Ti175 high-temperature titanium alloy cast ingot and preparation method thereof

Abstract

The invention discloses a Ti175 high-temperature titanium alloy cast ingot and a preparation method thereof, and the preparation method comprises the following steps: S1, burdening according to the target element content of a Ti175 high-temperature titanium alloy, mixing the raw materials, distributing the materials, and then pressing into an electrode block; the material distribution mode is a multi-layer material distribution mode, and comprises a bottommost layer, a middle layer and an uppermost layer; the middle layer is divided into three layers of cloth; and S2, stacking a plurality of electrode blocks, welding the electrode blocks into a consumable electrode, and performing vacuum consumable arc melting to obtain the Ti175 high-temperature titanium alloy cast ingot. According to the preparation method of the Ti175 high-temperature titanium alloy cast ingot, the specification of the titanium alloy cast ingot can reach phi 680-phi 780 mm, cast ingot segregation is improved through raw material control, electrode block distribution mode improvement, finished product smelting process adjustment and feeding process adjustment, and the cast ingot with uniform chemical components and low impurity content is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy smelting, and in particular relates to a Ti175 high-temperature titanium alloy ingot and a preparation method thereof. Background Art

[0002] In order to improve the thrust-to-weight ratio of aircraft engines, materials with high specific strength and specific stiffness are required. Titanium alloys have high specific strength, excellent corrosion resistance and high temperature resistance, and are key structural materials for modern aircraft engines. Aircraft engine components serve in harsh environments of high temperature, complex stress, airflow scouring, high-speed vibration, and environmental stress corrosion, and the performance requirements of their materials are very strict. High-temperature titanium alloys must have a good match between strength, plasticity, toughness, creep and fatigue properties. Long-term creep and endurance performance at medium and high temperatures are characteristic indicators of high-temperature titanium alloys. With the need for long-term stability of aircraft engines, higher and higher requirements are placed on the uniformity of the composition of high-temperature titanium alloy ingots and the control of impurity elements.

[0003] There are many kinds of alloying elements in Ti175 high-temperature titanium alloy, and there are many elements that are easy to segregate, resulting in large differences in the composition of the head and bottom of the ingot. And when the ingot size is larger, the segregation is particularly obvious. Therefore, it is of great significance to obtain large-size Ti175 high-temperature titanium alloy ingots with uniform chemical composition and low impurity element content by improving the smelting process. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a Ti175 high-temperature titanium alloy ingot with uniform composition and low impurity content and a preparation method thereof.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for preparing a Ti175 high-temperature titanium alloy ingot comprises the following steps: S1. According to the target element content of Ti175 high temperature titanium alloy, the raw materials are mixed, laid, and then pressed into electrode blocks; The fabric is a multi-layer fabric, including a bottom layer, a middle layer and an upper layer; The middle layer is divided into three layers, namely, middle layer 1, middle layer 2 and middle layer 3 from top to bottom, each layer is a mixture of sponge titanium, AlW50 master alloy, AlMo65 master alloy and TiO2 powder; the proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 38-42%, 33-37.5% and 22-28% of the addition amount respectively, totaling 100%; S2. Stack and weld multiple electrode blocks into consumable electrodes, and then melt them into Ti175 high-temperature titanium alloy ingots through vacuum consumable arc melting.

[0006] As a further improvement, the raw materials for S1 are 0a grade sponge titanium with a particle size of 3 mm to 12.7 mm, AlMo65 master alloy, AlW50 master alloy, TiSn80 master alloy, AlSi11 master alloy, sponge zirconium, aluminum beans and TiO2 powder.

[0007] As a further improvement, the bottom layer is a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans; the top layer is also a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans.

[0008] As a further improvement, in the middle layer 1, middle layer 2, and middle layer 3, the proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 40%, 35%, and 25% of the addition amount in sequence.

[0009] As a further improvement, the density of the electrode block in S1 is 3.4 to 3.65 g / cm 3 .

[0010] As a further improvement, the melting current of S2 is 23 KA to 25 KA, the voltage is 32 V to 35 V, the stable arc stirring current is 10 A to 14 A AC, the commutation time is 8 s to 12 s, and the inlet temperature of the cooling water in the melting furnace cooling tower is 22 °C to 25 °C.

[0011] As a further improvement, S2 undergoes three times of vacuum consumable arc melting, and enters the feeding stage when the weight of the remaining consumable electrode in the third vacuum consumable arc melting is 260 Kg to 350 Kg.

[0012] As a further improvement, the feeding is carried out by gradually reducing the current in four stages: in the first stage, the melting current is 10 KA to 24 KA, the feeding voltage is 28 V to 34 V, and the feeding time is 15 min to 30 min; in the second stage, the melting current is 8 KA to 10 KA, the feeding voltage is 24 V to 28 V, and the feeding time is 10 min to 20 min; in the third stage, the melting current is 5 KA to 8 KA, the feeding voltage is 24 V, and the feeding time is 60 min to 100 min; in the fourth stage, the melting current is 2 KA to 5 KA, the feeding voltage is 24 V, and the feeding time is ≥ 30 min.

[0013] As a further improvement, the specification of the Ti175 high-temperature titanium alloy ingot is Φ680 to Φ780 mm.

[0014] A Ti175 high-temperature titanium alloy ingot provided by the present invention is prepared by the method described above.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, the electrode block feeding method is changed from three-layer feeding to multi-layer feeding, among which the middle layer is divided into three-layer feeding, and the proportions of AlW50 master alloy and AlMo65 master alloy decrease successively in a specific ratio from top to bottom. By improving the feeding method, the risk of segregation of high melting point and high density elements such as tungsten and molybdenum is reduced.

[0016] In addition, by adjusting smelting process parameters such as smelting current, risering reserved mass, risering time, and inlet water temperature, the ingot segregation is improved.

[0017] The preparation method of the Ti175 high-temperature titanium alloy ingot provided by the present invention can reach a specification of Φ680~Φ780mm for the titanium alloy ingot. By controlling raw materials, improving the electrode block feeding method, adjusting the finished product smelting process, and risering process, the ingot segregation is improved, and an ingot with uniform chemical composition and low impurity content is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic diagram of the sampling position on the cross-section of the head of the titanium alloy ingot; Figure 2 It is the electrode block feeding method of a specific embodiment of the present invention; Figure 3 It is the microstructural morphology at the center of the head of the ingot in Example 1 of the present invention; Figure 4 It is the microstructural morphology at the center of the head of the ingot in Comparative Example 1 of the present invention; Figure 5 It is the microstructural morphology at the center of the head of the ingot in Comparative Example 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To facilitate the understanding of the present invention, the following will describe the present invention more comprehensively and meticulously in combination with the accompanying drawings of the specification and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0021] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0022] Unless otherwise specified, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or prepared by existing methods.

[0023] In some specific embodiments, the method for preparing the Ti175 high-temperature titanium alloy ingot of the present invention comprises the following steps: S1. Weighing and mixing the raw materials, spreading the mixed raw materials, and then pressing them into electrode blocks.

[0024] Weigh the components of each element of the Ti175 high-temperature titanium alloy according to the technical standard requirements (as shown in the following table, wt%, with the balance being Ti), and then mix and spread them.

[0025]

[0026] The raw materials selected are 0a grade sponge titanium with a particle size of 3 mm to 12.7 mm, AlMo65 master alloy, AlW50 master alloy, TiSn80 master alloy, AlSi11 master alloy, sponge zirconium, aluminum beans, and TiO2 powder. By selecting small-particle-size 0a grade sponge titanium and master alloys with low impurity content, melting point, density, and particle size close to those of the matrix metal, the purpose of controlling the impurity element content in the alloy is achieved, and at the same time, the risk of alloy element segregation and inclusion is reduced.

[0027] In some embodiments, the raw materials selected are 0a grade sponge titanium with a particle size of 3 mm to 12.7 mm; AlMo65 master alloy with a particle size ≤ 6 mm; AlW50 master alloy with a particle size of 0.25 mm to 13 mm; TiSn80 master alloy with a thickness < 0.8 mm, width < 15 mm, and length < 15 mm; AlSi11 master alloy with a thickness of 0.08 mm to 1.0 mm, width of 1 mm - 15 mm, and length of 1 mm to 15 mm; sponge zirconium HZr-1 with a particle size of 1 to 12 mm; aluminum beans of Al99.70 with a particle size of 3 to 15 mm; and TiO2 powder with a particle size not less than 160 mesh.

[0028] In some embodiments, the total weight of the weighed materials is 3000 kg to 4000 kg.

[0029] Reference Figure 2 , and the spreading method is multi-layer spreading: the bottom layer is a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans; the middle layer is a mixture of sponge titanium, AlW50 master alloy, AlMo65 master alloy, and TiO2 powder; the top layer is a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans.

[0030] Among them, the middle layer is further divided into three layers of fabric (from top to bottom are middle layer 1, middle layer 2, and middle layer 3). Each layer is a mixture of titanium sponge, AlW50 master alloy, AlMo65 master alloy, and TiO2 powder. The proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 38 - 42%, 33 - 37.5%, and 22 - 28% of the addition amount in sequence, with a total of 100% (preferably 40%, 35%, 25%). That is, the total addition amount of AlW50 master alloy is counted as 100%. The amount of AlW50 master alloy in middle layer 1 is 38 - 42%, the amount of AlW50 master alloy in middle layer 2 is 33 - 37.5%, and the amount of AlW50 master alloy in middle layer 3 is 22 - 28%. The total addition amount of AlMo65 master alloy is counted as 100%. The amounts of AlMo65 master alloy in middle layer 1, middle layer 2, and middle layer 3 are 38 - 42%, 33 - 37.5%, and 22 - 28% respectively.

[0031] The use of the above specific ratios for middle layer 1, middle layer 2, and middle layer 3 is beneficial to improving the compositional segregation of W and Mo. If the middle layer is not stratified and is simply mixed, the high-density W and Mo will sink, resulting in the segregation of W and Mo in the height direction.

[0032] In some embodiments, the amounts of titanium sponge in the topmost layer, middle layer, and bottommost layer are equal, and the amounts of titanium sponge in middle layer 1, middle layer 2, and middle layer 3 are equal. In Example 1 below, the mass ratio of titanium sponge in the topmost layer, middle layer 1, middle layer 2, middle layer 3, and bottommost layer is 3:1:1:1:3.

[0033] In some embodiments, the amounts of TiO2 powder in middle layer 1, middle layer 2, and middle layer 3 are equal, and the mass ratio in Example 1 below is 1:1:1.

[0034] In some embodiments, the amounts of TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, or Al99.70 aluminum beans in the topmost layer and the bottommost layer are the same. In Example 1 below, the mass ratio of TiSn80 master alloy in the topmost layer and the bottommost layer is 1:1, the mass ratio of AlSi11 master alloy in the topmost layer and the bottommost layer is 1:1, the mass ratio of HZr-1 sponge zirconium in the topmost layer and the bottommost layer is 1:1, and the mass ratio of Al99.70 aluminum beans in the topmost layer and the bottommost layer is 1:1.

[0035] According to the above requirements, the raw materials required for each layer are laid in sequence from bottom to top after mixing.

[0036] In some embodiments, it is pressed into an electrode block with a density of 3.4 - 3.65 g / cm 3 ³. The higher the density of the electrode block, the less likely it is to have block dropping and falling off during the smelting process, reducing the risk of segregation and inclusion generation.

[0037] S2. Stack multiple electrode blocks, weld them into a consumable electrode, and then perform three times of vacuum consumable arc melting. After cooling (cooling by the cooling tower of the melting furnace), flaw detection, and cutting off the riser, a finished ingot is obtained.

[0038] In some embodiments, the welding of the electrode blocks is carried out using a vacuum plasma welding box.

[0039] In some embodiments, the melting current for the three times of melting is 23KA - 25KA, the voltage is 32V - 35V, the stable arc stirring current is 10A - 14A AC, the commutation time is 8s - 12s, and the inlet temperature (the inlet temperature of the cooling water of the cooling tower of the melting furnace) is 22°C - 25°C.

[0040] In some embodiments, when the weight of the remaining consumable electrode in the third vacuum consumable arc melting is 260 Kg - 350 Kg, the feeding stage is entered.

[0041] In this process, the stirring commutation period is adjusted from 6s - 8s to 8s - 12s, the inlet temperature is adjusted from 25°C - 28°C to 22°C - 25°C, and the reserved feeding mass is adjusted from 220 kg - 260 kg to 260 kg - 350 kg.

[0042] By lowering the inlet temperature of the cooling water, the supercooling degree and temperature gradient at the solidification front are increased, the cooling rate is accelerated, and the solidification time of the solid-liquid two-phase zone is shortened. As the solidification rate increases, the solute distribution coefficient approaches 1, and the crystal segregation is inhibited.

[0043] Increasing the commutation time of the stable arc stirring in the finished product melting stage, that is, increasing the stirring intensity of the molten pool, the alloy flow rate is accelerated, the Reynolds number of the molten pool increases, the convective heat transfer coefficient is enhanced, and the solidification time is shortened. And after the stirring intensity increases, the scouring effect of the fluid on the solidification front is strengthened, the width of the solid-liquid two-phase zone is reduced, the broken dendrites are involved in the interior of the molten pool, providing nucleation conditions for crystallization, increasing the solidification rate, and effectively inhibiting the segregation of elements in the center of the ingot.

[0044] Increasing the reserved feeding mass, the feeding time is extended, the heat input into the molten pool per unit time is reduced, enabling the depth of the molten pool to have enough time to rise, which is beneficial to improving the segregation in the center of the ingot.

[0045] In some embodiments, feeding is performed by gradually decreasing the current in four stages. In the first stage, the melting current is 10 KA to 24 KA, the feeding voltage is 28 V to 34 V, and the feeding time is 15 min to 30 min. In the second stage, the melting current is 8 KA to 10 KA, the feeding voltage is 24 V to 28 V, and the feeding time is 10 min to 20 min. In the third stage, the melting current is 5 KA to 8 KA, the feeding voltage is 24 V, and the feeding time is 60 min to 100 min. In the fourth stage, the melting current is 2 KA to 5 KA, the feeding voltage is 24 V, and the feeding time is ≥30 min. By extending the feeding time and reducing the heat input to the molten pool, the solidification rate of the central molten pool is accelerated, and the segregation in the core of the ingot is improved.

[0046] In some embodiments, argon is filled for cooling during all three meltings, and the argon filling pressure ranges from 3000 Pa to 8000 Pa, and the cooling time is not less than 330 min.

[0047] In some embodiments, the Ti175 high-temperature titanium alloy ingot prepared by the present invention has a specification of Φ680 to Φ780 mm.

[0048] Example 1 This example provides a melting method for a Ti175 titanium alloy ingot with a specification of Φ720 mm. By controlling the raw materials, improving the electrode block feeding method, optimizing the finished product melting process, and feeding process, an ingot with uniform chemical composition is obtained. Specifically as follows: The raw materials selected are 0a grade sponge titanium with a particle size of 3 mm to 12.7 mm; AlMo65 master alloy with a particle size ≤6 mm; AlW50 master alloy with a particle size of 0.25 mm to 13 mm; TiSn80 master alloy with a thickness <0.8 mm, a width <15 mm, and a length <15 mm; AlSi11 master alloy with a thickness of 0.08 mm to 1.0 mm, a width of 1 mm - 15 mm, and a length of 1 mm to 15 mm; sponge zirconium HZr-1 with a particle size of 1 to 12 mm; aluminum beans with a particle size of 3 to 15 mm of Al99.70; TiO2 powder with a particle size not less than 160 mesh. The target contents are: Al: 6.5%; Sn: 2.1%, Zr: 3.5%; Mo: 4.0%; Si: 0.25%; W: 1.3%; Fe: ≤0.05; O ≤0.15; the balance is Ti and other impurity elements.

[0049] As Figure 2, the electrode block is charged in three layers: the bottom layer is a mixture of titanium sponge, TilSn80 master alloy, AlSi11 master alloy, HZr-1 zirconium sponge, and Al99.70 aluminum beans; the middle layer is a mixture of titanium sponge, AlW50 master alloy, AlMo65 master alloy, and TiO2 powder. Among them, the middle layer is further charged in three layers, and the proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 40%, 35%, and 25% of the addition amount in turn; the top layer is a mixture of titanium sponge, TiSn80 master alloy, AlSi11 master alloy, HZr-1 zirconium sponge, and Al99.70 aluminum beans.

[0050] After charging, it is pressed into a single electrode with a density of 3.4~3.65 g / cm 3 by a hydraulic press.

[0051] The electrode blocks are stacked and welded into a consumable electrode using a vacuum plasma welding box.

[0052] The consumable electrode is melted into an ingot through three times of vacuum consumable arc melting, cooled, inspected for defects, and the riser is removed to obtain the finished ingot.

[0053] Among them, in the finished product feeding stage, feeding starts when the remaining mass of the electrode is 260 kg~350 kg. The finished product feeding adopts step-by-step current reduction feeding, which is divided into four stages. In the first stage, the melting current is 10 KA~24 KA, the feeding voltage is 28 V~34 V, and the feeding time is 15 min~30 min. In the second stage, the melting current is 8 KA~10 KA, the feeding voltage is 24 V~28 V, and the feeding time is 10 min~20 min. In the third stage, the melting current is 5 KA~8 KA, the feeding voltage is 24 V, and the feeding time is 60 min~100 min. In the fourth stage, the melting current is 2 KA~5 KA, the feeding voltage is 24 V, and the feeding time is ≥30 min.

[0054] The melting current for the finished product melting is 23 KA~25 KA, the voltage is 32 V~35 V, the arc stabilizing stirring current is 10 A~14 A AC, the commutation time is 8 s~12 s, and the water inlet temperature is 22 °C~25 °C.

[0055] For the Ti175 titanium alloy ingot with a specification of Φ720 mm obtained in this embodiment, after removing the riser, nine samples are taken at the center of the cross-section of the ingot head, 1 / 2R, and the edge. The sampling positions are as Figure 1 shown, and the samples are subjected to composition detection. The results are shown in Table 1.

[0056] Table 1 Content of some elements in the cross-section of the Ti175 ingot head (wt%)

[0057] The longitudinal chemical composition of the Ti175 ingot is detected, and the results are shown in Table 2.

[0058] Table 2 Longitudinal Chemical Composition of Ti175 Ingot (wt%)

[0059] As can be seen from Table 1 and Table 2, the longitudinal composition of the Ti175 titanium alloy ingot obtained in this example is uniform, meeting the standard requirements. The test results of sampling at 9 points on the cross-section of the head show that the range of Al is controlled within 0.4%, the range of Mo is 0.25%, the range of W is 0.07%, and the ranges of other elements are controlled within 0.25%, indicating good compositional uniformity. The results of longitudinal chemical composition show that the elements W and Mo are evenly distributed longitudinally without obvious longitudinal distribution gradient. Figure 3 It is the microstructure at the center of the ingot head. It can be seen from the figure that the microstructure is a coarse lamellar structure with uniform lamellar tissue size and no obvious segregation.

[0060] Comparative Example 1 Ti175 was selected as the comparative example. The difference between this comparative example and Example 1 is that the charging method uses the conventional three-layer charging (the middle layer is not stratified).

[0061] The raw materials selected are the same as those in Example 1. 0a grade titanium sponge with a particle size of 3 mm - 12.7 mm was selected; AlMo65 master alloy with a particle size ≤ 6 mm; AlW50 master alloy with a particle size of 0.25 mm - 13 mm; TiSn80 master alloy with a thickness < 0.8 mm, a width < 15 mm, and a length < 15 mm; AlSi11 master alloy with a thickness of 0.08 mm - 1.0 mm, a width of 1 mm - 15 mm, and a length of 1 mm - 15 mm; sponge zirconium HZr-1 with a particle size of 1 - 12 mm; aluminum beans with a particle size of 3 - 15 mm of Al99.70; TiO2 powder with a particle size not less than 160 mesh.

[0062] The charging method is three-layer charging. The bottom layer is a mixture of titanium sponge, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans; the middle layer is a mixture of titanium sponge, AlW50 master alloy, AlMo65 master alloy, and TiO2 powder; the top layer is a mixture of titanium sponge, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans. (The mass ratio of titanium sponge in the top layer, middle layer, and bottom layer is 1:1:1, the mass ratio of TiSn80 master alloy in the top layer and bottom layer is 1:1, the mass ratio of AlSi11 master alloy in the top layer and bottom layer is 1:1, the mass ratio of HZr-1 sponge zirconium in the top layer and bottom layer is 1:1, and the mass ratio of Al99.70 aluminum beans in the top layer and bottom layer is 1:1) After charging, it was pressed by a hydraulic press to a density of 3.4 - 3.65 g / cm 3Single-piece electrode.

[0063] The electrode blocks are stacked and welded into a consumable electrode using a vacuum plasma welding box.

[0064] The consumable electrode is melted into an ingot through three times of vacuum consumable arc melting, cooled, inspected for flaws, and the riser is removed to obtain the finished ingot.

[0065] The finished melting process is the same as that in Example 1.

[0066] For the Ti175 titanium alloy ingot with a specification of Φ720mm obtained in the comparative example, after removing the riser, nine samples are taken at the center of the cross-section of the ingot head, 1 / 2R, and the edge. The sampling positions are as Figure 1 shown, and the samples are subjected to composition detection. The results are shown in Table 3.

[0067] Table 3 Content of partial elements in the cross-section of the Ti175 ingot head (wt%)

[0068] The longitudinal chemical composition of the Ti175 ingot is detected. The results are shown in Table 4.

[0069] Table 4 Longitudinal chemical composition of the Ti175 ingot (wt%)

[0070] It can be seen from Table 3 and Table 4 that the longitudinal composition of the Ti175 titanium alloy ingot obtained in this example meets the standard requirements, but compared with Example 1, the uniformity of W and Mo components is poor, and other elements are equivalent to those in Example 1. The test results of sampling at 9 points on the cross-section of the ingot head show that the range of Al is controlled within 0.4%, the range of Mo is 0.41%, the range of W is 0.14%, and the range of other elements is controlled within 0.25%. The results of the longitudinal chemical composition show that there are obvious distribution gradients of W and Mo elements in the longitudinal direction. Figure 4 It is the micro-structure at the center of the ingot head. It can be seen from the figure that there is a small amount of thick lamellar structure locally, but the segregation is not serious.

[0071] Comparative Example 2 Ti175 is selected as Comparative Example 2, and the feeding method is the same as that in Example 1. The difference from Example 1 is that the finished melting process is changed.

[0072] The raw materials selected are the same as those in Example 1, and the feeding method is the same as that in Example 1. The intermediate layer is fed in three layers, and the proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 40%, 35%, and 25% of the addition amounts in turn.

[0073] After feeding, it is pressed into a single-piece electrode with a density of 3.4~3.65g / cm 3 by a hydraulic press.

[0074] The electrode blocks are stacked and welded into a consumable electrode by using a vacuum plasma welding box.

[0075] The consumable electrode is melted into an ingot through three times of vacuum consumable arc melting, cooled, inspected for flaws, and the riser is removed to obtain a finished ingot. In the final feeding stage of the finished product, feeding starts when the remaining mass of the electrode is 220 kg to 260 kg. The finished product is fed by gradually decreasing the current in four stages. In the first stage, the melting current is 10 KA to 24 KA, the feeding voltage is 28 V to 34 V, and the feeding time is 15 min to 30 min. In the second stage, the melting current is 8 KA to 10 KA, the feeding voltage is 24 V to 28 V, and the feeding time is 10 min to 20 min. In the third stage, the melting current is 5 KA to 8 KA, the feeding voltage is 24 V, and the feeding time is 60 min to 100 min. In the fourth stage, the melting current is 2 KA to 5 KA, the feeding voltage is 24 V, and the feeding time is ≥30 min.

[0076] The process parameters of the finished product melting are as follows: the melting current of the finished product melting is 25 KA to 28 KA, the voltage is 32 V to 35 V, the arc stabilizing stirring current is 10 A to 14 A AC, the commutation time is 6 s to 8 s, and the water inlet temperature is 25 °C to 28 °C.

[0077] For the Ti175 titanium alloy ingot with a specification of Φ720 mm obtained in the comparative example, after removing the riser, nine samples are taken at the center of the cross-section of the head of the ingot, 1 / 2R, and the edge. The sampling positions are as Figure 1 shown, and the components of the samples are detected. The results are shown in Table 5.

[0078] Table 5 Content of some elements in the cross-section of the head of the Ti175 ingot (wt%)

[0079] The longitudinal chemical components of the Ti175 ingot are detected. The results are shown in Table 6.

[0080] Table 6 Longitudinal chemical components of the Ti175 ingot (wt%)

[0081] It can be seen from Table 5 and Table 6 that the longitudinal components of the Ti175 titanium alloy ingot obtained in this example meet the standard requirements, but the uniformity is poor compared with that of Example 1. The test results of sampling at nine points on the cross-section of the head show that the range of Al is controlled within 0.6%, and the ranges of other elements are controlled within 0.3%. The ranges of elements such as Al and Si are larger than those in Example 1. There is no obvious distribution gradient of elements such as Mo and W longitudinally. Generally speaking, the uniformity of the components of Al and Si elements is slightly worse than that in Example 1. Figure 5It is the microstructure at the center of the ingot head. It can be seen from the figure that there are obvious thick lamellar structures locally and obvious segregation exists.

[0082] The above are only the preferred embodiments of the present invention and do not impose any formal restrictions on the present invention. Therefore, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a Ti175 high-temperature titanium alloy ingot, characterized in that, The following steps are involved: S1. According to the target element content of Ti175 high temperature titanium alloy, the raw materials are mixed, laid, and then pressed into electrode blocks; The fabric is a multi-layer fabric, including a bottom layer, a middle layer and an upper layer; The middle layer is divided into three layers, namely, middle layer 1, middle layer 2 and middle layer 3 from top to bottom, each layer is a mixture of sponge titanium, AlW50 master alloy, AlMo65 master alloy and TiO2 powder; the proportions of AlW50 master alloy and AlMo65 master alloy from top to bottom are 38-42%, 33-37.5% and 22-28% of the addition amount respectively, totaling 100%; S2. Stack and weld multiple electrode blocks into consumable electrodes, and then melt them into Ti175 high-temperature titanium alloy ingots through vacuum consumable arc melting.

2. The preparation method according to claim 1, characterized in that, The S1 raw materials are 0a grade titanium sponge with a particle size of 3mm~12.7mm, AlMo65 master alloy, AlW50 master alloy, TiSn80 master alloy, AlSi11 master alloy, zirconium sponge, aluminum beans and TiO2 powder.

3. The preparation method according to claim 1 or 2, characterized in that, The bottom layer is a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans; the top layer is a mixture of sponge titanium, TiSn80 master alloy, AlSi11 master alloy, HZr-1 sponge zirconium, and Al99.70 aluminum beans.

4. The preparation method according to claim 1 or 2, characterized in that, In the middle layer 1, middle layer 2 and middle layer 3, the proportions of AlW50 master alloy and AlMo65 master alloy are 40%, 35% and 25% of the addition amount respectively from top to bottom.

5. The preparation method according to claim 1 or 2, characterized in that, The density of the electrode block described in S1 is 3.4~3.65 g / cm 3 .

6. The preparation method according to claim 1 or 2, characterized in that, The S2 smelting current is 23KA~25KA, the voltage is 32V~35V, the arc stabilization stirring current is AC 10A~14A, the switching time is 8s~12s, and the cooling water inlet temperature of the smelting furnace cooling tower is 22℃~25℃.

7. The preparation method according to claim 1 or 2, characterized in that, S2 undergoes three vacuum consumable arc meltings and enters the feeding stage when the weight of the remaining consumable electrode after the third vacuum consumable arc melting is 260 kg to 350 kg.

8. The preparation method according to claim 7, characterized in that, The compensation adopts step-by-step current reduction compensation, which is divided into four stages: the first stage has a melting current of 10KA~24KA, a compensation voltage of 28V~34V, and a compensation time of 15min~30min; the second stage has a melting current of 8KA~10KA, a compensation voltage of 24V~28V, and a compensation time of 10min~20min; the third stage has a melting current of 5KA~8KA, a compensation voltage of 24V, and a compensation time of 60min~100min; the fourth stage has a melting current of 2KA~5KA, a compensation voltage of 24V, and a compensation time of ≥30min.

9. The preparation method according to claim 1 or 2, characterized in that, The specification of the Ti175 high temperature titanium alloy ingot is Φ680~Φ780mm.

10. A Ti175 high-temperature titanium alloy ingot, characterized in that, The method is prepared by any one of claims 1 to 9.

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