Process for preparing high-homogenization titanium cathode roller at low cost

Abstract

The invention belongs to the technical field of titanium-based cathode rollers, and discloses a low-cost process for preparing a high-homogenization titanium cathode roller, which comprises the following steps: a welding process: carrying out friction stir welding on a titanium material to obtain a welded titanium material; in the first heat treatment process, the welding titanium material is placed at the temperature of 905-915 DEG C to be subjected to heat preservation for 3-5 min and then cooled to the room temperature; repeating the first heat treatment process for 3-4 times to obtain a first heat-treated titanium material; and in the second heat treatment process, the titanium material subjected to the first heat treatment is placed at the temperature of 595-605 DEG C, heat preservation is conducted for 8-10 min, then the titanium material is cooled to the room temperature, and the uniform titanium material for the cathode roller is obtained. According to the method, the welded industrial pure titanium is subjected to circulating heat treatment-annealing composite heat treatment, the grain size can be homogenized, and therefore the titanium material meeting the quality and performance requirements of the cathode roller is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium-based cathode rollers, and in particular relates to a process for preparing a highly uniform titanium cathode roller at low cost. Background Art

[0002] As an important "connection hub" for electronic components, electrolytic copper foil is a key material for manufacturing high-frequency and high-speed printed circuit boards for 5G communications and high-energy-density lithium-ion batteries. As the core and key component of the complete set of electrolytic copper foil equipment, the quality of the titanium cathode roller determines the grade and quality of the copper foil, and is known as the heart of electrolytic copper foil production. There are two main manufacturing processes for the cathode roller: spinning and welding. The titanium cathode roller manufactured by the spinning process has the advantages of uniform surface grain size, no bright bands, color difference and other defects in the copper foil produced, and easy processing. However, before spinning, the titanium cylinder ring blank must go through the process steps of vacuum melting, ingot division, forging, punching, hole expansion, ring rolling, ring turning, spinning and other process steps of sponge titanium, and the process is complicated and costly. Relatively speaking, the welding process is inexpensive and the preparation steps are simple, which can reduce the preparation cost and optimize the preparation process to a certain extent. However, there is a longitudinal weld on the surface of the welded cathode roller. If the welding and post-processing processes are not well controlled, light spots or bright bands will appear at the corresponding position of the copper foil, which will seriously affect and restrict the high-quality and high-efficiency production of copper foil. Therefore, the development of welded cathode rollers with higher surface grain size grade, uniform microstructure and consistent grain size is a key issue.

[0003] At present, the traditional cathode roller welding preparation process adopts the melting welding process, which has high heat input and wide weld area. Impurities are easily introduced during the welding process, thus affecting the raw foil. In addition, due to the large difference between the weld structure and the parent material structure, it is necessary to further improve the structure through forging, rolling, heat treatment and other processes, but it is still impossible to achieve complete consistency between the weld and the parent material structure.

[0004] The friction stir welding technology has low welding heat input, small residual stress, and high welding efficiency, which is conducive to welding large-sized cathode rollers. In addition, the friction stir welding process can avoid the influence of impurities introduced by traditional melting welding on the raw foil, and improve the efficiency and accuracy of cathode roller titanium cylinder processing. However, due to the large difference between the weld structure and the parent material structure after welding, the cathode roller will have problems such as color difference and bright band when raw foil. Summary of the invention

[0005] In view of the above-mentioned deficiencies and defects of the prior art, the purpose of the present invention is to provide a low-cost process for preparing a highly uniform titanium cathode roller, so as to solve the problems of color difference, bright bands, etc. caused by the difference in grain size between the cathode roller weld and the base material during foil production.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems: A process for preparing a highly homogenized titanium cathode roller at low cost includes the following steps: Welding process: Stir friction welding the titanium material to obtain welded titanium material; The first heat treatment process: the welding titanium material is placed at 905-915°C for 3-5 minutes and then cooled to room temperature; Repeat the first heat treatment process 3 to 4 times to obtain a first heat-treated titanium material; The second heat treatment process: the first heat-treated titanium material is placed at 595-605°C for 8-10 minutes, and then cooled to room temperature.

[0007] Preferably, during the first heat treatment, the cooling method is air cooling.

[0008] Preferably, the first heat treatment process is carried out in a protective atmosphere.

[0009] Preferably, during the second heat treatment, the cooling method is air cooling.

[0010] Preferably, the second heat treatment process is carried out in a protective atmosphere.

[0011] Preferably, when the titanium material is subjected to friction stir welding, the material of the stirring head is W-Re alloy, the rotation speed of the stirring head is 80-200 r / min, and the forward speed is 80-150 mm / min.

[0012] Preferably, the friction stir welding process of the titanium material is carried out in a protective atmosphere.

[0013] Preferably, in terms of mass percentage, the impurity element composition and content of the titanium material are as follows: Fe≤0.05%, C≤0.03%, N≤0.03%, O≤0.06%, H≤0.002%.

[0014] The present invention also provides a cathode roller, and the preparation process of the cathode roller includes the process of preparing a highly uniform titanium cathode roller at low cost as described above.

[0015] Preferably, the base material, the heat affected zone and the stirring zone of the friction stir welded titanium material are uniform equiaxed grains.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The essence of the process of preparing a highly homogenized titanium cathode roller at low cost of the present invention is to transform the α phase into α→β→α phase through a cyclic heat treatment process, during which the holding time and cooling rate are controlled to make the phase transformation incomplete, increase the number of grain boundaries and nucleation points, solve the problem that the parent material only grows grains during the heat treatment process due to the lack of recrystallization driving force, and achieve the purpose of uniform refinement of the weld structure and the parent material through multiple cycles. After the treatment of the present invention, the average grain size of each part of the titanium material is basically the same. Therefore, the method of the present invention effectively solves the problems of color difference, bright bands, etc. caused by the difference in grain size between the cathode roller weld and the parent material when producing foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cyclic heat treatment process in the process of preparing a highly homogenized titanium cathode roller at low cost according to the present invention; FIG2(a) is a microstructure morphology of the titanium base material (BM) after heat treatment in Example 1 of the present invention; FIG2(b) is a microstructure morphology of the heat affected zone (HAZ) of the titanium material after heat treatment in Example 1 of the present invention; FIG2(c) is a microstructure morphology of the stirring zone (SZ) of the titanium material after heat treatment in Example 1 of the present invention; FIG3 (a) is a microstructure morphology of the titanium base material (BM) after heat treatment in Comparative Example 1 of the present invention; FIG3 (b) is a microstructure morphology of the heat affected zone (HAZ) of the titanium material after heat treatment in Comparative Example 1 of the present invention; FIG3 (c) is a microstructure morphology of the stirring zone (SZ) of the titanium material after heat treatment in Comparative Example 1 of the present invention; Figure 4 (a) is the microstructure morphology of the titanium base material (BM) after heat treatment in comparative example 2 of the present invention; Figure 4 (b) is the microstructure morphology of the heat affected zone (HAZ) of the titanium material after heat treatment in comparative example 2 of the present invention; Figure 4 (c) is the microstructure morphology of the stirring zone (SZ) of the titanium material after heat treatment in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The process for preparing a highly homogenized titanium cathode roller at low cost according to the present invention comprises the following steps: Step 1, performing friction stir welding on a titanium material to prepare a welded titanium material; Specifically, the impurity element composition and content of industrial pure titanium (the above-mentioned titanium material) are, by mass percentage, Fe≤0.05%, C≤0.03%, N≤0.03%, O≤0.06%, and H≤0.002%.

[0020] Specifically, the stirring head is made of W-Re alloy, the stirring head speed is 80-200 r / min, and the forward speed is 80-150 mm / min. Argon protective gas is introduced during the friction stir welding process.

[0021] Step 2, using the welding titanium material prepared in step 1 to perform a heat preservation treatment at 905-915° C. and cool to room temperature; Specifically, the titanium material after welding is subjected to a heat preservation treatment at 905-915° C. for 3-5 minutes, and the cooling method is air cooling.

[0022] Step 3, repeat the process of step 2 3 to 4 times; Step 4, subjecting the titanium material obtained in step 3 to a heat preservation treatment at 595-605° C. and cooling it to room temperature to obtain a uniform titanium material for the cathode roller.

[0023] Specifically, the titanium material obtained in step 3 is subjected to a heat preservation treatment at 595-605° C. for 8-10 minutes, and the cooling method is air cooling. Argon protective gas is introduced during the heat preservation process.

[0024] Preferably, the preparation process in step 1 is stir friction welding. The stirring head speed is 80-200 r / min, for example, 80 r / min, 100 r / min, 150 r / min and 200 r / min and any value therebetween; the forward speed is 80-150 mm / min, for example, 80 mm / min, 100 mm / min, 120 mm / min and 150 mm / min and any value therebetween.

[0025] Preferably, in step 2, the titanium material is subjected to a heat preservation treatment at 905-915° C. after welding, the heat preservation time is 3-5 minutes, and the cooling method is air cooling. For example, 905-915° C., 3-5 minutes, and any value therebetween.

[0026] Preferably, in step 4, the titanium material is subjected to a heat preservation treatment at 595-605°C for 8-10 minutes, and the cooling method is air cooling. For example, 595-605°C, 8-10 minutes, and any value therebetween.

[0027] In the following embodiments of the present invention, industrial pure titanium with the above composition is used.

[0028] Example 1 This embodiment provides a low-cost process for preparing a highly uniform titanium cathode roller. In this embodiment, industrial pure titanium is subjected to friction stir welding at a stirring head speed of 100 r / min and a forward speed of 100 mm / min, and then subjected to a "cyclic heat treatment + annealing" composite heat treatment to prepare a titanium material with uniform grain size between the weld and the base material. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 100 r / min, the forward speed is 100mm / min, and argon protective gas is introduced during welding.

[0029] Step 2: Place the welded titanium material in a tube furnace for cyclic heat treatment ( Figure 1 ), the holding temperature is 910℃, the holding time is 3 minutes / time, the number of cycles is 3 times, and the cooling method is air cooling.

[0030] Step 3: Adjust the temperature of the tube furnace to 595°C, place the titanium material processed in step 2 in the tube furnace, keep the temperature for 10 minutes, and cool it in air.

[0031] The successful implementation of this embodiment prepared a welded titanium material with uniform and equiaxed grains. As shown in Figure 2 (a) to Figure 2 (c), it can be seen that the base material, heat-affected zone and stirring zone are all uniform and equiaxed grains, and the grain sizes are close. The average grain sizes of the base material, heat-affected zone and stirring zone are 40.7µm, 43.3µm and 38.3µm respectively. This is because the base material has no driving force for recrystallization, so its grain size is almost unchanged through phase transformation. However, due to the presence of stress and fine grains at the weld, as the number of cycles reaches 3, the grains recrystallize and grow until they are close to the grain size of the base material.

[0032] Comparative Example 1 In this comparative example, the stirring head speed is 100 r / min and the forward speed is 100 mm / min to stir friction welding of industrial pure titanium, and then a "cyclic heat treatment + annealing" composite heat treatment is performed. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 100 r / min, the forward speed is 100mm / min, and argon protective gas is introduced during welding.

[0033] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 930°C, a holding time of 3 minutes / time, 3 cycles, and air cooling.

[0034] Step 3: Adjust the temperature of the tube furnace to 595°C, place the titanium material processed in step 2 in the tube furnace, keep the temperature for 10 minutes, and cool it in air.

[0035] Since the holding temperature during the cyclic heat treatment is too high, the grains grow further after the phase transformation. The grain growth in the stirring zone, base material and heat affected zone is obvious, and an α lamellar structure is produced. This is mainly caused by the excessively fast cooling rate during the β→α transformation, as shown in Figure 3 (a) to Figure 3 (c). It is impossible to achieve an equiaxed and uniform structure as a whole.

[0036] Comparative Example 2 In this comparative example, the stirring head speed is 100 r / min and the forward speed is 100 mm / min to stir friction welding of industrial pure titanium, and then a "cyclic heat treatment + annealing" composite heat treatment is performed. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 100 r / min, the forward speed is 100mm / min, and argon protective gas is introduced during welding.

[0037] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 910°C, a holding time of 3 minutes / time, a cycle of 1 time, and an air cooling method.

[0038] Step 3: Adjust the temperature of the tube furnace to 595°C, place the titanium material in the tube furnace, keep the temperature for 10 minutes, and cool it in air.

[0039] When the number of cycles is 1, as shown in Figure 4 (a) to Figure 4 (c), recrystallization and grain growth occur in the weld, but the grains are still relatively fine. A small amount of lamellar structure appears in the parent material and heat-affected zone, and the overall structure cannot achieve uniform equiaxed.

[0040] Comparative Example 3 In this comparative example, the stirring head speed is 100 r / min and the forward speed is 100 mm / min to stir friction welding of industrial pure titanium, and then a "cyclic heat treatment + annealing" composite heat treatment is performed. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 100 r / min, the forward speed is 100mm / min, and argon protective gas is introduced during welding.

[0041] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 890°C, a holding time of 3 minutes / time, 3 cycles, and air cooling.

[0042] Step 3: Adjust the temperature of the tube furnace to 595°C, place the titanium material processed in step 2 in the tube furnace, keep the temperature for 10 minutes, and cool it in air.

[0043] Since the holding temperature of the cyclic heat treatment is at the phase transition point at this time, only a few grains undergo phase transformation, and the remaining grains undergo recrystallization and grain growth, resulting in a large difference in grain size between the base material and the weld area, making it impossible to achieve overall equiaxed uniformity of the organization.

[0044] Comparative Example 4 In this comparative example, the stirring head speed is 600 r / min and the forward speed is 50 mm / min to stir friction welding of industrial pure titanium, and then a "cyclic heat treatment + annealing" composite heat treatment is performed. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 100 r / min, the forward speed is 100mm / min, and argon protective gas is introduced during welding.

[0045] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 910°C, a holding time of 3 minutes / time, 3 cycles, and air cooling.

[0046] Step 3: Adjust the temperature of the tube furnace to 595°C, place the titanium material in the tube furnace, keep it warm for 10 minutes, and cool it in air.

[0047] Under the process parameters of stirring head speed of 600 r / min and forward speed of 50 mm / min, the macroscopic morphology of the welding surface is poor, and due to the increase in heat input, the grain size of the weld increases. After heat treatment, the grain size is large, and uniform and equiaxial structure cannot be achieved.

[0048] Example 2 This embodiment provides a low-cost process for preparing a highly uniform titanium cathode roller. In this embodiment, industrial pure titanium is subjected to friction stir welding at a stirring head speed of 150 r / min and a forward speed of 80 mm / min, and then subjected to a "cyclic heat treatment + annealing" composite heat treatment to prepare a titanium material with uniform grain size between the weld and the base material. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 150 r / min, the forward speed is 80mm / min, and argon protective gas is introduced during welding.

[0049] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 905°C, a holding time of 5 minutes / time, 3 cycles, and air cooling.

[0050] Step 3: Adjust the temperature of the tube furnace to 600°C, place the titanium material in the tube furnace, keep the temperature for 10 minutes, and cool it in air.

[0051] The successful implementation of this embodiment prepares a welded titanium material with equiaxed and uniformly distributed grains. It can be seen that the base material, heat-affected zone and stirred zone are uniform equiaxed grains with an average grain size of 39.5 µm.

[0052] Example 3 This embodiment provides a low-cost process for preparing a highly uniform titanium cathode roller. In this embodiment, industrial pure titanium is subjected to friction stir welding at a stirring head speed of 200 r / min and a forward speed of 150 mm / min, and then subjected to a "cyclic heat treatment + annealing" composite heat treatment to prepare a titanium material with uniform grain size between the weld and the base material. The specific steps are as follows: Step 1: Select two 150mm×70mm×3mm industrial pure titanium TA1 plates for stir friction welding. The stirring head speed is 200 r / min, the forward speed is 150mm / min, and argon protective gas is introduced during welding.

[0053] Step 2: Place the welded titanium material in a tubular furnace for cyclic heat treatment, with a holding temperature of 915°C, a holding time of 3 minutes / time, 4 cycles, and air cooling.

[0054] Step 3: Adjust the temperature of the tube furnace to 605°C, place the titanium material in the tube furnace, keep it at a temperature for 8 minutes, and cool it in air.

[0055] The successful implementation of this embodiment prepares a welded titanium material with equiaxed and uniformly distributed grains. It can be seen that the base material, heat-affected zone and stirred zone are uniform equiaxed grains with an average grain size of 41.7 µm.

[0056] The method of the present invention uses a stir friction welding process with low heat input, small residual stress and high welding efficiency, which can avoid the influence of impurities introduced by traditional fusion welding on the electrolytic copper foil, improve the efficiency and accuracy of cathode roller titanium cylinder processing and forming, and is conducive to welding large-size cathode rollers.

[0057] The above descriptions are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A process for preparing a highly homogenized titanium cathode roller at low cost, characterized in that: The process includes the following: Welding process: Stir friction welding the titanium material to obtain welded titanium material; The first heat treatment process: the welding titanium material is placed at 905-915°C for 3-5 minutes and then cooled to room temperature; Repeat the first heat treatment process 3 to 4 times to obtain a first heat-treated titanium material; The second heat treatment process: the first heat-treated titanium material is placed at 595-605°C for 8-10 minutes, and then cooled to room temperature.

2. A process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: During the first heat treatment, the cooling method is air cooling.

3. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: The first heat treatment process is carried out in a protective atmosphere.

4. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: During the second heat treatment, the cooling method is air cooling.

5. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: The second heat treatment process is carried out in a protective atmosphere.

6. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: When friction stir welding of titanium materials is performed, the stirring head material is W-Re alloy, the stirring head speed is 80~200r / min, and the forward speed is 80~150mm / min.

7. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: The friction stir welding process of titanium is carried out in a protective atmosphere.

8. The process for preparing a highly homogenized titanium cathode roller at low cost according to claim 1, characterized in that: In terms of mass percentage, the impurity element composition and content of the titanium material are as follows: Fe≤0.05%, C≤0.03%, N≤0.03%, O≤0.06%, H≤0.002%.

9. A cathode roller, characterized in that: The cathode roller preparation process includes the low-cost preparation process of a highly homogenized titanium cathode roller as described in any one of claims 1-8.

10. A cathode roller according to claim 9, characterized in that: After friction stir welding, the base material, heat affected zone and stirred zone of titanium material are uniform equiaxed grains.

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