%, Cu: 2.0-2.5%, Ti: 0.8-1.0%, Mg: 0.003-0.005%, Al≤0.15%, C≤0.05%, Si≤0.3%, Mn≤1.0%, P≤0.03%, S≤0.02%, and the balance is Fe.

[0073] The charge is: corrosion-resistant alloy return material, ferrochrome, ferromolybdenum, nickel plate, copper plate, titanium bar, metal manganese, nickel magnesium and fluorite; the charge is baked at a temperature of 200°C before being placed in the medium frequency furnace;

[0074] The charge is placed in a medium frequency furnace for melting under an argon protective atmosphere;

[0075] After the charge is melted and the temperature reaches 1615℃, double slag smelting is carried out to achieve deoxidation, desulfurization, dephosphorization and inclusion removal of the charge; after slag whitening, the slag in the medium frequency furnace is removed to obtain molten steel with chemical composition, weighing 4.8t;

[0076] 2) baking the tundish and ingot mold at 100°C;

[0077] The molten steel obtained in step 1) is transferred to a tundish, wherein the temperature of the molten steel in the tundish is 1585° C.; the molten steel is poured into an ingot mold under argon protection, and a heating agent and an igniter are added to the ingot mold after the pouring is completed; and an electrode rod with a diameter of 520 mm is obtained after the molten steel is cooled;

[0078] 3) using the electrode rod obtained in step 2) as a consumable electrode of an electroslag remelting furnace; applying a voltage of 48V and a current of 10000A to the consumable electrode, and melting the electrode rod at a melting rate of 7.0kg / min;

[0079] The molten droplets of the electrode rods gather in the crystallizer of the electroslag remelting furnace and form steel ingots after cooling;

[0080] 4) heating the steel ingot obtained in step 3) to 1100° C. and then forging it, with the starting forging temperature being 1080° C. and the final forging temperature being 800° C.;

[0081] 5) The steel ingot forged in step 4) is heated again to 1100° C. and then hot rolled, with the starting rolling temperature being 1080° C. and the final rolling temperature being 820° C.; immediately cooling the steel ingot in water after hot rolling, with the water temperature of the steel ingot after hot rolling being 800° C., and obtaining a steel billet after cooling;

[0082] 6) Grinding the surface of the steel billet obtained in step 5) to preliminarily remove defects on the surface of the steel billet, that is, removing oxide scale, cracks, pits or scars on the surface of the steel billet;

[0083] 7) heating the steel billet after grinding in step 6) to 1080° C. and keeping the temperature for 20 minutes; after the heat preservation is completed, immediately cooling it in water, and further removing the defects on the surface of the steel billet by pickling, so that the surface of the steel billet becomes a 2B surface;

[0084] 8) The steel billet after pickling in step 7) is subjected to two cold rolling passes in one rolling process to obtain a δ2.6*700 corrosion-resistant alloy plate.

[0085] By measuring the weight of the initial charge input in Example 1 and Example 2, and the weight of the corrosion-resistant alloy plate obtained, the approximate yield of Example 1 and Example 2 is obtained, as shown in Table 1; at the same time, a spectrometer is used to detect the chemical composition of the corrosion-resistant alloy plate obtained in Example 1 and Example 2, and the specific chemical composition is shown in Table 1.

[0086] Table 1: Specific chemical composition and yield of Example 1 and Example 2

[0087]

[0088] According to Table 1, adding 0.003-0.005% Mg to the charge, and then using the medium frequency furnace smelting - die casting electrode rod - electroslag remelting - forging - hot rolling water cooling - grinding - heating pickling - cold rolling process to manufacture corrosion-resistant alloy plates, the alloy yield is greatly improved compared to the alloy yield in the existing process (80-85%).

[0089] Moreover, after the introduction of Mg, the corrosion-resistant alloy plate manufactured according to the process of medium frequency furnace smelting - die casting electrode rod - electroslag remelting - forging - hot rolling water cooling - grinding - heating pickling - cold rolling has a maximum reduction of 4% in oxygen, sulfur and inclusion content, an increase of 13% in yield strength, an increase of 18% in tensile strength, an increase of 4% in elongation after fracture, an increase of 3% in cross-sectional shrinkage, an increase of 3% in corrosion resistance, and an increase of 2% in impact toughness compared with the corrosion-resistant alloy (UNS N08825).

[0090] At the same time, compared with electric arc furnace smelting, the advantages of medium frequency furnace smelting are shown in Table 2.

[0091] Table 2: Comparison of medium frequency furnace and electric arc furnace

[0092] Smelting method Power consumption (yuan / t) Smelting cycle (min) Work Environment Difficulty of solid waste treatment Electric Arc Furnace 350 180 High noise and high pollution Disaster Medium frequency furnace 320 150 Low noise, low pollution easy

[0093] The following conclusions can be drawn from Table 2: In the smelting process, the use of medium frequency furnaces has many advantages over electric arc furnaces: First, the power consumption of medium frequency furnace smelting is lower, which means that under the same smelting task, the medium frequency furnace requires less power resources, which helps to reduce production costs; secondly, the smelting cycle of the medium frequency furnace is relatively short, which improves production efficiency and makes the smelting process faster and more efficient; in addition, from the perspective of the working environment, the working environment of medium frequency furnace smelting is better than that of electric arc furnace; finally, in terms of solid waste treatment, the solid waste generated by medium frequency furnace smelting is easier to clean than that of electric arc furnace.

[0094] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A corrosion-resistant alloy, characterized in that, in terms of mass percentage, Chemical ingredients include: Cr: 22-23%, Ni: 41-42%, Mo: 2.8-3.3%, Cu: 2.0-2.5%, Ti: 0.8-1.0%, Mg: 0.003-0.005%, Al≤0.15%, C≤0.05%, Si≤0.3%, Mn≤1.0%, P≤0.03%, S≤0.02%, and the balance is Fe.

2. A method for preparing the corrosion-resistant alloy sheet according to claim 1, characterized in that: The steps include: 1) Prepare the charge and place it into the medium frequency furnace for smelting under a protective atmosphere; After the charge is melted and the temperature exceeds 1600℃, double slag smelting is carried out. After the slag is whitened, the slag in the medium frequency furnace is removed to obtain molten steel with the chemical composition. 2) pouring the molten steel obtained in step 1) under a protective atmosphere, and obtaining an electrode rod after the molten steel is cooled; 3) using the electrode rod obtained in step 2) as a consumable electrode of an electroslag remelting furnace; applying a voltage of 30 to 50 V and a current of 4500 to 11000 A to the consumable electrode, and melting the electrode rod at a melting rate of 5.3 to 8.0 kg / min; The molten droplets of the electrode rods gather in the crystallizer of the electroslag remelting furnace and form steel ingots after cooling; 4) heating the steel ingot obtained in step 3) to 1100° C. and then forging it, with the starting forging temperature being 1080° C. and the final forging temperature being 800° C.; 5) The steel ingot forged in step 4) is heated again to 1100° C. and then hot rolled, with the starting rolling temperature being 1080° C. and the final rolling temperature being 820° C. After the hot rolling is completed, it is immediately cooled in water to obtain a steel billet; 6) Grinding the surface of the steel billet obtained in step 5) to preliminarily remove defects on the surface of the steel billet; 7) heating the steel billet after grinding in step 6) to 1080° C. and keeping the temperature for 20 minutes; After the insulation is completed, the billet is immediately cooled in water and pickled to make the surface of the billet a 2B surface; 8) cold rolling the steel billet after pickling in step 7) to obtain a corrosion-resistant alloy plate.

3. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: In step 1) and step 2), the protective atmosphere is argon.

4. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: Step 2) is specifically as follows: The molten steel obtained in step 1) is transferred to a tundish, and poured into an ingot mold under argon protection. After the pouring is completed, a heating agent and an ignition agent are added to the ingot mold; and the electrode rod is obtained after the molten steel is cooled.

5. The method for preparing the corrosion-resistant alloy sheet according to claim 4, characterized in that: In step 2), before transferring the molten steel obtained in step 1) to the tundish and before pouring the molten steel into the ingot mold, the tundish and the ingot mold are baked at a temperature exceeding 100°C.

6. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: In step 3), the electroslag slag material used in the electroslag remelting furnace is a five-element slag material; In terms of mass percentage, the quinary slag includes 30-33% CaO, 30-33% Al2O3, 6-12% TiO2, 20-30% CaF2, and 1-5% MgO.

7. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: In step 5), the steel billet is immediately cooled in water after hot rolling, and the water temperature of the steel billet after hot rolling is ≥800°C.

8. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: Step 8) is specifically as follows: the steel billet after pickling in step 7) is subjected to two cold rolling passes in one rolling process to obtain a corrosion-resistant alloy plate.

9. The method for preparing the corrosion-resistant alloy sheet according to claim 2, characterized in that: The charge in step 1) is one or more of return material, ferrochrome, ferromolybdenum, nickel plate, copper plate, titanium bar, metallic manganese, nickel magnesium and fluorite; the charge is baked at a temperature exceeding 200° C. before being placed in the intermediate frequency furnace; The returned material is scrap steel returned material.

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