A package and a package method suitable for hot rolling of TiAl alloy plate

Abstract

The application belongs to the technical field of titanium alloy preparation, and particularly relates to a package suitable for hot rolling of TiAl alloy plate and a package method. The package comprises an upper cover plate, a lower cover plate, a first edge strip and a second edge strip. The upper cover plate and the lower cover plate are both TC4 alloy, and the first edge strip and the second edge strip are both pure titanium or TC4 alloy. The first edge strip and the second edge strip are used for contacting two sides of TiAl blank in a non-entry-exit direction of a rolling mill and are welded with the TiAl blank. The upper cover plate and the lower cover plate are used for covering the upper and lower surfaces of the TiAl blank and are welded with the first edge strip and the second edge strip. The upper cover plate and the lower cover plate on both sides of the entry-exit direction of the package are directly closed and welded. The short-flow efficient hot rolling of the TiAl alloy plate is realized by reducing the package material cost and simplifying the package process. The package structure and manufacturing process are simple, the package reliability is strong in the hot rolling process, and the package has a positive effect on the industrialized batch preparation of the TiAl alloy plate.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy preparation technology, specifically relating to a cladding and cladding method suitable for hot rolling of TiAl alloy plates. Background Technology

[0002] High-temperature titanium alloys, due to their high specific strength, excellent corrosion resistance, and high-temperature performance (creep resistance, endurance strength, and structural stability), have become key materials for modern aero-engines. They are used in components such as engine disks, casings, and blades to reduce aircraft weight and thus improve the thrust-to-weight ratio. Typical high-temperature titanium alloys (Ti-1100, IMI834, Ti60, and Ti600, etc.) exhibit good structural and performance stability at 600℃, but cannot operate at temperatures above 600℃. TiAl intermetallic compounds have low density (3.9~4.2 g / cm³). 3 It features high elastic modulus (up to 170 GPa at room temperature, approximately 150 GPa at 750℃, comparable to GH4169), high specific strength, high specific stiffness, low coefficient of thermal expansion, high thermal conductivity, excellent oxidation resistance, creep resistance, and fatigue performance. It exhibits stable performance within a temperature range of 700℃ to 900℃ and can be used for short periods up to 1100℃. Lightweight, high-temperature resistant TiAl alloy sheets have enormous application potential in aircraft skins, integral panel components, and wing control structures, effectively improving the overall performance of aircraft.

[0003] However, TiAl intermetallic compounds have disadvantages such as low plasticity, high resistance to hot deformation, and narrow hot working window, making rolling difficult and prone to cracking during plate processing. As is well known, cladding rolling technology is widely used in traditional titanium alloy plate production; therefore, a reasonable cladding design is an important approach to achieving TiAl alloy plate preparation.

[0004] Currently, traditional cladding materials are high-temperature titanium alloys and stainless steels, which have similar high-temperature deformation compatibility to TiAl alloys, and are welded using vacuum electron beam welding. The economic and time costs of cladding material processing and welding are high, making them unsuitable for the industrial production of TiAl alloy sheets.

[0005] For example, patent CN117225922A uses a non-circular cladding design for TiAl alloys in subsequent rolling processes. This method isolates the TiAl alloy from the external air through vacuum electron beam welding of a stainless steel cladding. This reduces the rate of temperature drop during rolling and prevents oxidation of the TiAl alloy during heating, rolling, and post-rolling cooling. However, both the cladding material processing method (machining grooves) and the welding method (vacuum electron beam welding) are costly in terms of both economy and time, hindering the mass production of TiAl products.

[0006] The cladding material in patent CN112958626A is Inconel 625 high-temperature alloy, and to prevent the risk of FeTi reaction between the TiAl alloy and the outer cladding material, Nb and Ta foils are added as insulating materials in between. This method involves high costs for the cladding and insulating materials, and is only suitable for experimental work on small-sized TiAl alloys, which is not conducive to the commercial promotion and production of TiAl products.

[0007] Therefore, there is an urgent need to develop low-cost and simple cladding and cladding methods for hot rolling of TiAl alloy plates suitable for industrial production, so as to realize the commercial application of TiAl alloy plates. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a low-cost, simple cladding and cladding method suitable for hot rolling of TiAl alloy plates. This method not only achieves the same effect as traditional cladding methods in mitigating the temperature drop of TiAl alloys during rolling, but also reduces both economic and time costs in the cladding preparation process. The cladding is low-cost and simple, which helps TiAl alloy plates achieve large-scale industrial production.

[0009] The present invention is specifically implemented through the following technical solutions.

[0010] The present invention provides a cladding suitable for hot rolling of TiAl alloy plates. The cladding includes an upper cover plate, a lower cover plate, a first edge strip, and a second edge strip. The upper cover plate and the lower cover plate are both made of TC4 alloy, and the first edge strip and the second edge strip are both made of pure titanium or TC4 alloy.

[0011] The first and second edge strips are used to contact the two sides of the TiAl billet in the direction not entering or exiting the mill and to weld with the TiAl billet; the upper and lower cover plates are used to cover the upper and lower surfaces of the TiAl billet and to weld with the first and second edge strips at the corresponding positions, and the upper and lower cover plates covering the two sides in the direction of entering or exiting the mill are used for closing welding.

[0012] The cladding provided by this invention not only plays the same role as traditional cladding methods in mitigating the temperature drop of TiAl alloy during rolling, but also achieves a double reduction in economic and time costs during cladding preparation, which helps TiAl alloy plates achieve large-scale industrial production.

[0013] Preferably, the thickness of the upper and lower cover plates is 1mm to 2mm. The purpose of the upper and lower cover plates is to cover the TiAl billet and edge strips, preventing direct contact between the TiAl billet and the rolls, reducing the risk of rolling cracking of the TiAl billet, and maintaining good surface quality of the TiAl alloy sheet. To prevent the risk of reaction between the TiAl billet and the outer cladding material, and because industrial pure titanium has too low strength during rolling, which can easily cause the upper and lower cover plates to crack and lead to direct contact between the rolls and the TiAl billet, increasing the risk of rolling cracking of the TiAl alloy, TC4 alloy thin sheet, which has lower cost and allows for better application of rolling force to the TiAl billet, is selected.

[0014] Preferably, the thickness of the first and second edge strips is 105%-120% of the thickness of the TiAl billet, the width of the first and second edge strips is 5%-30% of the width of the TiAl billet, and the length is consistent with the length of the TiAl billet. The function of the first and second edge strips is to insulate the edges of the TiAl billet, prevent edge cracking during hot rolling, and improve rolling yield and plate quality. To prevent the risk of reaction between the TiAl billet and the outer cladding material, and to mitigate the temperature drop of the TiAl alloy during rolling (especially at the edges of the plate), while also possessing good high-temperature deformability, low-cost industrial pure titanium (TA1, TA2, TA3, etc.) or TC4 alloy is selected as the cladding edge strip.

[0015] Preferably, the TiAl billet contains a γ phase, including TNM alloys, TNB alloys, and TiAl-V alloys.

[0016] Preferably, the first or second side strip is not used on either side of the roll in and out of the mill.

[0017] The present invention also provides the above-mentioned cladding method applicable to hot rolling of TiAl alloy plates, comprising the following steps:

[0018] Step 1, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0019] Step 2, edge strip fabrication: Use industrial pure titanium or TC4 alloy as the first and second edge strips.

[0020] Step 3, edge strip welding: The first and second edge strips are brought into close contact with both sides of the TiAl billet and argon arc welded together to obtain the intermediate structure.

[0021] Step 4, Cover Plate Welding: Cover the upper and lower cover plates onto the upper and lower surfaces of the intermediate structure in Step 3. Then, perform argon arc welding on the structure welded in Step 3 to the upper and lower cover plates. The upper and lower cover plates are then welded to the corresponding first and second side strips. Since the upper and lower cover plates, as well as the first and second side strips, have good weldability, and argon arc welding has lower economic and time costs, argon arc welding can achieve a good weld between the first and second side strips and the upper and lower cover plates in Step 3. Vacuum electron beam welding is not always necessary. It should be noted that if there are special circumstances where argon arc welding cannot be used, vacuum electron beam welding can also be employed.

[0022] Preferably, since the side strips are not used to weld the cladding to the TiAl billet on both sides of the mill in step 3, the upper and lower cover plates on both sides of the mill in step 4 are directly welded together during the cover plate welding process. Argon arc welding can be used for welding. If there are special circumstances where argon arc welding cannot be used, vacuum electron beam welding can also be used.

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

[0024] This invention provides a novel, low-cost, and simple cladding method for hot-rolling TiAl alloy plates. It not only achieves the same effect as traditional cladding methods in mitigating temperature drop during TiAl alloy rolling, but also reduces both economic and time costs in the cladding preparation process, facilitating large-scale industrial production of TiAl alloy plates. Specifically:

[0025] The cladding of this invention includes an upper cover plate, a lower cover plate, a first side strip, and a second side strip. The first and second side strips are used to contact and weld with the TiAl billet on both sides outside the mill entry / exit direction. The upper and lower cover plates cover the upper and lower surfaces of the TiAl billet and are welded to the corresponding first and second side strips. The upper and lower cover plates on both sides of the cladding in the mill entry / exit direction are directly welded together. The upper and lower cover plates of this invention are made of TC4 alloy thin plates. The TC4 outer cladding does not react with the TiAl alloy at high temperatures, preventing the Fe-Ti reaction risk associated with traditional carbon steel and stainless steel as cladding materials. Although TC4 alloy does not have the same deformation coordination as TiAl billet during high-temperature rolling, its smaller thickness (1mm~2mm) makes it easier to transmit rolling force during the rolling process compared to traditional thicker steel cladding. This avoids the phenomenon that the rolling force cannot be transmitted to the TiAl billet layer during hot rolling, ensuring that the TiAl billet achieves effective deformation in each rolling pass.

[0026] The cladding provided by this invention does not use expensive high-temperature alloys as cladding materials, nor does it use insulating materials or coatings between the TiAl billet and the outer cladding. Furthermore, TC4 alloy and industrial pure titanium have good weldability, allowing for cladding welding using ordinary argon arc welding, eliminating the need for vacuum electron beam welding. The weld seam exhibits good stability and is less prone to cracking, thus improving the reliability of the cladding during the rolling process. This invention achieves a dual reduction in economic and time costs in material selection, cladding design, and welding, and is suitable for cladding rolling of various TiAl alloys under different process conditions. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cladding structure applicable to the hot rolling of TiAl alloy plates according to the present invention.

[0028] Explanation of reference numerals in the attached drawings: 1. Upper cover plate, 2. Lower cover plate, 3. First side strip, 4. Second side strip, 5. TiAl billet.

[0029] Figure 2 The image shows the actual packaging prepared in Example 1.

[0030] Figure 3 In the image, (a) shows the TiAl alloy prepared using a traditional steel cladding in Comparative Example 1 before the cladding is removed, and (b) shows the TiAl alloy after the cladding is removed.

[0031] Figure 4 In the image, (a) is a photograph of the TiAl alloy prepared in Example 1 before the packaging is removed, and (b) is a photograph of the TiAl alloy after the packaging is removed.

[0032] Figure 5 The image shows the actual TiAl alloy after disassembly and packaging, as shown in Comparative Example 2. Detailed Implementation

[0033] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0034] This invention provides a low-cost, simple cladding suitable for hot rolling of TiAl alloy plates, such as... Figure 1 As shown, the cover includes an upper cover plate 1, a lower cover plate 2, a first side strip 3, and a second side strip 4. The upper cover plate 1 and the lower cover plate 2 are both made of TC4 alloy, and the first side strip 3 and the second side strip 4 are both made of pure titanium or TC4 alloy.

[0035] The first edge strip 3 and the second edge strip 4 are used to contact the two sides of the TiAl billet 5 in the direction not entering or exiting the rolling mill, and are welded to the TiAl billet 5; the upper cover plate 1 and the lower cover plate 2 are used to cover the upper and lower surfaces of the TiAl billet 5, and are welded to the first edge strip 3 and the second edge strip 4 at the corresponding positions, and the upper cover plate 1 and the lower cover plate 2 on both sides in the direction of entering or exiting the rolling mill are directly welded together.

[0036] The cover plates are upper cover plate 1 and lower cover plate 2: the cover plate materials used are all TC4 alloy thin plates with a uniform thickness (about 1.0 mm-2.0 mm). The purpose is to cover the TiAl billet 5, the first edge strip 3 and the second edge strip 4 to prevent the TiAl billet 5 from directly contacting the rolls, reduce the risk of TiAl billet cracking during rolling and maintain a good surface quality.

[0037] The edge strips consist of a first edge strip 3 and a second edge strip 4. The edge strip material is industrial pure titanium (TA1, TA2, TA3, etc.) or TC4 alloy, and the edge strip thickness is 105%-120% of the TiAl billet thickness. Because TiAl alloy has poor room temperature plasticity, it cannot undergo cold working deformation. Simultaneously, it has high resistance to hot deformation and a narrow hot working window, which can lead to significant cracks at the edges during hot rolling, causing hot rolling failure. Therefore, the purpose of adding the first edge strip 3 and the second edge strip 4 is to insulate the edges of the TiAl, preventing edge cracks during hot rolling, thereby improving rolling yield and plate quality.

[0038] The welding is performed using argon arc welding. If there are special circumstances where argon arc welding cannot be used, vacuum electron beam welding can be used.

[0039] TiAl billet: The TiAl billet contains a γ phase, including TNM alloy, TNB alloy and TiAl-V system alloy.

[0040] This invention also provides the above-mentioned low-cost and simple cladding method applicable to hot rolling of TiAl alloy plates, comprising the following steps:

[0041] Step 1, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0042] Step 2, Edge strip fabrication: Use industrial pure titanium or TC4 alloy as the first and second edge strips;

[0043] Step 3, edge strip welding: The first and second edge strips are brought into close contact with both sides of the TiAl billet and welded together by argon arc welding;

[0044] Step 4, Cover Plate Welding: The structure welded in Step 3 is then argon-arc welded to the upper and lower cover plates. Since the upper and lower cover plates, as well as the first and second side strips, have good weldability, and argon-arc welding is economical and time-efficient, argon-arc welding can achieve a good weld between the side strips and the upper and lower cover plates described in Step 3.

[0045] Preferably, since the side strips are not used to weld the TiAl billet to the two sides of the cladding entering and exiting the mill in step 3, the upper and lower cover plates on both sides of the cladding entering and exiting the mill are directly welded together using argon arc welding during the cover plate welding process in step 4.

[0046] This invention not only achieves the same effect as traditional cladding methods in mitigating the temperature drop of TiAl alloy during rolling, but also reduces both economic and time costs in the cladding preparation process, thus facilitating the large-scale industrial production of TiAl alloy plates.

[0047] It should be noted that this invention is applicable to the hot rolling of TiAl alloy plates. No intermediate separating material or separator is added between the outer cladding material and the TiAl billet. However, adding an intermediate separating material or separator could also achieve this invention; therefore, adding an intermediate separating material or separator is an alternative. The function of the intermediate separating material is to prevent the outer cladding material from reacting with the inner billet during heating or rolling. Specifically, it includes high-melting-point metals such as niobium, molybdenum, and tungsten. The function of the separator is to facilitate the separation between the outer cladding material and the inner billet after hot rolling; specifically, it refers to a separator used in metal processing. Furthermore, this invention does not require vacuum electron beam welding for welding the components. While vacuum electron beam welding could also achieve this invention, using vacuum electron beam welding for welding the components is an alternative.

[0048] The present invention will be specifically described below through the following embodiments and comparative examples.

[0049] Example 1

[0050] The upper and lower cover plates used in this embodiment are made of TC4 alloy with a thickness of 1 mm. The edge strip material is industrial pure titanium TA2. The TiAl alloy used is an alloy with a nominal composition of Ti-41.2Al-2.65Nb-1.2Cr-0.7Mo (TNM alloy), and the composition is in atomic percentage.

[0051] A cladding method applicable to hot rolling of TiAl alloy plates includes the following steps:

[0052] Step 1, Billet Preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and then made into a square billet with a thickness of 12mm × width of 320mm × length of 400mm by wire electrical discharge machining.

[0053] Step 2, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates, with a thickness of 1mm. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0054] Step 3, Edge Strip Fabrication: Use industrial pure titanium (TA2) as the first and second edge strips, and ensure they are in close contact with the TiAl billet. The thickness of the first and second edge strips is 110% of the thickness of the TiAl billet, the width of the first and second edge strips is 20% of the width of the TiAl billet, and the length of the first and second edge strips is consistent with the length of the TiAl billet.

[0055] Step 4, edge strip welding: The first and second edge strips are brought into close contact with the TiAl billet and then welded together by argon arc welding.

[0056] Step 5, Cover Plate Welding: After welding the first and second side strips to the TiAl billet, perform argon arc welding to the upper and lower cover plates. Since the upper and lower cover plates and side strips have good weldability, and argon arc welding has lower economic and time costs, it is sufficient to achieve a good weld between the side strips and the upper and lower cover plates. See the actual product image below. Figure 2 As shown.

[0057] Rolling process:

[0058] Sheath rolling: The welded sheath and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the billet is reheated in the furnace for 5 minutes between every two rolling passes.

[0059] cladding removal: The cladding of the rolled sheet is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0060] Example 2

[0061] The upper and lower cover plates used in this embodiment are made of TC4 alloy with a thickness of 1 mm. The edge strip material is industrial pure titanium TA1. The TiAl alloy used is an alloy with a nominal composition of Ti-41.2Al-2.65Nb-1.2Cr-0.7Mo (TNM alloy), and the composition is in atomic percentage.

[0062] A cladding method applicable to hot rolling of TiAl alloy plates includes the following steps:

[0063] Step 1, Billet Preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and then made into a 12×320×400mm square billet by wire electrical discharge machining.

[0064] Step 2, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates, with a thickness of 1mm. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0065] Step 3, Edge Strip Fabrication: Use industrial pure titanium (TA1) as the first and second edge strips, and ensure close contact between the first and second edge strips and the TiAl billet. The thickness of the first and second edge strips is 110% of the thickness of the TiAl billet, the width of the first and second edge strips is 20% of the width of the TiAl billet, and the length of the first and second edge strips is consistent with the length of the TiAl billet.

[0066] Step 4, edge strip welding: The first and second edge strips are brought into close contact with the TiAl billet and then welded together by argon arc welding.

[0067] Step 5, cover plate welding: After welding the first and second side strips to the TiAl billet, they are then welded to the upper and lower cover plates using argon arc welding. Since the upper and lower cover plates and side strips have good weldability, and the economic and time costs of argon arc welding are low, argon arc welding can be used to achieve good welding of the first and second side strips to the upper and lower cover plates.

[0068] Rolling process:

[0069] Sheath rolling: The welded sheath and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the billet is reheated in the furnace for 5 minutes between every two rolling passes.

[0070] cladding removal: The cladding of the rolled sheet is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0071] Example 3

[0072] The upper and lower cover plates used in this embodiment are made of TC4 alloy with a thickness of 1 mm. The edge strip material is industrial pure titanium TA3. The TiAl alloy used is an alloy with a nominal composition of Ti-41.2Al-2.65Nb-1.2Cr-0.7Mo (TNM alloy), and the composition is in atomic percentage.

[0073] A cladding method applicable to hot rolling of TiAl alloy plates includes the following steps:

[0074] Step 1, Billet Preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and then made into a 12×320×400mm square billet by wire electrical discharge machining.

[0075] Step 2, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates, with a thickness of 1mm. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0076] Step 3, Edge Strip Fabrication: Use industrial pure titanium (TA3) as the first and second edge strips, and ensure they are in close contact with the TiAl billet. The thickness of the first and second edge strips is 110% of the thickness of the TiAl billet, the width of the first and second edge strips is 20% of the width of the TiAl billet, and the length of the first and second edge strips is consistent with the length of the TiAl billet.

[0077] Step 4, edge strip welding: The first and second edge strips are brought into close contact with the TiAl billet and then welded together by argon arc welding.

[0078] Step 5, cover plate welding: After welding the first and second side strips to the TiAl billet, they are then welded to the upper and lower cover plates using argon arc welding. Since the upper and lower cover plates, as well as the first and second side strips, have good weldability, and the economic and time costs of argon arc welding are relatively low, argon arc welding can be used to achieve a good weld between the side strips and the upper and lower cover plates.

[0079] Rolling process:

[0080] Sheath rolling: The welded sheath and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the billet is reheated in the furnace for 5 minutes between every two rolling passes.

[0081] cladding removal: The cladding of the rolled sheet is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0082] Example 4

[0083] A cladding method applicable to hot rolling of TiAl alloy plates includes the following steps:

[0084] Step 1, billet preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and a square billet of 12×320×400mm is made by electrical discharge wire cutting; the TiAl alloy has a nominal composition of Ti-41.2Al-2.65Nb-1.2Cr-0.7Mo, and the composition is in atomic percentage.

[0085] Step 2, Fabrication of the upper and lower cover plates: TC4 alloy is selected as the material for the upper and lower cover plates, with a thickness of 1mm. The dimensions of the TC4 alloy are determined based on the dimensions of the TiAl billet.

[0086] Step 3, Edge Strip Fabrication: Use titanium alloy (TC4) as the first and second edge strips, and ensure they are in close contact with the TiAl billet. The thickness of the first and second edge strips is 110% of the thickness of the TiAl billet, the width of the first and second edge strips is 20% of the width of the TiAl billet, and the length of the first and second edge strips is consistent with the length of the TiAl billet.

[0087] Step 4, edge strip welding: The first and second edge strips are brought into close contact with the TiAl billet and then welded together by argon arc welding.

[0088] Step 5, cover plate welding: After welding the first and second side strips to the TiAl billet, they are then welded to the upper and lower cover plates using argon arc welding. Since the upper and lower cover plates and the side strips have good weldability, and the economic and time costs of argon arc welding are low, argon arc welding can be used to achieve a good weld between the side strips and the upper and lower cover plates.

[0089] Rolling process:

[0090] Sheath rolling: The welded sheath and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the billet is reheated in the furnace for 5 minutes between every two rolling passes.

[0091] cladding removal: The cladding of the rolled sheet is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0092] Comparative Example 1

[0093] The rolling process using a steel cladding involves the following steps:

[0094] Step 1, Billet Preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and then made into a 12×320×400mm square billet by wire electrical discharge machining.

[0095] Step 2, Fabrication of the upper and lower cover plates: Select stainless steel (such as 310S) as the material for the upper and lower cover plates, and determine the dimensions of the TC4 alloy according to the dimensions of the TiAl billet.

[0096] Step 3, edge strip fabrication: Use stainless steel (such as 310S) as the first and second edge strips, and make close contact between the first and second edge strips and the TiAl billet.

[0097] Step 4, welding the edge strips to the cover plate: the upper and lower cover plates from step 2 are argon arc welded to the first and second edge strips from step 3, and then vacuum electron beam welding is performed.

[0098] Step 5, cladding rolling: The welded cladding and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the cladding is reheated for 5 minutes between every two rolling passes.

[0099] Step 6, cladding removal: The cladding of the rolled sheet in Step 6 is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0100] Figure 3 In the image, (a) shows a TiAl alloy prepared using a traditional steel cladding before the cladding is removed, and (b) shows a TiAl alloy after the cladding is removed. Compared to Comparative Example 1, the cladding used in Example 1 exhibits better cladding condition and plate quality after rolling, such as... Figure 4 As shown in (a) and (b) in Example 1, there is almost no adhesion between the sleeve and the board, the sleeve is easy to remove, there are no traces of chemical reaction on the board surface, no cracking, and the surface quality is good.

[0101] The performance of the other embodiments is similar to that of Embodiment 1, and will not be described in detail here.

[0102] Comparative Example 2

[0103] The rolling process uses 4mm TC4 sheet metal as a sheath. The specific steps are as follows:

[0104] Step 1, billet preparation: The original billet is prepared by vacuum consumable electrode arc melting + hot isostatic pressing, and a square billet of 12×320×400mm is made by electrical discharge wire cutting; the TiAl alloy has a nominal composition of Ti-41.2Al-2.65Nb-1.2Cr-0.7Mo, and the composition is in atomic percentage.

[0105] Step 2, Fabrication of upper and lower cover plates: Select TC4 sheet with a thickness of 4mm as the material for the upper and lower cover plates, and determine the size of the TC4 alloy according to the size of the TiAl billet.

[0106] Step 3, Edge Strip Fabrication: Use TC4 sheet metal as the first and second edge strips, ensuring close contact between the first and second edge strips and the TiAl billet. The thickness of the first and second edge strips is 110% of the thickness of the TiAl billet, the width of the first and second edge strips is 20% of the width of the TiAl billet, and the length of the first and second edge strips is consistent with the length of the TiAl billet.

[0107] Step 4, welding the edge strips to the cover plate: the upper and lower cover plates from step 2 are argon arc welded to the first and second edge strips from step 3, and then vacuum electron beam welding is performed.

[0108] Step 5, cladding rolling: The welded cladding and billet are heated to 1240℃ together in a hydrogen heat treatment furnace, and rolled 5 times at a rolling speed of 50mm / s and a single-pass deformation of 10%, with a cumulative total deformation of 50%, and then air-cooled to room temperature; the cladding is reheated for 5 minutes between every two rolling passes.

[0109] Step 6, cladding removal: The cladding of the rolled sheet is removed by water jet processing. After annealing at 900℃ and straightening, a flat TiAl alloy sheet is obtained.

[0110] Comparative Example 2 uses 4mm thick TC4 sheet material for rolling, and the case after removing the cladding is as follows: Figure 5 ,from Figure 5 As can be seen, the outer casing and the internal TiAl alloy in this comparative example cannot be separated, and at the same time from... Figure 5 As can be seen, the edges of the TiAl alloy have fractured.

[0111] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A can suitable for hot rolling of TiAl alloy sheet material, characterized in that, The cover sleeve comprises an upper cover plate, a lower cover plate, a first edge strip and a second edge strip, the upper cover plate and the lower cover plate are both TC4 alloy, and the first edge strip and the second edge strip are both pure titanium or TC4 alloy; The first edge strip and the second edge strip are used to contact and weld with the TiAl blank along the two side edges in the non-entry-exit direction of the rolling mill; the upper cover plate and the lower cover plate are used to cover the upper and lower surfaces of the TiAl blank and are welded with the first edge strip and the second edge strip, and the upper cover plate and the lower cover plate in the entry-exit direction of the cover sleeve are used for closing welding; The thickness of the upper cover plate and the lower cover plate is 1mm-2mm; The thickness of the first edge strip and the second edge strip is 105%-120% of the thickness of the TiAl blank, the width of the first edge strip and the second edge strip is 5%-30% of the width of the TiAl blank, and the length of the first edge strip and the second edge strip is consistent with the length of the TiAl blank.

2. The package suitable for hot rolling of TiAl alloy sheet according to claim 1, characterized in that, The pure titanium is TA1, TA2 or TA3.

3. The package suitable for hot rolling of TiAl alloy sheet according to claim 1, characterized in that, The welding is performed by argon arc welding.

4. The package suitable for hot rolling of TiAl alloy sheet according to claim 1, characterized in that, The welding is performed by vacuum electron beam.

5. The package suitable for hot rolling of TiAl alloy sheet according to claim 1, characterized in that, The TiAl blank contains γ phase.

6. The enclosure suitable for hot rolling of TiAl alloy sheet according to claim 5, characterized in that The TiAl blank is TNM alloy, TNB alloy or TiAl-V alloy.

7. A method of encasement suitable for hot rolling of TiAl alloy sheet material, characterised in that, The cover sleeve suitable for hot rolling of TiAl alloy plate according to claim 1 comprises the following steps: TC4 alloy is selected as the material of the upper cover plate and the lower cover plate, and the size of the TC4 alloy is determined according to the size of the TiAl blank; Industrial pure titanium or TC4 alloy is used as the first edge strip and the second edge strip; The first edge strip and the second edge strip are contacted and welded with the TiAl blank along the two side edges in the non-entry-exit direction of the rolling mill to obtain an intermediate structure; The upper cover plate and the lower cover plate are covered on the upper surface and the lower surface of the intermediate structure, and the upper cover plate and the lower cover plate are welded with the first edge strip and the second edge strip; the upper cover plate and the lower cover plate in the entry-exit direction of the cover sleeve are directly closed and welded.

8. The method according to claim 7, characterized in that, The edge strip welding and the cover plate welding are performed by argon arc welding or vacuum electron beam.

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