A method for preparing ingots using titanium scrap to achieve uniform oxygenation and alloy addition.

Abstract

This invention provides a method for preparing ingots using titanium scrap to achieve uniform oxidation and alloy addition, comprising the following steps: pretreating the titanium scrap; determining the main material, batching materials, and process scheme according to the composition requirements of the titanium or titanium alloy ingot, wherein the main material is sponge titanium or recycled material, and the batching materials include titanium scrap, an oxygenator, and / or an intermediate alloy; mixing the titanium scrap with the oxygenator and / or intermediate alloy powder, pressing it into a block to form an intermediate electrode; placing the intermediate electrode in the main material to form a consumable electrode; and performing vacuum consumable melting on the consumable electrode to obtain a titanium or titanium alloy ingot. The method of this invention can significantly improve the proportion of recycled material added and the uniformity of composition, while reducing raw material costs.

Description

Technical Field

[0001] This invention relates to the field of titanium metal recycling and ingot preparation technology, and more specifically, to an ingot preparation method that utilizes titanium scrap to achieve uniform oxygenation and alloy addition. Background Technology

[0002] Titanium metal is widely used in aerospace, shipbuilding and marine engineering, petrochemical and other fields due to its excellent properties such as light weight, high strength, corrosion resistance, high temperature resistance and non-magnetic properties. With the rapid growth of titanium processed material production, the utilization rate of titanium metal from raw materials to final parts is only about 20%, resulting in a large amount of waste material generated during processing, especially shavings of titanium waste.

[0003] To reduce production costs, the recycling and smelting technology for titanium scrap has been gradually developing in recent years. Typically, scrap is packaged, pressed, or welded to form consumable electrodes for vacuum consumable melting. However, existing recycling processes are only suitable for recycling materials of the same grade, making it difficult to control composition, add alloying elements, or convert material grades, thus limiting their application scope.

[0004] Furthermore, when preparing titanium alloy ingots using sponge titanium as the main raw material, the electrodes are typically formed by layering or mixing sponge titanium with intermediate alloys or additives such as titanium dioxide and then pressing them together. However, since the particle size of intermediate alloys and oxide additives is generally smaller than that of sponge titanium particles, they are prone to agglomeration during the layering process, resulting in uneven composition distribution and affecting the uniformity of the final ingot's microstructure and quality stability.

[0005] Chinese patent CN118480707A discloses a method for improving the uniformity of oxygen content in titanium or titanium alloy ingots. This method involves graded mixing of sponge titanium with different particle sizes, raw material titanium dioxide, and intermediate alloy, thereby improving the uniformity of titanium dioxide distribution in the electrode block. However, this method is only applicable to sponge titanium and not to the processing of recycled materials.

[0006] Therefore, there is a need for a casting preparation method that utilizes titanium scrap to achieve uniform oxygenation and alloy addition, in order to enhance the application value of recycled materials and expand their applicability in the production of multiple grades of titanium and titanium alloys. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing ingots using titanium scrap to achieve uniform oxygenation and alloy addition, which significantly improves the proportion of recycled materials added and the uniformity of composition, reduces raw material costs, and promotes green manufacturing and high-quality development of titanium materials.

[0008] To achieve the above objectives, this invention provides a method for preparing ingots using titanium scrap to achieve uniform oxidation and alloy addition. The technical solution of this invention is implemented as follows:

[0009] A method for preparing ingots using titanium scrap to achieve uniform oxygenation and alloy addition includes the following steps:

[0010] S1, Pre-treat the titanium shavings;

[0011] S2. Based on the composition requirements of titanium or titanium alloy ingots, determine the main material, batching material and process plan. The main material is sponge titanium or recycled material, and the batching material includes titanium scrap, oxygenating agent and / or intermediate alloy.

[0012] S3, mix titanium shavings with an oxygenating agent and / or intermediate alloy powder to make an intermediate electrode;

[0013] S4, the intermediate electrode is placed in the main material to make a consumable electrode;

[0014] S5, the consumable electrode is subjected to vacuum consumable melting to obtain titanium or titanium alloy ingots.

[0015] Furthermore, the pretreatment includes crushing, magnetic separation, washing, and drying.

[0016] Furthermore, after the pretreatment, the length of the titanium chips is ≤4cm and the width is ≤2cm.

[0017] Furthermore, step S2 includes:

[0018] S21, titanium scrap mixing and composition calibration to obtain the reference composition of titanium scrap;

[0019] S22, Selection of main ingredients and batching materials and determination of process scheme;

[0020] S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

[0021] Furthermore, step S21 includes: uniformly mixing different batches of titanium shavings, defining the mixed titanium shavings as a whole as a raw material batch; taking samples from different locations and testing them, and taking the average value of each element as the benchmark composition of the raw material batch of titanium shavings.

[0022] Furthermore, the oxygenating agent is titanium dioxide, and the intermediate alloy includes one or more of TiFe, AlV, AlMo, AlSn, AlCr, and TiSn.

[0023] Furthermore, the mixing method is mechanical stirring or layer-by-layer spreading; the layer-by-layer spreading involves alternately spreading titanium shavings with an oxygenating agent or intermediate alloy.

[0024] Furthermore, the process includes: determining the diameter of the intermediate electrode based on the ingot diameter and establishing a mapping relationship between the two.

[0025] Furthermore, the process scheme includes: determining the method of preparing consumable electrodes by pressing, packaging, or welding, based on the material, specifications, and type of the ingot.

[0026] Furthermore, when the main material is sponge titanium, the intermediate electrode and sponge titanium are pressed together to form the consumable electrode; when the main material is recycled material, the intermediate electrode and recycled material are welded or packaged to form the consumable electrode.

[0027] Furthermore, step S3 includes: pressing the mixture into blocks according to specifications to produce an intermediate electrode, the intermediate electrode comprising one or more blocks.

[0028] Furthermore, the intermediate electrode is located in the central region of the consumable electrode, and the intermediate electrode extends through the head and tail of the consumable electrode.

[0029] Compared with existing technologies, the ingot preparation method of the present invention, which utilizes titanium scrap to achieve uniform oxygenation and alloy addition, has the following advantages:

[0030] Achieving precise control of recycled material composition: By using titanium scrap as a carrier and mixing it with titanium dioxide or intermediate alloys, the technical difficulties of oxygenating and adding alloying elements to titanium metal recycled materials are effectively solved, and the composition of recycled materials can be precisely adjusted.

[0031] Facilitating the conversion of different material grades: By adjusting the types and ratios of additives, pure metallic titanium recycled materials can be transformed into high-alloy titanium materials, thereby improving resource utilization and product added value.

[0032] The oxygenation and alloying process is simple and controllable: taking advantage of the loose structure and large specific surface area of ​​titanium chips, it is easy to uniformly adsorb or mix titanium dioxide powder and intermediate alloy particles, making oxygen and alloying elements easier to dissolve and diffuse during the smelting process, thus achieving efficient and uniform component introduction.

[0033] Improving material uniformity and ingot quality: Titanium chips themselves have a uniform composition and are easy to mix thoroughly with other powder materials or be laid in layers, significantly improving the segregation problem existing in traditional material feeding processes and enhancing the uniformity of consumable electrode loading, especially suitable for sponge titanium raw material systems. Through uniform material feeding, titanium alloy ingots with highly uniform oxygen content and alloy element distribution are obtained, effectively suppressing defects such as segregation and inclusions, and improving material consistency and reliability.

[0034] Enhance the uniformity of additive distribution: Use titanium shavings as a carrier to carry oxygenating agents or alloy powders, forming a stable intermediate electrode structure during the pressing process, avoiding fine powder from floating or agglomerating during melting, and ensuring that additives are released uniformly in space.

[0035] Improving the comprehensive utilization rate of titanium scrap and reducing production costs: Previously difficult-to-process titanium scrap can be directly used in the preparation of core electrodes, significantly increasing its recycling rate to over 95% and reducing resource waste. This promotes a circular economy in titanium metallurgy, reduces industrial solid waste emissions, and aligns with the development direction of low-carbon manufacturing and efficient resource utilization. It also reduces the use of high-cost sponge titanium by 10%–30%, while achieving a high proportion of recycled material doping, significantly reducing the manufacturing cost of titanium ingots and yielding good economic benefits.

[0036] It has strong process compatibility and is easy to promote industrially: the equipment used is a conventional mixer, press and vacuum arc furnace, without the need for additional investment in special equipment, and can be seamlessly integrated into the existing titanium smelting production line. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] This invention provides a method for preparing ingots using titanium scrap to achieve uniform oxygenation and alloy addition, comprising the following steps:

[0040] S1 involves pre-treating titanium scrap by screening, washing, and drying to obtain titanium scrap raw materials with uniform particle size.

[0041] The titanium chips are metal chips produced from turning, milling, or grinding of TA1, TA2, or other industrial pure titanium grades. Titanium chips of the same material from different batches are subjected to conventional processing such as crushing, magnetic separation, cleaning, and drying to obtain titanium chips with a length ≤4cm and a width ≤2cm.

[0042] After being crushed, magnetically separated, cleaned, and dried, titanium chips are characterized by being fluffy, porous, uniform in size, and having a large specific surface area. They not only have good flowability and are easy to mix and press, but can also serve as an ideal "carrier" to efficiently load titanium dioxide or intermediate alloys (such as AlV55 and aluminum briquettes), significantly improving the problems of easy agglomeration of titanium dioxide and alloy segregation in traditional processes.

[0043] S2. Determine the main materials, batching, and process plan based on the composition requirements of the target titanium or titanium alloy ingot.

[0044] S21, titanium scrap mixing and composition calibration, to obtain the reference composition of titanium scrap.

[0045] Different batches of titanium scrap were uniformly mixed, and the mixed titanium scrap was defined as a single raw material batch. Samples were taken from different locations to detect impurity elements such as Fe, N, and O, and the average value of each element was taken as the baseline composition of the raw material batch of titanium scrap.

[0046] A mixing calibration experiment was conducted to establish a model for evaluating the mixing uniformity of titanium scrap-titanium dioxide and / or titanium scrap-master alloy, which can be used to guide the setting of batching ratios and mixing process parameters.

[0047] S22, Selection of main ingredients and batching materials and determination of process scheme.

[0048] The main material is sponge titanium or recycled material. The ingredients include titanium shavings, an oxygenating agent, and / or a master alloy. Preferably, the oxygenating agent is titanium dioxide powder with a purity ≥99% and a particle size ≤100μm; the oxygen content in the final ingot is adjusted by controlling the amount of titanium dioxide added, achieving uniform introduction of oxygen. The master alloy includes one or more of TiFe, AlV, AlMo, AlSn, AlCr, and TiSn, used to add iron, aluminum, vanadium, tin, molybdenum, and manganese alloying elements to the ingot to prepare titanium alloys such as TC4, TA15, and TA18.

[0049] The process scheme is determined based on the material and specifications of the ingot and the type of main material used (sponge titanium or recycled material), as shown in Table 1.

[0050] Table 1. Process schemes for preparing ingots of various sizes using titanium scrap.

[0051] Based on the material, specifications, and type of main material of the ingot, the method of preparing the consumable electrode—either pressing, packaging, or welding—is determined. For sponge titanium main material, pressing (combined with titanium scrap briquettes) is used to achieve precise proportioning. For recycled main material (plates, scraps, etc.), due to their irregular shape, high density, and difficulty in compaction, packaging or welding is selected to effectively fix the position of the central electrode in the titanium scrap, preventing displacement or segregation during smelting.

[0052] The diameter of the intermediate electrode is determined based on the ingot diameter. On one hand, matching the intermediate electrode diameter to the ingot diameter ensures it occupies a suitable radial position within the electrode, guaranteeing the stable and synchronous release of oxygen or alloying elements from the central region of the molten pool. This avoids segregation, localized enrichment, or melting lag caused by size mismatch, preventing deformation, displacement, or collapse during melting, maintaining a constant melting rate and stable arc spot, thus obtaining an ingot with more uniform composition and microstructure. On the other hand, the intermediate electrode diameter adapts to the ingot specifications, accommodating different main materials and preparation methods. Establishing a reusable size mapping relationship facilitates rapid selection, mold standardization, and production line switching, reducing trial-and-error costs.

[0053] S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

[0054] Perform batching calculations for the main material and auxiliary materials such as titanium scrap, titanium dioxide, and intermediate alloys, and calculate the usage of each material according to the weight ratio.

[0055] S3, the titanium shavings are thoroughly mixed with titanium dioxide and / or intermediate alloy powder to obtain a uniformly composed mixture; the mixture is then pressed into an intermediate electrode.

[0056] The mixing method is either mechanical stirring or layer-by-layer spreading. In the layer-by-layer spreading method, titanium shavings and titanium dioxide or intermediate alloy are alternately spread in the mold to ensure that the additives are evenly distributed in space.

[0057] The mixture is pressed into blocks according to appropriate specifications using a press to obtain an intermediate electrode consisting of titanium scrap plus an intermediate alloy or titanium dioxide. The intermediate electrode comprises one or more blocks. The density of the intermediate electrode blocks is controlled between 1.8 and 2.2 g / cm³. 3 The size is adapted to the fabric space of the main electrode, the pressing pressure is 150-600MPa, the holding time is 10-60 seconds, and the resulting electrode density is not less than 70% of the corresponding block material.

[0058] S4, the intermediate electrode is placed in sponge titanium or recycled material to form a consumable electrode.

[0059] When preparing consumable electrodes, differentiated molding processes are adopted according to the type of main material. When the main material is sponge titanium, its weight is calculated first, the intermediate electrode is placed in the sponge titanium, and the whole assembly is pressed into a consumable electrode; when the main material is recycled material, the recycled material is welded or packaged with the intermediate electrode to prepare the consumable electrode.

[0060] When the main material is sponge titanium, a "two-stage feeding and pressing" process is adopted. First, the titanium shavings intermediate electrode is placed in the middle of the sponge titanium block, and then the whole block is pressed to form a large block, which is then welded to prepare the consumable electrode. When the main material is recycled material (such as TA1, TA5 plates / residue), the titanium shavings intermediate electrode is placed in the middle of the recycled material to be packaged, and integrated with the recycled material through hydraulic packaging or welding, ensuring that the titanium shavings electrode runs through the head and tail and its length is consistent with the consumable electrode. This differentiated preparation strategy takes into account the physical characteristics of the two types of main materials: sponge titanium is loose and easy to compact, and is suitable for whole pressing; recycled material has high density and poor formability, and is suitable for packaging / welding to ensure structural integrity and continuous element release, thereby uniformly introducing oxygen and alloying elements.

[0061] Preferably, the intermediate electrode extends through the consumable electrode from beginning to end without any gaps, and the length of the intermediate electrode is consistent with the length of the consumable electrode. This ensures that during vacuum consumable melting, titanium dioxide or the intermediate alloy can be continuously, stably, and uniformly released along the depth of the molten pool, thereby effectively avoiding compositional gradients or element enrichment caused by local interruptions, and significantly improving the axial and radial oxygen content and the uniformity of alloy element distribution in the ingot.

[0062] Preferably, the intermediate electrode is located in the central region of the consumable electrode and is surrounded by sponge titanium or recycled titanium material, achieving uniform diffusion during the melting process. The intermediate electrode blocks can be symmetrically arranged axially or radially inside the consumable electrode, with a quantity of 1 to 6, to achieve uniform release and diffusion of solute elements during the melting process.

[0063] S5, the consumable electrode is subjected to vacuum consumable melting to obtain a titanium or titanium alloy ingot with uniform composition distribution.

[0064] The self-consumption smelting process involves controlling parameters such as smelting current, voltage, and pressure. Preferably, pure titanium or titanium alloy ingots are obtained through two to three vacuum self-consumption smelting processes.

[0065] This method overcomes the technical bottleneck of not being able to add intermediate alloys in a fully recycled material system. By uniformly compounding titanium shavings with titanium dioxide / alloy and pressing them into an intermediate electrode that matches the ingot specifications, and then placing it through the center of a consumable electrode, the stable preparation and controllable melting of fully recycled material electrodes have been successfully achieved. This method is also compatible with sponge titanium raw material systems, and only requires adding a titanium shavings intermediate electrode pressing step to the conventional electrode preparation process. It does not require new large-scale equipment or complex tooling, has low raw material costs, low industrialization barriers, and is both economical and universally applicable.

[0066] The following examples illustrate how this method was applied to the preparation of TA2 grade pure titanium ingots using oxygenation of TA1 recycled materials, the preparation of TC4 titanium alloy ingots using Al-V master alloy added to TA5 recycled materials, and the preparation of TA18 high-strength titanium alloy ingots using Ti-Fe master alloy and titanium dioxide added to sponge titanium raw materials.

[0067] Example 1

[0068] This embodiment provides a method for preparing ingots using titanium scrap to achieve uniform oxygenation, enabling the preparation of TA2 ingots from recycled TA1 material. The specific steps are as follows:

[0069] S1 involves pre-treating titanium scrap by screening, washing, and drying to obtain titanium scrap raw materials with uniform particle size.

[0070] Three batches of TA1 titanium scrap were selected and subjected to crushing, magnetic separation to remove ferromagnetic impurities, water washing to remove surface oil and adhering substances, and drying to remove moisture. The final product consisted of clean titanium scrap with a length ≤4cm and a width ≤2cm, meeting the requirements for subsequent mixing and pressing.

[0071] S2. Determine the main materials, batching materials, and process plan based on the composition requirements of the target titanium ingot.

[0072] S21, titanium scrap mixing and composition calibration, to obtain the reference composition of titanium scrap.

[0073] The three batches of titanium scrap were thoroughly mixed in a large homogenizer to form a homogenized batch, designated as batch number "250109". During the mixing process, five barrels (barrels 1, 4, 7, 10, and 13) were sampled at equal intervals to test the content of key impurity elements such as Fe, N, O, and C. The test results are shown in Table 2 below.

[0074] Table 2. Mixing test results of Example 1

[0075]

[0076] The average value of the test results for each element is taken as the baseline composition for this batch of titanium scrap, which is then used for subsequent batching calculations.

[0077] S22, Selection of main ingredients and batching materials and determination of process scheme.

[0078] Based on the target product being TA2 pure titanium ingots, and using TA1 recycled sheet as the main material; based on the target ingot diameter of 980mm, the maximum diameter of the intermediate electrode was determined to be 320mm; the intermediate electrode was prepared by layer-by-layer titanium dioxide spreading followed by pressing, and the intermediate electrode was embedded in the middle of the recycled material electrode using the "intermediate electrode + recycled material packaging" process.

[0079] S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

[0080] The usage of each ingredient was calculated based on their weight ratio. Based on the oxygen content requirement of TA2 pure titanium ingots (≥0.08%), and considering the background oxygen content of the raw materials and the oxygen-enhancing capacity of titanium dioxide, precise ingredient calculations were performed. The final ingredient ratios were determined as follows: main ingredient: 10500 kg of recycled TA1 sheet; carrier titanium scrap: 850 kg; oxygenating agent: 23.2 kg of titanium dioxide.

[0081] S3, fabricate the intermediate electrode.

[0082] S31, the titanium shavings and titanium dioxide are thoroughly mixed to obtain a uniform mixture; the mixture is then pressed into a block.

[0083] Titanium dioxide was uniformly introduced into titanium shavings using a layered feeding method to create briquettes. The intermediate electrode was 380 mm long, and each intermediate electrode used 21.2 kg of titanium shavings and 570 g of titanium dioxide. The feeding process consisted of three additions of titanium shavings and two intermediate spreadings of titanium dioxide, for a total of five feedings and three pressings, resulting in briquettes with a diameter of 320 mm.

[0084] S32, multiple pressure blocks are welded and assembled into an integral intermediate electrode.

[0085] The three clamping blocks are welded together to form a single intermediate electrode. The intermediate electrode has a diameter of 320 mm and a length of approximately 1135 mm. The required number of intermediate electrodes are prepared by repeating the process.

[0086] S4, embed the intermediate electrode block into the recycled titanium material to prepare a consumable electrode.

[0087] The prepared intermediate electrode is placed at the center of the electrode to be packaged, which is made of recycled TA1 sheet material, ensuring that it is centered along the axial direction and that its length direction is consistent with that of the main electrode. The entire structure is then compacted and packaged using a hydraulic baler to form a complete consumable electrode. After welding reinforcement, a consumable electrode suitable for smelting is obtained, with a total length of 5630mm~5635mm, matching the length of the intermediate electrode.

[0088] S5, the consumable electrode is subjected to vacuum consumable melting to obtain a titanium ingot with uniform composition distribution.

[0089] The aforementioned consumable electrodes were placed in a vacuum consumable melting furnace and subjected to two remelting processes to improve compositional uniformity and density. The final product was a TA2 pure titanium ingot with a total weight of 10897 kg. Oxygen content was measured at different axial positions of the ingot, with the following results: from top to bottom, oxygen contents were 0.161%, 0.158%, 0.153%, 0.160%, and 0.154%. The data shows that the oxygen distribution is uniform, with a maximum deviation of less than ±0.005%, meeting the TA2 grade standard requirements. This verifies the effectiveness and stability of this invention in achieving controlled oxygenation using recycled materials.

[0090] Example 2

[0091] This embodiment provides a method for preparing ingots using titanium scrap to achieve uniform alloy addition, enabling the preparation of TC4 ingots from recycled TA5 material. The specific steps are as follows:

[0092] S1, the titanium shavings are cleaned, dried and sieved to obtain titanium shavings raw materials with uniform particle size.

[0093] Two batches of TA1 titanium scrap were selected and subjected to crushing, magnetic separation to remove ferromagnetic impurities, water washing to remove surface oil and adhering substances, and drying to remove moisture. The final product consisted of clean titanium scrap with a length ≤4cm and a width ≤2cm, meeting the requirements for subsequent mixing and pressing.

[0094] S2. Based on the composition requirements of the target titanium alloy ingot, determine the main materials, batching, and process plan.

[0095] S21, titanium scrap mixing and composition calibration, to obtain the reference composition of titanium scrap.

[0096] The two batches of titanium scrap were thoroughly mixed in a large homogenizer to form a homogenized batch, designated as batch number "250211". During the mixing process, samples were taken from four barrels (barrels 1, 5, 9, and 12) at equal intervals to test the content of key impurity elements such as Fe, N, O, and C. The test results are shown in Table 3 below.

[0097] Table 3. Mixing test results of Example 2

[0098]

[0099] The average value of the test results for each element is taken as the baseline composition for this batch of titanium scrap, which is then used for subsequent batching calculations.

[0100] S22, Selection of main ingredients and batching materials and determination of process scheme.

[0101] Based on the target product being TC4 pure titanium ingots, and using TA5 recycled sheet as the main material, and considering the target ingot diameter of 740mm, the maximum diameter of the intermediate electrode was determined to be 280mm. The intermediate electrode was prepared by pressing a mixture of titanium chips and intermediate alloy, and then welded to the center of the TA5 recycled sheet using a "intermediate electrode + recycled material welding" process.

[0102] S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

[0103] The usage of each ingredient was calculated according to the weight ratio. Precise ingredient calculations were performed based on the oxygen content requirements of TC4 pure titanium ingots. The final ingredient ratios were determined as follows: Main ingredient: 4500 kg of TA5 recycled plate; Carrier titanium scrap: 1120 kg; Intermediate alloy: 345 kg of AlV55 alloy and 25 kg of aluminum briquettes.

[0104] S3, fabricate the intermediate electrode.

[0105] S31, the titanium shavings and intermediate alloy powder are thoroughly mixed to obtain a uniformly composed mixture; the mixture is then pressed into a block.

[0106] The titanium chips, AlV55 alloy, and aluminum granules were mixed evenly in a ratio of 29.4 kg, 9.1 kg, and 0.72 kg to ensure that the alloy components were evenly dispersed in the titanium chip matrix. The mixture was then loaded into a mold with a diameter of 280 mm and unidirectionally pressed on a hydraulic press to obtain a cylindrical block with uniform density and stable dimensions.

[0107] S32, multiple pressure blocks are welded and assembled into an integral intermediate electrode.

[0108] The pressure block is welded to a diameter of 280mm and a length of approximately 5250mm to obtain an intermediate electrode made of titanium chips and intermediate alloy.

[0109] S4, embed the intermediate electrode block into the recycled titanium material to prepare a consumable electrode.

[0110] The prepared intermediate electrode is placed in the middle of the TA5 recovery plate, and the TA5 recovery plate is welded to the intermediate electrode to obtain a consumable electrode for smelting. The intermediate electrode runs through the consumable electrode from beginning to end without any gaps.

[0111] S5, the consumable electrode is subjected to vacuum consumable melting to obtain a titanium alloy ingot with uniform composition distribution.

[0112] After three vacuum self-consumption melting processes, 5330 kg of TC4 titanium alloy ingots were obtained. The results of sampling and testing of the element content of the titanium alloy ingots are shown in Table 4 below.

[0113] Table 4. Test results of elemental content in titanium alloy ingots in Example 2.

[0114]

[0115] The TC4 titanium alloy ingots prepared by three vacuum self-consumption melting processes all met the TC4 standard requirements (Al 5.5~6.75%, V 3.5~4.5%, Fe≤0.30%, O≤0.20%, N≤0.05%) in the chemical composition (Al 5.5~6.75%, V 3.5~4.5%, Fe≤0.30%, O≤0.20%, N≤0.05%) when sampled and tested at five different locations on the ingots. Moreover, the content of each element fluctuated little and was evenly distributed, which verified the stability and effectiveness of the process in controlling the composition.

[0116] Example 3

[0117] This embodiment provides a method for preparing TA18 ingots using titanium scrap to achieve uniform oxygenation and alloy addition. The specific steps are as follows:

[0118] S1, the titanium shavings are cleaned, dried and sieved to obtain titanium shavings raw materials with uniform particle size.

[0119] Four batches of TA1 titanium scrap were selected and subjected to crushing, magnetic separation to remove ferromagnetic impurities, water washing to remove surface oil and adhering substances, and drying to remove moisture. The final product consisted of clean titanium scrap with a length ≤4cm and a width ≤2cm, meeting the requirements for subsequent mixing and pressing.

[0120] S2. Based on the composition requirements of the target titanium alloy ingot, determine the main materials, batching, and process plan.

[0121] S21, titanium scrap mixing and composition calibration, to obtain the reference composition of titanium scrap.

[0122] The four batches of titanium scrap were thoroughly mixed in a large homogenizer to form a homogenized batch, designated as batch number "250408". During the mixing process, five barrels (barrels 1, 4, 7, 10, and 14) were sampled at equal intervals to test the content of key impurity elements such as Fe, N, O, and C. The test results are shown in Table 5 below.

[0123] Table 5. Mixing test results of Example 3

[0124]

[0125] The average value of the test results for each element is taken as the baseline composition for this batch of titanium scrap, which is then used for subsequent batching calculations.

[0126] S22, Selection of main ingredients and batching materials and determination of process scheme.

[0127] Based on the target product being TA18 pure titanium ingots, and using sponge titanium as the main material, and considering the target ingot diameter of 860mm, the maximum diameter of the intermediate electrode was determined to be 420mm. The intermediate electrode was prepared by mixing titanium shavings with the intermediate alloy and pressing them together, employing a "intermediate electrode + sponge titanium in-middle pressing" process to embed it into the center of the sponge titanium.

[0128] S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

[0129] The usage of each ingredient was calculated according to the weight ratio. Based on the oxygen content requirements of TA18 pure titanium ingots, combined with the background oxygen content of the raw materials and the oxygen-enhancing capacity of titanium dioxide, precise ingredient calculations were performed. The final proportions of each raw material were determined as follows: main material: 6000 kg of sponge titanium; carrier titanium scrap: 1420 kg; intermediate alloy: 315 kg of AlV55 alloy and 152 kg of aluminum briquettes; oxidant: 12.7 kg of titanium dioxide.

[0130] S3, fabricate the intermediate electrode.

[0131] Sponge titanium, titanium shavings, intermediate alloy powder and oxidant are thoroughly mixed to obtain a uniform mixture; the mixture is then pressed into blocks.

[0132] The materials are mixed uniformly in the following proportions: 169.8 kg of sponge titanium, 40.2 kg of titanium shavings, 8.92 kg of AlV55 alloy, 4.30 kg of aluminum granules, and 360 g of titanium dioxide. This ensures that the alloy components are evenly dispersed in the titanium shaving matrix. The mixture is then loaded into a mold with a diameter of 420 mm and unidirectionally pressed on a hydraulic press to obtain a cylindrical block with uniform density and stable dimensions, which is the intermediate electrode.

[0133] S4, embed the intermediate electrode block into the sponge titanium to prepare a consumable electrode.

[0134] The prepared intermediate electrode was placed in the middle of the sponge titanium, and the TA5 recycled plate was welded to the intermediate electrode to prepare a consumable electrode for smelting. The intermediate electrode runs through the consumable electrode from beginning to end without any gaps.

[0135] The intermediate electrode block is placed in the middle of the sponge titanium by adding sponge titanium in two stages, and then the whole block is pressed to obtain a large block of sponge titanium plus titanium scrap. After welding reinforcement, a consumable electrode that can be used for smelting is obtained.

[0136] S5, the consumable electrode is subjected to vacuum consumable melting to obtain a titanium alloy ingot with uniform composition distribution.

[0137] 7112 kg of TA18 titanium alloy ingots were obtained after two vacuum self-consumption melting processes. The results of the element content tests on the ingots are shown in Table 6 below.

[0138] Table 6. Elemental content test results of titanium alloy ingot in Example 3.

[0139]

[0140] TA18 titanium alloy ingots were obtained through double vacuum consumable melting. The chemical composition (Al, V, Fe, O, N) of the ingots met the TA18 standard requirements (3.0–3.8%, V 2.0–3.0%, Fe≤0.25%, O≤0.15%, N≤0.03%) in samples taken from five different locations on the ingots. Moreover, the content of each element fluctuated little and was evenly distributed, which verified the stability and effectiveness of the process in controlling the composition.

[0141] This method significantly improves the comprehensive utilization rate of recycled materials to over 95%, reduces the amount of high-value sponge titanium used by 10% to 30%, lowers production costs, and avoids the segregation defects caused by uneven material distribution in traditional methods.

[0142] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing ingots using titanium scrap to achieve uniform oxygenation and alloy addition, characterized in that, Includes the following steps: S1, Pre-treat the titanium shavings; S2. Based on the composition requirements of titanium or titanium alloy ingots, determine the main material, batching material and process plan. The main material is sponge titanium or recycled material, and the batching material includes titanium scrap, oxygenating agent and / or intermediate alloy. S3, mix titanium shavings with an oxygenating agent and / or intermediate alloy powder to make an intermediate electrode; S4, the intermediate electrode is placed in the main material to make a consumable electrode; S5, the consumable electrode is subjected to vacuum consumable melting to obtain titanium or titanium alloy ingots.

2. The ingot preparation method according to claim 1, characterized in that, The pretreatment includes crushing, magnetic separation, washing, and drying.

3. The ingot preparation method according to claim 2, characterized in that, After the pretreatment, the length of the titanium shavings is ≤4cm and the width is ≤2cm.

4. The ingot preparation method according to claim 1, characterized in that, Step S2 includes the following steps: S21, titanium scrap mixing and composition calibration to obtain the reference composition of titanium scrap; S22, Selection of main ingredients and batching materials and determination of process scheme; S23, calculate the weight of main ingredients and auxiliary ingredients according to the proportional relationship.

5. The ingot preparation method according to claim 4, characterized in that, Step S21 includes: uniformly mixing different batches of titanium shavings, defining the mixed titanium shavings as a whole as a raw material batch; taking samples from different locations and testing them, and taking the average value of each element as the reference composition of the raw material batch of titanium shavings.

6. The ingot preparation method according to claim 1, characterized in that, The oxygenating agent is titanium dioxide, and the intermediate alloy includes one or more of TiFe, AlV, AlMo, AlSn, AlCr, and TiSn.

7. The ingot preparation method according to claim 1, characterized in that, The mixing method is mechanical stirring or layer-by-layer spreading, wherein the layer-by-layer spreading involves alternately spreading titanium shavings with an oxygenating agent or intermediate alloy.

8. The ingot preparation method according to claim 1, characterized in that, The process includes: determining the diameter of the intermediate electrode based on the ingot diameter and establishing a mapping relationship between the two.

9. The ingot preparation method according to claim 1, characterized in that, The process scheme includes: determining the method of preparing consumable electrodes by pressing, packaging, or welding, based on the material, specifications, and type of main material of the ingot.

10. The ingot preparation method according to claim 9, characterized in that, When the main material is sponge titanium, the intermediate electrode and sponge titanium are pressed together to form the consumable electrode; when the main material is recycled material, the intermediate electrode and recycled material are welded or packaged to form the consumable electrode.

11. The ingot preparation method according to claim 1, characterized in that, Step S3 includes: pressing the mixture into blocks according to specifications to produce an intermediate electrode, wherein the intermediate electrode comprises one or more blocks.

12. The ingot preparation method according to claim 1, characterized in that, The intermediate electrode is located in the central region of the consumable electrode and extends through the head and tail of the consumable electrode.

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