A TB18 titanium alloy standard material and its preparation method

Abstract

The present invention belongs to the technical field of titanium alloy materials, and relates to a TB18 titanium alloy standard material and a preparation method thereof. The standard material has the following element contents: Al: 3.0% to 5.0%, Mo: 5.05% to 5.45%, V: 4.0% to 5.8%, Cr: 4.5% to 6.5%, Nb: 0.5% to 1.5%, and Fe: 0.03% to 1.0%. It fills the gap in domestic standard materials and solves the problem that there is no TB18 brand in existing titanium alloy standard materials, and that there are no effective distribution points in the titanium alloy standard samples for niobium elements in the content range of 0.5% to 1.5% and chromium elements in the content range of 4.5% to 6.5%, making it impossible to effectively detect alloying elements. The smelting method provided by the present invention is reliable and easy to implement. Combining the advantages of vacuum consumable electrode arc furnace smelting and vacuum suspension furnace smelting, it can prepare a TB18 titanium alloy standard material that meets design requirements and has good composition uniformity.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy materials and relates to a TB18 titanium alloy standard substance and a preparation method thereof. Background Art

[0002] As an advanced aviation material, titanium alloy has become one of the main structural materials for modern aircraft and engines due to its low density, excellent corrosion resistance, higher specific strength, good high-temperature performance and fatigue resistance. In advanced foreign aviation engines, the amount of titanium alloy used has accounted for 25% to 40% of the total engine mass. The number of applications and level of use of titanium alloys have become one of the indicators of a country's aviation industry level. With the continuous development of domestic aircraft and engines, the use of titanium and titanium alloys has also increased year by year. At the same time, the use of standard samples of titanium and titanium alloys will also gradually increase. As an excellent aviation material, TB18 titanium alloy is an ultra-high strength and toughness titanium alloy for aviation structures with good development prospects due to its high specific strength, deep hardenability, good corrosion resistance and excellent strength-plasticity-toughness matching that can be achieved through heat treatment strengthening.

[0003] The development of TB18 titanium alloy reference materials is difficult, and while imported reference samples can cover multiple test elements, their content range is limited. With the increasing demand for material composition uniformity and test accuracy, this has created a significant conflict with the lack of high-quality TB18 chemical standards. Therefore, the development of TB18 titanium alloy chemical reference materials can meet market demand.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a TB18 titanium alloy chip-shaped standard material and a preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a TB18 titanium alloy chip-shaped standard material, wherein the content of each main element ranges as follows: Al: 3.0% to 5.0%, Mo: 5.05% to 5.45%, V: 4.0% to 5.8%, Cr: 4.5% to 6.5%, Nb: 0.5% to 1.5%, Fe: 0.03% to 1.0%, and the rest are Ti and unavoidable impurity elements, and the sum of the weight percentages of each element is 100%.

[0008] In addition, the present invention also provides a method for preparing a TB18 titanium alloy chip-shaped standard material, comprising the following steps:

[0009] Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use;

[0010] Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally the consumable electrode is produced by a non-tungsten electrode argon shielded plasma welding process;

[0011] Step 3, smelting: smelting the consumable electrode at least four times to obtain a TB18 titanium alloy ingot;

[0012] Step 4: homogenization heat treatment: performing homogenization heat treatment on the TB18 titanium alloy ingot to make the unbalanced eutectic structure in the TB18 titanium alloy ingot uniformly distributed in the matrix, and the composition and structure are more uniform;

[0013] Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a forged rod blank of a high-homogeneity titanium alloy standard material;

[0014] Step 6: Process the forged rod blank of the high-uniformity titanium alloy standard material to complete the preparation of the TB18 titanium alloy standard material.

[0015] Specifically, in step 1, the use of grade 0 titanium sponge can reduce the impurity content in the titanium sponge and improve the purity of the ingot; the particle size diameter of the grade 0 titanium sponge is 0.83 mm to 12.7 mm, which can make the distribution of the titanium sponge more uniform; at the same time, since niobium has a high melting point and is prone to produce unmelted blocks, it is added in the form of niobium-aluminum alloy in the form of chips; molybdenum and chromium elements are added in the form of a quaternary alloy, which significantly reduces the melting point of the intermediate alloy.

[0016] Specifically, in step 2, to achieve a more uniform chemical composition, the raw materials are weighed and then stirred using a mixing system for at least 30 seconds to ensure thorough mixing. The mixed raw materials are then pressed into electrode blocks of corresponding specifications using a hydraulic press, with a pressing strength of 20 MPa to 50 MPa. The pressed blocks are then placed in a vacuum plasma welding chamber. To prevent oxidation of the consumable electrodes, the pre-vacuum level is less than 20 Pa. The consumable electrodes are then welded using a non-tungsten argon shielded plasma welding process. After welding, the consumable electrodes are inspected to prevent chipping during the melting process and to ensure the absence of through-hole cracks.

[0017] Specifically, in the smelting method in step 3, the first smelting and the last smelting are both carried out by vacuum consumable arc furnace smelting.

[0018] Furthermore, step 3 includes three vacuum consumable arc furnace smeltings and one vacuum suspension melting furnace smelting. The present invention stipulates that the first smelting and the last smelting are both carried out in a vacuum consumable arc furnace, wherein the second smelting is carried out in a vacuum consumable arc furnace, and the third smelting is carried out in a vacuum suspension melting furnace. The smelting process parameters are as follows:

[0019] For the first smelting, the consumable electrode is placed in a vacuum consumable electrode arc furnace for the first smelting to obtain an ingot; the process parameters for the first smelting are: vacuum degree is less than 0.1 Pa, arc stabilization current is 2A to 10A, smelting current is set to 10KA to 15KA, voltage is set to 30V to 35V, and cooling time after smelting is greater than 4h.

[0020] In the second smelting, the primary ingot is machined to remove the flash at the head of the primary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for a second smelting to obtain a secondary ingot; the process parameters of the second smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 2A~8A, smelting current is set to 12KA~20KA, voltage is set to 30V~35V, and cooling time after smelting is greater than 4h.

[0021] For the third smelting, the secondary ingot obtained in the previous step is machined to remove the flash at the head of the secondary ingot. After the head and tail are swapped, it is placed in a vacuum suspension melting furnace for suspension melting to obtain a tertiary ingot. The process parameters of the third smelting are as follows: the melting furnace chamber and the casting chamber are repeatedly vacuumed at least 3 times: among which the vacuum degree of the melting furnace chamber must be less than 0.04Pa, and the vacuum degree of the casting chamber must be less than 0.5Pa; after turning on the induction heating power supply, the graphite mold is heated to 1000℃~1200℃ at a rate of 20℃ / min~30℃ / min and kept warm for 1h~2h; the melting power is gradually increased to 500kW~900kW at a rate of 40kW / min~50kW / min, and then the furnace temperature reaches 1300℃~1600℃ and is maintained for 30min~60min; after the melting is completed, the alloy is cast into a graphite mold of specified specifications through a funnel at a speed of 5kg / s~10kg / s.

[0022] Fourth smelting: The tertiary ingots are machined to remove the flash at the heads of the tertiary ingots. After the heads and tails are swapped, they are placed in a vacuum consumable electrode arc furnace for the fourth smelting to obtain TB18 titanium alloy ingots; the process parameters of the fourth smelting are: vacuum degree is less than 0.1 Pa, arc stabilization current is set to 2A~8A, melting current is set to 10KA~18KA, voltage is set to 25V~30V, and cooling time after smelting is greater than 4h.

[0023] In the above four melting processes, the second melting can also be performed in a vacuum suspension melting furnace, while the third melting can be performed in a vacuum consumable arc furnace. The applicant should note that, in principle, vacuum suspension furnace melting can occur in any other melting process except the first and last melting processes. Combining the advantages of vacuum consumable electrode arc furnace melting to produce materials with very uniform and accurate composition, and the vacuum suspension furnace melting process to produce materials with very high purity, greatly improves the composition accuracy of titanium alloy ingot melting.

[0024] Specifically, the heating temperature of the homogenization heat treatment in step 4 is 900° C. to 1100° C., and the heat preservation time is 10 h to 15 h.

[0025] Specifically, in step 5, the forging temperature is 800° C. to 1200° C., and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 1.0 to 2.0, and 3 to 6 fires of forging are performed cumulatively.

[0026] Specifically, in step 6, the preparation of chip-like TB18 titanium alloy standard material: first use a lathe to remove the oxide scale on the surface of the titanium alloy rod blank, and then use a milling machine to mill the chips, and finally obtain chip-like TB18 titanium alloy standard material with a thickness of 0.2mm~0.5mm and a length of 1mm~3mm for inductively coupled plasma emission spectrometer testing.

[0027] Furthermore, the milling machine is equipped with a milling cutter made of YG8 material, with a milling cutter blade of 2 mm and a groove of 1 mm; the milling machine parameters are set as: chip speed 95 r / min, feed rate 76 mm / r, and feed depth 1.2 mm / time.

[0028] Specifically, in step 6, the preparation of the block TB18 titanium alloy standard material: the rod blank is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

[0029] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0030] 1) The TB18 titanium alloy standard material provided by the present invention solves the problem that there is no TB18 brand in existing titanium alloy standard materials, and that there are no effective distribution points for niobium elements in the content range of 0.5% to 1.5% and chromium elements in the content range of 4.5% to 6.5% in titanium alloy standard samples, making it impossible to effectively detect alloying elements.

[0031] 2) The present invention provides an advanced method for melting titanium alloy ingots with high uniformity, which combines the advantages of vacuum consumable electrode arc furnace melting to obtain materials with very uniform and accurate composition, and vacuum suspension melting to produce materials with very high purity, greatly improving the uniformity and composition accuracy of titanium alloy ingot melting. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0033] Figure 1 A diagram showing the physical state of an ingot (not stripped) after four smeltings obtained during the preparation process of the preparation method provided in Example 1 of the present invention;

[0034] Figure 2 A physical picture of a forged rod obtained during the preparation process of the preparation method provided in Example 1 of the present invention;

[0035] Figure 3 A diagram showing the process of screening, mixing, cleaning, and bottling the chips during the chip preparation process provided in Examples 1 to 4 of the present invention;

[0036] Figure 4 This is a flow chart of a method for preparing a TB18 titanium alloy standard material provided by the present invention. DETAILED DESCRIPTION

[0037] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0038] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Example 1

[0040] This embodiment provides a TB18 titanium alloy standard material, in which the content of each main element ranges as follows: Al: 3.0%, Mo: 5.05%, V: 4.0%, Cr: 4.5%, Nb: 0.5%, Fe: 0.03%, and the rest are Ti and unavoidable impurity elements, and the sum of the weight percentages of each element is 100%.

[0041] The flow chart of the preparation method of the standard substance is shown in Figure 4 , specifically including the following steps:

[0042] Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use;

[0043] Specifically, in step 1, the use of grade 0 titanium sponge can reduce the impurity content in the titanium sponge and improve the purity of the ingot; the particle size diameter of the grade 0 titanium sponge is 0.83 mm to 12.7 mm, which can make the distribution of the titanium sponge more uniform; at the same time, since niobium has a high melting point and is prone to produce unmelted blocks, it is added in the form of niobium-aluminum alloy in the form of chips; molybdenum and chromium elements are added in the form of a quaternary alloy, which significantly reduces the melting point of the intermediate alloy.

[0044] Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally the consumable electrode is produced by a non-tungsten electrode argon shielded plasma welding process;

[0045] Specifically, in step 2, to achieve a more uniform chemical composition, the raw materials are weighed and then stirred using a mixing system for 40 seconds to ensure thorough mixing. The mixed raw materials are then pressed into electrode blocks of corresponding specifications using a hydraulic press, with a pressing strength of 20 MPa. The pressed blocks are then placed in a vacuum plasma welding chamber. To prevent oxidation of the consumable electrodes, the pre-vacuum level is less than 20 Pa. The consumable electrodes are then welded using a non-tungsten argon shielded plasma welding process. After welding, the consumable electrodes are inspected to prevent chipping during the melting process and to ensure the absence of through-hole cracks.

[0046] Step 3: The four smelting methods and related process parameters are as follows:

[0047] First smelting: Place the consumable electrode in a vacuum consumable electrode arc furnace for the first smelting to obtain a primary ingot; the process parameters for the first smelting are: vacuum degree less than 0.1pa, arc stabilization current is set to 2A~10A, smelting current is set to 10KA~15KA, and voltage is set to 30V~35V; it should be emphasized that: appropriate vacuum degree can ensure the removal of gas elements in the raw materials, such as Cl element, and appropriate stirring intensity can make the molten pool fully move to ensure the uniformity of macroscopic composition; the current needs to be reduced before the end of smelting to reduce the molten pool depth at the head of the primary ingot and alleviate head segregation; after the end of smelting, the primary ingot can be fully cooled to ensure that the surface of the primary ingot has a silvery white luster and is free of yellowing, purple and other oxidation phenomena.

[0048] Second smelting: the primary ingot is machined to remove the flash at the head of the primary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for a second smelting to obtain a secondary ingot; the process parameters of the second smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 5A~15A, smelting current is set to 12KA~20KA, voltage is set to 30V~35V, and cooling time after smelting is 5h; since the gas impurities in the primary smelting have been basically removed, the secondary smelting can appropriately increase the smelting current, further increase the molten pool stirring intensity, and improve the uniformity of the macroscopic composition of the ingot.

[0049] The third smelting: the secondary ingot is machined to remove the flash at the head of the secondary ingot, and after the head and tail are swapped, it is placed in a vacuum suspension smelting furnace for suspension smelting to obtain a tertiary ingot; the process parameters of the third smelting are as follows: the smelting furnace chamber and the casting chamber are repeatedly vacuumed three times: among which, the vacuum degree of the smelting furnace chamber must be less than 0.04Pa, and the vacuum degree of the casting chamber must be less than 0.5Pa; after turning on the induction heating power supply, the graphite mold is heated to 1000℃ at a rate of 20℃ / min and kept warm for 1h; the smelting power is gradually increased to 500kW at a rate of 40kW / min, and then the furnace temperature reaches 1300℃ and is maintained for 30min; after the smelting is completed, the alloy is cast into a graphite mold of specified specifications through a funnel at a speed of 5kg / s.

[0050] Fourth smelting: The three ingots are machined to remove the flash at the head of the three ingots. After the head and tail are swapped, they are placed in a vacuum consumable electrode arc furnace for the fourth smelting to obtain TB18 titanium alloy ingots. The actual state of the unpeeled ingot is shown in the figure. Figure 1 As shown; the process parameters of the fourth smelting are: vacuum degree less than 0.1Pa, arc stabilization current is set to 2A~8A, melting current is set to 10KA~18KA, voltage is set to 25V~30V, and cooling time after melting is 4h.

[0051] Step 4: Homogenization heat treatment: The TB18 titanium alloy ingot is subjected to homogenization heat treatment at a heating temperature of 900° C. for 10 hours, so that the unbalanced eutectic structure in the TB18 titanium alloy ingot is evenly distributed in the matrix, and the composition and structure are more uniform.

[0052] Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a high uniformity titanium alloy standard material forging rod blank, such as Figure 2 As shown; the forging temperature is 800°C, and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 1.0, and a total of 3 fire forgings are performed.

[0053] Step 6, Preparation of chip-like TB18 titanium alloy standard material: First, use a lathe to remove the oxide scale on the surface of the titanium alloy bar blank, and then use a milling machine to mill the chips. Equipped with a YG8 material milling cutter, the milling cutter blade is 2mm, and the groove is 1mm. The milling machine parameters are set to: chip speed 95r / min, feed rate 76mm / r, feed depth 1.2mm / time, and finally prepare chip-like TB18 titanium alloy standard material with a thickness of 0.2mm~0.5mm and a length of 1~3mm. The specific packaging process is as follows Figure 3 As shown, it can be used for inductively coupled plasma optical emission spectrometer testing.

[0054] Alternatively, in step 6, the preparation of block TB18 titanium alloy standard material: the bar blank is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

[0055] Example 2

[0056] This embodiment provides another TB18 titanium alloy chip-like standard material, in which the content of each main element ranges as follows: Al: 4.0%, Mo: 5.25%, V: 5.0%, Cr: 5.5%, Nb: 1.0%, Fe: 0.06%, and the rest is Ti and unavoidable impurity elements, and the sum of the weight percentages of each element is 100%.

[0057] The flow chart of the preparation method of the standard substance is shown in Figure 4 , specifically including the following steps:

[0058] Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use;

[0059] Specifically, in step 1, the use of grade 0 titanium sponge can reduce the impurity content in the titanium sponge and improve the purity of the ingot; the particle size diameter of the grade 0 titanium sponge is 0.83 mm to 12.7 mm, which can make the distribution of the titanium sponge more uniform; at the same time, since niobium has a high melting point and is prone to produce unmelted blocks, it is added in the form of niobium-aluminum alloy in the form of chips; molybdenum and chromium elements are added in the form of a quaternary alloy, which significantly reduces the melting point of the intermediate alloy.

[0060] Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally the consumable electrode is produced by a non-tungsten electrode argon shielded plasma welding process;

[0061] Specifically, in step 2, to achieve a more uniform chemical composition, the raw materials are weighed and then stirred using a mixing system for 50 seconds to ensure thorough mixing. The mixed raw materials are then pressed into electrode blocks of corresponding specifications using a hydraulic press, with a pressing strength of 50 MPa. The pressed blocks are then placed in a vacuum plasma welding chamber. To prevent oxidation of the consumable electrodes, the pre-vacuum level is less than 20 Pa. The consumable electrodes are then welded using a non-tungsten argon shielded plasma welding process. After welding, the consumable electrodes are inspected to prevent chipping during the melting process and to ensure the absence of through-hole cracks.

[0062] Step 3: The four smelting methods and related process parameters are as follows:

[0063] First smelting: Place the consumable electrode in a vacuum consumable electrode arc furnace for the first smelting to obtain a primary ingot; the process parameters for the first smelting are: vacuum degree less than 0.1pa, arc stabilization current is set to 2A~10A, smelting current is set to 10KA~15KA, and voltage is set to 30V~35V; it should be emphasized that: appropriate vacuum degree can ensure the removal of gas elements in the raw materials, such as Cl element, and appropriate stirring intensity can make the molten pool fully move to ensure the uniformity of macroscopic composition; the current needs to be reduced before the end of smelting to reduce the molten pool depth at the head of the primary ingot and alleviate head segregation; after the end of smelting, the primary ingot is fully cooled to ensure that the surface of the primary ingot is silvery white and shiny, without yellowing, purple or other oxidation phenomena.

[0064] Second smelting: the primary ingot is machined to remove the flash at the head of the primary ingot, and after the head and tail are swapped, it is placed in a vacuum suspension smelting furnace for suspension smelting to obtain a secondary ingot; the process parameters of the second smelting are as follows: the smelting furnace chamber and the casting chamber are repeatedly vacuumed at least 3 times: among which, the vacuum degree of the smelting furnace chamber must be less than 0.04Pa, and the vacuum degree of the casting chamber must be less than 0.5Pa; after turning on the induction heating power supply, the graphite mold is heated to 1200℃ at a rate of 30℃ / min and kept warm for 2h; the smelting power is gradually increased to 900kW at a rate of 50kW / min, and then the furnace temperature reaches 1600℃ and is maintained for 60min; after the smelting is completed, the alloy is cast into a graphite mold of specified specifications through a funnel at a speed of 10kg / s.

[0065] The third smelting: the secondary ingot is machined to remove the flash at the head of the secondary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for the third smelting to obtain a tertiary ingot; the process parameters of the third smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 5A~15A, smelting current is set to 12KA~20KA, voltage is set to 30V~35V, and cooling time after smelting is 6h; since the gas impurities in the first smelting have been basically removed, the smelting current can be appropriately increased in the third smelting, further increasing the stirring intensity of the molten pool and improving the macroscopic composition uniformity of the tertiary ingot.

[0066] Fourth smelting: The three ingots are machined to remove the flash at the heads of the three ingots. After the heads and tails are swapped, they are placed in a vacuum consumable electrode arc furnace for the fourth smelting to obtain TB18 titanium alloy ingots; the process parameters of the fourth smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 2A~8A, melting current is set to 10KA~18KA, voltage is set to 25V~30V, and cooling time after smelting is 5h.

[0067] Step 4: Homogenization heat treatment: The TB18 titanium alloy ingot is subjected to homogenization heat treatment at a heating temperature of 1100° C. for 15 hours, so that the unbalanced eutectic structure in the TB18 titanium alloy ingot is evenly distributed in the matrix, and the composition and structure are more uniform.

[0068] Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a high-uniformity titanium alloy standard material forging rod blank; the forging temperature is 1200°C, and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 2.0, and a total of 5 fires of forging are performed.

[0069] Step 6: Preparation of Chip-like TB18 Titanium Alloy Reference Material: First, use a lathe to remove the oxide scale from the titanium alloy bar blank. Then, use a milling machine to mill the chips. Use a YG8 milling cutter with a 2mm blade and a 1mm groove. The milling machine parameters are set to: a chipping speed of 95 rpm, a feed rate of 76 mm / min, and a feed depth of 1.2 mm / cut. Finally, TB18 titanium alloy reference material chips with a thickness of 0.2 mm to 0.5 mm and a length of 1 to 3 mm are prepared for inductively coupled plasma optical emission spectrometry testing.

[0070] Alternatively, in step 6, the preparation of block TB18 titanium alloy standard material: the bar blank is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

[0071] Example 3

[0072] This embodiment provides another TB18 titanium alloy chip-like standard material, in which the content of each main element ranges as follows: Al: 5.0%, Mo: 5.45%, V: 5.8%, Cr: 6.5%, Nb: 1.5%, Fe: 1.0%, and the rest are Ti and unavoidable impurity elements, and the sum of the weight percentages of each element is 100%.

[0073] The flow chart of the preparation method of the standard substance is shown in Figure 4 , specifically including the following steps:

[0074] Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use;

[0075] Specifically, in step 1, the use of grade 0 titanium sponge can reduce the impurity content in the titanium sponge and improve the purity of the ingot; the particle size diameter of the grade 0 titanium sponge is 0.83 mm to 12.7 mm, which can make the distribution of the titanium sponge more uniform; at the same time, since niobium has a high melting point and is prone to produce unmelted blocks, it is added in the form of niobium-aluminum alloy in the form of chips; molybdenum and chromium elements are added in the form of a quaternary alloy, which significantly reduces the melting point of the intermediate alloy.

[0076] Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally, the consumable electrode is produced by non-tungsten electrode argon shielded plasma welding;

[0077] Specifically, in step 2, to achieve a more uniform chemical composition, the raw materials are weighed and then stirred using a mixing system for 50 seconds to ensure thorough mixing. The mixed raw materials are then pressed into electrode blocks of the corresponding specifications using a hydraulic press, with a pressing strength of 50 MPa. The pressed blocks are then placed in a vacuum plasma welding chamber. To prevent oxidation of the consumable electrodes, the pre-vacuum level is less than 20 Pa, and the consumable electrodes are welded using non-tungsten argon shielded plasma welding. After welding, the consumable electrodes are inspected to prevent chipping during the melting process and to ensure the absence of through-hole cracks.

[0078] Step 3: The four smelting methods and related process parameters are as follows:

[0079] First smelting: Place the consumable electrode in a vacuum consumable electrode arc furnace for the first smelting to obtain a primary ingot; the process parameters for the first smelting are: vacuum degree less than 0.1pa, arc stabilization current of 2A~10A, smelting current set to 10KA~15KA, and voltage set to 30V~35V; it should be emphasized that: appropriate vacuum degree can ensure the removal of gas elements in the raw materials, such as Cl element, and appropriate stirring intensity can make the molten pool fully move to ensure the uniformity of macroscopic composition; the current needs to be reduced before the end of smelting to reduce the molten pool depth at the head of the primary ingot and alleviate head segregation; after the end of smelting, the primary ingot is fully cooled to ensure that the surface of the primary ingot is silvery white and shiny, without yellowing, purple or other oxidation phenomena.

[0080] Second smelting: the primary ingot is machined to remove the flash at the head of the primary ingot, and after the head and tail are swapped, it is placed in a vacuum suspension smelting furnace for suspension smelting to obtain a secondary ingot; the process parameters of the second smelting are as follows: the smelting furnace chamber and the casting chamber are repeatedly vacuumed at least 3 times: among which, the vacuum degree of the smelting furnace chamber must be less than 0.04Pa, and the vacuum degree of the casting chamber must be less than 0.5Pa; after turning on the induction heating power supply, the graphite mold is heated to 1200℃ at a rate of 25℃ / min and kept warm for 3h; the smelting power is gradually increased to 900kW at a rate of 45kW / min, and then the furnace temperature reaches 1600℃ and is maintained for 30min; after the smelting is completed, the alloy is cast into a graphite mold of specified specifications through a funnel at a speed of 10kg / s.

[0081] Third smelting: the secondary ingot is machined to remove the flash at the head of the secondary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for a third smelting to obtain a tertiary ingot; the process parameters of the third smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 5A~15A, smelting current is set to 12KA~20KA, voltage is set to 30V~35V, and cooling time after smelting is 5h; since the gas impurities in the first smelting have been basically removed, the smelting current can be appropriately increased in the third smelting, further increasing the molten pool stirring intensity and improving the uniformity of the macroscopic composition of the ingot.

[0082] Fourth smelting: The three ingots are machined to remove the flash at the heads of the three ingots. After the heads and tails are swapped, they are placed in a vacuum consumable electrode arc furnace for the fourth smelting to obtain TB18 titanium alloy ingots; the process parameters of the fourth smelting are: vacuum degree is less than 0.1Pa, stable arc current is set to 2A~8A, melting current is set to 10KA~18KA, voltage is set to 25V~30V, and cooling time after smelting is 4h.

[0083] Step 4: Homogenization heat treatment: The TB18 titanium alloy ingot is subjected to homogenization heat treatment at a heating temperature of 1100° C. for 15 hours, so that the unbalanced eutectic structure in the TB18 titanium alloy ingot is evenly distributed in the matrix, and the composition and structure are more uniform.

[0084] Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a high-uniformity titanium alloy standard material forging rod blank; the forging temperature is 1100°C, and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 1.5, and a total of 6 fires of forging are performed.

[0085] Step 6: Preparation of Chip-like TB18 Titanium Alloy Reference Material: First, use a lathe to remove the oxide scale from the titanium alloy bar blank. Then, use a milling machine to mill the chips. Use a YG8 milling cutter with a 2mm blade and a 1mm groove. The milling machine parameters are set to: a chipping speed of 95 rpm, a feed rate of 76 mm / min, and a feed depth of 1.2 mm / cut. Finally, TB18 titanium alloy reference material chips with a thickness of 0.2 mm to 0.5 mm and a length of 1 to 3 mm are prepared for inductively coupled plasma optical emission spectrometry testing.

[0086] Alternatively, in step 6, the preparation of block TB18 titanium alloy standard material: the bar blank is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

[0087] Example 4

[0088] This embodiment provides another TB18 titanium alloy chip-like standard material, in which the content of each main element ranges as follows: Al: 4.2%, Mo: 5.15%, V: 4.8%, Cr: 5.0%, Nb: 1.2%, Fe: 0.08%, and the rest is Ti and unavoidable impurity elements, and the sum of the weight percentages of each element is 100%.

[0089] The flow chart of the preparation method of the standard substance is shown in Figure 4 , specifically including the following steps:

[0090] Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use;

[0091] Specifically, in step 1, the use of grade 0 titanium sponge can reduce the impurity content in the titanium sponge and improve the purity of the ingot; the particle size diameter of the grade 0 titanium sponge is 0.83 mm to 12.7 mm, which can make the distribution of the titanium sponge more uniform; at the same time, since niobium has a high melting point and is prone to produce unmelted blocks, it is added in the form of niobium-aluminum alloy in the form of chips; molybdenum and chromium elements are added in the form of a quaternary alloy, which significantly reduces the melting point of the intermediate alloy.

[0092] Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally the consumable electrode is produced by a non-tungsten electrode argon shielded plasma welding process;

[0093] Specifically, in step 2, to achieve a more uniform chemical composition, the raw materials are weighed and then stirred using a mixing system for 50 seconds to ensure thorough mixing. The mixed raw materials are then pressed into electrode blocks of corresponding specifications using a hydraulic press, with a pressing strength of 50 MPa. The pressed blocks are then placed in a vacuum plasma welding chamber. To prevent oxidation of the consumable electrodes, the pre-vacuum level is less than 20 Pa, and the consumable electrodes are produced using a non-tungsten argon shielded plasma welding process. After welding, the consumable electrodes are inspected to prevent chipping during the melting process and to ensure the absence of through-hole cracks.

[0094] Step 3, five smeltings, the smelting method and related process parameters are as follows:

[0095] First smelting: Place the consumable electrode in a vacuum consumable electrode arc furnace for the first smelting to obtain a primary ingot; the process parameters for the first smelting are: vacuum degree less than 0.1pa, arc stabilization current is set to 2A~10A, smelting current is set to 10KA~15KA, and voltage is set to 30V~35V; it should be emphasized that: appropriate vacuum degree can ensure the removal of gas elements in the raw materials, such as Cl element, and appropriate stirring intensity can make the molten pool fully move to ensure the uniformity of macroscopic composition; the current needs to be reduced before the end of smelting to reduce the molten pool depth at the head of the primary ingot and alleviate head segregation; after the end of smelting, the primary ingot can be fully cooled to ensure that the surface of the primary ingot has a silvery white luster and is free of yellowing, purple and other oxidation phenomena.

[0096] Second smelting: the primary ingot is machined to remove the flash at the head of the primary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for a second smelting to obtain a secondary ingot; the process parameters of the second smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 5A~15A, smelting current is set to 12KA~20KA, voltage is set to 30V~35V, and cooling time after smelting is 5h; since the gas impurities in the primary smelting have been basically removed, the secondary smelting can appropriately increase the smelting current, further increase the molten pool stirring intensity, and improve the uniformity of the macroscopic composition of the ingot.

[0097] The third smelting: the secondary ingot is machined to remove the flash at the head of the secondary ingot, and after the head and tail are swapped, it is placed in a vacuum consumable electrode arc furnace for the third smelting to obtain a tertiary ingot; the process parameters of the third smelting are: vacuum degree is less than 0.1Pa, arc stabilization current is set to 2A~8A, melting current is set to 10KA~18KA, voltage is set to 25V~30V, and cooling time after smelting is 5h.

[0098] Fourth smelting: the three ingots are machined to remove the flash at the heads of the three ingots, and after the heads and tails are swapped, they are placed in a vacuum suspension melting furnace for suspension melting to obtain four ingots; the process parameters of the fourth smelting are as follows: the melting furnace chamber and the casting chamber are repeatedly vacuumed three times: among which, the vacuum degree of the melting furnace chamber must be less than 0.04Pa, and the vacuum degree of the casting chamber must be less than 0.5Pa; after turning on the induction heating power supply, the graphite mold is heated to 1200℃ at a rate of 25℃ / min and kept warm for 3h; the melting power is gradually increased to 900kW at a rate of 40kW / min, and then the furnace temperature reaches 1300℃ and is maintained for 30min; after the smelting is completed, the alloy is cast into a graphite mold of specified specifications through a funnel at a speed of 10kg / s.

[0099] Fifth smelting: The four ingots are machined to remove the flash at the heads of the four ingots. After the heads and tails are swapped, they are placed in a vacuum consumable electrode arc furnace for the fifth smelting to obtain TB18 titanium alloy ingots; the process parameters of the fifth smelting are: vacuum degree is less than 0.1 Pa, arc stabilization current is set to 2A~8A, melting current is set to 8KA~16KA, voltage is set to 25V~30V, and cooling time after smelting is 4h.

[0100] Step 4: Homogenization heat treatment: The TB18 titanium alloy ingot is subjected to homogenization heat treatment at a heating temperature of 1100° C. for 15 hours, so that the unbalanced eutectic structure in the TB18 titanium alloy ingot is evenly distributed in the matrix, and the composition and structure are more uniform.

[0101] Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a high-uniformity titanium alloy standard material forging rod blank; the forging temperature is 1100°C, and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 1.5, and a total of 6 fires of forging are performed.

[0102] Step 6: Preparation of Chip-like TB18 Titanium Alloy Reference Material: First, use a lathe to remove the oxide scale from the titanium alloy bar blank obtained in Step 5. Then, use a milling machine to mill the chips using a YG8 milling cutter with a 2mm blade and a 1mm groove. The milling machine parameters are set to: a chipping speed of 95 rpm, a feed rate of 76 mm / min, and a feed depth of 1.2 mm / cut. Finally, TB18 titanium alloy reference material chips with a thickness of 0.2 mm to 0.5 mm and a length of 1 to 3 mm are prepared for inductively coupled plasma optical emission spectrometry testing.

[0103] Alternatively, in step 6, the preparation of block TB18 titanium alloy standard material: the rod blank obtained in step 5 is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

[0104] It should be noted that the homogeneity of the standard substance is one of its most critical indicators. Therefore, it is necessary to perform a homogeneity test on the standard substances prepared in Examples 1 to 4 above. The specific test process is as follows:

[0105] ①The initial inspection process of ingot uniformity is as follows:

[0106] After multiple smelting cycles, the uniformity of element distribution is preliminarily assessed using standard deviation. Three samples, equidistant along the radial direction, are taken from the head, middle, and tail ports for uniformity testing. According to the YS / T 409 "Technical Specifications for Standard Samples," the standard deviation, s, of the test results is calculated and compared with the inter-laboratory tolerance, Δ. The uniformity test is considered qualified when 1.5s ≤ 1 / 2Δ. Statistical analysis shows that the standard deviations of Al, Mo, Cr, V, Nb, and Fe in the TB18 titanium alloy cylindrical ingots prepared in the above example meet standard requirements.

[0107] ② Homogeneity test: Based on GB / T 15000.3 "Guidelines for Standard Samples" and YS / T 409 "Technical Specifications for Standard Samples," the sampled samples were tested for homogeneity using the variance method. Homogeneity testing includes two aspects: inter-unit uniformity and intra-unit uniformity. Inter-unit uniformity reflects the differences in measurement results between each unit of the sample; intra-unit uniformity reflects the minimum sample size that can represent the entire unit. The typical sample size for daily analysis should be larger than, or at least equal to, the minimum sample size.

[0108] To further validate the effectiveness of the technical solution provided by this invention, a uniformity test protocol for TB18 titanium alloy chip reference material was designed. Twenty bottles of different numbers were randomly selected as homogeneity samples, and each bottle was analyzed in triplicate. A one-way analysis of variance (ANOVA) was used, comparing the inter-bottle standard deviation (Samong) with the intra-bottle standard deviation (Swithin).

[0109] To avoid fluctuations in the measurement process, the three measurements were performed in the following order (by unit number):

[0110] First measurement: 1-3-5-7-9-11-13-15-17-19-2-4-6-8-10-12-14-16-18-20

[0111] Second measurement: 20-19-18-17-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-1

[0112] The third measurement: 2-4-6-8-10-12-14-16-18-20-1-3-5-7-9-11-13-15-17-19

[0113] x 11 ,x 12 ,……x 1n ,average value

[0114] x 21 ,x 22 ,……x 2n ,average value

[0115] …………………, ………;

[0116] x m1 ,x m2 ,……x mn ,average value

[0117] Calculate the overall average

[0118] Calculate the sum of squared deviations within the bottle (where Q1 = MSwithin)

[0119] Calculate the sum of squared deviations between bottles (where Q2 = MSamong)

[0120] Calculation of degrees of freedom ν1 = m-1; ν2 = m(n-1)

[0121] Calculating statistics

[0122] According to the significance level and degrees of freedom, F can be obtained from the F test critical value table. α Compare F and F α :

[0123] If F < F α , it is considered that there is no significant difference within and between groups and the sample is uniform.

[0124] If F ≥ F α , it is suspected that there are systematic errors between the groups and the samples are considered to be uneven.

[0125] From the results of the uniformity inspection F method in Table 1 below, it can be seen that the uniformity inspection of the TB18 titanium alloy chip standard material is qualified.

[0126] Table 1 Uniformity of TB18 titanium alloy chips

[0127]

[0128] In summary, the technical solution provided by the present invention, combined with the vacuum consumable electrode arc furnace smelting to obtain materials with very uniform and accurate composition, and the vacuum suspension smelting to produce materials with very high purity, greatly improves the uniformity and composition accuracy of titanium alloy ingot melting, which can not only meet market demand, but also further contribute to the development of my country's aviation industry.

[0129] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present 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 present invention.

[0130] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing TB18 titanium alloy standard material, characterized in that: The steps include: Step 1, ingredients: select grade 0 titanium sponge, molybdenum-vanadium-aluminum-chromium master alloy, molybdenum-aluminum master alloy, vanadium-aluminum master alloy, niobium-titanium master alloy and aluminum beans as raw materials, calculate the ingredients according to the requirements of the content of each element of TB18 titanium alloy standard material, and weigh the raw materials of each component separately for use; Step 2, consumable electrode preparation: first, the raw materials of each component are mixed evenly and then pressed into electrode blocks of corresponding specifications, and then the pressed electrode blocks are placed in a vacuum plasma welding box, and finally the consumable electrode is produced by a non-tungsten electrode argon shielded plasma welding process; Step 3, smelting: smelting the consumable electrode at least four times to obtain a TB18 titanium alloy ingot; Step 4: homogenization heat treatment: performing homogenization heat treatment on the TB18 titanium alloy ingot to make the unbalanced eutectic structure in the TB18 titanium alloy ingot evenly distributed in the matrix, and the composition and structure are more uniform; Step 5, forging: forging the TB18 titanium alloy ingot after homogenization heat treatment to obtain a forged rod blank of a high-homogeneity titanium alloy standard material; Step 6: Processing the forged rod blank of the high uniformity titanium alloy standard material to complete the preparation of the TB18 titanium alloy standard material; The smelting in step 3 includes: at least three vacuum consumable arc furnace smeltings and one vacuum suspension melting furnace smelting, and the first smelting and the last smelting are both carried out in a vacuum consumable arc furnace; The heating temperature of the homogenization heat treatment in step 4 is 900°C~1100°C, and the heat preservation time is 10h~15h; in step 5, the forging temperature is 800°C~1200°C, and the forging temperature is reduced to below the phase transformation point in each fire, the forging ratio of each fire is 1.0~2.0, and a total of 3~6 fires of forging are performed.

2. The method for preparing the TB18 titanium alloy standard material according to claim 1, characterized in that: In the TB18 titanium alloy standard material, the content range of each element is: Al: 3.0%~5.0%, Mo: 5.05%~5.45%, V: 4.0%~5.8%, Cr: 4.5%~6.5%, Nb: 0.5%~15%, Fe: 0.03%~1.0%, and the rest are Ti and unavoidable impurity elements. The sum of the weight percentages of each element is 100%.

3. The method for preparing the TB18 titanium alloy standard material according to claim 1, characterized in that: In step 2, the various component raw materials are stirred and mixed using a mixing system for a stirring time of not less than 30 seconds; the mixed component raw materials are pressed into electrode blocks of corresponding specifications using an oil press with a pressing strength of 20MPa~50MPa; the pre-vacuum degree of the vacuum plasma welding box is less than 20Pa.

4. The method for preparing the TB18 titanium alloy standard material according to claim 1, characterized in that: The smelting process of the vacuum suspension furnace smelting is: The ingot obtained by the previous step of vacuum consumable arc furnace melting is machined to remove the flash at the head, and then the head and tail are swapped and placed in a vacuum suspension melting furnace for suspension melting to obtain an intermediate ingot. The specific process of suspension melting is as follows: The melting furnace chamber and casting chamber are repeatedly vacuumed at least 3 times, and the vacuum degree of the melting furnace chamber is less than 0.04Pa, and the vacuum degree of the casting chamber is less than 0.5Pa; after turning on the induction heating power supply, heat the graphite mold to 1000℃~1200℃ at a rate of 20℃ / min~30℃ / min and keep it warm for 1h~3h; increase the melting power to 500kW~900kW at a rate of 40kW / min~50kW / min, and then bring the furnace temperature to 1300℃~1600℃ and maintain it for 30min~60min; after the melting is completed, cast the alloy into a graphite mold of specified specifications through a funnel at a speed of 5kg / s~10kg / s.

5. The method for preparing the TB18 titanium alloy standard material according to claim 1, characterized in that: In step 6, the chip-like TB18 titanium alloy standard material is prepared by first using a lathe to remove the oxide scale on the surface of the rod blank, and then using a milling machine to mill the chips, and finally obtaining the chip-like TB18 titanium alloy standard material with a thickness of 0.2mm~0.5mm and a length of 1mm~3mm for inductively coupled plasma emission spectrometer testing.

6. The method for preparing the TB18 titanium alloy standard material according to claim 1, characterized in that: In step 6, the preparation of block TB18 titanium alloy standard material: the bar blank is processed into Φ38mm×25mm using a lathe for testing with a photoelectric direct reading spectrometer.

Images