Evaluation method for microstructure uniformity of titanium alloy ingot

Abstract

The application discloses a kind of titanium alloy ingot microcosmic component uniformity evaluation method, the evaluation method is when finished product smelting, ingot unprocessed state sampling piece and cutting phase change ring test sample and utilize metallographic method detection phase change point;Then adopt the way of " low high low " near phase change point to heat treatment to sample;Again by low power removal oxide skin, vertical alternate corrosion etc., finally by multi-angle observation method is carried out low power inspection, and to low power abnormal position is microcosmic component confirmation.The application evaluation method is directly sampled on ingot and detected, not only can evaluate the slight level microcosmic component segregation that prior art cannot evaluate, for example, ingot streamline, also realize that microcosmic segregation problem possibly generated in ingot on foreknowledge processing process;In addition, the application is not only suitable for titanium alloy ingot produced by any equipment, as long as its shape is cylinder, and suitable for all titanium alloy grades, for example TA15, TC4, TC21 etc.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material processing technology, specifically relating to a method for evaluating the microstructure uniformity of titanium alloy ingots. This evaluation method is applicable not only to titanium alloy ingots produced by all vacuum consumable arc furnaces, but also to titanium alloy ingots produced by other equipment (e.g., vacuum non-consumable arc furnaces, electron beam furnaces, etc.), as long as their shape is cylindrical. In addition, this evaluation method is applicable to all titanium alloy grades, such as TA15, TC4, TC21, etc. Background Technology

[0002] Titanium and titanium alloys have excellent specific strength, specific stiffness and corrosion resistance, and are therefore widely used in aerospace, conventional weapons, ships and marine engineering, nuclear power and thermal power generation, chemical and petrochemical, metallurgy, construction, transportation, sports and daily necessities and other fields.

[0003] Currently, common production methods for titanium and titanium alloys include vacuum arc melting, cold hearth melting, and electron beam melting. However, regardless of the melting method used, the resulting ingots all exhibit a certain degree of micro-segregation. The only difference lies in the degree of segregation of each element under different grades and melting methods. However, due to various factors in actual production, it is difficult to evaluate the micro-uniformity from the ingots.

[0004] In existing technologies, to ensure that the microstructure uniformity meets the basic requirements of materials, the microstructure composition uniformity is usually evaluated in deformed titanium alloys. Common deformation methods include forging, rolling, and extrusion. The existing evaluation method involves heat treatment at approximately 25°C below the phase transformation point followed by inspection to check whether the β-spots meet the standards. However, this method is only applicable to some easily segregating alloys and cannot effectively evaluate the microstructure uniformity of conventional titanium alloys such as TC21, TA15, and TC4, or even some specific microstructure composition uniformities. The main reason for this is that β-spots are a common type of microstructure segregation in titanium alloys. Once formed, they are difficult to eliminate in subsequent forging, extrusion, and rolling processes, severely affecting the material's mechanical properties. Other types of microstructure segregation are rarely reported. Furthermore, some minor microstructure segregations can be eliminated through subsequent processing, while others may be inherited. Therefore, they receive insufficient attention in the industry, and few studies have been conducted on their characterization and evaluation, especially on ingots.

[0005] In view of this, the inventors provide a method for evaluating the microstructure uniformity of titanium alloy ingots to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and propose a method for evaluating the micro-composition uniformity of titanium alloy ingots. This evaluation method can not only evaluate slight micro-composition segregation that cannot be evaluated in existing technologies, but also predict micro-segregation problems that may occur during the processing of the ingot, providing an effective reference for subsequent processing technology. It avoids the processing cost and material loss cost caused by the conventional method of only being able to determine micro-segregation under deformed conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for evaluating the microstructure uniformity of titanium alloy ingots, the evaluation method specifically including the following steps:

[0009] Step 1: Take samples from the unprocessed state of the titanium alloy ingot. The samples include longitudinal low-magnification samples and transverse low-magnification samples.

[0010] Step 2: Cut a phase transformation ring test sample from the titanium alloy ingot and use metallographic method to detect the phase transformation point;

[0011] Step 3: Perform "low-high-low" heat treatment on the longitudinal low-magnification sample and the transverse low-magnification sample obtained in Step 1 in an electric resistance furnace, and then remove them from the furnace and cool them to room temperature with water.

[0012] Step 4: Perform low-magnification machining on the sample after heat treatment in Step 3 to remove the oxide scale produced during heat treatment;

[0013] Step 5: Perform low-magnification etching on the sample using the vertical alternating etching method;

[0014] Step 6: Clean the etchant off the low-magnification sample.

[0015] Step 7: Use multi-angle observation to perform low-magnification inspection to confirm whether there is any low-magnification anomaly; if the low-magnification is normal, the evaluation process ends; if there is a low-magnification anomaly, cut a high-magnification sample from the corresponding position and observe the high-magnification sample on a high-magnification display device to confirm the degree of microscopic component segregation.

[0016] In step one, the unprocessed state specifically means that the surface of the titanium alloy ingot was not peeled off when the sample was taken.

[0017] In step five, the vertical alternating corrosion method is specifically carried out in four stages: the first and third corrosions are performed parallel to the length of the ingot to ensure that all positions are evenly covered with the corrosive agent; the second and fourth corrosions are performed perpendicular to the length of the ingot to ensure that all positions are evenly covered with the corrosive agent; and there is a 1-minute interval between each corrosion to allow for the corrosion reaction.

[0018] Furthermore, when taking samples, first saw a cylinder with a thickness ≥20mm from both the first and last ends of the titanium alloy ingot as a transverse low-magnification sample, and simultaneously saw a cylindrical blank with a thickness ≥200mm, with a sawing deviation ≤5mm; then saw a longitudinal low-magnification sample with a width ≥20mm and a thickness ≥200mm from the middle of the cylindrical blank along the axial direction, requiring a sawing deviation ≤5mm.

[0019] Furthermore, in step two, when cutting the phase transformation ring test sample from the titanium alloy ingot, the sampling depth is at least 10 mm.

[0020] Furthermore, in step three, when heat-treating the sample, a temperature-controlled placement method is used, requiring the resistance furnace heating error to be less than 5°C. The temperature-controlled placement method refers to first raising the resistance furnace temperature to the target temperature, then opening the furnace and placing the sample in for heat preservation; whereas the commonly used furnace-heated method involves placing the sample directly into the furnace at room temperature or the furnace's original temperature, then heating it to the target temperature and holding it thereafter.

[0021] The specific heat treatment process is as follows: First, heat treatment is carried out at 5℃~20℃ below the phase transformation point for 1h~2h. Then, the temperature is raised in the furnace to 5℃~15℃ above the phase transformation point for heat treatment, and the holding time is 0.5h~1.5h. Subsequently, the temperature is lowered in the furnace to 5℃~20℃ below the phase transformation point for heat treatment, and the holding time is 1h~2h. Finally, the furnace is directly removed and water-cooled to room temperature.

[0022] Furthermore, in step four, when performing low-magnification machining on the sample, any side is selected for low-magnification machining, with a machining depth greater than 3mm, to ensure the removal of heat-treated oxide scale, while controlling the surface roughness to ≤3.2μm, which facilitates the observation of the low-magnification structure.

[0023] Furthermore, in step five, when etching the sample, the etchant used is a mixture of hydrofluoric acid, nitric acid, and water, and the volume ratio of the three is hydrofluoric acid: nitric acid: water = 1:1:3.

[0024] Furthermore, in step six, when cleaning the low-magnification sample, tap water is used as the cleaning agent, and laminar flow cooling is used to gradually clean the entire area of ​​the low-magnification surface. The cleaning time is at least 5 minutes to ensure that residual acid is completely removed. After cleaning, high-pressure air is used to blow dry the sample evenly to ensure that there is no residual cleaning agent on the low-magnification sample.

[0025] Furthermore, the multiple angles in step seven are five angles, namely the top view angle of the sample, the vertical 45° oblique view angle of the sample, and the horizontal 45° oblique view angle of the sample.

[0026] Furthermore, the high-magnification display device in step seven is a high-magnification scanning electron microscope, a transmission electron microscope, or an electron probe microscope.

[0027] Furthermore, the titanium alloy ingot is cylindrical in shape.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention discloses a method for evaluating the microstructure uniformity of titanium alloy ingots. The method involves two aspects: first, direct sampling and testing of the ingot without peeling, allowing observation of the entire original morphology; and second, subjecting the sample to a "low-high-low" heat treatment, which fully utilizes the phase transformation of the titanium alloy to further eliminate other interfering factors, confirming that the issue is compositional inheritance rather than structural inheritance. Furthermore, the corrosion technique not only evaluates subtle microstructure segregation, such as ingot flow lines, which cannot be assessed in existing techniques, but also allows for the prediction of potential microstructure segregation issues that may arise during processing. Compared to existing techniques that require evaluating microstructure uniformity in wrought titanium alloys, this method significantly reduces material and production costs and provides a basis for subsequent processing steps, such as high-temperature homogenization, forging, and rolling. Attached Figure Description

[0030] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of the method for evaluating the microstructure uniformity of titanium alloy ingots according to the present invention;

[0033] Figure 2 This is a schematic diagram of the process of taking longitudinal and transverse low-magnification samples from both the head and tail of a titanium alloy ingot in Embodiment 1 of the present invention.

[0034] Figure 3 This is a physical image of the tail section of the low-magnification evaluation result (ingot flow line) of Example 1-TA15 of the present invention;

[0035] Figure 4 This is a low-magnification evaluation result (ingot flow line) of Embodiment 2-TC21 of the present invention, showing the actual tail section.

[0036] Figure 5This is a photograph of the tail section of the TC4 low-magnification evaluation result (normal) of Embodiment 3 of the present invention. Detailed Implementation

[0037] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses consistent with some aspects of the invention as detailed in the appended claims.

[0038] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to embodiments.

[0039] Example 1 (Evaluation of the microstructure uniformity of TA15 titanium alloy ingot)

[0040] 1) Cut two sample pieces with thicknesses of 20mm and 200mm from the head and tail of a TA15 ingot with a diameter of φ720mm. The sawing deviation should be ≤5mm. Two samples with a diameter of φ720mm*20mm are used as transverse low-magnification samples. Two cylindrical samples with a diameter of φ720mm*200mm are then longitudinally sectioned along the diameter of the circular cross-section to cut two longitudinal low-magnification samples with a diameter of 720mm*200mm*20mm (length*thickness (height)*width, where the thickness is parallel to the ingot axis). The sawing deviation of the longitudinal section should be ≤5mm. Figure 2 As shown.

[0041] 2) A phase transformation ring test sample was cut from the longitudinal section of the ingot. The phase transformation point of the ingot was measured to be 990℃ using metallographic method.

[0042] 3) Heat the resistance heating furnace to 970℃, and place the above four samples (including two transverse low-magnification samples with dimensions of φ720mm*20mm; and two longitudinal low-magnification samples with dimensions of 720mm*200mm*20mm) into the heating furnace and hold for 2 hours; then raise the temperature of the heating furnace to 1005℃ and hold for 1.5 hours; then lower the temperature of the heating furnace to 970℃ and hold for 2 hours; finally, remove the samples from the furnace and quench them directly in a water tank until the temperature drops to room temperature.

[0043] 4) After the sample has cooled to room temperature, perform low-magnification machining with a machining depth greater than 3 mm to ensure the removal of heat-treated oxide scale. At the same time, control the surface roughness to ≤3.2 μm to facilitate observation of the low-magnification structure.

[0044] 5) The low-magnification sample was etched using an etchant (the etchant was a mixture of hydrofluoric acid, nitric acid and water, with a volume ratio of hydrofluoric acid: nitric acid: water = 1:1:3). The entire etching process was carried out in 4 stages. Specifically, the first and third stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. The second and fourth stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. Each etching was completed with a 1-minute interval to allow for the etching reaction.

[0045] 6) Use a cleaning agent (tap water) and laminar flow cooling to gradually clean all areas of the low-magnification sample. The cleaning time should last for at least 5 minutes to ensure that residual acid is completely removed. After cleaning, use high-pressure air to dry the sample evenly for at least 5 minutes to ensure that there is no cleaning agent residue on the low-magnification sample.

[0046] 7) Low-magnification observation of the sample. The sample was observed at low magnification from five angles: top view, vertical (45°) oblique view, and horizontal (45°) oblique view. The results showed that the head sample appeared normal under low magnification; only the tail sample, viewed longitudinally, showed ingot flow lines. Figure 3 As shown.

[0047] 8) Microscopic composition confirmation. High-magnification samples were taken from the flow lines of the ingot. After grinding, polishing, and etching, the microstructure and composition were confirmed using a high-magnification scanning electron microscope. The results are shown in Table 1 below:

[0048] Table 1 - Energy Spectroscopy Microstructure Results of TA15 Ingot Streamline Location

[0049]

[0050] Example 2 (Evaluation of the microstructure uniformity of TC21 titanium alloy ingot)

[0051] 1) Cut two sample pieces with thicknesses of 30mm and 100mm from the head and tail of a TC21 ingot with a diameter of φ720mm. The sawing deviation should be ≤5mm. Two samples with a diameter of φ720mm*30mm are used as transverse low-magnification samples. Two cylindrical samples with a diameter of φ720mm*100mm are longitudinally sectioned along the diameter of the circular section to cut two longitudinal low-magnification samples with a diameter of 720mm*100mm*30mm (length*thickness (height)*width, where the thickness is parallel to the ingot axis). The sawing deviation of the longitudinal section should be ≤5mm. (Similar to...) Figure 2 The sawing method is shown.

[0052] 2) A phase transformation ring test sample was cut from the longitudinal section of the ingot. The phase transformation point of the ingot was measured to be 960℃ using metallographic method.

[0053] 3) Heat the resistance heating furnace to 950℃, place the above four samples (including two transverse low-magnification samples with dimensions of φ720mm*30mm; two longitudinal low-magnification samples with dimensions of 720mm*100mm*30mm) into the heating furnace, and hold for 1.5h; then raise the furnace temperature to 970℃ and hold for 1.0h; then lower the furnace temperature to 950℃ and hold for 1.0h; finally, remove the samples from the furnace and quench them directly in a water tank until the temperature drops to room temperature.

[0054] 4) After the sample has cooled to room temperature, perform low-magnification machining with a machining depth greater than 3 mm to ensure the removal of heat-treated oxide scale. At the same time, control the surface roughness to ≤3.2 μm to facilitate observation of the low-magnification structure.

[0055] 5) The low-magnification sample was etched using an etchant (the etchant was a mixture of hydrofluoric acid, nitric acid and water, with a volume ratio of hydrofluoric acid: nitric acid: water = 1:1:3). The entire etching process was carried out in 4 stages. Specifically, the first and third stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. The second and fourth stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. Each etching was completed with a 1-minute interval to allow for the etching reaction.

[0056] 6) Use a cleaning agent (tap water) and laminar flow cooling to gradually clean all areas of the low-magnification sample. The cleaning time should last for at least 5 minutes to ensure that residual acid is completely removed. After cleaning, use high-pressure air to dry the sample evenly for at least 5 minutes to ensure that there is no cleaning agent residue on the low-magnification sample.

[0057] 7) Low-magnification observation of the sample. The sample was observed at low magnification from five angles: top view, vertical (45°) oblique view, and horizontal (45°) oblique view. The results showed that the head sample appeared normal under low magnification; only the tail sample, viewed longitudinally, showed ingot flow lines. Figure 4 As shown.

[0058] 8) Microscopic composition confirmation. High-magnification samples were taken from the flow lines of the ingot. After grinding, polishing, and etching, the microstructure and composition were confirmed using a high-magnification scanning electron microscope. The results are shown in Table 2 below:

[0059] Table 2 - Energy Spectrum Micro-composition Results of TC21 Ingot Streamline Location

[0060]

[0061] Example 3 (Evaluation of the microstructure uniformity of TC4 titanium alloy ingot)

[0062] 1) Cut two sample pieces with thicknesses of 30mm and 300mm from the head and tail of a TC4 ingot with a specification of φ920mm, respectively, with a sawing deviation of ≤5mm. Two samples with a specification of φ920mm*30mm are used as transverse low-magnification samples. Two cylindrical samples with a specification of φ920mm*300mm are then longitudinally sectioned along the diameter of their circular cross-sections, yielding two longitudinal low-magnification samples with a specification of 920mm*300mm*30mm (length*thickness (height)*width, where thickness is parallel to the ingot axis). The sawing deviation of the longitudinal section is ≤5mm, similar to... Figure 2 The sawing method is shown.

[0063] 2) A phase transformation test sample was cut from the longitudinal section of the ingot, and the phase transformation point of the ingot was determined to be 1000℃ by metallographic method.

[0064] 3) Heat the resistance heating furnace to 995℃, and place the above four samples (including two transverse low-magnification samples with dimensions of φ920mm*30mm; and two longitudinal low-magnification samples with dimensions of 920mm*300mm*30mm) into the heating furnace and hold for 1.0h; then raise the temperature of the heating furnace to 1005℃ and hold for 0.5h; then lower the temperature of the heating furnace to 995℃ and hold for 2h; finally, remove the samples from the furnace and quench them directly in a water tank until the temperature drops to room temperature.

[0065] 4) After the sample has cooled to room temperature, perform low-magnification machining with a machining depth greater than 3 mm to ensure the removal of heat-treated oxide scale. At the same time, control the surface roughness to ≤3.2 μm to facilitate observation of the low-magnification structure.

[0066] 5) The low-magnification sample was etched using an etchant (the etchant was a mixture of hydrofluoric acid, nitric acid and water, with a volume ratio of hydrofluoric acid: nitric acid: water = 1:1:3). The entire etching process was carried out in 4 stages. Specifically, the first and third stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. The second and fourth stages were etched along the length of the ingot to ensure that all positions were evenly covered with the etchant. Each etching was completed with a 1-minute interval to allow for the etching reaction.

[0067] 6) Use a cleaning agent (tap water) and laminar flow cooling to gradually clean all areas of the low-magnification sample. The cleaning time should last for at least 5 minutes to ensure that residual acid is completely removed. After cleaning, use high-pressure air to dry the sample evenly for at least 5 minutes to ensure that there is no cleaning agent residue on the low-magnification sample.

[0068] 7) Low-magnification observation of the sample. The sample was observed at low magnification from five angles: top view, vertical (45°) oblique view, and horizontal (45°) oblique view. The result was: if the low-magnification observation was normal, no high-magnification confirmation was needed. Figure 5As shown.

[0069] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0070] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for evaluating the microstructure uniformity of titanium alloy ingots, characterized in that, The evaluation method specifically includes the following steps: Step 1: Take samples from the unprocessed state of the titanium alloy ingot. The samples include longitudinal low-magnification samples and transverse low-magnification samples. Step 2: Cut a phase transformation ring test sample from the titanium alloy ingot and use metallographic method to detect the phase transformation point; Step 3: Perform "low-high-low" heat treatment on the longitudinal low-magnification sample and the transverse low-magnification sample obtained in Step 1 in an electric resistance furnace, and then remove them from the furnace and cool them to room temperature with water. Step 4: Perform low-magnification machining on the sample after heat treatment in Step 3 to remove the oxide scale produced during heat treatment; Step 5: Perform low-magnification etching on the sample using the vertical alternating etching method; Step 6: Clean the etchant off the low-magnification sample. Step 7: Use multi-angle observation to perform low-magnification inspection to confirm whether there is any low-magnification anomaly; if the low-magnification is normal, the evaluation process ends; if there is a low-magnification anomaly, cut a high-magnification sample from the corresponding position and observe the high-magnification sample on a high-magnification display device to confirm the degree of microscopic component segregation. In step one, the unprocessed state specifically means that the surface of the titanium alloy ingot was not peeled off when the sample was taken. In step five, the vertical alternating corrosion method is specifically carried out in four stages: the first and third corrosions are performed parallel to the length of the ingot to ensure that all positions are evenly covered with the corrosive agent; the second and fourth corrosions are performed perpendicular to the length of the ingot to ensure that all positions are evenly covered with the corrosive agent; and there is a 1-minute interval between each corrosion to allow for the corrosion reaction.

2. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, When taking specific samples, first saw a cylinder with a thickness of ≥20mm from both the beginning and end of the titanium alloy ingot as a transverse low-magnification sample, and at the same time saw a cylindrical blank with a thickness of ≥200mm, with a sawing deviation of ≤5mm; then saw a longitudinal low-magnification sample with a width of ≥20mm and a thickness of ≥200mm from the middle of the cylindrical blank along the axial direction, requiring a sawing deviation of ≤5mm.

3. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, In step two, when cutting the phase transformation ring test sample from the titanium alloy ingot, the sampling depth should be at least 10 mm.

4. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, In step three, when heat-treating the sample, the sample is placed in a heated state, and the heating error of the resistance furnace is required to be less than 5°C. The specific heat treatment process is as follows: First, heat treatment is carried out at 5℃~20℃ below the phase transformation point for 1h~2h. Then, the temperature is raised in the furnace to 5℃~15℃ above the phase transformation point for heat treatment, and the holding time is 0.5h~1.5h. Subsequently, the temperature is lowered in the furnace to 5℃~20℃ below the phase transformation point for heat treatment, and the holding time is 1h~2h. Finally, the furnace is directly removed and water-cooled to room temperature.

5. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, In step four, when performing low-magnification machining on the sample, any side is selected for low-magnification machining, with a machining depth greater than 3mm to ensure the removal of heat-treated oxide scale. At the same time, the surface roughness is controlled to ≤3.2μm to facilitate observation of the low-magnification structure.

6. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, In step five, when etching the sample, the etchant used is a mixture of hydrofluoric acid, nitric acid, and water, with a volume ratio of hydrofluoric acid: nitric acid: water = 1:1:

3.

7. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, In step six, when cleaning the low-magnification sample, tap water is used as the cleaning agent. Laminar flow cooling is used to gradually clean the entire area of ​​the low-magnification surface. The cleaning time is at least 5 minutes to ensure that residual acid is completely removed. After cleaning, high-pressure air is used to blow dry the sample evenly to ensure that there is no residual cleaning agent on the low-magnification sample.

8. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, The multiple angles in step seven are five angles: the top view of the sample, the vertical 45° oblique view of the sample, and the horizontal 45° oblique view of the sample.

9. The method for evaluating the microstructure uniformity of titanium alloy ingots according to claim 1, characterized in that, The high-magnification display device in step seven is a high-magnification scanning electron microscope, a transmission electron microscope, or an electron probe microscope.

10. A method for evaluating the microstructure uniformity of titanium alloy ingots according to any one of claims 1 to 9, characterized in that, The titanium alloy ingot is cylindrical in shape.

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