A seamless titanium cylinder preparation process

Abstract

The present invention relates to the technical field of titanium alloys and discloses a seamless titanium cylinder preparation process, comprising the following steps: 1. selecting industrial pure titanium and pure nickel for smelting and semi-continuously casting to obtain an ingot; 2. performing homogenization annealing treatment on the ingot; 3. performing multi-directional forging on the ingot; 4. punching a hole in the center of the ingot and performing ring rolling to obtain a spun blank; 5. performing spinning processing on the spun blank until the spinning forming of the cathode roller titanium cylinder is completed; 6. performing annealing treatment on the titanium cylinder; 7. performing machining on the titanium cylinder; the preparation process adopted by the present invention adopts semi-continuous casting to produce an ingot with the advantages of large size, no cracks, few defects and small component segregation; performing homogenization and multi-directional forging treatment before ring forming and spinning can reduce or eliminate dendrite segregation generated during non-equilibrium solidification, so that the internal structure of the material is uniform, the grains are fine, the grain size can reach above level 10, and the corrosion resistance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium alloys, and in particular to a process for preparing a seamless titanium cylinder. Background Art

[0002] The cathode roller is a key component of electrolytic copper foil equipment. Its surface material must exhibit strong corrosion resistance to the electrolyte and provide a foundation for copper foil growth. Therefore, the roller surface material must possess excellent corrosion resistance, good and uniform conductivity, and a uniform and fine microstructure. Only in this way can high-quality copper foil with uniform thickness and a smooth surface be produced. Fine titanium grains on the cathode roller surface result in fine copper foil crystallization, while coarse grains result in coarse copper foil crystallization. Coarse grains and inconsistent geometry on the cathode roller surface can lead to uneven roughness on the foil's matte surface. Therefore, improving the processing technology to achieve fine and uniform titanium roller grains is essential for producing high-quality copper foil.

[0003] According to the invention patent with application number CN201110382759, a method for manufacturing a seamless titanium cylinder for a cathode roller is disclosed. A pure titanium ingot is selected, which is expanded and stretched, spun 3 to 4 times, and then annealed and heat treated to finally obtain the formed cathode roller titanium cylinder. The obtained titanium cylinder has relatively coarse grains, which will affect the quality of copper foil in actual production.

[0004] According to the invention patent with application number CN201911388308, a method for preparing a fine-grained titanium cylinder for a cathode roller is disclosed. Staggered spinning is adopted to reduce the pressure of a single spinning wheel, while optimizing the blank structure and increasing the deformation stability during spinning. The room temperature spinning of TA1 titanium alloy is achieved. The microstructure of the titanium cylinder obtained is fine and uniform, and the grain size can reach above level 9. However, the material used in this invention is pure titanium, and its corrosion resistance needs to be improved during use. Summary of the Invention

[0005] The invention provides a process for preparing a seamless titanium cylinder with uniform and fine grains and strong corrosion resistance.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A preparation process of a seamless titanium cylinder comprises the following steps:

[0007] Step 1: Select industrial pure titanium and pure nickel for smelting and semi-continuous casting to obtain ingots;

[0008] Step 2: homogenizing annealing treatment of the ingot;

[0009] Step 3: Multi-directional forging of the ingot;

[0010] Step 4: Punch a hole in the center of the ingot and perform ring rolling to obtain a spinning blank;

[0011] Step 5: Spin the spinning blank until the spinning forming of the cathode roller titanium cylinder is completed;

[0012] Step 6: Annealing the titanium cylinder;

[0013] Step 7: Machining the titanium cylinder.

[0014] Preferably, the chemical composition (weight percentage) of the ingot in step 1 is: Ni: 1-1.5, Fe<0.06, O<0.06, C<0.02, N<0.02, H<0.01, other impurity elements individually <0.05, the total content of other elements <0.2, and the rest is titanium.

[0015] Preferably, in step 2, the ingot is subjected to homogenization annealing treatment by keeping the temperature at 900-1050° C. for 2 hours.

[0016] Preferably, in step three, the ingot is kept at 750-800°C for 4-8h, and then subjected to upsetting and drawing multi-directional forging, with a reduction rate of 200-400mm / min, a reduction of 30-40% in the upsetting pass, and a reduction of 5-10% in the drawing pass. When the ingot temperature is lower than 650°C, it is furnace-annealed at 700-750°C for 2-4h, and the furnace annealing temperature is reduced by 20-50°C each time relative to the previous annealing temperature.

[0017] Preferably, in step 4, the ingot is kept at 480° C. for 3 hours and then ring-formed to remove the oxide layer on the surface of the spun blank.

[0018] Preferably, in the step five, the spun blank is heated to 600°C, kept warm for 2 hours, and hot-mounted on the spinning machine core mold to heat the outer surface of the spun blank. When the temperature of the spun blank reaches 500°C, the first spinning process of the spun blank is started. After the first spinning process is completed, the spinning wheel withdraws and returns to the initial spinning position, and the second spinning process is started. After the second spinning process is completed, the spinning wheel withdraws and returns to the initial spinning position. The spinning process is repeated until the cathode roller titanium cylinder is spun into shape. During the spinning process, the temperature of the cathode roller titanium cylinder is maintained at 400-550°C, and the thinning amount of each pass is 7-10 mm.

[0019] Preferably, in step six, the cathode roller titanium cylinder is kept at 500° C. for 8 hours, cooled to 300° C. in the furnace, taken out of the furnace, and air-cooled to room temperature.

[0020] Preferably, in step seven, the cathode roller titanium cylinder is turned, and the thickness of the cathode roller titanium cylinder after turning is 10 to 12 mm, and then polished until the surface is smooth and free of defects.

[0021] The present invention has the following beneficial effects:

[0022] The present invention provides a seamless titanium cylinder preparation process, in which the ingot cast by semi-continuous casting has the advantages of large size, no cracks, few defects and small composition segregation. Homogenization and multi-directional forging are performed before ring forming and spinning. Homogenization can reduce or eliminate dendrite segregation produced during non-equilibrium solidification, and multi-directional forging can make the internal structure of the material uniform and the grains fine. The cathode roller titanium cylinder prepared by the preparation method of the present invention has uniform and fine grains, the grain size can reach more than level 10, and has good corrosion resistance. DETAILED DESCRIPTION

[0023] The present invention is described in detail below. The present invention provides a technical solution: a preparation process of a seamless titanium cylinder, comprising the following steps:

[0024] Step 1: Melting and casting: industrial pure titanium (TA1) and pure nickel (N6) are selected for smelting in a vacuum consumable electrode arc furnace, and copper crystallizer ingots are used on a semi-continuous casting machine. The titanium alloy liquid is introduced into a diverter plate placed at the center of the inner sleeve of the crystallizer. After being diverted by the diverter plate, it enters the space formed by the metal inner sleeve and the guide ingot of the crystallizer. At the same time, the protective gas ring is turned on to provide gas protection for the metal liquid. The pouring temperature is 1670℃~1720℃, the ingot pulling speed is 40~60mm / min, the liquid level in the crystallizer is controlled at 30~50mm, the cooling water pressure is 0.01~0.08MPa, and the secondary cooling water temperature is 40~50℃. The chemical composition (weight percentage) of the obtained ingot is: Ni: 1-1.5, Fe < 0.06, O < 0.06, C < 0.02, N < 0.02, H < 0.01, other impurity elements individually < 0.05, the total content of other elements < 0.2, and the rest is titanium. The ingot cast by semi-continuous casting has the advantages of large size, no cracks, few defects and small composition segregation. The high-quality ingot is a strong guarantee for the smooth progress of subsequent deformation processing.

[0025] Step 2: Homogenization: To reduce or eliminate dendritic segregation during the non-equilibrium solidification process, the ingot is subjected to homogenization annealing treatment at 900-1050°C for 2 hours.

[0026] Step 3: Multi-directional forging: keep the homogenized ingot at 750-800℃ for 4-8h, then perform upsetting-drawing multi-directional forging on the hydraulic press, with a reduction speed of 200-400mm / min, a reduction of 30-40% in the upsetting pass, and a reduction of 5-10% in the drawing pass. When the ingot temperature is lower than 650℃, return to the furnace for annealing at 700-750℃ for 2-4h. The temperature of each return to the furnace for annealing is reduced by 20-50℃ relative to the previous annealing temperature. Multi-directional forging can make the internal structure of the material uniform and the grains fine.

[0027] Step 4: Mechanically punch a hole at the center of the ingot, keep the ingot at 480-500°C for 2-4 hours, perform ring rolling on a ring rolling mill, air-cool the ingot to obtain a spinning blank, and grind the blank to remove the oxide layer on the surface of the blank;

[0028] Step 5: Spinning, placing the turned spun blank in an electric furnace and heating it to 600℃, keeping it warm for 2 hours, hot-mounting it on the spinning machine core mold, heating the outer surface of the spun blank, and when the temperature of the spun blank reaches 500℃, starting the first spinning process of the spun blank, completing the first spinning, the spinning wheel withdraws and returns to the initial spinning position, starting the second spinning, completing the second spinning, the spinning wheel withdraws and returns to the initial spinning position, repeating the spinning process of the second spinning, until the spinning of the cathode roller titanium cylinder is completed, withdrawing the spinning wheel, stopping heating, and removing the cylindrical piece from the spinning machine to obtain the initially formed cathode roller titanium cylinder. During the spinning process, the temperature of the spun titanium cylinder is maintained at 400-550℃, and the thinning amount of each pass is 7-10mm.

[0029] Step 6: Annealing treatment: anneal the cylindrical part obtained by spinning at 500℃ for 8 hours, cool it to 300℃, take it out of the furnace, and air cool it to room temperature;

[0030] Step 7: Turn the annealed cylindrical part to remove surface defects. The thickness of the titanium cylinder after turning is 10 to 12 mm, and then polish it until the surface is smooth and free of defects.

[0031] The present invention is described in further detail below in conjunction with the embodiments:

[0032] Example 1: Preparation of a cathode roller titanium cylinder of φ500mm×350mm:

[0033] Step 1: Industrial pure titanium (TA1) and pure nickel (N6) are smelted in a vacuum consumable electrode arc furnace, and ingots are cast using a copper crystallizer on a semi-continuous casting machine. The titanium alloy liquid is introduced into a diverter plate placed at the center of the inner sleeve of the crystallizer, and after being diverted by the diverter plate, it enters the space formed by the metal inner sleeve and the ingot of the crystallizer. At the same time, the protective gas ring is turned on to provide gas protection for the metal liquid. The pouring temperature is 1670℃~1720℃, the ingot pulling speed is 40mm / min, the liquid level in the crystallizer is controlled at 30~50mm, the cooling water pressure is 0.01~0.08MPa, and the secondary cooling water temperature is 40~50℃ to obtain an ingot;

[0034] Step 2: homogenizing annealing the ingot at 900°C for 2 hours;

[0035] Step 3: Multi-directional forging: The homogenized ingot is kept at 750°C for 5 hours. Then, the ingot is subjected to upsetting and drawing multi-directional forging on a hydraulic press at a reduction speed of 200-400 mm / min. The upsetting pass reduction is 30-40%, and the drawing pass reduction is 5-10%. When the ingot temperature drops below 650°C, it is returned to the furnace for annealing at 730°C for 2 hours. The annealing temperature for each return is reduced by 20°C relative to the previous annealing temperature.

[0036] Step 4: Mechanically punch a hole at the center of the ingot, keep the ingot at 480℃ for 3 hours, perform ring rolling on a ring rolling mill, air-cool the ingot to obtain a spinning blank, and grind the blank to remove the oxide layer on the surface of the blank;

[0037] Step 5: Spinning, placing the turned spun blank in an electric furnace and heating it to 600℃, keeping it warm for 2 hours, hot-mounting it on the spinning machine core mold, heating the outer surface of the spun blank, and when the temperature of the spun blank reaches 500℃, starting the first spinning process of the spun blank, completing the first spinning, the spinning wheel withdraws and returns to the initial spinning position, starting the second spinning, completing the second spinning, the spinning wheel withdraws and returns to the initial spinning position, repeating the spinning process of the second spinning, until the spinning of the cathode roller titanium cylinder is completed, withdrawing the spinning wheel, stopping heating, and removing the cylindrical part from the spinning machine to obtain the initially formed cathode roller titanium cylinder. During the spinning process, the temperature of the spun titanium cylinder is maintained at 400-550℃, and the thinning amount of each pass is 7-10mm to obtain a titanium cylinder of φ500mm×350mm;

[0038] Step 6: Annealing treatment: anneal the cylindrical part obtained by spinning at 500℃ for 8 hours, cool it to 300℃, take it out of the furnace, and air cool it to room temperature;

[0039] Step 7: Turn the annealed cylindrical part to remove surface defects. The thickness of the titanium cylinder after turning is 10mm, and then polish it until the surface is smooth and free of defects.

[0040] Example 2: Preparation of a cathode roller titanium cylinder of φ2000mm×1380mm:

[0041] Step 1: Industrial pure titanium (TA1) and pure nickel (N6) are smelted in a vacuum consumable electrode arc furnace, and ingots are cast using a copper crystallizer on a semi-continuous casting machine. The titanium alloy liquid is introduced into a diverter plate placed at the center of the inner sleeve of the crystallizer, and after being diverted by the diverter plate, it enters the space formed by the metal inner sleeve and the ingot of the crystallizer. At the same time, the protective gas ring is turned on to provide gas protection for the metal liquid. The pouring temperature is 1670℃~1720℃, the ingot pulling speed is 40mm / min, the liquid level in the crystallizer is controlled at 30~50mm, the cooling water pressure is 0.01~0.08MPa, and the secondary cooling water temperature is 40~50℃ to obtain an ingot;

[0042] Step 2: homogenizing annealing the ingot at 1000°C for 2 hours;

[0043] Step 3: Multi-directional forging: The ingot after homogenization treatment is kept at 800℃ for 5 hours, and then the ingot is subjected to upsetting multi-directional forging on a hydraulic press. The pressing speed is 200-400mm / min, the upsetting pass reduction is 30-40%, and the drawing pass reduction is 5-10%. When the ingot temperature is lower than 650℃, the ingot is returned to the furnace for annealing at 750℃ for 2 hours. The annealing temperature of each return to the furnace is reduced by 50℃ relative to the previous annealing temperature.

[0044] Step 4: Mechanically perforate the center of the ingot, heat the ingot at 500℃ for 3 hours, and then ring roll it on a ring rolling mill. Then, air cool it to obtain a spinning blank, which is then polished to remove the oxide layer on the surface.

[0045] Step 5: Spinning, placing the turned spun blank in an electric furnace and heating it to 600℃, keeping it warm for 2 hours, hot-mounting it on the spinning machine core mold, heating the outer surface of the spun blank, and when the temperature of the spun blank reaches 500℃, starting the first spinning process of the spun blank, completing the first spinning, the spinning wheel withdraws and returns to the initial spinning position, starting the second spinning, completing the second spinning, the spinning wheel withdraws and returns to the initial spinning position, repeating the spinning process of the second spinning, until the spinning of the cathode roller titanium cylinder is completed, withdrawing the spinning wheel, stopping heating, and removing the cylindrical part from the spinning machine to obtain the initially formed cathode roller titanium cylinder. During the spinning process, the temperature of the spun titanium cylinder is maintained at 400-550℃, and the thinning amount of each pass is 7-10mm to obtain a titanium cylinder of φ2000mm×1380mm;

[0046] Step 6: Annealing treatment: anneal the cylindrical part obtained by spinning at 500℃ for 8 hours, cool it to 300℃, take it out of the furnace, and air cool it to room temperature;

[0047] Step 7: Turn the annealed cylindrical part to remove surface defects. The thickness of the titanium cylinder after turning is 10mm, and then polish it until the surface is smooth and free of defects.

[0048] Example 3: Preparation of a cathode roller titanium cylinder of φ2700mm×1420mm:

[0049] Step 1: Melting and casting: industrial pure titanium (TA1) and pure nickel (N6) are smelted in a vacuum consumable electrode arc furnace, and ingots are cast using a copper crystallizer on a semi-continuous casting machine. The titanium alloy liquid is introduced into a diverter plate placed in the center of the inner sleeve of the crystallizer. After being diverted by the diverter plate, it enters the space formed by the metal inner sleeve and the ingot of the crystallizer. At the same time, the protective gas ring is turned on to provide gas protection for the metal liquid. The pouring temperature is 1670℃~1720℃, the ingot pulling speed is 60mm / min, the liquid level in the crystallizer is controlled at 30~50mm, the cooling water pressure is 0.01~0.08MPa, and the secondary cooling water temperature is 40~50℃ to obtain an ingot;

[0050] Step 2: Homogenization: To reduce or eliminate dendritic segregation during the non-equilibrium solidification process, the ingot is subjected to homogenization annealing treatment at 1050°C for 2 hours.

[0051] Step 3: Multi-directional forging: The ingot after homogenization treatment is kept at 800℃ for 6 hours, and then the ingot is subjected to upsetting multi-directional forging on a hydraulic press. The pressing speed is 200-400mm / min, the upsetting pass reduction is 30-40%, and the drawing pass reduction is 5-10%. When the ingot temperature is lower than 650℃, the ingot is returned to the furnace for annealing at 750℃ for 4 hours. The annealing temperature of each return to the furnace is reduced by 30℃ relative to the previous annealing temperature.

[0052] Step 4: Mechanically punch a hole at the center of the ingot, heat the ingot at 500℃ for 4 hours, perform ring rolling on a ring rolling mill, air cool the ingot to obtain a spinning blank, and grind the blank to remove the oxide layer on the surface of the blank;

[0053] Step 5: Spinning, placing the turned spun blank in an electric furnace and heating it to 600℃, keeping it warm for 2 hours, hot-mounting it on the spinning machine core mold, heating the outer surface of the spun blank, and when the temperature of the spun blank reaches 500℃, starting the first spinning process of the spun blank, completing the first spinning, the spinning wheel withdraws and returns to the initial spinning position, starting the second spinning, completing the second spinning, the spinning wheel withdraws and returns to the initial spinning position, repeating the spinning process of the second spinning, until the spinning of the cathode roller titanium cylinder is completed, withdrawing the spinning wheel, stopping heating, and removing the cylindrical part from the spinning machine to obtain the initially formed cathode roller titanium cylinder. During the spinning process, the temperature of the spun titanium cylinder is maintained at 400-550℃, and the thinning amount of each pass is 7-10mm to obtain a titanium cylinder of φ2700mm×1420mm;

[0054] Step 6: Annealing treatment: anneal the cylindrical part obtained by spinning at 500℃ for 8 hours, cool it to 300℃, take it out of the furnace, and air cool it to room temperature;

[0055] Step 7: Turn the annealed cylindrical part to remove surface defects. The thickness of the titanium cylinder after turning is 12mm, and then polish it until the surface is smooth and free of defects.

[0056] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments. It cannot be considered that the specific implementation of the present invention is limited to these descriptions. It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

Claims

1. A process for preparing a seamless titanium cylinder, characterized in that: The following steps are involved: Step 1: Select industrial pure titanium and pure nickel for smelting, and semi-continuously cast to obtain ingots. The semi-continuous casting process parameters are as follows: use a copper crystallizer to cast the ingot, open the protective gas ring to provide gas protection for the molten metal, pouring temperature 1670℃~1720℃, ingot pulling speed 40~60 mm / min, control the liquid level in the crystallizer at 30~50 mm, cooling water pressure 0.01~0.08 MPa, and secondary cooling water temperature 40~50℃; Ingot chemical composition, in weight percentage: Ni: 1-1.5, Fe < 0.06, O < 0.06, C < 0.02, N < 0.02, H < 0.01, other impurity elements individually < 0.05, the total content of other elements < 0.2, the rest is titanium; Step 2: homogenizing annealing the ingot at 900-1050℃ for 2h; Step 3: Multi-directional forging of the ingot: The ingot is kept at 750-800℃ for 4-8 hours, and then subjected to upsetting multi-directional forging. When the ingot temperature is lower than 650℃, it is returned to the furnace for annealing at 700-750℃ for 2-4 hours. The temperature of each return annealing is reduced by 20-50℃ relative to the previous annealing temperature. Step 4: Punch a hole in the center of the ingot and perform ring rolling to obtain a spinning blank; Step 5: Spin the spinning blank until the spinning forming of the cathode roller titanium cylinder is completed; Step 6: Annealing the titanium cylinder; Step 7: Machining the titanium cylinder.

2. The preparation process of the seamless titanium cylinder according to claim 1, characterized in that: In the step 3, the pressing speed is 200-400 mm / min, the pressing amount of the upsetting pass is 30-40%, and the pressing amount of the drawing pass is 5-10%.

3. The preparation process of the seamless titanium cylinder according to claim 1, characterized in that: In the step 4, the ingot is kept at 480° C. for 3 hours and then ring-formed to remove the oxide layer on the surface of the spun blank.

4. The preparation process of the seamless titanium cylinder according to claim 1, characterized in that: In the step five, the spun blank is heated to 600°C, kept warm for 2 hours, and hot-mounted on the spinning machine core mold to heat the outer surface of the spun blank. When the temperature of the spun blank reaches 500°C, the first spinning process of the spun blank is started. After the first spinning process is completed, the spinning wheel withdraws and returns to the initial spinning position, and the second spinning process is started. After the second spinning process is completed, the spinning wheel withdraws and returns to the initial spinning position. The spinning process is repeated until the cathode roller titanium cylinder is spun into shape. During the spinning process, the temperature of the cathode roller titanium cylinder is maintained at 400~550°C, and the thinning amount of each pass is 7~10mm.

5. The preparation process of the seamless titanium cylinder according to claim 1, characterized in that: In the step 6, the cathode roller titanium cylinder is kept at 500° C. for 8 hours, cooled to 300° C. in the furnace, taken out of the furnace, and air-cooled to room temperature.

6. The process for preparing a seamless titanium cylinder according to claim 1, characterized in that: In the step seven, the cathode roller titanium cylinder is turned, and the thickness of the cathode roller titanium cylinder after turning is 10-12 mm, and then polished until the surface is smooth and free of defects.