Method for preparing extremely thin strip from tc4 titanium alloy eb ingot
By combining electron beam cold hearth furnace melting and asynchronous rolling, the problems of long process, high cost and minimum rollable thickness limitation in the production of TC4 titanium alloy ultra-thin strip were solved, realizing the efficient and low-cost preparation of TC4 titanium alloy ultra-thin strip and improving the plasticity and mechanical properties of the material.
Patent Information
- Application Number
- CN202310784383.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-29
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2043-06-29
AI Technical Summary
Existing technologies for preparing ultra-thin TC4 titanium alloy strips suffer from problems such as long production processes, high material losses, high costs, minimum rollable thickness limitations, and complex equipment, making it difficult to meet the needs of high-end applications.
TC4 titanium alloy flat ingots are smelted in an electron beam cold hearth furnace, coated with a high-temperature glass lubricant, and then hot-rolled and asynchronously rolled. Combined with warm rolling process, ultra-thin strips are prepared by cross rolling and a four-roll asynchronous mill, avoiding complex cold rolling processes.
It has achieved efficient and low-cost production of ultra-thin TC4 titanium alloy strip, breaking through the minimum rollable thickness limit, improving the plasticity and mechanical properties of the material, and ensuring thickness accuracy and quality stability.
Smart Images
Figure CN117019914B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of strip manufacturing, in particular to a method for preparing extremely thin strip from TC4 titanium alloy EB ingot. BACKGROUND
[0002] Titanium and titanium alloy is an extremely important lightweight structural material, which has high specific strength, good corrosion resistance, high and low temperature performance, and other outstanding characteristics, and has very important application value and broad application prospect in the fields of aviation, aerospace, navigation and medical treatment. Among the products of titanium and titanium alloy, titanium extremely thin strip has excellent chemical properties, mechanical properties, thickness precision and surface characteristics, and belongs to the technical intensive high-end product in the field of titanium strip coil. TC4 titanium alloy extremely thin strip has become an excellent material for precision instruments and biotechnology products, and is recognized by the precision manufacturing fields of aerospace, medical treatment, national defense and the like. In recent years, with the rapid development of high-end chemical industry, new energy industry, electronics industry and the like in China, there is an urgent demand for domestic high-quality titanium extremely thin strip products.
[0003] However, due to the plastic processing capacity of TC4 titanium alloy being inferior to that of pure titanium, the TC4 titanium alloy extremely thin strip is difficult to process, and its popularization and application are limited by the processing capacity. At present, the mainstream production methods of titanium alloy extremely thin strip are as follows:
[0004] The titanium sponge is pressed into a consumable electrode, and then a cast ingot is prepared through 2-3 times of melting by a vacuum consumable arc furnace (VAR furnace). The cast ingot is forged into a hot-rolled rough blank through multiple forging processes, and the rough blank is obtained through subsequent hot rolling + cold rolling and the like. The above-mentioned hot-rolled rough blank obtaining method has the disadvantages of long production process, large material loss and high production cost.
[0005] Compared with the VAR furnace melting method, the electron beam cold hearth furnace melting (EB) can effectively eliminate high and low density inclusions, which is an important way to realize the purification technology of titanium and titanium alloy materials. In addition, the EB furnace can also add a large amount of returned material to reduce the cost. The EB furnace melting has the characteristics of short process, high efficiency and strong controllability. Moreover, the slab obtained by the EB furnace melting can save the traditional cogging process, and the slab can be directly processed into titanium extremely thin strip through hot rolling + cold rolling and the like, which greatly shortens the production cycle of titanium alloy and reduces the production cost. It is a new emerging process route with high efficiency, short process and low cost.
[0006] The heating temperature of warm rolling is below the recrystallization temperature. Compared with hot rolling, it reduces the oxidation and air absorption degree of the metal, and reduces the workload of removing the oxidation and air absorption layer; compared with cold rolling, it improves the process plasticity of the metal, and can increase the rolling deformation, thereby avoiding multiple intermediate annealing and auxiliary processes, and shortening the production cycle of the sheet. However, in actual production, when the thickness of the rolled piece is reduced to a certain value, it is difficult to continue to thin under the synchronous rolling process, even if the rolling force of the equipment is increased to the maximum and the rolling passes are increased. This thickness is called the minimum rollable thickness. Under the guidance of the traditional minimum rollable thickness theory Stone formula, people generally reduce the work roll diameter to achieve the purpose of thinning the rolled piece, and thus various multi-roll mills represented by Sendzimir mills are invented. However, multi-roll mills have many problems, such as complex equipment structure, too small work roll diameter to be used as a driving roll, high price, and troublesome fault handling. Therefore, people are also constantly seeking a rolling method that can break through the limit of the minimum rollable thickness and has a relatively simple equipment structure.
[0007] Asynchronous rolling: Asynchronous rolling can break through the limit of the minimum rollable thickness of traditional synchronous rolling. Due to the difference in speed between the upper and lower work rolls, asynchronous rolling increases the shear strain compared with synchronous rolling during the deformation process of the rolled piece, which has a certain influence on the microstructure and texture of the material, and then reflects to the macro mechanical properties of the material. Asynchronous rolling is not only beneficial to the formation of shear texture, but also can refine the grains along the thickness direction.
[0008] At present, the TC4 ultra-thin strip product produced in China still has a significant gap with the international advanced level, mainly in the low titanium ingot metallurgical quality, poor thickness precision, shape control and quality consistency stability, and low yield.
[0009] In the invention patent with the authorized announcement number CN102941228B, a preparation method of titanium alloy foil is provided. The method uses a cladding and stacking process on a titanium alloy plate to obtain a titanium alloy foil with a thickness of 0.05-0.3 mm. However, cladding and stacking belongs to an old hot rolling thin plate production method, which has the disadvantages of low yield, quality and material yield, and high labor intensity. The introduction of pure titanium plate and welding requirements in this method significantly increases the cost of the product.
[0010] In the invention patent with the authorization announcement number CN114951273A, a rolling process for efficiently preparing near-alpha type high-temperature titanium alloy ultra-thin strip is provided. The method obtains the finished product thickness of 0.08-0.15 mm ultra-thin strip only through the hot rolling process on the basis of cladding rolling and reversing rolling. Although the method effectively improves the anisotropy of the ultra-thin strip, in addition to the above-mentioned cladding and stacking rolling defects, TC4 titanium alloy is not included in the near-alpha type high-temperature titanium alloy. For the alpha+beta type TC4 titanium alloy, a new thin strip production process needs to be proposed.
[0011] In summary, it is the current research focus of TC4 titanium alloy ultra-thin strip to study a new TC4 titanium alloy ultra-thin strip production process, optimize the production technology and process of TC4 titanium alloy ultra-thin strip, and improve the quality of TC4 titanium alloy ultra-thin strip product. SUMMARY
[0012] In order to solve the above-mentioned problems of the prior art, the present application provides a method for preparing an ultra-thin strip using a TC4 titanium alloy EB ingot. The TC4 titanium alloy slab is melted by an electron beam cold hearth furnace (EB furnace), and the surface of the slab is coated with high-temperature glass lubricating paint before being loaded into the furnace to prevent temperature drop, oxidation and reduce friction and wear. After the TC4 slab reaches the heating and heat preservation requirements in the electric heating furnace, the hot rolling process is directly carried out. The hot rolling process obtains a hot rolling finished product through cross rolling. Finally, the hot rolling finished product is obtained by warm rolling on a four-roll asynchronous rolling mill to obtain a TC4 ultra-thin strip with a thickness of less than 0.1 mm.
[0013] Specifically, the present application provides a method for preparing an ultra-thin strip using a TC4 titanium alloy EB ingot, which comprises the following steps:
[0014] S1, selecting a TC4 titanium alloy slab melted by an electron beam cold hearth furnace, coating the surface of the TC4 titanium alloy slab with glass lubricating paint at room temperature, and waiting for air drying before proceeding to step S2;
[0015] S2, the TC4 titanium alloy slab obtained in step S1 is heated in three stages in an electric heating furnace. The first stage electric heating furnace is first heated to 650-750℃, and then the TC4 titanium alloy slab is placed in the furnace. After the TC4 titanium alloy slab is properly placed, the second stage is heated to 950℃ at a rate of 10℃ / min, and the temperature is maintained for 4-7h. The third stage is heated to 1050℃ at a rate of 10℃ / min, and the temperature is maintained for 2-4h;
[0016] S3, hot rolling process;
[0017] The step S2 is kept at a required temperature, and then the TC4 titanium alloy flat ingot is transported to a hot rolling mill, the initial rolling temperature is 1000 DEG C, the final rolling temperature is 800 DEG C, and the one-pass multi-pass hot rolling process is carried out, so that the one-pass hot-rolled titanium plate is obtained, and the total deformation is 50-80%; the two-pass multi-pass hot rolling is carried out in a cross-rolling mode, so that the hot-rolled titanium plate is obtained; the rolling temperature of the cross-rolling is 950 DEG C, so that the hot-rolled titanium plate with a thickness of 1-2 mm is obtained, and the total deformation of the two-pass rolling is greater than 95%;
[0018] S4, the hot-rolled titanium plate obtained in the step S3 is subjected to annealing treatment, creep correction, alkali and acid washing and sanding, so that the TC4 hot-rolled titanium plate with a surface smoothness and flatness meeting the standard is obtained;
[0019] S5, the titanium plate obtained in the step S4 is kept in a heating furnace at 650-750 DEG C for 60-120 min, then is transported to an asynchronous rolling mill to carry out the warm rolling of the TC4 titanium alloy ultra-thin strip, the warm rolling adopts 2-4 rolling passes, the total pass number is 9-20 passes, after each rolling pass is finished, the titanium plate is returned to the heating furnace at 650-750 DEG C for 60-120 min, and then is subjected to the next rolling pass, until the last rolling pass is finished; the speed ratio of the fast roller to the slow roller in the asynchronous rolling mill is 1.05-1.5, the rolling speed is 20-50 mm / s, the actual voltage of the torque motor is controlled to be 100-200 V, and the total reduction is greater than 90%, so that the rolled ultra-thin strip with a thickness of less than 0.1 mm is finally obtained;
[0020] S6, before annealing, the rolled ultra-thin strip obtained in the step S5 is subjected to degreasing treatment, then is placed in a vacuum cover furnace to carry out vacuum annealing heat treatment, the annealing temperature is 650-700 DEG C, and the time is 2-6 h, so that the TC4 ultra-thin strip with a thickness of less than 0.1 mm is obtained; the average grain size is 5-10 mu m, the room temperature tensile strength is greater than or equal to 895 MPa, the yield strength is greater than or equal to 830 MPa, the elongation is greater than or equal to 8%, and the thickness deviation of the ultra-thin strip is not greater than ± 0.015 mm.
[0021] Preferably, the machine spraying glass lubricating coating is adopted in the step S1.
[0022] Preferably, the step S3 further comprises: cutting off the head and tail of the one-pass hot-rolled titanium plate to obtain an intermediate blank, the intermediate blank after the one-pass rolling is subjected to surface grinding, the intermediate blank after the grinding is subjected to surface flaw detection and ultrasonic flaw detection, and the intermediate blank after the flaw detection is qualified is subjected to the two-pass multi-pass hot rolling.
[0023] Preferably, the asynchronous rolling mill in the step S5 is a four-roll asynchronous rolling mill.
[0024] Compared with the prior art, the present application has the following beneficial effects:
[0025] (1) The present application covers the whole process preparation technology and method of TC4 titanium alloy extremely thin strip preparation, including ingot preparation, plate hot rolling, extremely thin strip preparation and extremely thin strip heat treatment, which can effectively control the microstructure and mechanical properties of the extremely thin strip.
[0026] (2) In the hot rolling process, the present application weakens the rolling texture of TC4 titanium material by cross rolling, improves the anisotropy of the alloy, and obtains a rolling plate suitable for asynchronous warm rolling.
[0027] (3) The present application adopts the combination of warm rolling and asynchronous rolling, breaks through the limit of the minimum rollable thickness of traditional synchronous rolling, increases the rolling deformation, and at the same time can avoid the multiple intermediate annealing and auxiliary processes in the cold rolling process; and without using the conventional cold rolling conditions of complex and expensive twenty-roll rolling mill, TC4 titanium alloy extremely thin strip can be prepared.
[0028] (4) The TC4 titanium alloy extremely thin strip prepared by the method of the present application has an average grain size of 5-10 μm, a room temperature tensile strength of ≥895 MPa, a yield strength of ≥830 MPa, an elongation of ≥8%, and a thickness deviation of the extremely thin strip of not more than ±0.015 mm. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 is a flowchart of the present application;
[0030] Figure 2 is an example diagram of the Abaqus simulation of the asynchronous warm rolling process in the embodiment of the present application. DETAILED DESCRIPTION
[0031] In order to better understand the technical scheme of the present application, the specific embodiments of the present application are described in detail below in combination with the drawings and examples. The same reference signs in the drawings represent functionally identical or similar elements. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
[0032] The present application provides a method for preparing an extremely thin strip using a TC4 titanium alloy EB ingot, as shown in Figure 1 which comprises the following steps:
[0033] S1, selecting an electron beam cold hearth melting (EB) TC4 titanium alloy slab, applying glass lubricating paint on the surface of the TC4 titanium alloy slab at room temperature, and after waiting for air drying, performing step S2.
[0034] The TC4 slab melted by the electron beam cold hearth can be directly rolled to obtain TC4 titanium alloy plate, eliminating the processes of forging and grinding, and realizing short process and low cost preparation of TC4 titanium alloy plate blank.
[0035] In the process of coating the glass lubricating coating on the surface of the TC4 titanium alloy slab, machine spraying can be used to improve the use effect of the coating. After the coating is naturally cooled and dried, the TC4 titanium alloy slab is subsequently heated in the furnace, and the coating can be stretched and peeled off with the deformation of the metal during rolling. By coating the coating, the serious oxidation or hydrogen absorption of the TC4 titanium alloy slab during the heating stage can be prevented, the requirement of large reduction rate in hot rolling can be met, the serious surface cracks of the rolled piece can be prevented, and the as-cast structure of the rolled piece can be fully broken.
[0036] S2, the TC4 titanium alloy slab obtained in step S1 is heated in an electric heating furnace in three stages, the first stage of the electric heating furnace is first heated to 650-750℃, and then the TC4 titanium alloy slab is placed in the furnace; after the TC4 titanium alloy slab is properly placed, the second stage is heated to 950℃ at a rate of 10℃ / min, and the temperature is kept for 4-7h; the third stage is heated to 1050℃ at a rate of 10℃ / min, and the temperature is kept for 2-4h.
[0037] S3, hot rolling process;
[0038] The TC4 titanium alloy slab after the temperature is kept to the required temperature in step S2 is transported out of the furnace to a hot rolling mill, the initial rolling temperature is 1000℃, the final rolling temperature is 800℃, a one-pass multi-pass hot rolling process is carried out, and a one-pass hot rolled titanium plate is obtained, the total deformation is 50-80%; the head and tail of the one-pass hot rolled titanium plate are cut to obtain an intermediate blank, the cutting amount is determined according to the curvature and quality of the head and tail of the one-pass hot rolled titanium plate, the surface of the intermediate blank after the one-pass rolling is ground, and the scale, cracks and other surface defects are removed, if the defects are deep, local grinding can be carried out to remove the defects, but attention should be paid to excessive smoothing during local grinding, the width-depth ratio of grinding should be ≥10:1, and the intermediate blank after grinding needs to be subjected to surface inspection and ultrasonic inspection, and the intermediate blank after the inspection is qualified is subjected to a two-pass multi-pass hot rolling in a cross-rolling manner, and a hot rolled titanium plate is obtained. By cross-rolling, the anisotropy of the hot rolled titanium plate is reduced, so that the titanium plate does not appear rolling cracks in the subsequent warm rolling process, the rolling temperature of the cross-rolling is 950℃, a hot rolled titanium plate with a thickness of 1-2mm is obtained, and the total deformation of the two-pass rolling is greater than 95%.
[0039] The TC4 titanium alloy slab is rolled into a hot rolled titanium plate by a hot rolling process, in the hot rolling process, the rolling texture of the TC4 titanium material is weakened by reversing rolling, and the anisotropy of the alloy is improved to obtain a hot rolled titanium plate suitable for asynchronous warm rolling.
[0040] S4, the hot rolled titanium plate obtained in step S3 is subjected to annealing treatment, creep correction, alkali and acid washing and sanding to obtain a TC4 hot rolled titanium plate with a surface finish and flatness meeting the standard, which is used in the subsequent warm rolling process. Generally, the surface finish Ra is 0.4-3.2, the flatness is less than 1mm / m, and the warping is less than 0.5mm / m.
[0041] S5. The titanium plate obtained in step S4 is held in a furnace at 650-750℃ for 60-120 minutes. After exiting the furnace, it is transferred to an asynchronous rolling mill for TC4 titanium alloy ultra-thin strip rolling. The warm rolling process uses 2-4 passes, with a total of 9-20 passes. After each pass, the strip is returned to the furnace at 650-750℃ for 60-120 minutes before starting the next pass, until the last pass is completed. In the asynchronous rolling mill, the speed ratio of the fast roll to the slow roll is 1.05-1.5, the rolling speed is 20-50 mm / s, the actual voltage control of the torque motor is 100-200V, and the total reduction rate reaches more than 90%, finally obtaining a rolled ultra-thin strip with a thickness of less than 0.1 mm.
[0042] In practical applications, to better set the rolling process parameters in the warm rolling process according to different batches of TC4 titanium alloy, Abaqus simulation software can be used. The basic property parameters of TC4 titanium alloy, such as density, Poisson's ratio, elastic modulus, coefficient of linear expansion, specific heat and thermal conductivity, can be input for simulation to obtain more accurate speed ratio of fast and slow rolls, rolling speed and torque motor actual voltage control for asynchronous rolling mill settings. Figure 2 This is a schematic diagram of an asynchronous warm rolling simulation using Abaqus.
[0043] During the cold rolling process of TC4 titanium alloy, severe work hardening and uneven distribution of plastic deformation and strain during cold deformation can easily lead to cracking, severely damaging the quality of the finished product. Compared with cold rolling, warm rolling can improve the process plasticity of TC4 titanium alloy, increase the rolling deformation, and shorten the production cycle of thin plates.
[0044] This invention combines warm rolling with asynchronous rolling, which improves the process plasticity of metals, increases the amount of rolling deformation, breaks through the limit of the minimum rollable thickness of traditional synchronous rolling, and avoids multiple intermediate annealing and auxiliary processes in cold rolling. Moreover, it can produce TC4 titanium alloy ultrathin strips without the need for conventional cold rolling under the conditions of complex and expensive 20-roll mills.
[0045] S6. Before annealing, the rolled ultra-thin strip obtained in step S5 is degreased and placed in a vacuum bell furnace for vacuum annealing heat treatment. The annealing temperature is 650-700℃ and the time is 2-6h to obtain TC4 ultra-thin strip with a thickness of less than 0.1mm.
[0046] The TC4 titanium alloy ultra-thin strip prepared by the method has an average grain size of 5-10 microns, a room temperature tensile strength of ≥895 MPa, a yield strength of ≥830 MPa, an elongation of ≥8%, and a thickness deviation of not more than ±0.015 mm.
[0047] The method of the present application is described in detail below in conjunction with specific examples:
[0048] Example 1, preparation of TC4 titanium alloy ultra-thin strip with a thickness of 0.1 mm.
[0049] S1, select a TC4 titanium alloy slab produced by one-time melting of a 3200 kW electron beam cold bed furnace, mill the surface, grind and chamfer the blank, and then perform underwater ultrasonic detection. After determining that it is correct, cut off the head of the slab, and then perform glass lubricating coating by machine spraying at room temperature. The main components of the coating are SiO2, Al2O3, B2O3, CaO, MgO, Na2O, TiO2, etc. After air drying, step S2 is performed.
[0050] S2, the TC4 titanium alloy slab obtained in step S1 is heated by three stages, and the heating equipment is an electric heating furnace. The first stage electric heating furnace is first heated to 650-750 DEG C, and then the slab is placed in the furnace. After the slab is properly placed, the second stage is heated to 950 DEG C at a rate of 10 DEG C / min, and the temperature is maintained for 4 hours. The third stage is heated to 1050 DEG C at a rate of 10 DEG C / min, and the temperature is maintained for 2 hours.
[0051] S3, hot rolling process;
[0052] The TC4 titanium alloy slab obtained in step S2 is transported to the hot rolling mill after the temperature is maintained to the required temperature. The initial rolling temperature is 1000 DEG C, and the final rolling temperature is 800 DEG C. One-pass multi-pass hot rolling process is performed to obtain a one-pass hot rolled titanium plate, and the total deformation is 50-80%. The one-pass hot rolled titanium plate is polished and cut. The cut titanium plate is cross-rolled to perform two-pass multi-pass hot rolling to obtain a titanium plate with a thickness of 1 mm.
[0053] S4, the hot rolled titanium plate obtained in S3 is subjected to annealing treatment, creep correction, alkali and acid washing, and sanding to obtain a TC4 hot rolled titanium plate for warm rolling;
[0054] S5, warm rolling process;
[0055] The titanium plate obtained in step S4 was held at 750℃ for 90 minutes in a furnace. After exiting the furnace, it was transferred to an asynchronous rolling mill for TC4 titanium alloy ultra-thin strip rolling. The warm rolling process consisted of two passes, with a total of 20 passes. After each pass, the strip was returned to the 750℃ furnace for another 90 minutes. A four-roll asynchronous rolling mill was used for rolling the TC4 titanium alloy ultra-thin strip. The speed ratio of the fast roll to the slow roll was 1.2, the rolling speed was 40 mm / s, the actual voltage of the torque motor was controlled at 120V, and the total reduction rate reached over 90%, ultimately yielding a rolled ultra-thin strip with a thickness of 0.1 mm.
[0056] S6. After degreasing and cleaning the rolled ultrathin titanium strip, it is placed in a vacuum furnace for vacuum annealing heat treatment. The temperature of the vacuum heating furnace is 650℃. After holding at the temperature for 2 hours, it is cooled with the furnace to finally obtain the finished TC4 ultrathin strip with a thickness of 0.1mm.
[0057] Example 2: Preparation of ultra-thin TC4 titanium alloy strip with a thickness of 0.08 mm.
[0058] S1. For TC4 titanium alloy flat ingots produced by one-time melting in an electron beam cold hearth furnace, the blanks are milled, ground, and chamfered. Then, underwater ultrasonic testing is used to confirm that there are no defects. After that, the head of the flat ingot is cut off, and glass lubricating coating is applied at room temperature. Machine spraying is used to improve the coating effect. After waiting for it to air dry, it is heated and kept warm.
[0059] S2. The TC4 titanium alloy flat ingot obtained in step S1 is heated in an electric heating furnace in three stages. In the first stage, the electric heating furnace is heated to 650-750℃, and then the TC4 titanium alloy flat ingot is placed in the furnace. After the TC4 titanium alloy flat ingot is properly placed, the second stage is carried out, with the temperature increased to 950℃ at 10℃ / min and held for 5 hours. In the third stage, the temperature is increased to 1050℃ at 10℃ / min and held for 3 hours.
[0060] S3, Hot rolling process;
[0061] The TC4 titanium alloy flat ingots that have reached the required temperature in step S2 are transferred from the furnace to a hot rolling mill. The initial rolling temperature is 1000℃, and the final rolling temperature is 800℃. A single-pass, multi-stage hot rolling process is performed to obtain a single-pass hot-rolled titanium plate with a total deformation of 50-80%. After grinding, the single-pass hot-rolled titanium plate is cut. The cut titanium plate is then subjected to a second-pass, multi-stage hot rolling process using a cross-rolling method. The cross-rolling temperature is 950℃, and the total deformation of the two-pass rolling process is greater than 95%. The final titanium plate thickness is 1mm.
[0062] S4. The hot-rolled titanium plate obtained in S3 is subjected to annealing, creep correction, alkali and acid washing and sanding to obtain TC4 hot-rolled titanium plate for warm rolling.
[0063] S5, Warm rolling process;
[0064] The titanium plate obtained in step S4 is kept in a 850 DEG C heating furnace for 60 min, and TC4 titanium alloy ultra-thin strip rolling is realized by using a four-roll asynchronous rolling mill. The speed of the fast roller and the speed of the slow roller are adjusted by adjusting the voltage of the torque motor. The speed ratio of the fast roller and the slow roller is 1.2, the rolling speed is 30 mm / s, the actual voltage of the torque motor is controlled to be 180 V, vacuum annealing heat treatment is carried out between each rolling process, and finally, the rolling state ultra-thin strip with a thickness of 0.08 mm is obtained;
[0065] S6, the rolling state ultra-thin strip is put into a vacuum furnace for vacuum annealing heat treatment, and finally, the finished product TC4 ultra-thin strip with a thickness of 0.08 mm is obtained.
[0066] The above-described embodiments are only used to describe the preferred embodiments of the present application, and are not used to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application.
Claims
1. A method for preparing an ultra-thin strip from an EB ingot of TC4 titanium alloy, characterized in that: It comprises the following steps: S1, selecting TC4 titanium alloy slab smelted by electron beam cold hearth, coating glass lubricating paint on the surface of TC4 titanium alloy slab at room temperature, waiting for air drying, and then performing step S2; S2, heating the TC4 titanium alloy slab obtained in step S1 in an electric heating furnace by three-stage heating, the first-stage electric heating furnace is first heated to 650-750℃, then the TC4 titanium alloy slab is placed in the furnace; after the TC4 titanium alloy slab is properly placed, the second-stage is heated to 950℃ at a rate of 10℃ / min, and the temperature is kept for 4-7h; the third-stage is heated to 1050℃ at a rate of 10℃ / min, and the temperature is kept for 2-4h; S3, hot rolling process; The TC4 titanium alloy slab after the temperature is kept to the required temperature in step S2 is transported to a hot rolling mill, the initial rolling temperature is 1000℃, the final rolling temperature is 800℃, one-pass multi-pass hot rolling process is performed, one-pass hot rolled titanium plate is obtained, and the total deformation is 50-80%; two-pass multi-pass hot rolling is performed in a cross-rolling manner, and hot rolled titanium plate is obtained; the rolling temperature of the cross-rolling is 950℃, and the thickness of the hot rolled titanium plate is 1-2mm, and the total deformation of the two-pass rolling is greater than 95%; S4, the hot rolled titanium plate obtained in step S3 is subjected to annealing treatment, creep correction, alkali and acid washing, and sanding to obtain TC4 hot rolled titanium plate with surface smoothness and flatness meeting the standard; S5, the titanium plate obtained in step S4 is heated in a 650-750℃ heating furnace for 60-120min, transported to an asynchronous rolling mill after being taken out of the furnace, and subjected to warm rolling of TC4 titanium alloy ultra-thin strip, the warm rolling adopts 2-4 rolling passes, the total pass number is 9-20, after each rolling pass is completed, it is returned to the 650-750℃ heating furnace for 60-120min, and then enters the next rolling pass until the last rolling pass is completed; the speed ratio of the fast roller to the slow roller in the asynchronous rolling mill is 1.05-1.5, the rolling speed is 20-50mm / s, the actual voltage control of the torque motor is 100-200V, and the total reduction rate is more than 90%, and finally the rolled ultra-thin strip with a thickness of less than 0.1mm is obtained; S6, before annealing, the rolled ultra-thin strip obtained in step S5 is subjected to degreasing treatment, and then the rolled ultra-thin strip is placed in a vacuum cover furnace for vacuum annealing heat treatment, the annealing temperature is 650-700℃, and the time is 2-6h, and the TC4 ultra-thin strip with a thickness of less than 0.1mm is obtained; The average grain size is 5-10μm, the room temperature tensile strength is ≥895MPa, the yield strength is ≥830MPa, the elongation is ≥8%, and the thickness deviation of the ultra-thin strip is not greater than ±0.015mm.
2. The method for preparing an extremely thin strip from an EB ingot of TC4 titanium alloy according to claim 1, characterized in that: In step S1, the glass lubricating paint is sprayed by a machine.
3. The method for preparing an extremely thin strip from an EB ingot of TC4 titanium alloy according to claim 1, characterized in that: In step S3, the head and tail of the one-pass hot rolled titanium plate are cut off to obtain an intermediate blank, the surface of the one-pass rolled intermediate blank is ground, the surface of the ground intermediate blank is subjected to surface inspection and ultrasonic inspection, and the intermediate blank after the inspection is qualified is subjected to two-pass multi-pass hot rolling.
4. The method for preparing an extremely thin strip from an EB ingot of TC4 titanium alloy according to claim 1, characterized in that: In step S5, the asynchronous rolling mill is a four-high asynchronous rolling mill.