Heat treatment method for improving plasticity of TA18 titanium alloy thin strip
Through the heat treatment methods of multi-rolling strip tension cold rolling, intermediate annealing and high vacuum heat treatment, the plasticity and cold processing capabilities of TA18 titanium alloy thin strips are improved, the problems of work hardening and insufficient plasticity are solved, and the high-quality and uniform thickness of strip preparation is achieved.
Patent Information
- Application Number
- CN202510174941.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-18
- Publication Date
- 2025-05-13
AI Technical Summary
The process hardening of TA18 titanium alloy thin strips during the preparation process is significant and the anisotropy is strong, resulting in increased difficulty in subsequent processing. Moreover, the plasticity of TA18 strips prepared by ordinary vacuum annealing process cannot meet the performance requirements of stamping deformation.
The heat treatment methods of multi-rolling strip tension cold rolling, intermediate annealing and high vacuum heat treatment are adopted to adjust the total deformation amount and intermediate annealing process of the cold rolling process, and combine the optimization of the annealing temperature, insulation time and vacuum degree of the finished strip to improve the cold processing capacity of the TA18 strip.
Through this heat treatment method, a TA18 titanium alloy thin strip with uniform thickness, good surface quality and excellent plasticity is obtained, which solves the problem of cold rolling cracking and difficult production of high-plastic thin strips, and significantly improves the cold forming ability of the strip.
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Figure CN119980105A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nonferrous metal material processing, and in particular relates to a heat treatment method for improving the plasticity of a TA18 titanium alloy thin strip. Background Art
[0002] With the booming consumer electronics market, titanium alloys are gradually becoming the preferred material for high-end smartphones, smart wearable devices and other products due to their unique physical properties. However, the stamping parts that are currently used more frequently in electronic products are all made of pure titanium, which has low strength. Compared with pure titanium, TA18 titanium alloy has high strength and good toughness, and has good stamping performance. It is an ideal material for preparing structural parts in the 3C electronic field. However, the work hardening phenomenon of TA18 titanium alloy thin strips during the preparation process is significant, and the anisotropy is strong, which increases the difficulty of subsequent processing and requires reasonable arrangement of processing procedures and control of deformation. In addition, the plasticity of TA18 strips prepared by ordinary vacuum annealing process cannot meet the performance requirements of stamping deformation. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a heat treatment method for improving the plasticity of TA18 titanium alloy thin strips in view of the deficiencies of the above-mentioned prior art. The method sequentially performs multi-rolling process strip tension cold rolling, intermediate annealing and high vacuum heat treatment of the finished strip on the annealed TA18 titanium alloy hot-rolled plate, and improves the cold processing capacity of the TA18 strip by adjusting the total deformation amount of the cold rolling process and the intermediate annealing process, combined with optimizing the annealing temperature, holding time and vacuum degree of the finished strip, to obtain a TA18 titanium alloy thin strip with uniform thickness, good surface quality and excellent plasticity, thereby solving the technical problems of cold rolling cracking of the titanium alloy thin strip and the difficulty in producing high-plasticity thin strips.
[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a heat treatment method for improving the plasticity of TA18 titanium alloy thin strip, characterized in that the method comprises the following steps:
[0005] Step 1, cold rolling and intermediate annealing: the annealed TA18 titanium alloy hot-rolled slab is subjected to multi-pass tension cold rolling, and the strip prepared by the tension cold rolling in each rolling pass is subjected to intermediate annealing and trimming to obtain a TA18 titanium alloy strip with a thickness of 0.1 mm to 0.6 mm;
[0006] Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing to obtain a high-plasticity TA18 titanium alloy thin strip.
[0007] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that the total deformation of each rolling pass of the multi-pass band tension cold rolling in step one is 30% to 45%, the deformation of each pass is 5% to 10%, and after each rolling pass of the band tension cold rolling is completed, the cold-rolled billet is cleaned and degreased, and the cracked edges and heads are removed.
[0008] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that the temperature of the intermediate annealing treatment in step one is 750°C to 780°C, and the holding time is 30min to 60min.
[0009] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that the temperature of the high vacuum annealing in step 2 is 780°C to 820°C, and the holding time is 40min to 70min.
[0010] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that during the high vacuum annealing process in step 2, when the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa.
[0011] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that the high plasticity TA18 titanium alloy thin strip described in step 2 is composed of the following components in percentage by mass: Al 2.0%~3.5%, V 1.5%~3%, Fe≤0.25%, C≤0.08%, N≤0.05%, H≤0.015%, O≤0.12%, and the remainder is Ti and unavoidable impurities.
[0012] The above-mentioned heat treatment method for improving the plasticity of TA18 titanium alloy thin strip is characterized in that the tensile strength of the high-plasticity TA18 titanium alloy thin strip in step 2 is 574MPa~610MPa, the yield strength is 532MPa~571MPa, and the elongation is 41%~55.5%.
[0013] Compared with the prior art, the present invention has the following advantages:
[0014] 1. The present invention adopts a multi-pass belt tension cold rolling process to prepare TA18 titanium alloy strip, which effectively eliminates the edge waves of the TA18 titanium alloy strip during the rolling process, not only improves the plate shape of the TA18 titanium alloy strip, but also helps to improve the rolling accuracy, thereby more accurately controlling the thickness of the TA18 titanium alloy strip, realizing the processing of the titanium alloy strip under a lower rolling force, and reducing equipment wear.
[0015] 2. The present invention regulates the total deformation of the strip tension cold rolling in each rolling process, controls the deformation of each pass, and combines intermediate annealing after each rolling process to remove work hardening and residual stress. It not only improves the uniformity of the structure of the TA18 titanium alloy strip, but also effectively breaks and refines the grains, reduces the risk of crack initiation and propagation in the subsequent cold rolling process or use of the strip, thereby obtaining a TA18 titanium alloy strip with better deformation ability.
[0016] 3. The present invention uses a high vacuum annealing heat treatment process to effectively prevent interstitial elements such as hydrogen, oxygen, carbon, and nitrogen from penetrating into the surface of the TA18 titanium alloy strip when the temperature of the titanium alloy material is higher than 500°C, thereby reducing the possibility of gas saturation layer and oxide layer causing the plasticity of the strip to deteriorate.
[0017] 4. The present invention adopts a high vacuum annealing heat treatment process and adjusts the vacuum annealing process parameters to make the grain structure of the prepared TA18 titanium alloy thin strip uniform and refined, thereby significantly improving the elongation after fracture of the TA18 titanium alloy thin strip, and then improving its cold forming ability, thereby achieving the optimization of the surface quality, microstructure and mechanical properties of the TA18 titanium alloy thin strip.
[0018] 5. The heat treatment method of the present invention is simple, has strong process applicability, is not limited by production equipment, is easy to operate and implement, has low costs, can be mass-produced, and has broad application prospects.
[0019] 6. The TA18 titanium alloy thin strip prepared by the present invention after high vacuum annealing has a tensile strength of 574MPa~610MPa, a yield strength of 532MPa~571MPa, an elongation of 41%~55.5%, and has uniform thickness and good surface quality. It also has excellent plasticity, which can meet the application requirements of different fields and is conducive to the industrial promotion and application of high-plasticity titanium alloy thin strips.
[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is the microstructure diagram of the TA18 titanium alloy thin strip with a thickness of 0.35 mm prepared in Example 1 of the present invention.
[0022] Figure 2 This is the microstructure diagram of the TA18 titanium alloy thin strip with a thickness of 0.2 mm prepared in Example 2 of the present invention.
[0023] Figure 3 This is the microstructure diagram of the TA18 titanium alloy thin strip with a thickness of 0.1 mm prepared in Example 3 of the present invention.
[0024] Figure 4This is the microstructure diagram of the TA18 titanium alloy thin strip with a thickness of 0.6 mm prepared in Example 4 of the present invention. DETAILED DESCRIPTION
[0025] Example 1
[0026] This embodiment includes the following steps:
[0027] Step 1, cold rolling and intermediate annealing: the annealed TA18 titanium alloy hot-rolled slab with a thickness of 0.8 mm is subjected to two-pass tension cold rolling with welding strips at both ends, wherein the total deformation of the tension cold rolling in the first pass is 37.5%, and the first cold-rolled slab with a thickness of δ0.5 mm is obtained, and the total deformation of the tension cold rolling in the second pass is 30%, and the second cold-rolled slab with a thickness of δ0.35 mm is obtained, and the deformation of each pass of the tension cold rolling is 5% to 10%, and after each pass of the tension cold rolling is completed, the cold-rolled slab is cleaned and degreased, and the cracked edge and head are removed, and the first cold-rolled slab after cleaning and degreasing is subjected to intermediate annealing and trimming, and the intermediate annealing system is 750°C / 30min, to obtain a TA18 titanium alloy strip with a thickness of 0.35 mm;
[0028] Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing. When the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa, continue heating to 780°C and keep warm for 70 minutes to obtain a TA18 titanium alloy thin strip with a thickness of 0.35 mm; the TA18 titanium alloy thin strip is composed of the following components in percentage by mass: Al 2%, V 1.5%, Fe 0.22%, C 0.07%, N0.05%, H 0.013%, O 0.09%, and the balance is Ti and unavoidable impurities.
[0029] Figure 1 The microstructure of the TA18 titanium alloy thin strip with a thickness of 0.35 mm prepared in this embodiment is shown in FIG. Figure 1 It can be seen that the structure of the titanium alloy thin strip prepared by the process of this embodiment is a uniform and fine equiaxed structure, and the grain size is about 10 μm to 15 μm.
[0030] Example 2
[0031] This embodiment includes the following steps:
[0032] Step 1, cold rolling and intermediate annealing: the annealed TA18 titanium alloy hot-rolled slab with a thickness of 1.0 mm is subjected to three-pass tension cold rolling with welding strips at both ends, wherein the total deformation of the tension cold rolling in the first pass is 40%, and the first cold-rolled slab with a thickness of δ0.6 mm is obtained, the total deformation of the tension cold rolling in the second pass is 45%, and the second cold-rolled slab with a thickness of δ0.33 mm is obtained, the total deformation of the tension cold rolling in the third pass is 39%, and the third cold-rolled slab with a thickness of δ0.2 mm is obtained, and the deformation of each pass of the tension cold rolling is 5% to 10%, and after each pass of the tension cold rolling is completed, the cold-rolled slab is cleaned and degreased, and the cracked edge and the head are removed, and the first cold-rolled slab and the second cold-rolled slab after cleaning and degreasing are subjected to intermediate annealing and trimming, and the intermediate annealing system is 780°C / 60min to obtain a TA18 titanium alloy strip with a thickness of 0.2 mm;
[0033] Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing. When the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa, continue heating to 820°C and keep warm for 70 minutes to obtain a TA18 titanium alloy thin strip with a thickness of 0.2 mm; the TA18 titanium alloy thin strip is composed of the following components in percentage by mass: Al 3.5%, V 3%, Fe 0.25%, C 0.08%, N0.05%, H 0.014%, O 0.10%, and the balance is Ti and unavoidable impurities.
[0034] Figure 2 The microstructure of the TA18 titanium alloy thin strip with a thickness of 0.2 mm prepared in this embodiment is shown in FIG. Figure 2 It can be seen that the structure of the titanium alloy thin strip prepared by the process of this embodiment is a uniform and fine equiaxed structure, and the grain size is about 5 μm to 15 μm.
[0035] Example 3
[0036] This embodiment includes the following steps:
[0037] Step 1, cold rolling and intermediate annealing: The annealed TA18 titanium alloy hot-rolled slab with a thickness of 0.8 mm is subjected to four-pass band tension cold rolling with welding leads at both ends, wherein the total deformation of the band tension cold rolling in the first pass is 45%, and the first cold-rolled slab with a thickness of δ0.44 mm is obtained; the total deformation of the band tension cold rolling in the second pass is 35%, and the second cold-rolled slab with a thickness of δ0.27 mm is obtained; the total deformation of the band tension cold rolling in the third pass is 33%, and the third cold-rolled slab with a thickness of δ0.18 mm is obtained. , the total deformation of the fourth rolling process with tension cold rolling is 44%, and the fourth cold-rolled billet with a thickness of δ0.1mm is obtained, and the deformation of each rolling process with tension cold rolling is 5% to 10%. After each rolling process with tension cold rolling is completed, the cold-rolled billet is cleaned and degreased, and the cracked edge and head are removed. The first cold-rolled billet, the second cold-rolled billet and the third cold-rolled billet after cleaning and degreasing are subjected to intermediate annealing and trimming. The system of the intermediate annealing treatment is 750℃ / 60min, and a TA18 titanium alloy strip with a thickness of 0.1mm is obtained;
[0038] Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing. When the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa, continue heating to 780°C and keep warm for 40 minutes to obtain a TA18 titanium alloy thin strip with a thickness of 0.1 mm; the TA18 titanium alloy thin strip is composed of the following components in percentage by mass: Al 2.5%, V 2.8%, Fe 0.19%, C 0.06%, N0.03%, H 0.011%, O 0.12%, and the balance is Ti and unavoidable impurities.
[0039] Figure 3 The microstructure of the TA18 titanium alloy thin strip with a thickness of 0.1 mm prepared in this embodiment is shown in FIG. Figure 3 It can be seen that the structure of the titanium alloy thin strip prepared by the process of this embodiment is a uniform and fine equiaxed structure, and the grain size is less than 10 μm.
[0040] Example 4
[0041] This embodiment includes the following steps:
[0042] Step 1, cold rolling and intermediate annealing: the annealed TA18 titanium alloy hot-rolled slab with a thickness of 1.5 mm is subjected to two-pass tension cold rolling with welding strips at both ends, wherein the total deformation of the tension cold rolling in the first pass is 35%, and a first cold-rolled slab with a thickness of δ0.98 mm is obtained, and the total deformation of the tension cold rolling in the second pass is 38%, and a second cold-rolled slab with a thickness of δ0.6 mm is obtained, and the deformation of each pass of the tension cold rolling is 5% to 10%, and after each pass of the tension cold rolling is completed, the cold-rolled slab is cleaned and degreased, and the cracked edge and head are removed, and the first cold-rolled slab after cleaning and degreasing is subjected to intermediate annealing and trimming, and the intermediate annealing treatment system is 750°C / 60min, to obtain a TA18 titanium alloy strip with a thickness of 0.6 mm;
[0043] Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing. When the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa, continue heating to 820°C and keep warm for 40 minutes to obtain a TA18 titanium alloy thin strip with a thickness of 0.6 mm; the TA18 titanium alloy thin strip is composed of the following components in percentage by mass: Al 3.0%, V 2.4%, Fe 0.23%, C 0.08%, N0.05%, H 0.015%, O 0.10%, and the balance is Ti and unavoidable impurities.
[0044] Figure 4 The microstructure of the TA18 titanium alloy thin strip with a thickness of 0.35 mm prepared in this embodiment is shown in FIG. Figure 4 It can be seen that the structure of the titanium alloy thin strip prepared by the process of this embodiment is a uniform and fine equiaxed structure, and the grain size is less than 10 μm.
[0045] The tensile properties test was carried out on the TA18 titanium alloy thin strips prepared in Examples 1 to 4 of the present invention, and the test results are shown in Table 1 below.
[0046] Table 1
[0047] Serial number Thickness / mm Tensile strength / MPa Yield strength / MPa Elongation / % Example 1 0.35 610 571 49.0 Example 2 0.2 574 532 47.0 Example 3 0.1 606 563 41.0 Example 4 0.6 605 565 55.5
[0048] It can be seen from Table 1 in combination with Examples 1 to 4 that the TA18 titanium alloy thin strip prepared by the present invention has excellent plasticity, uniform thickness and good surface quality.
[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.
Claims
1. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip, characterized in that: The method comprises the following steps: Step 1, cold rolling and intermediate annealing: the annealed TA18 titanium alloy hot-rolled slab is subjected to multi-pass tension cold rolling, and the strip prepared by the tension cold rolling in each rolling pass is subjected to intermediate annealing and trimming to obtain a TA18 titanium alloy strip with a thickness of 0.1 mm to 0.6 mm; Step 2: Finished product annealing: The TA18 titanium alloy strip obtained in step 1 is subjected to high vacuum annealing to obtain a high-plasticity TA18 titanium alloy thin strip.
2. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: In the multi-pass tension cold rolling in step one, the total deformation of each pass of the tension cold rolling is 30% to 45%, and the deformation of each pass is 5% to 10%. After each pass of the tension cold rolling is completed, the cold-rolled billet is cleaned, degreased, and cracked edges and heads are removed.
3. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: The temperature of the intermediate annealing treatment in step 1 is 750° C. to 780° C., and the holding time is 30 min to 60 min.
4. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: The temperature of the high vacuum annealing in step 2 is 780° C. to 820° C., and the insulation time is 40 min to 70 min.
5. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: During the high vacuum annealing process in step 2, when the vacuum degree in the vacuum annealing furnace is less than 5.0×10 -3 Pa, heating begins. When the furnace temperature is greater than 300°C and the vacuum degree is less than 1.0×10 -4 Pa.
6. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: The high-plasticity TA18 titanium alloy thin strip described in step 2 is composed of the following components in percentage by mass: Al 2.0% to 3.5%, V 1.5% to 3%, Fe≤0.25%, C≤0.08%, N≤0.05%, H≤0.015%, O≤0.12%, and the remainder is Ti and unavoidable impurities.
7. A heat treatment method for improving the plasticity of TA18 titanium alloy thin strip according to claim 1, characterized in that: The high-plasticity TA18 titanium alloy thin strip described in step 2 has a tensile strength of 574MPa-610MPa, a yield strength of 532MPa-571MPa, and an elongation of 41%-55.5%.