Preparation method and product of titanium alloy ingot

Abstract

The present invention discloses a method for preparing a titanium alloy ingot and a product thereof, which can produce a large-scale Ti1350 titanium alloy ingot with a diameter of 500 mm to 780 mm and uniform chemical composition, and is suitable for industrial production. The method comprises: (1) selecting a small-grained binary alloy as raw material; (2) preparing an electrode block: using an automatic mixing machine and a large-tonnage vertical hydraulic press to press the electrode block; (3) welding an electrode: stacking a plurality of electrode blocks and welding them in a vacuum plasma welding box with argon protection to obtain a consumable electrode; (4) performing a primary smelting: welding the consumable electrode with an auxiliary electrode of the same brand in a vacuum consumable furnace and smelting the consumable electrode; (5) performing a secondary smelting: turning the ingot after the primary smelting into a furnace, welding the auxiliary electrode, and then performing a secondary smelting; (6) performing a tertiary smelting: turning the ingot after the secondary smelting into a furnace, welding the auxiliary electrode, and then performing a third smelting; and (7) machining and cutting off the riser to obtain a finished ingot.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium alloy material processing, and in particular to a method for preparing a titanium alloy ingot, and a product manufactured according to the method for preparing the titanium alloy ingot. Background Art

[0002] Ti1350 is an ultra-high-strength titanium alloy with a room temperature tensile strength of ≥1300MPa. It has the characteristics of high structural efficiency and high reliability and can be used to make various important load-bearing structural parts in aircraft landing gear, fuselage, and wings.

[0003] Ti1350 is a β-type titanium alloy containing 7 kinds of alloying elements, about 19%, of which about 7% is Mo and about 3% is Cr. The density of Mo is 10.2g / cm 3 , much higher than the titanium matrix density of 4.5g / cm 3 Therefore, in the molten state, under the influence of gravity, Mo tends to concentrate in the lower layer of the molten pool, and this concentration increases as the pool deepens. Furthermore, during vacuum consumable arc melting, the electrode melts slowly from bottom to top, resulting in a prolonged molten pool existence. The solid-liquid interface slowly migrates along the crucible from bottom to top and from the edges to the core. This long molten pool existence and slow solidification rate leave ample room for Mo to sink due to gravity. Consequently, the gravity-segregated Mo content in ingots melted by conventional methods is often lower at the top and higher at the bottom. This alloying inhomogeneity often leads to serious defects such as the formation of β-spots or compositions exceeding standard specifications. Cr, with an equilibrium concentration distribution coefficient k = 0.56, is a typical positively segregating element. During alloy solidification, it concentrates at the solid / liquid interface front. Therefore, its macroscopic segregation is significantly affected by the depth of the molten pool. The deeper the molten pool, the longer the grain solidification distance, and the more severe the diffusion segregation, forming β-spots that are detrimental to the alloy's plasticity and fracture toughness, thus failing to meet service requirements. The larger the size of the ingot, the larger and deeper the molten pool of vacuum consumable melting will be, the more difficult it will be to suppress the inclusion of high-melting-point elements and the segregation of eutectoid elements, and the more difficult it will be to control the uniformity of the ingot composition. Summary of the Invention

[0004] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a method for preparing titanium alloy ingots, which can produce large-sized Ti1350 titanium alloy ingots with a diameter specification of Φ500mm~Φ780mm and uniform chemical composition, which is suitable for industrial production.

[0005] The technical solution of the present invention is: a method for preparing a titanium alloy ingot, which comprises the following steps:

[0006] (1) Raw material selection: Select sponge titanium, Al-85Mo master alloy, Al-70Cr master alloy, Al-85V master alloy, Al-75Nb master alloy, Ti-80Sn master alloy,

[0007] Al beans and sponge Zr are used as raw materials, among which the particle sizes of Al-85Mo, Al-85V and Al-75Nb master alloys are controlled at ≤0.8mm, ≤3.0mm and ≤1.2mm respectively, and the maximum particle size of other master alloys is ≤12mm;

[0008] (2) Electrode block preparation: Electrode blocks are pressed using an automatic mixing machine and a large-tonnage vertical hydraulic press. The pressing of each electrode block includes the following steps:

[0009] (2.1) Add a certain amount of titanium sponge to the bottom of the hydraulic press mold cavity and level it;

[0010] (2.2) Mix half the weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press;

[0011] (2.3) Mix the other half weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press;

[0012] (2.4) Start the large-tonnage hydraulic press to complete the pressing of a single electrode block;

[0013] (3) Electrode welding: Multiple electrode blocks are stacked and welded using a vacuum plasma welding box with argon protection to obtain a consumable electrode;

[0014] (4) Primary smelting: The consumable electrode is welded with the auxiliary electrode of the same brand in a vacuum consumable furnace, and then smelted. The smelting current is 9-14KA, the smelting voltage is 29-35V, the arc stabilization current is DC 6A-10A, the vacuum degree is controlled ≤10.0Pa during the smelting process, and the cooling time after smelting is ≥4 hours;

[0015] (5) Secondary smelting: After the first smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the second smelting is carried out. The smelting current is 13-18KA, the smelting voltage is 29-36V, the arc stabilization current is AC (10A-15)A / (6-10)s, the vacuum degree is controlled to be ≤5.0Pa during the smelting process, and the cooling time after smelting is greater than 5 hours;

[0016] (6) Tertiary smelting: After the secondary smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the third smelting is carried out. The smelting current is 9-14KA, the smelting voltage is 24-36V, the arc stabilization current is (7A-17)A / (4-8)s, the vacuum degree is controlled to be ≤2.0Pa during the smelting process, and the cooling time after smelting is greater than 7 hours;

[0017] (7) The smelted ingot is machined and the riser is removed to obtain the finished ingot.

[0018] Compared with the prior art, the invention has the following innovative features and beneficial effects:

[0019] 1. Since the density of Al-80Mo is 6.81g / cm 3 , the density of Al-85V is 5.14g / cm 3 , the density of Al-75Nb is 5.55g / cm 3 , which is much different from the density of titanium matrix (4.3g / cm 3 ), so in the molten state, these master alloy particles will sink in the titanium solution, and there is a risk of gravity segregation and high-density inclusions due to excessively fast sinking speed. Therefore, controlling the particle size of the high-density master alloy can effectively prevent gravity segregation and high-density inclusions.

[0020] 2. When pressing the electrode block, each time the material is laid, the alloy with higher density will be deposited at the bottom of the hydraulic press cavity. By carrying out batch laying and reverse segregation laying on a single electrode, the alloy segregation problem can be improved. At the same time, a layer of sponge titanium is laid at the bottom of the hydraulic press cavity to prevent the fine-grained intermediate alloy containing the Mo element from falling to the bottom of the cavity through the gaps during pressing, causing Mo element loss or Mo element enrichment, making Mo element composition control more difficult. At the same time, the sponge titanium layer at the bottom of the electrode block acts as a buffer zone for the gravity sinking of gravity segregated elements during the titanium alloy vacuum consumable arc melting process, reducing the tendency of gravity segregated elements to enrich at the bottom of the molten pool.

[0021] 3. Rationally design the smelting process parameters to reduce the depth of the molten pool during the smelting of large-sized ingots. Since the smelting current and voltage are positively correlated with the molten pool depth, an excessively high smelting current will cause the molten pool to be too deep, the diffusion and segregation of metal elements will be aggravated, and columnar crystals will tend to develop radially; however, an excessively low smelting current will lead to an imperfect molten pool, deteriorating the surface quality of the ingot, and may also cause insufficient alloying. Therefore, lower smelting currents and smelting voltages are used in the first, second, and third smelting to reduce the depth of the molten pool, narrow the supercooling zone at the solidification front of the molten pool, and suppress the diffusion and segregation of the Cr element. At the same time, the reduction in the molten pool depth also reduces the descending distance of the Mo element in the titanium matrix solution, suppressing the gravity segregation of the Mo element. At the same time, the use of a U-turn charging method in the second and third smelting can further homogenize the Mo element.

[0022] Also provided is a titanium alloy ingot manufactured by the method for preparing the titanium alloy ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of longitudinal sampling of ingot.

[0024] Figure 2 Schematic diagram of nine-point transverse sampling of ingot.

[0025] Figure 3 The figure is a flow chart of a method for preparing a titanium alloy ingot according to the present invention. DETAILED DESCRIPTION

[0026] like Figure 3 As shown, a method for preparing a Ti1350 titanium alloy ingot comprises the following steps:

[0027] (1) Raw material selection: Select sponge titanium, Al-85Mo master alloy, Al-70Cr master alloy, Al-85V master alloy, Al-75Nb master alloy, Ti-80Sn master alloy, Al bean, and sponge Zr with qualified composition as raw materials. The particle sizes of Al-85Mo, Al-85V, and Al-75Nb master alloys are controlled to ≤0.8 mm, ≤3.0 mm, and ≤1.2 mm, respectively. The maximum particle size of other master alloys is ≤12 mm.

[0028] (2) Electrode block preparation: Electrode blocks are pressed using an automatic mixing machine and a large-tonnage vertical hydraulic press. The pressing of each electrode block includes the following steps:

[0029] (2.1) Add a certain amount of titanium sponge to the bottom of the hydraulic press mold cavity and level it;

[0030] (2.2) Mix half the weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press;

[0031] (2.3) Mix the other half weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press;

[0032] (2.4) Start the large-tonnage hydraulic press to complete the pressing of a single electrode block;

[0033] (3) Electrode welding: Multiple electrode blocks are stacked and welded using a vacuum plasma welding box with argon protection to obtain a consumable electrode;

[0034] (4) Primary smelting: The consumable electrode is welded with the auxiliary electrode of the same brand in a vacuum consumable furnace, and then smelted. The smelting current is 9-14KA, the smelting voltage is 29-35V, the arc stabilization current is DC 6A-10A, the vacuum degree is controlled ≤10.0Pa during the smelting process, and the cooling time after smelting is ≥4 hours;

[0035] (5) Secondary smelting: After the first smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the second smelting is carried out. The smelting current is 13-18KA, the smelting voltage is 29-36V, and the arc stabilization current is AC (10A-15)A / (6-10)s. The vacuum degree is controlled during the smelting process.

[0036] ≤5.0Pa, cooling time after smelting is greater than 5 hours;

[0037] (6) Tertiary smelting: After the secondary smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the third smelting is carried out. The smelting current is 9-14KA, the smelting voltage is 24-36V, the arc stabilization current is (7A-17)A / (4-8)s, the vacuum degree is controlled to be ≤2.0Pa during the smelting process, and the cooling time after smelting is greater than 7 hours;

[0038] (7) The smelted ingot is machined and the riser is removed to obtain the finished ingot.

[0039] Compared with the prior art, the invention has the following innovative features and beneficial effects:

[0040] 1. Since the density of Al-80Mo is 6.81g / cm 3 , the density of Al-85V is 5.14g / cm 3 , the density of Al-75Nb is 5.55g / cm 3 , which is much different from the density of titanium matrix (4.3g / cm 3 ), so in the molten state, these master alloy particles will sink in the titanium solution, and there is a risk of gravity segregation and high-density inclusions due to excessively fast sinking speed. Therefore, controlling the particle size of the high-density master alloy can effectively prevent gravity segregation and high-density inclusions.

[0041] 2. When pressing the electrode block, each time the material is laid, the alloy with higher density will be deposited at the bottom of the hydraulic press cavity. By carrying out batch laying and reverse segregation laying on a single electrode, the alloy segregation problem can be improved. At the same time, a layer of sponge titanium is laid at the bottom of the hydraulic press cavity to prevent the fine-grained intermediate alloy containing the Mo element from falling to the bottom of the cavity through the gaps during pressing, causing Mo element loss or Mo element enrichment, making Mo element composition control more difficult. At the same time, the sponge titanium layer at the bottom of the electrode block acts as a buffer zone for the gravity sinking of gravity segregated elements during the titanium alloy vacuum consumable arc melting process, reducing the tendency of gravity segregated elements to enrich at the bottom of the molten pool.

[0042] 3. Rationally design the smelting process parameters to reduce the depth of the molten pool during the smelting of large-sized ingots. Since the smelting current and voltage are positively correlated with the molten pool depth, an excessively high smelting current will cause the molten pool to be too deep, the diffusion and segregation of metal elements will be aggravated, and columnar crystals will tend to develop radially; however, an excessively low smelting current will lead to an imperfect molten pool, deteriorating the surface quality of the ingot, and may also cause insufficient alloying. Therefore, lower smelting currents and smelting voltages are used in the first, second, and third smelting to reduce the depth of the molten pool, narrow the supercooling zone at the solidification front of the molten pool, and suppress the diffusion and segregation of the Cr element. At the same time, the reduction in the molten pool depth also reduces the descending distance of the Mo element in the titanium matrix solution, suppressing the gravity segregation of the Mo element. At the same time, the use of a U-turn charging method in the second and third smelting can further homogenize the Mo element.

[0043] Preferably, in the step (2.1), 2 kg of sponge titanium is added to the bottom of the hydraulic press cavity and flattened; in the step (3), a consumable electrode with a diameter of Φ420 mm is obtained; in the step (4), the first smelting is carried out in a crucible with a diameter of Φ500 mm, the smelting current is 10 KA, the smelting voltage is 30 V, and the arc stabilization current is DC 7 A; in the step (5), the second smelting is carried out in a crucible with a diameter of Φ580 mm, the smelting current is 14 KA, the smelting voltage is 32 V, and the arc stabilization current is AC 12 A / 8 s; in the step (6), the third smelting is carried out in a crucible with a diameter of Φ680 mm, the smelting current is 12 KA, the smelting voltage is 26 V, and the arc stabilization current is 9 A / 6 s; in the step (7), the smelted ingot is machined and the riser is removed to obtain a Ti1350 finished ingot with a diameter of Φ680 mm.

[0044] Preferably, in the step (2.1), 4 kg of sponge titanium is added to the bottom of the hydraulic press cavity and flattened; in the step (3), a consumable electrode with a diameter of Φ480 mm is obtained; in the step (4), the first smelting is carried out in a crucible with a diameter of Φ580 mm, the smelting current is 12 KA, the smelting voltage is 32 V, and the arc stabilization current is DC 9 A; in the step (5), the second smelting is carried out in a crucible with a diameter of Φ680 mm, the smelting current is 16 KA, the smelting voltage is 34 V, and the arc stabilization current is AC 14 A / 9 s; in the step (6), the third smelting is carried out in a crucible with a diameter of Φ780 mm, the smelting current is 13 KA, the smelting voltage is 28 V, and the arc stabilization current is 12 A / 7 s; in the step (7), the smelted ingot is machined, the riser is removed, and the diameter of the Ti1350 finished ingot is obtained.

[0045] Also provided is a Ti1350 titanium alloy ingot manufactured by the preparation method of the titanium alloy ingot.

[0046] The specific embodiments of the present invention are described in detail below.

[0047] Implementation Case 1: Φ680mm (weight 3-5 tons) ingot

[0048] 1. Raw Material Selection: Select qualified raw materials including titanium sponge, Al-85Mo master alloy, Al-70Cr master alloy, Al-85V master alloy, Al-75Nb master alloy, Ti-80Sn master alloy, Al-bean, and Zr sponge. The particle sizes of Al-85Mo, Al-85V, and Al-75Nb master alloys should be controlled to ≤0.8mm, ≤3.0mm, and ≤1.2mm, respectively. The maximum particle size of other master alloys should not exceed 12mm.

[0049] 2. Preparation of electrode blocks: Electrode blocks with a diameter of Φ420mm are pressed using an automatic mixing and large-tonnage vertical hydraulic press. The pressing of each electrode block includes the following four steps: 1) Add 2kg of sponge titanium to the bottom of the hydraulic press cavity and flatten it; 2) Mix half the weight of the sponge titanium and the intermediate alloy in a mixer and add them to the hydraulic press cavity; 3) Mix the other half the weight of the sponge titanium and the intermediate alloy in a mixer and add them to the hydraulic press cavity; 4) Start the large-tonnage hydraulic press to complete the pressing of a single electrode block.

[0050] 3. Electrode welding: Multiple electrode blocks are stacked and welded using a vacuum plasma welding box with argon protection to obtain a consumable electrode with a diameter of Φ420 mm.

[0051] 4. Primary smelting: The consumable electrode is welded with the auxiliary electrode of the same brand in a vacuum consumable furnace, and then the first smelting is carried out in a crucible with a diameter of Φ500mm. The smelting current is 10KA, the smelting voltage is 30V, the arc stabilization current is DC 7A, and the vacuum degree is controlled at ≤10.0Pa during the smelting process. The cooling time after smelting is not less than 4 hours.

[0052] 5. Secondary Melting: The ingot with a diameter of Φ500mm obtained after the primary melting is flattened at the head, turned around (with the head at the bottom and the bottom at the top), and loaded into the furnace for a second melting in a crucible with a diameter of Φ580mm. The melting current is 14kA, the melting voltage is 32V, and the arc stabilization current is AC 12A / 8s. The vacuum degree is controlled at ≤5.0Pa during the melting process, and the cooling time after melting is greater than 5 hours.

[0053] 6. Tertiary Melting: The Φ580mm diameter ingot obtained after the secondary melting is turned upside down (with the head at the bottom and the bottom at the top) and loaded into the furnace for the third melting in a crucible with a diameter of Φ680mm. The melting current is 12kA, the melting voltage is 26V, the arc stabilization current is 9A / 6s, and the vacuum is controlled at ≤2.0Pa during the melting process. The cooling time after melting is greater than 7 hours.

[0054] 7. The smelted ingot is machined and the riser is removed to obtain a Ti1350 finished ingot with a diameter of Φ680 mm.

[0055] Case study 2: Φ780mm (weight 5-7 tons) ingot

[0056] 1. Raw Material Selection: Select qualified raw materials including titanium sponge, Al-85Mo master alloy, Al-70Cr master alloy, Al-85V master alloy, Al-75Nb master alloy, Ti-80Sn master alloy, Al-bean, and Zr sponge. The particle sizes of Al-85Mo, Al-85V, and Al-75Nb master alloys should be controlled to ≤0.8mm, ≤3.0mm, and ≤1.2mm, respectively. The maximum particle size of other master alloys should not exceed 12mm.

[0057] 2. Preparation of electrode blocks: Electrode blocks with a diameter of Φ480mm are pressed using an automatic mixing and large-tonnage vertical hydraulic press. The pressing of each electrode block includes the following four steps: 1) 4kg of sponge titanium is added to the bottom of the hydraulic press cavity and leveled; 2) A mixer is used to mix half the weight of the sponge titanium and the intermediate alloy, and then add the mixture to the hydraulic press cavity; 3) A mixer is used to mix the other half the weight of the sponge titanium and the intermediate alloy, and then add the mixture to the hydraulic press cavity; 4) The large-tonnage hydraulic press is started to complete the pressing of a single electrode block.

[0058] 3. Electrode welding: Multiple electrode blocks are stacked and welded using a vacuum plasma welding box with argon protection to obtain a consumable electrode with a diameter of Φ480mm.

[0059] 4. Primary smelting: The consumable electrode is welded with the auxiliary electrode of the same brand in a vacuum consumable furnace, and then smelted for the first time in a crucible with a diameter of Φ580mm. The smelting current is 12KA, the smelting voltage is 32V, the arc stabilization current is DC 9A, and the vacuum degree is controlled at ≤10.0Pa during the smelting process. The cooling time after smelting is not less than 4 hours.

[0060] 5. Secondary Melting: The ingot with a diameter of Φ580mm obtained after the primary melting is flattened, turned around (with the head at the bottom and the bottom at the top) and loaded into the furnace for the second melting in a crucible with a diameter of Φ680mm. The melting current is 16kA, the melting voltage is 34V, the arc stabilization current is AC 14A / 9s, the vacuum degree is controlled at ≤5.0Pa during the melting process, and the cooling time after melting is greater than 5 hours.

[0061] 6. Tertiary Melting: The Φ680mm diameter ingot obtained after the secondary melting is turned upside down (with the head at the bottom and the bottom at the top) and loaded into the furnace for the third melting in a crucible with a diameter of Φ780mm. The melting current is 13kA, the melting voltage is 28V, the arc stabilization current is 12A / 7s, and the vacuum is controlled at ≤2.0Pa during the melting process. The cooling time after melting is greater than 7 hours.

[0062] 7. The smelted ingot is machined and the riser is removed to obtain a Ti1350 finished ingot with a diameter of Φ780 mm.

[0063] Finished ingot reference Figure 1 and Figure 2 Sampling was performed for chemical composition analysis. The chemical composition of the main elements in the longitudinal direction of the ingot is shown in Table 1. The chemical composition test results of each element at nine points in the transverse direction of the ingot are shown in Tables 2 to 8 respectively. The composition of the ingot is uniform and fully meets the standard requirements.

[0064] Table 1 Chemical composition of main elements in the longitudinal direction of ingot (mass fraction %)

[0065]

[0066] Table 2 Al element content at nine transverse points of ingot (mass fraction %)

[0067]

[0068] Table 3 Mo element content at nine points in the transverse direction of the ingot (mass fraction %)

[0069]

[0070] Table 4 V element content at nine transverse points of ingot (mass fraction %)

[0071]

[0072]

[0073] Table 5 Nb element content at nine transverse points of ingot (mass fraction %)

[0074]

[0075] Table 6 Cr element content at nine transverse points of ingot (mass fraction %)

[0076]

[0077] Table 7 Zr element content at nine transverse points of ingot (mass fraction %)

[0078]

[0079]

[0080] Table 8 Sn element content at nine transverse points of ingot (mass fraction %)

[0081]

[0082] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a titanium alloy ingot, characterized in that: It includes the following steps: (1) Raw material selection: Select sponge titanium, Al-85Mo master alloy, Al-70Cr master alloy, Al-85V master alloy, Al-75Nb master alloy, Ti-80Sn master alloy, Al bean, and sponge Zr with qualified composition as raw materials. The particle sizes of Al-85Mo, Al-85V, and Al-75Nb master alloys are controlled to ≤0.8 mm, ≤3.0 mm, and ≤1.2 mm, respectively. The maximum particle size of other master alloys is ≤12 mm. (2) Electrode block preparation: Electrode blocks are pressed using an automatic mixing machine and a large-tonnage vertical hydraulic press. The pressing of each electrode block includes the following steps: (2.1) Add a certain amount of titanium sponge to the bottom of the hydraulic press mold cavity and level it; (2.2) Mix half the weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press; (2.3) Mix the other half weight of titanium sponge and master alloy in a mixer and pour into the mold cavity of the hydraulic press; (2.4) Start the large-tonnage hydraulic press to complete the pressing of a single electrode block; (3) Electrode welding: Multiple electrode blocks are stacked and welded using a vacuum plasma welding box with argon protection to obtain a consumable electrode; (4) Primary smelting: The consumable electrode is welded with the auxiliary electrode of the same brand in a vacuum consumable furnace, and then smelted. The smelting current is 9-14KA, the smelting voltage is 29-35V, the arc stabilization current is DC 6A-10A, the vacuum degree is controlled ≤10.0Pa during the smelting process, and the cooling time after smelting is ≥4 hours; (5) Secondary smelting: After the first smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the second smelting is carried out. The smelting current is 13-18KA, the smelting voltage is 29-36V, the arc stabilization current is AC (10A-15)A / (6-10)s, the vacuum degree is controlled to be ≤5.0Pa during the smelting process, and the cooling time after smelting is greater than 5 hours; (6) Tertiary smelting: After the secondary smelting, the ingot is turned over and loaded into the furnace. After auxiliary electrode welding, the third smelting is carried out. The smelting current is 9-14KA, the smelting voltage is 24-36V, the arc stabilization current is (7A-17)A / (4-8)s, the vacuum degree is controlled to be ≤2.0Pa during the smelting process, and the cooling time after smelting is greater than 7 hours; (7) The smelted ingot is machined and the riser is removed to obtain the finished ingot.

2. The method for preparing a titanium alloy ingot according to claim 1, wherein: In the step (2.1), 2 kg of sponge titanium is added to the bottom of the hydraulic press cavity and flattened; in the step (3), a consumable electrode with a diameter of Φ420 mm is obtained; in the step (4), the first smelting is carried out in a crucible with a diameter of Φ500 mm, the smelting current is 10 KA, the smelting voltage is 30 V, and the arc stabilization current is DC 7 A; in the step (5), the second smelting is carried out in a crucible with a diameter of Φ580 mm, the smelting current is 14 KA, the smelting voltage is 32 V, and the arc stabilization current is AC 12 A / 8 s; in the step (6), the third smelting is carried out in a crucible with a diameter of Φ680 mm, the smelting current is 12 KA, the smelting voltage is 26 V, and the arc stabilization current is 9 A / 6 s; in the step (7), the smelted ingot is machined, the riser is removed, and the diameter of the finished ingot is Φ680 mm to obtain a finished ingot.

3. The method for preparing a titanium alloy ingot according to claim 1, wherein: In the step (2.1), 4 kg of sponge titanium is added to the bottom of the hydraulic press cavity and flattened; in the step (3), a consumable electrode with a diameter of Φ480 mm is obtained; in the step (4), the first smelting is carried out in a crucible with a diameter of Φ580 mm, the smelting current is 12 KA, the smelting voltage is 32 V, and the arc stabilization current is DC 9 A; in the step (5), the second smelting is carried out in a crucible with a diameter of Φ680 mm, the smelting current is 16 KA, the smelting voltage is 34 V, and the arc stabilization current is AC 14 A / 9 s; in the step (6), the third smelting is carried out in a crucible with a diameter of Φ780 mm, the smelting current is 13 KA, the smelting voltage is 28 V, and the arc stabilization current is 12 A / 7 s; in the step (7), the smelted ingot is machined, the riser is removed, and the diameter of the finished ingot is Φ780 mm to obtain a finished ingot.

4. A titanium alloy ingot manufactured according to the method for preparing a titanium alloy ingot according to any one of claims 1 to 3.

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