High-temperature-resistant and high-conductivity steel for electrolytic aluminum anode steel claw and preparation method thereof

Abstract

The application provides a high-temperature-resistant and high-conductivity steel for electrolytic aluminum anode steel claws and a preparation method, and relates to the technical field of steel materials for electrolytic aluminum industry production. The application adds trace alloy elements, controls alloy elements and their proportions, and combines corresponding preparation processes to control the amounts of solid solution and precipitation, so that a new type of high-conductivity steel for electrolytic aluminum anode steel claws with room temperature and high-temperature performance is obtained. The application prepares the high-temperature-resistant and high-conductivity steel for electrolytic aluminum anode steel claws by adjusting and controlling the (Ti+Mo) / C ratio, adding Cu elements, selecting low-cost raw materials, carrying out heat soaking treatment before hot rolling, and controlling the rolling reduction stage during the hot rolling process. The method is simple and easy to operate, green and environmentally friendly, low in cost, short in process, high in efficiency, wide in application range, and beneficial to industrial large-scale production and popularization.

Description

Technical Field

[0001] This invention relates to the technical field of steel materials used in the electrolytic aluminum industry, and in particular to a high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws and its preparation method. Background Technology

[0002] Electrolytic aluminum anode claws are key components used to fix the anodes in the electrolytic aluminum production process. Their main function is to secure the anodes in the electrolytic cell and withstand the strong mechanical forces and electrochemical corrosion environment from the anodes. In modern aluminum electrolysis production, the performance of the claws directly affects the operating efficiency and safety of the electrolytic cell. With the continuous increase in electrolytic aluminum production and the expansion of production scale, the requirements for anode claws are also becoming increasingly stringent.

[0003] Traditional anode steel claws are susceptible to wear, fatigue damage, and even breakage during use due to high temperatures, high current densities, and strong electrochemical corrosion. This not only affects production efficiency and leads to frequent claw replacements but also poses potential safety hazards. Therefore, developing anode steel claws with higher corrosion resistance, high-temperature resistance, and greater mechanical strength is essential.

[0004] Chinese patent CN109338228A discloses a high-conductivity anode steel claw and its preparation method. The steel is prepared through smelting, casting, rough rolling, and finish rolling. The steel contains at least 90% ferrite and at least 10% pearlite, with an average grain size greater than or equal to 20 μm and less than or equal to 200 μm. Clearly, strict control of the microstructure ratio is required, alloying elements must meet specific conditions, and room-temperature mechanical properties and conductivity can be controlled through microstructure adjustment. However, this method has certain application limitations, as it does not consider the high-temperature environment during the use of the anode steel claw, which can easily cause a decrease in strength.

[0005] Chinese patent CN116219283A discloses a steel for electrolytic aluminum anode claws and its production method. Its smelting, heating and rolling processes are relatively complex and difficult to operate. The hot-rolled round steel and hot-rolled flat steel produced have low yield strength, low strength-ductility product and relatively poor plasticity. In particular, although the high carbon content in its composition can improve tensile strength, it will reduce the machinability of the material, making it prone to breakage or cracking during processing, and its impact resistance is also poor.

[0006] Chinese patent CN106521557A discloses an anode steel claw for electrolytic aluminum. Its low carbon content results in low material strength, while its low copper content leads to poor conductivity. The material is directly cast without rolling, resulting in a rough surface. Although heat treatment can reduce resistivity, the resistivity of the anode steel claw is still above 12 μΩ·cm, and its conductivity is not ideal.

[0007] Chinese patent CN119286288A discloses a coating for high conductivity, high temperature resistance, oxidation prevention, and life extension of electrolytic aluminum anodes, as well as its preparation method and application. Obviously, the coating is prepared on the surface of electrolytic aluminum anodes to improve mechanical properties, conductivity, and high temperature resistance. However, this will increase the cost of raw materials and preparation. Moreover, the unevenness of the coating will lead to unstable corrosion resistance and conductivity, especially in high temperature environments. Summary of the Invention

[0008] To address the technical problems existing in current electrolytic aluminum anode steel claws: 1) The chemical composition of the steel is sensitive to performance requirements, and the addition of many elements, including high-cost alloying elements, leads to high production costs; 2) Low carbon content results in low strength, alloying element additions lead to low conductivity, and uneven oxide film layer leads to low corrosion resistance, all of which result in short service life of the steel claws; 3) High-temperature mechanical properties, corrosion resistance, conductivity, and stability are not fully considered; 4) Although surface coatings can improve overall performance, the choice of coating composition increases raw material costs, and different preparation processes can lead to uneven coating and poor adhesion. This invention proposes a high-temperature resistant, high-conductivity steel for electrolytic aluminum anode claws and its preparation method, which solves the aforementioned problems. The technical solution is as follows:

[0009] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.01-0.04%, Ti 0.06-0.09%, Cu 0.2-0.3%, Mo 0.01-0.1%, Si≤0.011%, Mn≤0.030%, Cr≤0.025%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is 3-6.

[0010] Optionally, the microstructure of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw is 93-99% ferrite and no more than 7% pearlite by volume, and there are also 0.2-0.4% (Ti,Mo)C and Cu precipitates by volume.

[0011] Optionally, the ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw is equiaxed with an average grain size of 10-50 μm; the pearlite is lamellar with an average grain size of 5-20 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of no more than 30 nm.

[0012] Optionally, the room temperature properties of the steel used for the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw are: tensile strength not less than 330 MPa, yield strength not less than 235 MPa, elongation after fracture not less than 35%, and resistivity not higher than 13 μΩ·cm; and the high-temperature properties at 400℃ are: tensile strength not less than 270 MPa, yield strength not less than 180 MPa, and resistivity not higher than 14 μΩ·cm.

[0013] A method for preparing high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws, comprising the following steps:

[0014] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws, and then each raw material is weighed to obtain the weighed raw materials.

[0015] S2, Smelting and Continuous Casting: The raw materials weighed in S1 are smelted and then continuously cast to obtain a continuously cast billet.

[0016] S3. Homogenization heat treatment: The slab formed by continuous casting in S2 is heated to the temperature of the homogenization zone and held at that temperature to obtain a continuous casting slab with a uniform microstructure before hot rolling.

[0017] S4. Hot rolling: The continuously cast billet with a uniform microstructure before hot rolling of S3 is hot rolled and then air-cooled to room temperature to obtain steel for high-temperature resistant and high-conductivity electrolytic aluminum anode claws.

[0018] Optionally, the raw materials for S1 include scrap steel, mixed steel and intermediate alloys.

[0019] Optionally, the S2 smelting temperature is 1600-1650℃, the continuous casting temperature is 1500-1550℃, and the billet size is 200mm×200mm×6000mm.

[0020] Optionally, the temperature of the S3 heat exchanger is 950-1050℃, the heating rate is 5-10℃ / min, and the holding time is ≥120min, which ensures uniform heating of the material while shortening the heating time and improving production efficiency.

[0021] Optionally, the initial rolling temperature of S4 hot rolling is controlled at 840-900℃, and the final rolling temperature is controlled at 720-780℃.

[0022] The principle of the chemical component content selection technology of this invention:

[0023] The following is a detailed analysis and explanation of the role and selection range of the components contained in the steel used for electrolytic aluminum steel claws of the present invention.

[0024] C: Carbon is the main strengthening element in steel. When C dissolves in Fe to form a solid solution, it significantly improves the strength and hardness of the steel. Furthermore, C makes austenite grains more stable at high temperatures and less prone to growth, thus enabling the formation of finer martensite structures during quenching, thereby improving the hardenability of the steel. However, excessive C content can reduce the ductility, toughness, and weldability of the steel. This invention controls the weight percentage of C to 0.01-0.03%.

[0025] Ti: Titanium is a strong carbide-forming element. It combines with carbon in steel to form stable, dispersed TiC particles, thereby improving the strength and toughness of the steel. Due to the interaction between titanium and iron atoms, it facilitates heat conduction, thus improving thermal conductivity. Titanium also helps form a dense oxide film, reducing the formation of easily corroded phases. In this invention, the weight percentage of Ti is controlled at 0.06-0.09%.

[0026] Cu: Copper is a good electrical conductor, second only to silver. It has a high coefficient of thermal expansion, which increases when added to steel. Copper significantly improves the corrosion resistance of steel by forming a dense oxide film on the steel surface. Furthermore, copper inhibits localized corrosion in steel, such as pitting and crevice corrosion. This is because the presence of copper alters the electrochemical properties of steel, resulting in a more uniform distribution of corrosion current. In this invention, the weight percentage of Cu is controlled at 0.08-0.018%.

[0027] Molybdenum (Mo): Molybdenum possesses excellent high-temperature resistance, significantly improving the strength and hardness of steel under high-temperature conditions. Molybdenum inhibits grain growth in steel, forming a finer grain structure, thereby enhancing the high-temperature strength of the steel. Molybdenum enhances the resistance of steel to acidic environments and corrosive media, especially in oxidizing media. It effectively inhibits the oxidation of iron in steel, reducing intergranular corrosion. In this invention, the weight percentage of Mo is controlled at 0.01-0.1%.

[0028] P and S: Phosphorus and sulfur are unavoidable harmful impurity elements in steel. P atoms can enter the grain boundaries of steel, damaging their strength and making the steel prone to brittle fracture under stress or impact, especially at low temperatures, affecting the service life and reliability of molds. S combines with iron in steel to form iron sulfides, which are distributed along the grain boundaries, leading to a significant decrease in the toughness and plasticity of the steel. Therefore, the P and S content in steel should be strictly limited. This invention controls the weight percentage of P to ≤0.010% and the weight percentage of sulfur to ≤0.005%.

[0029] In the microstructure, the volume ratio of ferrite + the volume ratio of pearlite = 100%, and the volume ratio of precipitates is counted separately.

[0030] The above technical solution has at least the following advantages compared with the existing technology:

[0031] The above-mentioned solution, proposed by this invention, provides a high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws and its preparation method, which can solve the technical problems existing in the prior art for electrolytic aluminum anode claws: 1) The chemical composition of the steel is sensitive to performance requirements, and a variety of added elements are required, including the addition of high-cost alloying elements, resulting in high production costs; 2) Low carbon content leads to low strength, the addition of alloying elements leads to low conductivity, and the unevenness of the oxide film layer leads to low corrosion resistance, all of which result in a short service life of the steel claws; 3) High-temperature mechanical properties, corrosion resistance, conductivity, and their stability are not fully considered; 4) Although the preparation of surface coatings can improve the overall performance, the selection of coating components will increase the raw material cost, and different preparation processes will result in uneven coatings and poor adhesion.

[0032] This invention utilizes the synergistic effect of Cu and Mo to form a dense oxide film on the steel surface, significantly improving the corrosion resistance of the steel, thereby extending the service life of the steel claw in the electrolytic aluminum bath and reducing maintenance costs.

[0033] This invention controls the amount and size of precipitates by adjusting the (Ti+Mo) / C ratio and adding Cu, thereby reducing the amount of dissolved C in the matrix, reducing electron scattering, and increasing electrical conductivity. At the same time, the precipitation of (Ti,Mo)C and Cu improves the room temperature and high temperature strength of the steel of this invention.

[0034] This invention enables the prepared material to synergistically improve room temperature mechanical properties, room temperature corrosion resistance, and room temperature electrical conductivity, as well as high temperature mechanical properties, high temperature corrosion resistance, and high temperature electrical conductivity and their high temperature stability without the need for surface coating, through low-cost raw material selection, heat preservation treatment in the soaking zone before hot rolling, and stage control of rolling reduction during the hot rolling process.

[0035] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared by this invention has the following room temperature properties: tensile strength not less than 330 MPa, yield strength not less than 235 MPa, elongation after fracture not less than 35%, and resistivity not higher than 13 μΩ·cm; and high-temperature properties at 400℃: tensile strength not less than 270 MPa, yield strength not less than 180 MPa, and resistivity not higher than 14 μΩ·cm.

[0036] In summary, compared with other traditional methods, the method of this invention prepares high-temperature resistant and highly conductive electrolytic aluminum anode steel claws by adjusting the (Ti+Mo) / C ratio, adding Cu element, selecting low-cost raw materials, heat preservation treatment in the soaking section before hot rolling, and controlling the rolling reduction stage during the hot rolling process. This method is simple to operate, environmentally friendly, low-cost, short process, high efficiency, and has a wide range of applications, which is conducive to large-scale industrial production and promotion. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a microstructure diagram of a high-temperature resistant and highly conductive electrolytic aluminum anode steel claw according to Embodiment 1 of the present invention;

[0039] Figure 2 This is a microstructure diagram of a high-temperature resistant and highly conductive electrolytic aluminum anode steel claw according to Embodiment 2 of the present invention;

[0040] Figure 3 This is a microstructure diagram of a high-temperature resistant and highly conductive electrolytic aluminum anode steel claw according to Embodiment 3 of the present invention. Detailed Implementation

[0041] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0042] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0043] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0044] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0045] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0046] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.01-0.04%, Ti 0.06-0.09%, Cu 0.2-0.3%, Mo 0.01-0.1%, Si≤0.011%, Mn≤0.030%, Cr≤0.025%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is 3-6.

[0047] Specifically, the microstructure of the steel used for the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw is 93-99% ferrite and no more than 7% pearlite by volume, with an additional 0.2-0.4% (Ti,Mo)C and Cu precipitates by volume.

[0048] Specifically, the ferrite of the steel used for the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw is equiaxed with an average grain size of 10-50 μm; the pearlite is lamellar with an average grain size of 5-20 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of no more than 30 nm.

[0049] Specifically, the room temperature properties of the steel used for the high-temperature resistant and highly conductive electrolytic aluminum anode steel claw are as follows: tensile strength not less than 330 MPa, yield strength not less than 235 MPa, elongation after fracture not less than 35%, and resistivity not higher than 13 μΩ·cm; the high temperature properties at 400℃ are as follows: tensile strength not less than 270 MPa, yield strength not less than 180 MPa, and resistivity not higher than 14 μΩ·cm.

[0050] A method for preparing high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws, comprising the following steps:

[0051] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws, and then each raw material is weighed to obtain the weighed raw materials.

[0052] S2, Smelting and Continuous Casting: The raw materials weighed in S1 are smelted and then continuously cast to obtain a continuously cast billet.

[0053] S3. Homogenization heat treatment: The slab formed by continuous casting in S2 is heated to the temperature of the homogenization zone and held at that temperature to obtain a continuous casting slab with a uniform microstructure before hot rolling.

[0054] S4. Hot rolling: The continuously cast billet with a uniform microstructure before hot rolling of S3 is hot rolled and then air-cooled to room temperature to obtain steel for high-temperature resistant and high-conductivity electrolytic aluminum anode claws.

[0055] Specifically, the raw materials for S1 include scrap steel, mixed steel and intermediate alloys.

[0056] Specifically, the S2 smelting temperature is 1600-1650℃, the continuous casting temperature is 1500-1550℃, and the billet size is 200mm×200mm×6000mm.

[0057] Specifically, the S3 heat spreader has a temperature of 950-1050℃, a heating rate of 5-10℃ / min, and a holding time of ≥120min, which ensures uniform heating of the material while shortening the heating time and improving production efficiency.

[0058] Specifically, the initial rolling temperature of S4 hot rolling is controlled at 840-900℃, and the final rolling temperature is controlled at 720-780℃.

[0059] Example 1

[0060] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.024%, Ti 0.08%, Cu 0.23%, Mo 0.05%, Si 0.008%, Mn 0.015%, Cr 0.020%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 5.417.

[0061] A method for preparing the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw based on the aforementioned method, comprising the following steps:

[0062] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0063] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0064] S3. Homogenization heat treatment: The slab formed by continuous casting in S2 is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 1000℃ and the holding time is 2.5h, to obtain a continuous casting slab with a uniform microstructure before hot rolling.

[0065] S4. Hot rolling: The continuous casting billet with uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 860℃ and the final rolling temperature is controlled at 770℃. After rolling, it is air-cooled to room temperature to obtain steel for high temperature resistant and high conductivity electrolytic aluminum anode steel claws.

[0066] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 96.3% ferrite and 3.7% pearlite by volume, with an additional 0.26% (Ti,Mo)C and Cu precipitates by volume.

[0067] like Figure 1 As shown, the ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment is equiaxed with an average grain size of 35 μm; the pearlite is lamellar with an average grain size of 9.4 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of 16 nm.

[0068] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 342 MPa, yield strength of 248 MPa, yield ratio of 0.725, elongation after fracture of 44%, and resistivity of 12.4 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 292 MPa, yield strength of 197 MPa, yield ratio of 0.675, and resistivity of 13.6 μΩ·cm.

[0069] Example 2

[0070] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.020%, Ti 0.06%, Cu 0.24%, Mo 0.04%, Si 0.009%, Mn 0.024%, Cr 0.021%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 5.

[0071] A method for preparing high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws, comprising the following steps:

[0072] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0073] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0074] S3. Homogenization heat treatment: The S2 continuously cast billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 980℃ and the holding time is 2.5h, to obtain a continuously cast billet with a uniform microstructure before hot rolling.

[0075] S4. Hot rolling: The continuous casting billet with uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 865℃ and the final rolling temperature is controlled at 750℃. After rolling, it is air-cooled to room temperature to obtain steel for high temperature resistant and high conductivity electrolytic aluminum anode claws.

[0076] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 95.9% ferrite and 4.1% pearlite by volume, with an additional 0.21% (Ti,Mo)C and Cu precipitates by volume.

[0077] like Figure 2 As shown, the ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment is equiaxed with an average grain size of 41 μm; the pearlite is lamellar with an average grain size of 6.0 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of 19 nm.

[0078] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 364 MPa, yield strength of 257 MPa, yield ratio of 0.706, elongation after fracture of 45%, and resistivity of 12.3 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 271 MPa, yield strength of 186 MPa, yield ratio of 0.686, and resistivity of 12.9 μΩ·cm.

[0079] Comparative Example 1

[0080] A type of steel for electrolytic aluminum anode claws, wherein the chemical composition of the steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.017%, Ti 0.03%, Cu 0.22%, Mo 0.02%, Si 0.007%, Mn 0.021%, Cr 0.018%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 2.94.

[0081] A method for preparing steel for electrolytic aluminum anode steel claws, comprising the following steps:

[0082] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0083] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0084] S3. Homogenization heat treatment: The S2 continuously cast billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 1010℃ and the holding time is 2 hours to obtain a continuously cast billet with a uniform microstructure before hot rolling.

[0085] S4. Hot rolling: The continuous casting billet with a uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 855℃ and the final rolling temperature is controlled at 760℃. After rolling, it is air-cooled to room temperature to obtain steel for electrolytic aluminum anode claws.

[0086] The microstructure of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this comparative example consists of 97.2% ferrite and 2.8% pearlite by volume, with an additional 0.1% (Ti,Mo)C and Cu precipitates by volume.

[0087] The ferrite in the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this comparative example has an equiaxed shape and an average grain size of 16 μm; the pearlite has a lamellar shape and an average grain size of 4.1 μm; and the (Ti,Mo)C and Cu have spherical shapes and an average particle size of 14 nm.

[0088] The room temperature properties of the steel used for electrolytic aluminum anode claws prepared in this comparative example are as follows: tensile strength of 336 MPa, yield strength of 242 MPa, yield ratio of 0.720, elongation after fracture of 48%, and resistivity of 12.5 μΩ·cm; and high temperature properties at 400℃ are as follows: tensile strength of 251 MPa, yield strength of 160 MPa, yield ratio of 0.637, and resistivity of 16.4 μΩ·cm.

[0089] Comparative Example 2

[0090] A type of steel for electrolytic aluminum anode claws, wherein the chemical composition of the steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.022%, Ti 0.06%, Cu 0.02%, Mo 0.06%, Si 0.006%, Mn 0.026%, Cr 0.022%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 5.45.

[0091] A method for preparing steel for electrolytic aluminum anode steel claws, comprising the following steps:

[0092] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0093] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0094] S3. Homogenization heat treatment: The slab formed by continuous casting in S2 is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 1000℃ and the holding time is 2.5h, to obtain a continuous casting slab with a uniform microstructure before hot rolling.

[0095] S4. Hot rolling: The continuous casting billet with a uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 870℃ and the final rolling temperature is controlled at 770℃. After rolling, it is air-cooled to room temperature to obtain steel for electrolytic aluminum anode claws.

[0096] The microstructure of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this comparative example consists of 93.7% ferrite and 6.3% pearlite by volume, with an additional 0.12% (Ti,Mo)C and Cu precipitates by volume.

[0097] The ferrite in the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this comparative example has an equiaxed shape and an average grain size of 33 μm; the pearlite has a lamellar shape and an average grain size of 8.2 μm; and the (Ti,Mo)C and Cu have spherical shapes and an average particle size of 15 nm.

[0098] The room temperature properties of the steel used for electrolytic aluminum anode claws prepared in this comparative example are as follows: tensile strength of 316 MPa, yield strength of 224 MPa, yield ratio of 0.709, elongation after fracture of 49%, and resistivity of 14.3 μΩ·cm; and high temperature properties at 400℃ are as follows: tensile strength of 268 MPa, yield strength of 155 MPa, yield ratio of 0.578, and resistivity of 15.3 μΩ·cm.

[0099] It can be seen that, compared with Examples 1-2 of this application, the amount of Ti added in Comparative Example 1 is insufficient, resulting in a (Ti+Mo) / C ratio of less than 3, which leads to insufficient amount of precipitate and low high-temperature strength value. At the same time, due to insufficient precipitate, not enough C is consumed, resulting in severe electron scattering and a significant increase in resistivity.

[0100] In Comparative Example 2, the amount of Cu added was insufficient, resulting in insufficient Cu precipitation and low strength values ​​at both room temperature and high temperature. At the same time, the lack of Cu severely affected its conductivity, causing a significant increase in resistivity.

[0101] Example 3

[0102] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.035%, Ti 0.06%, Cu 0.29%, Mo 0.05%, Si 0.008%, Mn 0.015%, Cr 0.023%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 3.14.

[0103] A method for preparing the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw based on the aforementioned method, comprising the following steps:

[0104] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0105] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0106] S3. Homogenization heat treatment: The S2 continuous casting billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 960℃ and the holding time is 2h, to obtain a continuous casting billet with a uniform microstructure before hot rolling.

[0107] S4. Hot rolling: The continuous casting billet with uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 875℃ and the final rolling temperature is controlled at 735℃. After rolling, it is air-cooled to room temperature to obtain steel for high temperature resistant and high conductivity electrolytic aluminum anode claws.

[0108] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 98.6% ferrite and 1.4% pearlite by volume, with an additional 0.34% (Ti,Mo)C and Cu precipitates by volume.

[0109] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has an equiaxed ferrite shape with an average grain size of 22 μm; a lamellar pearlite shape with an average grain size of 8.5 μm; and spherical (Ti,Mo)C and Cu shapes with an average particle size of 17 nm.

[0110] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 376 MPa, yield strength of 277 MPa, yield ratio of 0.737, elongation after fracture of 47%, and resistivity of 11.5 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 285 MPa, yield strength of 188 MPa, yield ratio of 0.660, and resistivity of 12.5 μΩ·cm.

[0111] Example 4

[0112] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.028%, Ti 0.09%, Cu 0.21%, Mo 0.08%, Si 0.006%, Mn 0.023%, Cr 0.017%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 5.71.

[0113] A method for preparing the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw based on the aforementioned method, comprising the following steps:

[0114] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0115] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0116] S3. Homogenization heat treatment: The S2 continuously cast billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 965℃ and the holding time is 2.5h, to obtain a continuously cast billet with a uniform microstructure before hot rolling.

[0117] S4. Hot rolling: The continuous casting billet with uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 870℃ and the final rolling temperature is controlled at 755℃. After rolling, it is air-cooled to room temperature to obtain steel for high temperature resistant and high conductivity electrolytic aluminum anode claws.

[0118] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 95.5% ferrite and 4.5% pearlite by volume, with an additional 0.31% (Ti,Mo)C and Cu precipitates by volume.

[0119] The ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment is equiaxed with an average grain size of 19 μm; the pearlite is lamellar with an average grain size of 10.2 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of 16 nm.

[0120] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 362 MPa, yield strength of 244 MPa, yield ratio of 0.674, elongation after fracture of 42%, and resistivity of 11.8 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 282 MPa, yield strength of 208 MPa, yield ratio of 0.738, and resistivity of 13.7 μΩ·cm.

[0121] Example 5

[0122] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.021%, Ti 0.07%, Cu 0.24%, Mo 0.08%, Si 0.009%, Mn 0.017%, Cr 0.025%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 5.71.

[0123] A method for preparing the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw based on the aforementioned method, comprising the following steps:

[0124] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0125] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0126] S3. Homogenization heat treatment: The S2 continuous casting billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 990℃ and the holding time is 2h, to obtain a continuous casting billet with a uniform microstructure before hot rolling.

[0127] S4. Hot rolling: The continuous casting billet with a uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 865℃ and the final rolling temperature is controlled at 760℃. After rolling, it is air-cooled to room temperature to obtain steel for high-temperature resistant and high-conductivity electrolytic aluminum anode claws.

[0128] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 95.2% ferrite and 4.8% pearlite by volume, with an additional 0.32% (Ti,Mo)C and Cu precipitates by volume.

[0129] The ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment is equiaxed with an average grain size of 33 μm; the pearlite is lamellar with an average grain size of 7.9 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of 18 nm.

[0130] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 369 MPa, yield strength of 264 MPa, yield ratio of 0.715, elongation after fracture of 41%, and resistivity of 12.1 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 311 MPa, yield strength of 204 MPa, yield ratio of 0.656, and resistivity of 12.8 μΩ·cm.

[0131] Example 6

[0132] A high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, wherein the chemical composition of the high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws, by mass percentage, is: C 0.037%, Ti 0.08%, Cu 0.27%, Mo 0.07%, Si 0.008%, Mn 0.019%, Cr 0.019%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, with the remainder being Fe and unavoidable trace chemical elements; wherein, (Ti+Mo) / C is approximately 4.05.

[0133] A method for preparing the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw based on the aforementioned method, comprising the following steps:

[0134] S1. Raw material weighing: The raw materials are proportioned according to the chemical composition of the steel used for high-temperature resistant and high-conductivity electrolytic aluminum anode steel claws. Then, each raw material is weighed, including scrap steel, mixed steel and intermediate alloy, to obtain the weighed raw materials.

[0135] S2. Melting and continuous casting: The raw materials weighed in S1 are melted at a temperature of 1600-1650℃, and then continuously cast at a temperature of 1500-1550℃ to obtain a continuously cast billet; the billet size is 200mm×200mm×6000mm.

[0136] S3. Homogenization heat treatment: The S2 continuous casting billet is heated to the temperature of the soaking zone and held at that temperature. The temperature of the soaking zone is 975℃ and the holding time is 2h, to obtain a continuous casting billet with a uniform microstructure before hot rolling.

[0137] S4. Hot rolling: The continuous casting billet with uniform microstructure before hot rolling of S3 is hot rolled. The initial rolling temperature is controlled at 880℃ and the final rolling temperature is controlled at 740℃. After rolling, it is air-cooled to room temperature to obtain steel for high temperature resistant and high conductivity electrolytic aluminum anode claws.

[0138] The high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment has a microstructure of 97.9% ferrite and 2.1% pearlite by volume, with an additional 0.37% (Ti,Mo)C and Cu precipitates by volume.

[0139] The ferrite of the high-temperature resistant and high-conductivity electrolytic aluminum anode steel claw prepared in this embodiment is equiaxed with an average grain size of 20 μm; the pearlite is lamellar with an average grain size of 13.2 μm; and the (Ti,Mo)C and Cu are spherical with an average particle size of 20 nm.

[0140] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared in this embodiment has the following room temperature properties: tensile strength of 381 MPa, yield strength of 272 MPa, yield ratio of 0.714, elongation after fracture of 40%, and resistivity of 11.7 μΩ·cm; and high-temperature properties at 400℃: tensile strength of 298 MPa, yield strength of 203 MPa, yield ratio of 0.681, and resistivity of 12.6 μΩ·cm.

[0141] The above-mentioned solution, proposed by this invention, provides a high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws and its preparation method, which can solve the technical problems existing in the prior art for electrolytic aluminum anode claws: 1) The chemical composition of the steel is sensitive to performance requirements, and a variety of added elements are required, including the addition of high-cost alloying elements, resulting in high production costs; 2) Low carbon content leads to low strength, the addition of alloying elements leads to low conductivity, and the unevenness of the oxide film layer leads to low corrosion resistance, all of which result in a short service life of the steel claws; 3) High-temperature mechanical properties, corrosion resistance, conductivity, and their stability are not fully considered; 4) Although the preparation of surface coatings can improve the overall performance, the selection of coating components will increase the raw material cost, and different preparation processes will result in uneven coatings and poor adhesion.

[0142] This invention utilizes the synergistic effect of Cu and Mo to form a dense oxide film on the steel surface, significantly improving the corrosion resistance of the steel, thereby extending the service life of the steel claw in the electrolytic aluminum bath and reducing maintenance costs.

[0143] This invention controls the amount and size of precipitates by adjusting the (Ti+Mo) / C ratio and adding Cu, thereby reducing the amount of dissolved C in the matrix, reducing electron scattering, and increasing electrical conductivity. At the same time, the precipitation of (Ti,Mo)C and Cu improves the room temperature and high temperature strength of the steel of this invention.

[0144] This invention enables the prepared material to synergistically improve room temperature mechanical properties, room temperature corrosion resistance, and room temperature electrical conductivity, as well as high temperature mechanical properties, high temperature corrosion resistance, and high temperature electrical conductivity and their high temperature stability without the need for surface coating, through low-cost raw material selection, heat preservation treatment in the soaking zone before hot rolling, and stage control of rolling reduction during the hot rolling process.

[0145] The high-temperature resistant and highly conductive steel for electrolytic aluminum anode claws prepared by this invention has the following room temperature properties: tensile strength not less than 330 MPa, yield strength not less than 235 MPa, elongation after fracture not less than 35%, and resistivity not higher than 13 μΩ·cm; and high-temperature properties at 400℃: tensile strength not less than 270 MPa, yield strength not less than 180 MPa, and resistivity not higher than 14 μΩ·cm.

[0146] In summary, compared with other traditional methods, the method of this invention prepares high-temperature resistant and highly conductive electrolytic aluminum anode steel claws by adjusting the (Ti+Mo) / C ratio, adding Cu element, selecting low-cost raw materials, heat preservation treatment in the soaking section before hot rolling, and controlling the rolling reduction stage during the hot rolling process. This method is simple to operate, environmentally friendly, low-cost, short process, high efficiency, and has a wide range of applications, which is conducive to large-scale industrial production and promotion.

[0147] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0148] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0149] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0150] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A steel for high-temperature-resistant high-conductivity electrolytic aluminum anode steel claw, characterized by, The high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel has the following chemical components in percentage by mass: C 0.01-0.04%, Ti 0.06-0.09%, Cu 0.2-0.3%, Mo 0.01-0.1%, Si≤0.011%, Mn≤0.030%, Cr≤0.025%, Ni≤0.011%, Al≤0.015%, P≤0.007%, S≤0.006%, and the rest Fe and inevitable trace chemical elements; wherein (Ti+Mo) / C is 3-6. The high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel has the following microstructure: 93-99% by volume fraction of ferrite and not more than 7% by volume fraction of pearlite, and additionally 0.2-0.4% by volume fraction of (Ti, Mo)C and Cu precipitation. The high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel has the following room-temperature performance: tensile strength not less than 330 MPa, yield strength not less than 235 MPa, elongation after fracture not less than 35%, and resistivity not higher than 13 μΩ·cm; and the following high-temperature performance at 400 ℃: tensile strength not less than 270 MPa, yield strength not less than 180 MPa, and resistivity not higher than 14 μΩ·cm.

2. The high temperature and high conductivity steel for electrolytic aluminium anode steel shoe according to claim 1, characterized in that, The ferrite of the high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel has an equiaxed shape with an average grain size of 10-50 μm; the pearlite has a lamellar shape with an average grain size of 5-20 μm; and the (Ti, Mo)C and Cu have a spherical shape with an average particle size not higher than 30 nm.

3. A method for producing a steel for high-temperature-resistant and highly conductive electrolytic aluminum anode steel claws based on the steel of claim 1, characterized by, The high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel is prepared by the following steps: S1, raw material weighing: the raw materials are proportioned according to the chemical component content of the high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel, and then each raw material is weighed to obtain weighed raw materials; S2, melting and continuous casting: the weighed raw materials in S1 are melted, and then continuously cast to obtain a continuously cast billet; S3, homogenization heat treatment: the continuously cast billet in S2 is heated to a soaking temperature and kept for a certain time to obtain a continuously cast billet with a uniform microstructure before hot rolling; S4, hot rolling: the continuously cast billet with a uniform microstructure before hot rolling in S3 is hot rolled, and then air cooled to room temperature to obtain the high-temperature-resistant and high-conductivity electrolytic aluminum anode steel claw steel.

4. The method of producing a steel for high-temperature high-conductivity aluminum electrolysis anode steel shoes according to claim 3, characterized by, The raw materials in S1 include scrap steel, miscellaneous steel and intermediate alloy.

5. The method of producing a steel for high temperature and high conductivity aluminum electrolysis anode steel shoe according to claim 3, characterized in that, The melting temperature in S2 is 1600-1650 ℃, the continuous casting temperature is 1500-1550 ℃, and the billet size is 200 mm×200 mm×6000 mm.

6. The method of producing a steel for high temperature and high conductivity aluminum electrolysis anode steel shoes according to claim 3, characterized in that, The soaking temperature in S3 is 950-1050 ℃, the heating rate is 5-10 ℃ / min, and the holding time is≥120 min.

7. The method of producing a steel for high temperature and high conductivity aluminum electrolysis anode steel shoes according to claim 3, characterized by, The opening rolling temperature in S4 is controlled at 840-900 ℃, and the final rolling temperature is controlled at 720-780 ℃.

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