Oxygen distribution method for accurately controlling oxygen content uniformity of regenerated titanium alloy cast ingot

Abstract

The invention relates to an oxygen distribution method for accurately controlling the uniformity of the oxygen content of a regenerated titanium alloy cast ingot, in the preparation process of regenerated titanium alloy, oxygen bags are uniformly arranged in a titanium alloy electrode at intervals, and the raw materials of the regenerated titanium alloy electrode are composed of reclaimed materials and TiO2 powder, the recycled material comprises one or two of a pure titanium residual material and a titanium alloy residual material, the oxygen content in the total weight of the recycled material is lower than that in the regenerated titanium alloy, and the preparation method of the oxygen bag comprises the following steps: wrapping TiO2 powder with the sheet-shaped recycled material; various pure titanium residues and titanium alloy residues generated in the titanium alloy machining process are collected in a classified mode and then bundled into electrodes, the electrodes are smelted into regenerated titanium alloy, in the electrode bundling process, TiO2 powder is prepared into a plurality of oxygen bags, the oxygen bags are arranged in a space wide distribution mode, the oxygen content of the regenerated titanium alloy is accurately controlled, and the titanium alloy regeneration efficiency is improved. And the titanium processing material residual material resources are effectively integrated, and the green production capacity of regenerated titanium alloy is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloys, and in particular to an oxygen distribution method for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot. Technical Background

[0002] Titanium and titanium alloys are widely used in various industries, from aerospace to deep-sea submarines. Titanium and titanium alloys play an important role with their excellent comprehensive performance. Lightweight, high specific strength and good corrosion resistance make them an important contribution to the weight reduction and endurance of aerospace, and promote the cross-era development of aerospace, ocean and other fields.

[0003] Titanium and titanium alloys have many processing steps and low comprehensive yield, so a large amount of titanium waste will be generated. The demand for titanium and titanium alloys is increasing year by year. The recycling and reuse of titanium waste and obtaining green production capacity is a potential research hotspot. There are many types of titanium and titanium alloys, and their chemical composition is designed to achieve the required performance. Therefore, there are many types of waste and the oxygen content is different. Studies have shown that in the research on the recycling process of TC4 chip cooling furnace, when the chip waste is added at a ratio of 60% to 70%, the oxygen content of the ingot can be effectively controlled. Furthermore, after more detailed research and experiments, TC4 titanium alloy processed materials with good room temperature and high temperature mechanical properties are produced when 25% to 30% waste is added.

[0004] The yield rate of titanium processed materials is generally around 50%, and a large amount of scrap metal is generated during the production process. The main sources are machining chips generated during the peeling and cutting of ingots, forgings, and hot extrusion billets; cutting heads, tails, excess and scraps in each process from ingot casting to finished products; and block and plate-shaped scraps that are scrapped due to short length and geometric shape in the processing of semi-finished and finished products. How to use these titanium scraps to produce recycled titanium alloys, realize resource integration and utilization, and obtain green production capacity is a technical difficulty that needs to be overcome in the field of titanium research.

[0005] In the titanium alloy processing process, a cooling hearth furnace is usually used. The electron beam cooling hearth melting technology has a unique impurity removal effect. It can effectively remove high and low density inclusions through dissolution and specific gravity separation. Working under high vacuum, high purity or ultra-pure ingots can be obtained, which can effectively avoid and eliminate quality risks. At the same time, its electrode preparation is simple, and 100% of titanium residues of various shapes can be added, which greatly reduces the production cost and production cycle of ingots. Studies have shown that adding 70% return material (titanium residue) has a greater cost reduction than 50% return material (titanium residue), which is 27% and 16% lower than the traditional process, respectively. Increasing the proportion of return material (titanium residue) is undoubtedly more in line with industrialization and low-cost production needs. However, it is worth noting that in the vacuum melting process of the cooling hearth furnace, the saturated vapor pressure of TiO2 is less than the saturated vapor pressure of titanium, which determines that the content of oxygen in the titanium matrix is ​​irreversible and cannot be reduced. Therefore, in the recycled titanium alloy, the control of oxygen content is a difficult problem, especially in the preparation of large-scale recycled titanium alloys. Another disadvantage of cold hearth smelting is that the molten pool is shallow and the alloy is melted and solidified at the same time, which determines that the cold hearth smelting alloy has poor homogenization ability, which determines that the oxygen in the regenerated ingot is difficult to be evenly distributed, which is another difficult problem.

[0006] As mentioned above, there are many types of titanium and titanium alloys with different oxygen contents. At the same time, in order to achieve the target composition, how to use existing waste materials to design the composition and add TiO2 to achieve the purpose of precise oxygen control is a hot topic and difficulty in research. However, by directly scattering TiO2 in the square electrode, it is easy to cause it to scatter or cause movement accumulation during transportation or smelting, which is more likely to cause uneven oxygen content. At the same time, the square electrode set in the electron beam cooling bed is large in size, and the 1~4# electron guns are mainly used for melting electrodes in the smelting zone. Single-layer oxygen distribution is easy to cause uneven oxygen content distribution. Therefore, in the present invention, the oxygen bags are evenly spaced in the titanium alloy electrode in a "small amount, large number" manner to obtain a recycled titanium alloy with uniform composition. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide an oxygen distribution method for accurately controlling the uniformity of oxygen content in recycled titanium alloy ingots. This method classifies and collects various pure titanium residues and titanium alloy residues generated in the processing of titanium and titanium alloys, bundles them into electrodes, and melts the electrodes into recycled titanium alloys. In the process of bundling the electrodes, TiO2 powder is prepared into a number of oxygen bags, and the several oxygen bags are arranged in a wide spatial distribution to accurately control the oxygen content of the recycled titanium alloy, effectively integrate the resources of titanium processing material residues, and realize the green production capacity of recycled titanium alloys.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention proposes an oxygen distribution method for accurately controlling the uniformity of oxygen content in recycled titanium alloy ingots, characterized in that, in the process of preparing the recycled titanium alloy, oxygen bags are evenly spaced inside the titanium alloy electrode, the raw materials of the recycled titanium alloy electrode are composed of recycled materials and TiO2 powder, the recycled materials include one or two of pure titanium residues and titanium alloy residues, the oxygen content in the total weight of the recycled materials is lower than the oxygen content in the recycled titanium alloy, and the preparation method of the oxygen bags is: wrapping the TiO2 powder with flaky materials.

[0010] Preferably, the method for preparing the titanium alloy electrode comprises the following steps:

[0011] S1. According to the type of recycled titanium alloy and the designed target weight, select the corresponding recycled materials and classify and recycle the recycled materials according to their materials;

[0012] S2. Cut each type of recycled material;

[0013] S3, cleaning the recycled materials after cutting to make their surface free of impurities;

[0014] S4, selecting strip-shaped pure titanium residue or strip-shaped titanium alloy residue of the same material to prepare a square electrode frame;

[0015] S5, weighing a required amount of TiO2 powder, dividing the weighed TiO2 powder into several portions, and wrapping each portion of TiO2 powder with a sheet material to make an oxygen bag;

[0016] S6. Place the remaining recycled materials evenly into the electrode frame along the length direction of the electrode frame. During the placement process, arrange several oxygen bags evenly and spaced apart in the electrode frame.

[0017] Preferably, the specifications of the electrode frame are: length ≤5700 mm; height ≤500 mm; width ≤800 mm.

[0018] Preferably, in S5, the sheet material wrapping the TiO2 powder is an aluminum foil or a titanium foil with a thickness of less than 0.2 mm, and each oxygen-containing TiO2 powder weighs no more than 30 g;

[0019] Preferably, in S6, multiple layers of oxygen packages are laid in the electrode, the total number of layers of oxygen packages is an even number, multiple rows of each layer are evenly arranged along the length direction of the electrode frame, and the oxygen packages between two adjacent layers are staggered.

[0020] Preferably, in S6, multiple layers of oxygen packages are laid in the electrode, the total number of layers of oxygen packages is an even number, and each layer is evenly arranged in multiple rows along the length direction of the electrode frame, two adjacent oxygen packages in each row are abutted, and the rows of two adjacent layers of oxygen packages are staggered.

[0021] Preferably, the titanium alloy electrode is melted into a recycled titanium alloy ingot by electron beam cooling hearth smelting, and the feeding method adopted by the electron beam cooling hearth smelting is double-side feeding.

[0022] Preferably, the process parameters of electron beam cold bed melting are: vacuum degree of melting chamber before melting ≤1Pa; vacuum degree of ingot pulling chamber before melting ≤1Pa; leakage rate before melting ≤0.5Pa / min; melting voltage: 30kv; feed speed 0-70mm / min; melting speed: 0-25kg / min; ingot pulling speed 0-30mm / min.

[0023] Preferably, the recycled materials are composed of pure titanium residues, titanium alloy residues, titanium-aluminum-steel composite material residues and aluminum residues.

[0024] Preferably, the recycled materials consist of pure titanium residues, titanium alloy residues and aluminum residues.

[0025] Preferably, the pure titanium residue is one or more of TA1, TA2 and TA4; the titanium alloy residue is one or two of TC4 and TC4E.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention prepares TiO2 powder into a plurality of oxygen bags, and arranges the plurality of oxygen bags at intervals at various positions in the electrode, that is, the oxygen bags are evenly arranged in different residual material layers along the length direction of the frame; in this way, oxygen is evenly distributed in the spatial dimension (i.e., the entire square frame electrode), achieving the purpose of uniform oxygen distribution, solving the application problem of difficult-to-control oxygen content in engineered and large-scale recycled titanium alloys, and realizing precise oxygen control of ingot products.

[0028] (2) In the electrode smelting process of the present invention, the electron beam cold hearth smelting furnace adopts double-sided smelting, which can not only add 100% of recycled waste materials in various shapes, but also accurately control oxygen and evenly distribute oxygen, which greatly reduces the production cost and production cycle of the ingot, further improves the product quality, and realizes the uniform distribution of the oxygen content of the ingot.

[0029] (3) The raw materials involved in the present invention are all titanium waste materials widely used in titanium and titanium alloy products in the market. Through the effective integration and utilization of titanium waste materials, the upgrading and re-output of green production capacity can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the oxygen bag cloth layer and the interlayers in Example 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the top view of the oxygen bag cloth according to Example 1 of the present invention;

[0032] Figure 3This is a schematic diagram of the structure of the oxygen-encapsulated cloth layer and the interlayers in Example 3 of the present invention;

[0033] Figure 4 This is a schematic diagram of the ingot sampling point of the present invention;

[0034] Figure 5 This is a schematic diagram of the sampling points of the flat ingot of the present invention; Specific embodiments

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] refer to Figure 1 The present invention proposes an oxygen distribution method for accurately controlling the uniformity of oxygen content in recycled titanium alloy ingots, wherein oxygen bags are evenly spaced in an electrode, and the raw materials of the recycled titanium alloy electrode are composed of recycled materials and TiO2 powder, wherein the recycled materials include one or two of pure titanium residues and titanium alloy residues, wherein the pure titanium residues are one or more of TA1, TA2 and TA4; the titanium alloy residues are one or two of TC4 and TC4E, and the oxygen content in the total weight of the recycled materials is lower than the oxygen content of the target recycled titanium alloy, so that after adding TiO2 powder, the target recycled titanium alloy can be prepared.

[0037] The preparation method of the recycled titanium alloy electrode is as follows:

[0038] S1. According to the type of recycled titanium alloy and the designed target weight, select the corresponding recycled materials and classify and recycle the recycled materials according to the material;

[0039] S2. Classify each type of recycled material according to the riser, plate and slab head and tail edge material, and edge strip material, and finally cut each type of residual material to ensure that the residual material after cutting can be smoothly placed in the electrode frame;

[0040] S3. Clean the recycled materials after cutting to make sure that there is no oxidation, oil stain, coupling agent or other impurities on the surface;

[0041] S4, selecting strip-shaped pure titanium residue or strip-shaped titanium alloy residue of the same material to prepare a square electrode frame; in this way, the entire electrode frame is made of the same material, which is conducive to the uniformity of the chemical composition of the finished product; the specifications of the electrode frame are preferably: length ≤5700mm; height ≤500mm; width ≤800mm;

[0042] S5, weighing a required amount of TiO2 powder, dividing the weighed TiO2 powder into several equal parts as needed, selecting flake recycled materials from the recycled materials, and wrapping each portion of TiO2 powder with the flake recycled materials to make oxygen bags;

[0043] S6. According to the design goal of recycled titanium alloy, the remaining recycled materials need to be evenly stacked inside the electrode frame along the length direction of the electrode frame according to different materials and types. During the placement of the recycled materials, several oxygen bags are evenly spaced inside the electrode frame.

[0044] The prepared titanium alloy electrode is melted into an ingot by an electron beam cold hearth melting furnace, wherein the electron beam cold hearth melting furnace adopts double-side feeding, and the process parameters are preferably: vacuum degree of melting chamber before melting (Pa): ≤1; vacuum degree of ingot pulling chamber before melting (Pa): ≤1; leakage rate before melting (Pa / min): ≤0.5; 1# electron gun current (A): 4.0-12.0; 2# electron gun current (A): 4.0-12.0; 3# electron gun current (A): 4.0-12.0; 4# electron gun current (A): 4.0-12.0; 5# electron gun current (A): 4.0-12.0; 6# electron gun current (A): 4 .0-10.0; 7# electron gun current (A): 4.0-10.0; smelting voltage (kv): 30; feeding speed (mm / min): 0-70; smelting speed (kg / min): 0-25; ingot pulling speed (mm / min): 0-30; 1~4# electron guns are mainly used for melting electrodes in the smelting area. According to different feeding forms and electrode sizes, the scanning pattern of the gun is adjusted to make the main energy used for melting materials to avoid local overheating; 5# electron gun is mainly used for refining in the refining area and ensures smooth outflow of liquid metal at the pouring channel; 6~7# electron guns are mainly used to keep the metal in the crystallizer in liquid state and provide energy for shrinkage compensation;

[0045] The smelted ingot is a round ingot or a flat ingot. If it is a round ingot, the diameter is 650mm; if it is a flat ingot, the size of the crystallizer determines the specifications of the flat ingot; the size of the flat ingot crystallizer can be 2250×370×660mm, 1380×370×660mm, 1580×240×660mm, 1080×240×660mm or 1230×125×660mm.

[0046] After smelting, samples are taken from different positions of the ingot for chemical composition testing. If the ingot is a round ingot, i.e. a cylindrical ingot, refer to Figure 4 , samples can be taken at sampling point D1 on the center axis of the ingot, sampling point D3 on the surface of the ingot, and sampling point D2 at half the radius for testing. If the ingot is a flat ingot, i.e. a rectangular ingot, refer to Figure 5Samples can be taken for testing at sampling point C1 on the center axis of the ingot, sampling point C3 on the surface of the ingot, and sampling point C2 at one-quarter of the width. For the smelted ingot, more samples can be taken for testing at different positions as needed.

[0047] The following is further described by specific examples:

[0048] Example 1

[0049] This embodiment proposes an oxygen distribution method for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot, wherein TiO2 powder is made into 640 oxygen bags, and the 640 oxygen bags are evenly spaced and arranged in an electrode.

[0050] In this embodiment, the grade of the recycled titanium alloy is Ti522, and the raw materials are composed of recycled materials and TiO2 powder. The recycled materials are composed of pure titanium residues, titanium alloy residues, titanium aluminum steel composite material residues and aluminum residues. The pure titanium residues are TA2 residues, and the titanium alloy residues are TC4 residues. The recycled materials and TiO2 powder are first made into square electrodes, and then the prepared titanium alloy electrodes are melted into ingots in an electron beam cold hearth melting furnace. The preparation method of the square electrode is:

[0051] S1. Classify the recycled pure titanium residues, titanium alloy residues, titanium-aluminum-steel composite material residues and aluminum residues according to their materials;

[0052] S2. Each type of recycled material is further classified according to the riser, plate and slab head and tail edge material, edge strip material, etc., and each type of residual material is finally cut. The cutting size of the riser and ingot bottom should be ≤650mm, the diameter of the titanium and titanium alloy bar residual material should be ≤650mm, the thickness of the titanium and titanium alloy tongue residual material should be ≤450mm, the width should be ≤760mm, and the length of the titanium and titanium alloy edge residual material should be ≤4000mm, to ensure that the residual material after cutting can be smoothly placed in the electrode frame;

[0053] S3. Clean the recycled materials after cutting to make sure that there is no oxidation, oil stain, coupling agent or other impurities on the surface;

[0054] S4. Using 2280kg of TA2 residual material and edge strips from the cleaned recycled material, a square electrode frame was prepared. The specifications of the prepared electrode frame were: length 4000mm; height 490mm; width 790mm;

[0055] S5. Weigh 16kg of TiO2 powder, divide the weighed TiO2 powder into 640 portions on average, select 10kg of flaky aluminum scraps from the cleaned recycled materials, cut the selected flaky aluminum scraps into 640 pieces, and use 640 pieces of aluminum scraps to wrap 640 portions of TiO2 powder respectively to make 640 oxygen bags; when wrapping, press the corners tightly to prevent the TiO2 powder from leaking out.

[0056] S6, weigh 83kg of aluminum residue and lay it on the bottom of the electrode frame, weigh 217kg of titanium aluminum steel composite residue and lay it on the top of the aluminum residue layer, weigh 3626kg of TC4 residue and lay it on the top of the titanium aluminum steel composite; Figure 1 and Figure 2 , Figure 1 and Figure 2 The solid line in the middle represents the odd-numbered layers of oxygen bags from bottom to top, and the dotted line represents the even-numbered layers of oxygen bags from bottom to top. During the material laying process in the electrode frame, 4 layers of oxygen bags are sandwiched in the electrode frame. The 4 layers of oxygen bags are sandwiched at one-fifth of the depth h1, two-fifths of the depth h2, three-fifths of the depth h3 and four-fifths of the depth h4 in the electrode frame. Each layer has 8 rows along the length of the electrode frame, and each row has 20 oxygen bags evenly spaced. During the oxygen bag laying process, the position of each layer of oxygen bags can be marked to facilitate staggering of rows between adjacent layers of oxygen bags and staggering of oxygen bags to ensure the uniformity of the chemical composition of the ingot.

[0057] After the electrode in this embodiment is melted into an ingot, the diameter of the ingot is 650 mm.

[0058] The composition of the round ingot of this embodiment was tested. The oxygen contents of the samples at points D1, D2 and D3 of the round ingot were 0.225%, 0.210% and 0.218% respectively. The chemical compositions of the outer circles of the head (T), middle (M) and bottom (B) are shown in Table 1:

[0059] Table 1 Ti522 chemical composition test results

[0060]

[0061] Example 2

[0062] This embodiment proposes an oxygen distribution method for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot, wherein TiO2 powder is made into 400 oxygen bags, and the 400 oxygen bags are evenly spaced and arranged in an electrode.

[0063] In this embodiment, the grade of the recycled titanium alloy is TC4B, the raw materials are composed of recycled materials and TiO2 powder, the recycled materials are composed of pure titanium residues, titanium alloy residues and aluminum residues, the pure titanium residues include TA1 residues and TA2 residues, and the titanium alloy residues include TC4 residues and TC4E residues. The recycled materials and TiO2 powder are first made into square electrodes, and then the prepared titanium alloy electrodes are melted into ingots in an electron beam cold hearth melting furnace; the preparation method of the square electrode is:

[0064] S1. Classify the recovered pure titanium residues, titanium alloy residues and aluminum residues according to their materials;

[0065] S2. Each type of recycled material is further classified according to the riser, plate and slab head and tail edge material, edge strip material, etc., and each type of residual material is finally cut. The cutting size of the riser and ingot bottom should be ≤650mm, the diameter of the titanium and titanium alloy bar residual material should be ≤650mm, the thickness of the titanium and titanium alloy tongue residual material should be ≤450mm, the width should be ≤760mm, and the length of the titanium and titanium alloy edge residual material should be ≤4500mm, to ensure that the residual material after cutting can be smoothly placed in the electrode frame;

[0066] S3. Clean the recycled materials after cutting to make sure that there is no oxidation, oil stain, coupling agent or other impurities on the surface;

[0067] S4. Using the tongue and edge strips of 2010kg TC4 residual materials from the cleaned recycled materials, a square electrode frame is prepared; the specifications of the prepared electrode frame are: length 4500mm; height 480mm; width 795mm;

[0068] S5. Weigh 10 kg TiO2 powder, divide the weighed TiO2 powder into 400 parts, select 5 kg TA1 scraps from the cleaned recycled materials, cut the selected TA1 scraps into 400 pieces, and use 400 pieces of TA1 scraps to wrap 400 parts of TiO2 powder respectively to make 400 oxygen bags; when wrapping, press the corners tightly to prevent the TiO2 powder from leaking out;

[0069] S6. Weigh 65kg of aluminum scraps and lay them on the bottom of the electrode frame, weigh 275kg of TA2 scraps and lay them on the upper end of the aluminum scrap layer, weigh 3731kg of TC4 scraps and lay them on the upper end of the TA2 scrap layer; during the laying process in the electrode frame, set 8 layers of oxygen bags in the electrode frame, and the 8 layers of oxygen bags are respectively located on the upper surface of the electrode frame, and the surface oxygen bags are spot welded to the surrounding scraps at one-seventh of the depth, two-sevenths of the depth, three-sevenths of the depth, four-sevenths of the depth, five-sevenths of the depth, six-sevenths of the depth and the bottom of the electrode frame. Each layer has 5 rows along the length of the electrode frame, and each row has 10 oxygen bags evenly spaced, and the oxygen bags between two adjacent layers are staggered.

[0070] After the electrode in this embodiment is melted into an ingot, the diameter of the ingot is 650 mm.

[0071] The composition of the round ingot of this embodiment was tested. The oxygen contents of the samples at points D1, D2 and D3 of the round ingot were 0.162%, 0.159% and 0.157% respectively. The chemical compositions of the outer circles of the head (T), middle (M) and bottom (B) are shown in Table 2:

[0072] Table 2 TC4B chemical composition test results

[0073] Element / % Al V Fe C O N H T 5.480 3.99 0.179 0.009 0.160 0.004 0.001 M 5.510 3.94 0.178 0.007 0.152 0.005 0.001 B 5.450 3.97 0.170 0.007 0.160 0.004 0.001 Design goals 5.00～6.30 3.00～4.30 ≤0.30 ≤0.08 ≤0.20 ≤0.05 ≤0.015

[0074] Example 3

[0075] This embodiment proposes an oxygen distribution method for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot, wherein TiO2 powder is made into 800 oxygen bags, and the 800 oxygen bags are evenly spaced and arranged in an electrode.

[0076] In this embodiment, the grade of the recycled titanium alloy is TC4, the raw materials are composed of recycled materials and TiO2 powder, the recycled materials are composed of pure titanium residues, titanium alloy residues and aluminum residues, the pure titanium residues are TA2 residues, and the titanium alloy residues include TC4 residues and TC4E residues. The recycled materials and TiO2 powder are first made into square electrodes, and then the prepared titanium alloy electrodes are melted into ingots in an electron beam cold hearth melting furnace; the preparation method of the square electrode is:

[0077] S1. Classify the recovered pure titanium residues, titanium alloy residues and aluminum residues according to their materials;

[0078] S2. Each type of recycled material is further classified according to the riser, plate and slab head and tail edge material, edge strip material, etc., and each type of residual material is finally cut. The cutting size of the riser and ingot bottom should be ≤650mm, the diameter of the titanium and titanium alloy bar residual material should be ≤650mm, the thickness of the titanium and titanium alloy tongue residual material should be ≤450mm, the width should be ≤760mm, and the length of the titanium and titanium alloy edge residual material should be ≤5500mm, to ensure that the residual material after cutting can be smoothly placed in the electrode frame;

[0079] S3. Clean the recycled materials after cutting to make sure that there is no oxidation, oil stain, coupling agent or other impurities on the surface;

[0080] S4. In the cleaned recycled materials, the tongue and edge strips of 2010kg TC4 residual materials are used to prepare square electrode frames; the specifications of the prepared electrode frames are: length 5500mm; height 460mm; width 790mm;

[0081] S5. Weigh 16kg of TiO2 powder, divide it into 800 equal portions, select 5kg of TA2 flake residues from the cleaned recycled materials, cut the selected TA2 flake residues into 800 pieces, and use 800 pieces of TA2 residues to wrap 800 portions of TiO2 powder respectively to make 800 oxygen bags; press the corners tightly when wrapping to prevent the TiO2 powder from leaking out.

[0082] S6, weigh 65kg of aluminum scraps and lay them on the bottom of the electrode frame, weigh 2076kg of TC4 scraps and 2000kg of TC4E scraps and lay them on the top of the aluminum scrap layer, refer to Figure 3During the material laying process in the electrode frame, two layers of oxygen bags are sandwiched in the electrode frame. The two layers of oxygen bags are sandwiched at one-third and two-thirds of the depth of the electrode frame respectively. Each layer has four rows along the length of the electrode frame. Each row has 100 oxygen bags evenly spaced. The two layers of oxygen bags are staggered between rows, and the 100 oxygen bags in each row of each layer are abutted.

[0083] After the electrode in this embodiment is melted into a flat ingot, the specification of the flat ingot is 370 mm×1380 mm×1407 mm.

[0084] The composition of the ingot of this embodiment is tested. The oxygen contents of the samples at points C1, C2 and C3 of the ingot are 0.152%, 0.156% and 0.152% respectively. The chemical compositions of the outer circles of the head (T), middle (M) and bottom (B) are shown in Table 3:

[0085] Table 3 TC4 chemical composition test results

[0086] Element / % Al V Fe C O N H T 5.49 4.17 0.163 0.018 0.150 0.005 0.001 M 5.40 4.13 0.161 0.018 0.155 0.003 0.001 B 5.48 4.14 0.165 0.014 0.147 0.003 0.001 Design goals 5.50～6.75 3.5～4.5 ≤0.30 ≤0.08 ≤0.20 ≤0.05 ≤0.015

[0087] In summary, it can be seen that the recycled titanium alloy ingots prepared by the present invention have uniform composition, meet their respective design objectives, and can meet the practical application of large-scale engineering.

[0088] In the above embodiments, the arrangement of oxygen bags can be determined according to design requirements. They can be distributed discontinuously or continuously in the same row, but the distribution amount in the same row is consistent. The number of oxygen bag layers can also be an odd number of layers, but the effect of an even number of layers is better. It is not limited to the distribution methods listed in the above embodiments.

[0089] In the above embodiments, the residual materials for making the oxygen bag are selected as thinner and softer as possible. In order to ensure the reliability of the oxygen bag and prevent the oxygen bag from moving, the formed oxygen bag can also be spot welded on the adjacent residual materials. The size specifications of the oxygen bag are: length ≤100mm; height ≤1mm; width ≤45mm, in the shape of a candy.

[0090] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot, characterized in that: During the preparation process of recycled titanium alloy, oxygen bags are evenly spaced inside the titanium alloy electrode. The raw materials of the recycled titanium alloy electrode are composed of recycled materials and TiO2 powder. The recycled materials include one or two of pure titanium residues and titanium alloy residues. The oxygen content in the total weight of the recycled materials is lower than the designed oxygen content of the recycled titanium alloy. The preparation method of the oxygen bags is: wrapping the TiO2 powder with flaky materials.

2. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 1, characterized in that: The preparation method of the titanium alloy electrode comprises the following steps: S1. According to the type of recycled titanium alloy and the designed target weight, select the corresponding recycled materials and classify and recycle the recycled materials according to the material; S2. Cut each type of recycled materials; S3. Clean the recycled materials after cutting to make sure that there is no oxidation or other impurities on the surface; S4, selecting strip-shaped pure titanium residue or strip-shaped titanium alloy residue of the same material to prepare a square electrode frame; S5, weighing a required amount of TiO2 powder, dividing the weighed TiO2 powder into several portions, and wrapping each portion of TiO2 powder with a sheet material to make an oxygen bag; S6. Place the remaining recycled materials evenly into the electrode frame along the height, width and length of the electrode frame. During the placement process, arrange several oxygen bags evenly at intervals in the electrode frame.

3. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 2, characterized in that: The specifications of the electrode frame are: length ≤5700mm; height ≤500mm; width ≤800mm.

4. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 2, characterized in that: In S5, the sheet material wrapping the TiO2 powder is an aluminum foil or a titanium foil with a thickness of less than 0.2 mm, and the weight of each oxygen-containing TiO2 powder is not more than 30 g; In S6, the oxygen packages are laid in multiple layers in the electrode, the total number of layers of the oxygen packages is an even number of layers, and each layer is evenly arranged in multiple rows along the length direction of the electrode frame, and the oxygen packages between two adjacent layers are staggered.

5. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 2, characterized in that: In S6, multiple layers of oxygen packages are laid in the electrode, the total number of layers of oxygen packages is an even number, and each layer is evenly arranged in multiple rows along the length direction of the electrode frame. Two adjacent oxygen packages in each row are abutted, and the rows of two adjacent layers of oxygen packages are staggered.

6. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 1, characterized in that: The titanium alloy electrode is melted into a recycled titanium alloy ingot through electron beam cold bed melting, and the feeding method adopted by the electron beam cold bed melting is double-side feeding.

7. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 6, characterized in that: The process parameters of electron beam cold bed melting are: vacuum degree of melting chamber before melting ≤1Pa; vacuum degree of ingot pulling chamber before melting ≤1Pa; gas leakage rate before melting ≤0.5Pa / min; melting voltage: 30kv; feeding speed 0-70mm / min; melting speed: 0-25kg / min; Ingot pulling speed 0-30mm / min.

8. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 1, characterized in that: The recycled materials are composed of pure titanium residues, titanium alloy residues, titanium-aluminum-steel composite material residues and aluminum residues.

9. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 1, characterized in that: The recycled materials consist of pure titanium residues, titanium alloy residues and aluminum residues.

10. The method for distributing oxygen for accurately controlling the uniformity of oxygen content in a recycled titanium alloy ingot according to claim 1, characterized in that: The pure titanium residue is one or more of TA1, TA2 and TA4; the titanium alloy residue is one or two of TC4 and TC4E.

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