Method for preparing TC4B titanium alloy plate for armored car by using total reclaimed materials

Abstract

The invention relates to a method for preparing a TC4B titanium alloy plate for an armored car by using full reclaimed materials. The method comprises the following steps: weighing the reclaimed materials; taking out one part from the weighed recycled material, and welding into an electrode frame with an opening in the upper end; laying the residual recycled material in the electrode frame to prepare an electrode; smelting the prepared electrode by adopting an EB furnace to obtain an ingot blank; the obtained ingot blank is heated and rolled, and a plate blank is obtained; the plate blank is subjected to air cooling treatment, and the titanium alloy plate is obtained; according to the method, the ingot blank is obtained through EB furnace smelting, the ingot blank is subjected to multi-heating-number rolling, and in the rolling process, the ingot blank is alternately reversed between heating numbers, so that the prepared TC4B titanium alloy plate is high in structure uniformity, excellent in mechanical property, good in strong plasticity matching and high in yield, and high-quality and high-value application of the low-cost titanium alloy plate is achieved.

Description

Technical Field

[0001] The invention relates to the field of titanium and titanium alloy processing, and specifically to a processing method for preparing low-cost TC4B titanium alloy plates for armored vehicles using fully recycled materials through forging-free direct rolling. Background Art

[0002] The production process of titanium and titanium alloys is complex, the process is long, and the manufacturing cost is high. As a strategic metal in the national defense military industry, it is a popular material for development and research in recent years. Titanium alloys for military use are usually high-quality and high-performance components by default, and scrap materials cannot be added, which seriously pushes up the cost of military titanium alloy products. Combined with the characteristics of titanium alloy processing procedures, including multiple smelting, forging, machining and leveling, the labor and processing costs are high, and the scraps and debris generated in the production process account for up to 30% to 40%. However, with the current development and utilization of titanium alloy materials, the effective use of titanium resources and the development of low-cost titanium alloys have become the key to scientific and technological development. Therefore, how to shorten the production process and recycle titanium and titanium alloy residues is an important issue that needs to be overcome urgently.

[0003] The currently popular EB furnace smelting technology has a higher utilization rate of returned materials, a shorter process and lower costs compared to the VAR furnace where the return materials are added at no more than 50%, and has great potential in the preparation of titanium alloys. Patent CN108359808 provides a method for preparing TC4 titanium alloy ingots with a TC4 titanium residue addition ratio of up to 55.8% to 70.7%; Patent CN106834697 obtains TC4 cost ingots by adding TC4 residues and pure aluminum strips through EB furnace smelting; Nonferrous Metals Institute CN104313394 discloses a low-cost titanium alloy that can add titanium residues, which uses sponge titanium and other pure titanium residues and aluminum beans to be melted into alloy ingots through pressed electrodes, reducing the preparation cost. Based on the existing return material preparation technology, the utilization rate of the residues has not yet reached 100%, and a certain proportion of intermediate alloys needs to be added.

[0004] In addition, when preparing forging-free direct-rolled billets through the EB furnace short process, on the one hand, in the process of adding residual materials to prepare ingots, most of the problems of inclusions and uneven composition are solved by combining EB furnace and VAR furnace for melting. For example, patent CN115537589 provides a dual melting method of EB furnace and VAR furnace for titanium alloy ingots, which solves the poor uniformity of EB melting composition while also lengthening the process flow; on the other hand, the microstructure of the plate prepared by the EB furnace after forging or rolling is coarse and uneven, which cannot meet the good strength-plasticity matching, which will greatly limit the later Patent CN117165882 provides a method for preparing fine and uniform equiaxed microstructure plates using TA10 titanium alloy EB ingots, wherein the ingots are first heat treated and then rolled using multiple hot rolls at different temperatures; Baoshan Iron & Steel's patent CN118321345 provides a method for preparing TC4 titanium alloy plates using asynchronous rolling and edge heating to compensate for the temperature drop at the edges of thick and wide titanium alloy plates. It can be seen from this that the existing EB smelting process still needs to be followed by VAR smelting to improve the uniformity of EB composition or use different temperatures or local temperature compensation to obtain uniform microstructure, and the process is relatively complicated. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention proposes a method for preparing TC4B titanium alloy plates for armored vehicles using fully recycled materials, which achieves 100% recycling of titanium alloy waste materials while having high processing efficiency and good uniformity of the prepared plates.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a TC4B titanium alloy plate for an armored vehicle using fully recycled materials, comprising the following steps:

[0008] S1, weigh the recycled material;

[0009] S2. Take out a portion of the weighed recycled material and weld it into an electrode frame with an open top;

[0010] S3, laying the remaining recycled materials in the electrode frame to make electrodes;

[0011] S4, using an EB furnace to melt the prepared electrode to obtain an ingot;

[0012] S5, heating and rolling the obtained ingot to obtain a slab;

[0013] S6. Heat-treating the slab to obtain a titanium alloy plate.

[0014] Preferably, in S1, the recycled material is TC4 titanium alloy residue or TC4-ELI titanium alloy residue.

[0015] Preferably, the recycled material comprises, by weight percentage, Al: 5.0-6.3%, V: 3.0-4.3%, O: ≤0.2%, Fe: ≤0.3%, C: ≤0.08%, N: ≤0.05%, H: ≤0.015%, other impurity elements ≤0.4%, and the balance is Ti.

[0016] Preferably, the electrode frame is a rectangular electrode frame, and the length of the rectangular electrode frame is: ≤4000mm, the width is: ≤800mm, and the height is: ≤500mm.

[0017] Preferably, in S4, the EB furnace melts the electrode once.

[0018] Preferably, in S4, the thickness of the ingot is 340-370 mm, and the width is 1500-1560 mm.

[0019] Preferably, in S5, the ingot is rolled for 3 to 4 times, and during the rolling process, the ingot is alternately rotated.

[0020] Preferably, when the ingot is rolled, the rolling temperature of the first rolling step is 40 to 60°C above the phase transformation point, and the rolling temperatures of the remaining rolling steps are 40 to 70°C below the phase transformation point.

[0021] Preferably, the method of alternately rotating the ingot is that the rolling direction of the second fire is perpendicular to the rolling direction of the first fire, and the rolling direction of the third fire is perpendicular to the rolling direction of the second fire.

[0022] Preferably, the slab is heat treated at 800-850° C. in S6, and the holding time is 1-1.5 h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention can realize the recycling of all TC4 or TC4ELI titanium alloy scraps without adding sponge titanium or adding intermediate alloy raw materials. The prepared electrode frame can accommodate scraps of various sizes and shapes, thereby expanding the scope of scrap utilization and reducing raw material costs.

[0025] (2) The present invention prepares TC4B titanium alloy for armored vehicles, adopts the full residual material ratio of TC4 or TC4EL1 titanium alloy, uses EB furnace for smelting, and the residual material utilization rate reaches 100%. There is no need to add additional Al plate / Al bean and other intermediate alloys, and the composition uniformity is better.

[0026] (3) The titanium alloy ingot prepared by the present invention only needs to be smelted once, and the obtained ingot has uniform composition. The prepared wide and thick flat ingot can be directly rolled without forging, which shortens the processing steps and reduces the manufacturing cost in the entire process from raw materials to hot processing. At the same time, the thickness of the smelted titanium alloy ingot reaches more than 300 mm and the width reaches more than 1000 mm, which can effectively ensure the total deformation of the finished plate, fully break the cast structure, and realize different types of rolling deformation.

[0027] (4) The present invention performs multi-fire rolling on the ingot. During the rolling process, the ingot is alternately rotated between fires. The prepared TC4B titanium alloy plate with a thickness of less than 20 mm has high uniformity of structure, good matching of strength and plasticity, and high yield. Tests show that the plate obtained by this process has excellent mechanical properties, realizing the high-quality and high-value application of low-cost titanium alloy plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a process flow chart of the present invention;

[0029] Figure 2 The recycled material electrode frame described in Example 1;

[0030] Figure 3 This is a microstructure diagram of the titanium alloy plate obtained in Example 1;

[0031] Figure 4 This is the microstructure diagram of the titanium alloy plate obtained in Example 2;

[0032] Figure 5 This is the microstructure diagram of the titanium alloy plate obtained in Example 3;

[0033] Figure 6 This is the microstructure diagram of the titanium alloy plate prepared in Comparative Example 1. DETAILED DESCRIPTION

[0034] 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.

[0035] refer to Figure 1 and Figure 2 The present invention provides a method for preparing a TC4B titanium alloy plate for armored vehicles using fully recycled materials, wherein the thickness of the TC4B titanium alloy plate is ≤20 mm, and the method comprises the following steps:

[0036] S1. Count the elements and their contents contained in each type of titanium alloy recycled materials, select titanium alloy recycled materials with suitable raw material composition according to the requirements of the content of each element in TC4B titanium alloy, the selected titanium alloy recycled materials include titanium alloy ingots, slabs, bars, forgings, risers, material heads, plate edges and turnings in the preparation process of plates, etc., and the recycled materials include Al: 5.0-6.3%, V: 3.0-4.3%, O: ≤0.2%, Fe: ≤0.3%, C: ≤0.08%, N: ≤0.05%, H: ≤0.015%, other impurity elements ≤0.4%, and the balance is Ti;

[0037] S2. Take out a portion of the weighed recycled material, preferably a plate, and weld it into an electrode frame with an open top, such as Figure 2 As shown;

[0038] S3, laying the remaining recycled materials in the electrode frame to make electrodes;

[0039] S4, using an EB furnace to perform single smelting on the prepared electrode to obtain an ingot;

[0040] S5, heating the obtained ingot and performing multiple-fire rolling to obtain a slab; during the rolling process, the ingot is alternately rotated between the fires;

[0041] S6. Heat-treating the slab to obtain a titanium alloy plate.

[0042] The present invention is described below by way of examples:

[0043] Example 1

[0044] This embodiment provides a method for preparing a TC4B titanium alloy plate for an armored vehicle using fully recycled materials, comprising the following steps:

[0045] S1. Selecting recycled materials that meet the requirements according to the content requirements of each element in TC4B titanium alloy. In this embodiment, the recycled materials selected are TC4 titanium alloy waste materials, wherein the design goal is: preparing 7493kg TC4B titanium alloy plates; weighing 7493kg TC4 titanium alloy waste materials according to the design goal;

[0046] S2. Take out 2286 kg of the weighed 7493 kg TC4 titanium alloy residue, and weld the taken out 2286 kg of residue into a rectangular electrode frame with an open top. The specifications of the electrode frame are: length is 3200 mm, width is 600 mm, height is 500 mm. The residue of the welded electrode frame is preferably a plate. The welded electrode frame bottom plate is made of thicker residue to avoid premature deformation and collapse during the smelting process.

[0047] S3, laying the remaining 5207kg of scraps evenly in a rectangular parallelepiped electrode frame to make an electrode;

[0048] S4. The prepared electrode is subjected to single smelting in an electron beam cooling furnace (EB furnace) to obtain a titanium alloy ingot having the following specifications: thickness × width × length = 347 × 1538 × 3134 mm, and the chemical composition of the ingot is: Al: 5.53%, V: 4.06%, Fe: 0.177%, O: 0.168%, and the rest is Ti and trace impurity elements;

[0049] S5. The titanium alloy ingot is rolled in four rounds to obtain a slab of the required thickness, wherein the rolling direction of the first round is the length direction of the ingot, the ingot is heated to 40°C above the phase transformation point for rolling, and the total deformation is 76.9%; after the first round of rolling, the material is cut to a width of 2260mm, and the second round of rolling is carried out at 40°C below the phase transformation point, the rolling direction of the second round is perpendicular to the rolling direction of the first round, and the total deformation is 55.4%; after the second round of rolling, the material is cut to a width of 1550mm, and the third round of rolling is carried out at the same temperature as the second round, the rolling direction of the third round is perpendicular to the rolling direction of the second round, and the deformation is 57.1%; the temperature and direction of the fourth round of rolling are the same as those of the third round, and the deformation is 54%;

[0050] S6. The obtained slab is heat treated at 850°C for 1 hour and then air-cooled to finally obtain a 6 mm thick titanium alloy plate.

[0051] Example 2

[0052] This embodiment provides a method for preparing a TC4B titanium alloy plate for an armored vehicle using fully recycled materials, comprising the following steps:

[0053] S1. Selecting recycled materials that meet the requirements according to the content requirements of each element in TC4B titanium alloy. In this embodiment, the recycled materials selected are TC4ELI titanium alloy waste materials, wherein the design goal is: preparing 5987kg TC4B titanium alloy plates; weighing 5987kg TC4ELI titanium alloy waste materials according to the design goal;

[0054] S2. Take out 2114 kg of the weighed TC4ELI titanium alloy residue, and weld the taken out 2114 kg of residue into a rectangular electrode frame with an open top. The specifications of the electrode frame are: length is 3000 mm, width is 800 mm, height is 400 mm. The residue of the welded electrode frame is preferably a plate, wherein the welded electrode frame bottom plate is selected from thicker residues to avoid premature deformation and collapse during the smelting process;

[0055] S3, laying the remaining 3873 kg of scraps evenly in a rectangular parallelepiped electrode frame to make an electrode;

[0056] S4. The prepared electrode is subjected to a single smelting in an electron beam cooling furnace (EB furnace) to obtain a titanium alloy ingot having the specifications of thickness × width × length = 347 × 1553 × 2410 mm and the chemical composition of the ingot being: Al: 5.53%, V: 4.06%, Fe: 0.177%, O: 0.168%, and the rest being Ti and trace impurity elements;

[0057] S5, rolling the titanium alloy ingot for three times to obtain a slab of the required thickness, wherein the rolling direction of the first time is the length direction of the ingot, the ingot is heated to 50°C above the phase transformation point for rolling, and the total deformation is 73.5%; after the first time, the material is cut to a width of 2200mm, and the second time is rolled at 60°C below the phase transformation point, the rolling direction of the second time is perpendicular to the rolling direction of the first time, and the total deformation is 56.8%; after the second time, the material is cut to a width of 1580mm, and the third time is rolled, the rolling temperature of the third time is the same as the second time, the rolling direction of the third time is perpendicular to the rolling direction of the second time, and the deformation is 67.8%;

[0058] S6. The obtained slab is heat treated: heat preservation at 800°C for 1.5h and air cooling, and finally a 12mm titanium alloy plate is obtained.

[0059] Example 3

[0060] This embodiment provides a method for preparing a TC4B titanium alloy plate for an armored vehicle using fully recycled materials, comprising the following steps:

[0061] S1. Selecting recycled materials that meet the requirements according to the content requirements of each element in TC4B titanium alloy. In this embodiment, the recycled materials selected are TC4 titanium alloy waste materials. The design goal is to prepare 8271 kg of TC4B titanium alloy plates. According to the design goal, 8271 kg of TC4 titanium alloy waste materials are weighed;

[0062] S2. Take out 2447 kg of the weighed TC4 titanium alloy residue, and weld the taken out 2447 kg of residue into a rectangular electrode frame with an open top. The specifications of the electrode frame are: length is 4000 mm, width is 800 mm, height is 300 mm. The residue of the welded electrode frame is preferably a plate. The welded electrode frame bottom plate is made of thicker residue to avoid premature deformation and collapse during the smelting process.

[0063] S3, laying the remaining 5824 kg of scraps evenly in a rectangular parallelepiped electrode frame to make an electrode;

[0064] S4. The prepared electrode is subjected to single smelting in an electron beam cooling furnace (EB furnace) to obtain a titanium alloy ingot having the specifications of thickness × width × length = 368 × 1554 × 3214 mm and the chemical composition of the ingot being: Al: 5.49%, V: 4.13%, Fe: 0.171%, O: 0.155%, and the rest being Ti and trace impurity elements;

[0065] S5, rolling the titanium alloy ingot in batches to obtain a slab of the required thickness, wherein the rolling direction of the first batch is the length direction of the ingot, the ingot is heated to 60°C above the phase transformation point for rolling, and the total deformation is 75.4%; after the first batch of rolling, the material is cut to a width of 2100mm, and the second batch of rolling is carried out at 70°C below the phase transformation point, the rolling direction of the second batch is perpendicular to the rolling direction of the first batch, and the total deformation is 55.1%; after the second batch of rolling, the material is cut to a width of 1580mm, and the third batch of rolling is carried out, the rolling temperature of the third batch is the same as that of the second batch, the rolling direction of the third batch is perpendicular to the rolling direction of the second batch, and the deformation is 52.3%;

[0066] S6. The obtained slab is heat treated by keeping at 825°C for 1.2h and air cooling to finally obtain a 20mm thick titanium alloy plate.

[0067] Comparative Example 1

[0068] This comparative example is a method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials, comprising the following steps:

[0069] S1. Selecting recycled materials that meet the requirements according to the content requirements of each element in TC4B titanium alloy. In this embodiment, the recycled materials selected are TC4 titanium alloy waste. The design goal is to prepare 4396 kg of TC4B titanium alloy plates. According to the design goal, 4396 kg of TC4 titanium alloy waste is weighed;

[0070] S2. Take out 2057 kg of the weighed TC4 titanium alloy residue, and weld the taken out 2057 kg of residue into a rectangular electrode frame with an upper end open. The specifications of the electrode frame are: length is 3800 mm, width is 800 mm, height is 300 mm. The residue for welding the electrode frame is preferably a plate, wherein the welded electrode frame bottom plate is selected from thicker residues;

[0071] S3, laying the remaining 2339 kg of scraps evenly in a rectangular parallelepiped electrode frame to make an electrode;

[0072] S4. The prepared electrode is subjected to single smelting in an electron beam cooling furnace (EB furnace) to obtain a titanium alloy slab having a specification of thickness × width × length = 353 × 1588 × 1725 mm and a chemical composition of the slab of 5.52% Al, 4.13% V, 0.172% Fe, 0.167% O, and the rest Ti and trace impurity elements;

[0073] S5, rolling the titanium alloy slab for four times to obtain a slab of required thickness, wherein the rolling direction of the first time is the length direction of the slab, the slab is heated to 60°C above the phase transformation point for rolling, and the total deformation is 73.8%; after the first time of rolling, the material is cut to a width of 1600mm, and the second time of rolling is carried out at 70°C below the phase transformation point, the rolling direction of the second time is perpendicular to the rolling direction of the first time, and the total deformation is 45.8%; after the second time of rolling, the rolling direction is not changed, and the third time of rolling is carried out, the rolling temperature is the same as the second time, and the deformation is 56.4%; in the fourth time of rolling, the temperature and direction of the slab are the same as the third time, and the deformation is 44.9%;

[0074] S6. The obtained slab is heat treated by keeping at 825°C for 1 hour and air cooling to finally obtain a 12 mm thick titanium alloy plate.

[0075] When selecting titanium alloy recycled materials, the present invention takes into account the volatilization of elements such as Al and V during the electron beam cold hearth furnace smelting process. During the smelting process, the volatilization amounts of elements such as Al and V are empirical values.

[0076] In order to better illustrate the beneficial effects of the present invention, the microstructures of the titanium alloy plates prepared in Examples 1 to 3 and Comparative Example 1 were observed by metallographic microscope. Figures 3 to 6 , and referring to GB / T228.1-2021, the titanium alloy plates prepared in Examples 1 to 3 and Comparative Example 1 were subjected to mechanical performance tests, and the test results are shown in Table 1.

[0077] Table 1 TC4B titanium alloy mechanical properties test results

[0078]

[0079] from Figures 3 to 6 It can be seen that the TC4B titanium alloy plates prepared in Examples 1 to 3 have better uniformity of structure, which is better than the titanium alloy plate prepared in Comparative Example 1. It can be seen from Table 1 that the TC4B titanium alloy plate prepared in the present invention has excellent mechanical properties and meets the standards.

[0080] The specific embodiments of the present invention enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0081] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials, characterized in that: The following steps are involved: S1, weigh the recycled material; S2. Take out a portion of the weighed recycled material and weld it into an electrode frame with an open top; S3, laying the remaining recycled materials in the electrode frame to make electrodes; S4, using an EB furnace to melt the prepared electrode to obtain an ingot; S5, heating and rolling the obtained ingot to obtain a slab; S6. Heat-treating the slab to obtain a titanium alloy plate.

2. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: In S1, the recycled material is TC4 titanium alloy residue or TC4-ELI titanium alloy residue.

3. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: The recycled material includes Al: 5.0-6.3%, V: 3.0-4.3%, O: ≤0.2%, Fe: ≤0.3%, C: ≤0.08%, N: ≤0.05%, H: ≤0.015%, other impurity elements ≤0.4%, and the balance is Ti.

4. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: The electrode frame is a rectangular electrode frame, and the length of the rectangular electrode frame is: ≤4000mm, the width is: ≤800mm, and the height is: ≤500mm.

5. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: In S4, the EB furnace melts the electrode once.

6. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: In S4, the thickness of the ingot is 340-370 mm, and the width is 1500-1560 mm.

7. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: In S5, the ingot is rolled for 3 to 4 times, and during the rolling process, the ingot is alternately rotated.

8. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 7, characterized in that: When the ingot is rolled, the rolling temperature of the first rolling process is 40 to 60°C above the phase transformation point, and the rolling temperature of the remaining rolling processes is 40 to 70°C below the phase transformation point.

9. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 7, characterized in that: The method of alternately rotating the ingot is that the rolling direction of the second fire is perpendicular to the rolling direction of the first fire, and the rolling direction of the third fire is perpendicular to the rolling direction of the second fire.

10. The method for preparing TC4B titanium alloy sheet for armored vehicles using fully recycled materials according to claim 1, characterized in that: In S6, the slab heat treatment system is 800-850°C and the holding time is 1-1.5h.

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