Preparation method of titanium alloy cast ingot containing copper element

Abstract

The invention discloses a preparation method of a titanium alloy cast ingot containing a copper element, and relates to the technical field of smelting. And selecting a titanium-copper intermediate alloy and / or a titanium-copper-aluminum intermediate alloy according to the raw material proportioning value of the copper-containing titanium alloy cast ingot. And uniformly mixing the sponge titanium and the intermediate alloy to prepare the consumable electrode. And the consumable electrode is prepared into a copper-containing titanium alloy cast ingot through vacuum consumable arc melting. On one hand, a titanium-copper intermediate alloy and / or a titanium-copper-aluminum intermediate alloy is selected as an adding mode of a copper element. And on the other hand, inert gas is introduced into the water-cooled copper crucible for vacuum consumable arc melting, so that the reduction of a molten pool is promoted. Under the combined action of the two aspects, the uniformity of the Cu element in the cast ingot is improved, the problem that the titanium alloy cast ingot has the beta spot defect in the hot working process due to copper element segregation is solved, and the application range of the titanium alloy material in the petrochemical industry, the aviation industry, the nuclear power generation industry, the hydrogen storage industry and the military industry is widened.

Description

Technical Field

[0001] The invention relates to the technical field of smelting, and in particular to a method for preparing a titanium alloy ingot containing copper elements. Background Art

[0002] Adding Cu element to titanium alloy material can improve the heat treatment strengthening ability of titanium alloy material, so as to expand the application of titanium alloy material in the fields of petrochemical industry, aviation industry, nuclear power generation, hydrogen storage industry and military industry. In the prior art, vacuum consumable arc melting (VAR) is a commonly used melting method for producing copper-containing titanium alloy materials. In vacuum consumable arc melting, Cu is a volatile element, and it is easy to volatilize and lose Cu element, resulting in Cu element segregation. During the forging process, copper-containing titanium alloy ingots with Cu element segregation are prone to β spot defects. On the one hand, it affects the safety and reliability of titanium alloy materials during use. On the other hand, in order to eliminate the hidden danger of β spot of Cu element in the melting process, it is necessary to increase the amount of ingot sawing, reduce the ingot yield rate, and increase the cost of raw materials. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects in the prior art and provide a method for preparing a titanium alloy ingot containing copper.

[0004] To achieve the above object, the technical solution of the present invention is as follows: A method for preparing a copper-containing titanium alloy ingot comprises the following steps: Selecting a master alloy according to the raw material ratio of the copper-containing titanium alloy ingot; the master alloy includes a titanium-copper master alloy and / or a titanium-copper-aluminum master alloy; The titanium sponge and the master alloy are uniformly mixed to form a raw material to be melted, Pressing the raw material to be melted into an electrode block; splicing the electrode blocks into consumable electrodes, and welding the consumable electrodes; The consumable electrode is subjected to vacuum consumable arc melting; during the vacuum consumable arc melting process, an inert gas is introduced into a water-cooled copper crucible used for vacuum consumable arc melting to prepare a titanium alloy ingot containing copper.

[0005] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the titanium-copper intermediate alloy is a Ti-40Cu alloy, and the titanium-copper-aluminum intermediate alloy is Ti-Cu40-Al40.

[0006] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the step of splicing the electrode blocks into a consumable electrode comprises: The axial cross-section of the electrode block is 1 / 2-1 circle, one or more electrode blocks form a single section of the consumable electrode, and multiple sections of the consumable electrode are spliced ​​into a whole consumable electrode. The consumable electrode is in the shape of a cylinder with a diameter of 400-700 mm.

[0007] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, a single section of the consumable electrode is provided with a recessed portion on one side along the axial direction, and a single section of the consumable electrode is provided with a protruding portion on the other side along the axial direction; the recessed portion of one of the two adjacent consumable electrodes is snap-connected with the protruding portion of the other of the two adjacent consumable electrodes.

[0008] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the step of performing vacuum consumable arc melting on the consumable electrode comprises: The consumable electrode is placed in a water-cooled copper crucible with a diameter of 580-650 mm for a smelting operation to prepare an ingot; and the inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible.

[0009] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the step of performing vacuum consumable arc melting on the consumable electrode further includes: The primary ingot is inverted and placed in a water-cooled copper crucible with a diameter of 650-720 mm for secondary smelting to prepare a titanium alloy ingot containing copper elements; similarly, the inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible.

[0010] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the vacuum degree inside the water-cooled copper crucible is less than 1000 Pa.

[0011] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the inert gas is argon or helium, and the purity of the argon or helium is greater than 99.99%.

[0012] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the gas flow rate of the inert gas is 5-20 L / min, and the pressure is 0.1-0.5 MPa.

[0013] According to the method for preparing a copper-containing titanium alloy ingot provided by an embodiment of the present invention, the step of welding the consumable electrode also includes: 6-10 welds are evenly arranged along the axial circumferential surface of the consumable electrode, each weld has a width of 20-30 mm, and a weld depth greater than 10 mm.

[0014] The advantages and beneficial effects of the present invention are: The preparation method of the titanium alloy ingot containing copper element provided in the present application selects titanium-copper master alloy and / or titanium-copper-aluminum master alloy according to the raw material ratio of the titanium alloy ingot containing copper element, and selects other master alloys. Sponge titanium and master alloy are evenly mixed to prepare consumable electrodes. The consumable electrode is prepared into a titanium alloy ingot containing copper element by vacuum consumable arc melting. On the one hand, by selecting titanium-copper master alloy and / or titanium-copper-aluminum master alloy as the addition method of copper element, the uniformity of Cu element in the titanium alloy ingot containing copper element is improved. On the other hand, by introducing an inert gas into the water-cooled copper crucible used for vacuum consumable arc melting, the inert gas conducts the heat of the ingot and its molten pool to the inner wall of the crucible, promotes the reduction of the molten pool, and improves the uniformity of the Cu element in the ingot. Due to the improvement of the uniformity of the Cu element in the titanium alloy ingot containing copper element, the problem of β spot defects in the titanium alloy ingot due to copper segregation during hot working and the problem of significant decrease in mechanical properties are avoided. In addition, since there is no need to increase the amount of ingot sawing, the ingot yield rate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a schematic flow chart of a method for preparing a copper-containing titanium alloy ingot according to an embodiment of the present invention; Figure 2 It is one of the three-dimensional structural schematic diagrams of a single-section consumable electrode in an embodiment of the present invention; Figure 3 for Figure 2 A schematic diagram of the top view of the single-section consumable electrode; Figure 4 for Figure 2 Schematic diagram of the cross section of a single consumable electrode; Figure 5 This is the second schematic diagram of the three-dimensional structure of a single-section consumable electrode in an embodiment of the present invention; Figure 6 for Figure 5 A schematic diagram of the top view of the single-section consumable electrode; Figure 7 for Figure 5 Schematic diagram of the cross section of a single consumable electrode; Figure 8 It is a schematic diagram of ingot melting; Fig. 9 It is a schematic diagram of the structure of the entire consumable electrode; Fig.10 It is a schematic diagram of the results of sampling and testing at the head, middle and bottom of the ingot; Fig.11 This is a schematic diagram of the results of 9-point sampling inspection on the ingot head radial direction; Fig.12 This is a schematic diagram of the results of radial sampling inspection at 9 points on the bottom of the ingot.

[0016] 1. Single-section consumable electrode; 2. Protrusion; 3. Depression; 4. Weld; 5. Consumable electrode; 6. Ingot; 7. Molten pool; 8. Water-cooled copper crucible. DETAILED DESCRIPTION

[0017] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0018] Figure 1 Schematic diagram of the process for preparing a copper-containing titanium alloy ingot according to an embodiment of the present invention. Figure 1 As shown, the present application provides a method for preparing a copper-containing titanium alloy ingot, comprising the following steps: S1: selecting a master alloy according to the raw material ratio of the copper-containing titanium alloy ingot; the master alloy includes a titanium-copper master alloy and / or a titanium-copper-aluminum master alloy; S2: uniformly mixing titanium sponge and master alloy to form raw materials to be melted; S3: pressing the raw material to be melted into electrode blocks; splicing the electrode blocks into consumable electrodes, and welding the consumable electrodes; S4: performing vacuum consumable arc melting on the consumable electrode; during the vacuum consumable arc melting process, introducing an inert gas into a water-cooled copper crucible used for vacuum consumable arc melting to prepare a titanium alloy ingot containing copper elements.

[0019] The preparation method of the titanium alloy ingot containing copper element provided in the present application selects titanium-copper master alloy and / or titanium-copper-aluminum master alloy according to the raw material ratio of the titanium alloy ingot containing copper element, and selects other master alloys. Sponge titanium and master alloy are evenly mixed to prepare consumable electrodes. The consumable electrode is prepared into a titanium alloy ingot containing copper element by vacuum consumable arc melting. On the one hand, by selecting titanium-copper master alloy and / or titanium-copper-aluminum master alloy as the addition method of copper element, the uniformity of Cu element in the titanium alloy ingot containing copper element is improved. On the other hand, by introducing an inert gas into the water-cooled copper crucible used for vacuum consumable arc melting, the inert gas conducts the heat of the ingot and its molten pool to the inner wall of the crucible, promotes the reduction of the molten pool, and improves the uniformity of the Cu element in the ingot. Due to the improvement of the uniformity of the Cu element in the titanium alloy ingot containing copper element, the problem of β spot defects in the titanium alloy ingot due to copper segregation during hot working and the problem of significant decrease in mechanical properties are avoided. In addition, since there is no need to increase the amount of ingot sawing, the ingot yield rate is improved.

[0020] It should be noted that the copper-containing titanium alloy ingot can be a Ti662 ingot. The mass percentage requirements of each element in the Ti662 ingot are Al: 5.5%-5.9%, V: 5.5%-5.9%, Sn: 2.1%-2.4%, Cu: 0.35%-1.00%, Fe: 0.35%-1.00%, O: 0.15%-0.19%, and the rest are Ti and trace impurity elements. In order to meet the above requirements, since aluminum and tin elements are prone to volatilization loss, and copper and iron elements are prone to segregation, the raw material ratio of the Ti662 titanium alloy ingot is set to Ti-5.8Al-5.75V-2.3Sn-0.50Cu-0.50Fe-0.155O. Specifically, the ratio of aluminum and tin elements is set higher than the median of the required range to compensate for the volatilization loss during the smelting process. The copper element ratio is set to 0.55%, and the iron element ratio is set to 0.5% to improve the segregation characteristics of the copper and iron elements.

[0021] It should also be noted that when titanium-copper master alloy is added, the liquidus temperature of Ti-Cu alloy is 1670-1700℃. The extremely small melting point difference (ΔT≤32℃) between the alloy and the pure titanium matrix (melting point 1668℃) is used to achieve synchronous melting of the alloy and the matrix, avoid element segregation caused by local temperature gradient in the molten pool, and promote uniform distribution of copper elements. When titanium-copper-aluminum master alloy is added, the cross-diffusion of Cu-Al-Ti in the ternary system is used to establish a multi-component synergistic diffusion channel, breaking the diffusion kinetic barrier of the binary alloy, which can also promote uniform distribution of copper elements.

[0022] In some embodiments, the titanium-copper intermediate alloy is Ti-40Cu alloy, and the titanium-copper-aluminum intermediate alloy is Ti-Cu40-Al40. Ti-Cu40-Al40 and / or Ti-40Cu alloy with a particle size of 1-6 mm, sponge titanium, and other intermediate alloys are mixed evenly. Since the particle size of Ti-Cu40-Al40 and / or Ti-40Cu alloy is 1-6 mm, the uniformity of the distribution of the Cu element in the consumable electrode is firstly improved, and further, the consumable electrode is subjected to vacuum consumable arc melting, so that the Cu element in the ingot is alloyed and homogenized, and the problem of β spots generated during the hot working process due to uneven composition of the ingot is solved, and a finished ingot containing the Cu element with stable quality and uniform composition is obtained.

[0023] In some embodiments, the step of splicing electrode blocks into consumable electrodes includes: the axial cross-sectional shape of the electrode block is 1 / 2-1 circle, one or more electrode blocks form a single-section consumable electrode, and multiple sections of consumable electrodes are spliced ​​into a whole consumable electrode, and the shape of the consumable electrode is a cylinder with a diameter of 400-700 mm.

[0024] Since the consumable electrode is a full circle, firstly, the gap between the consumable electrode and the crucible is the same at all places, which can reduce the arc deviation or uneven local discharge, thereby maintaining stable arc combustion and reducing the melting fluctuation caused by the asymmetric shape of the consumable electrode. Secondly, the molten pool formed by the full-circle consumable electrode during melting is more uniform, which is beneficial to reduce the local segregation of alloy elements. For example, the distribution uniformity of elements such as Cu and Fe in titanium alloy ingots can be optimized through symmetrical molten pool flow. Finally, the full-circle consumable electrode makes the heat load of the water-cooled copper crucible evenly distributed, which can extend the service life of the crucible and improve the deformation of the water-cooled copper crucible caused by local overheating.

[0025] For example, an 8000T hydraulic press can be used to press an electrode block with an axial cross-section shape of 1 / 2 circle, reducing the pressure requirements of the hydraulic press. Two electrode blocks are spliced ​​to form a single consumable electrode, and multiple consumable electrodes are spliced ​​to form a whole consumable electrode. The consumable electrode has a diameter of Φ480mm. During the pressing process, the pressure range is 6000-7000T, and the pressure holding time is 10~20s.

[0026] Preferably, the axial cross-section of the electrode block is a full circle. On the one hand, since the electrode block is a full circle electrode block, each pressing area is pressed evenly during the pressing process, and the raw material components of each pressing area are evenly distributed, which improves the uniformity of the distribution of the Cu element in the consumable electrode. On the other hand, since the full circle electrode block alone constitutes a single consumable electrode, the splicing surface of the consumable electrode is reduced, further enhancing the connection strength of the consumable electrode, and preventing the consumable electrode from falling off during the smelting process.

[0027] Figure 2 1 is one of the three-dimensional structural schematic diagrams of a single consumable electrode in an embodiment of the present invention. Figure 3 for Figure 2 Schematic diagram of the top view of the single-section consumable electrode. Figure 4 for Figure 2 Schematic diagram of the cross section of a single consumable electrode. Figure 5 2 is a schematic diagram of the three-dimensional structure of a single consumable electrode in an embodiment of the present invention. Figure 6 for Figure 5 Schematic diagram of the top view of the single-section consumable electrode. Figure 7 for Figure 5 The cross-sectional diagram of a single consumable electrode is shown in Figure 2. Figures 2 to 7 As shown, a single consumable electrode is provided with a recessed portion on one side along the axial direction, and a protruding portion is provided on the other side along the axial direction of the single consumable electrode; the recessed portion of one of two adjacent consumable electrodes is connected by a snap connection with the protruding portion of the other of the two adjacent consumable electrodes.

[0028] During the smelting process of consumable electrodes, electrode blocks often break and fall off, which leads to abnormal smelting. For example, when a block falls off during the smelting process of consumable electrodes, large blocks of electrode blocks fall into the molten pool in the crucible, resulting in uneven mixing of alloy elements in the ingot, defects such as inclusions, and affecting the quality of the ingot. The concave and convex parts of two adjacent consumable electrodes are connected to each other to enhance the connection strength between adjacent electrode blocks, thereby enhancing the connection strength of the entire consumable electrode and preventing the consumable electrode from falling off during the smelting process.

[0029] In some embodiments, the protrusion is a truncated cone, and the recessed portion is a corresponding cylindrical groove. The diameter of the truncated cone is 360-660 mm and the height is 10-20 mm; the corresponding cylindrical groove has a diameter of 360-660 mm, and the groove wall of the cylindrical groove is an annular groove wall with a height of 10-20 mm, so that the recessed portion and the protrusion can be clamped with each other. The size specifications of the protrusion and the recessed portion are limited to determine the clamping strength between the protrusion and the recessed portion. When the axial cross-sectional shape of the electrode block is 1 / 2-1 circle, one or more electrode blocks are spliced ​​to form the protrusion and the recessed portion.

[0030] In some embodiments, the step of performing vacuum consumable arc melting on the consumable electrode includes: The consumable electrode is placed in a water-cooled copper crucible with a diameter of 580-650 mm for a smelting to prepare an ingot. Inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible. The smelting voltage is 30-36V, the smelting current is 10-15KA, the arc stabilization current is 5-12A, and the arc stabilization stirring cycle is 4-8S.

[0031] For example, the consumable electrode to be smelted is placed in a Φ580mm water-cooled copper crucible for vacuum consumable arc smelting to obtain a primary ingot, and the vacuum degree before melting is ≤5Pa. During the smelting process, the smelting voltage is 30~36V, the smelting current is 10~15kA, the arc stabilization current is 5~12A, and the arc stabilization change cycle is 4~8s. By adopting a smelting current of 10-15KA, the melting rate of the consumable electrode is reduced, thereby reducing the depth of the molten pool for a single smelting, increasing the cooling rate of the ingot, preventing the excessive diffusion of copper elements, and avoiding the segregation of copper elements in the ingot. By adopting a 5~12A arc stabilization stirring current and switching the arc stabilization stirring direction every 4~8s, the copper element is promoted to diffuse evenly in the molten pool. After the smelting is completed, the ingot cooling time is not less than 5 hours to avoid oxidation and bluing on the surface of the ingot and ensure the quality of the ingot.

[0032] In some embodiments, the step of performing vacuum consumable arc melting on the consumable electrode further includes: The primary ingot is inverted and placed in a water-cooled copper crucible with a diameter of 650-720 mm for secondary smelting to prepare a titanium alloy ingot containing copper. Similarly, an inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible. The smelting voltage is 30-36 V, the smelting current is 16-20 KA, the arc stabilization current is 8-14 A, and the arc stabilization stirring cycle is 4-8 S.

[0033] Due to the difference in cooling and solidification conditions between the head of the titanium alloy ingot and the middle of the ingot, the alloy elements in the head of the titanium alloy ingot will be segregated compared with the middle of the ingot. The segregation of alloy elements in the head of the ingot can be improved by inverting the primary ingot for secondary smelting.

[0034] For example, the primary ingot is inverted and used as a consumable electrode for secondary smelting, and is placed in a Φ650mm water-cooled copper crucible for secondary vacuum consumable arc melting to obtain a finished ingot. The vacuum before melting is ≤5Pa, the melting voltage is 30~36V, and the melting current is 16~20kA. By selecting a melting current of 16~20kA, the depth of the molten pool can be controlled within the range of 80-120mm. A shallower molten pool can shorten the high-temperature residence time of the liquid metal and reduce the diffusion rate of the copper element into the melt, thereby reducing its enrichment tendency at the solidification front of the ingot. By setting the arc stabilization current to 8-14A and the arc stabilization stirring cycle to 4-8S, the melt convection in the molten pool is enhanced, the diffusion uniformity of the copper element in the molten pool is promoted, and the microsegregation caused by the temperature gradient or the difference in solidification rate is suppressed.

[0035] In some embodiments, during the secondary smelting, the feeding stage lasts for no less than 3 hours; during the feeding stage, the water flow rate of the water-cooled copper crucible inlet and outlet is 80-100 m / s. 3 / h. It should be noted that the secondary smelting includes the smelting stage and the feeding stage. The crucible water inlet flow rate and the crucible water outlet flow rate in the smelting stage are both 80~100m 3 / h, and during the feeding stage, the water flow rate of the water-cooled copper crucible is kept at 80~100m 3 / h, promote the reduction of the molten pool depth and avoid the diffusion and segregation of copper elements. After the smelting is completed, the furnace is filled with argon for cooling. The argon filling pressure is 4000~6000Pa. The ingot cooling time is not less than 6 hours to avoid oxidation and blueing on the ingot surface and ensure the quality of the ingot.

[0036] In some embodiments, the vacuum degree inside the water-cooled copper crucible is less than 1000 Pa.

[0037] In some embodiments, the inert gas is argon or helium, and the purity of the argon or helium is greater than 99.99%.

[0038] In some embodiments, the gas flow rate of the inert gas is 5-20 L / min, and the pressure is 0.1-0.5 MPa.

[0039] like Figure 8 As shown, in the first smelting and the second smelting, an inert gas, such as helium or argon, is introduced into the water-cooled copper crucible. The inert gas is located between the ingot and the inner wall of the water-cooled copper crucible. The inert gas conducts the heat of the ingot and its molten pool to the inner wall of the crucible, promotes the reduction of the molten pool, and quickly cools the ingot, avoiding indirect heat dissipation by the crucible water cooling system alone, and improving the uniformity of the Cu element in the ingot. The inert gas is the cooling gas.

[0040] Specifically, argon or helium with a purity greater than 99.99% can be introduced into the gas nozzle on the side wall of the water-cooled copper crucible, with a gas flow rate of 5-20L / min and a pressure of 0.1-0.5MPa. The gas forms a spiral laminar flow along the inner wall of the crucible, that is, the gas film layer covers the molten pool and the solidification interface, enhancing the convective heat transfer efficiency. The inert gas quickly conducts the radiant heat on the surface of the molten pool and the latent heat of solidification of the ingot to the inner wall of the crucible, thereby increasing the cooling rate at the edge of the molten pool. It should be noted that the vacuum degree in the furnace is less than 1000Pa to avoid the inert gas affecting the arc stability. Multiple gas nozzles can be evenly arranged on the circumferential side wall of the circular water-cooled copper crucible so that inert gas can be introduced into each area inside the water-cooled copper crucible at the same time, thereby improving the uniformity of the distribution of the inert gas in the crucible and evenly conducting the radiant heat on the surface of the molten pool and the latent heat of solidification of the ingot to the inner wall of the crucible.

[0041] The introduction of inert gas has the following beneficial effects: First, the overall cooling rate of the ingot is increased, the solidification time of the titanium liquid is shortened, and the grain size is refined. Secondly, the solute distribution is locked by rapid solidification, and the segregation of alloy elements such as copper is suppressed. Finally, the peak temperature of the thermal cycle of the water-cooled copper crucible is reduced (from 600°C to 450°C), the thermal stress is reduced by 30%-40%, and the service life of the crucible is extended by 2-3 times.

[0042] In some embodiments, the intermediate alloy further comprises aluminum beans, titanium-iron intermediate alloy, titanium-tin intermediate alloy, aluminum-vanadium intermediate alloy, and titanium dioxide. Specifically, aluminum beans with a particle size of 5-11 mm, Ti-32Fe alloy with a particle size of 1-6 mm, Ti-80Sn alloy with a particle size of 2-10 mm, Al-65V alloy with a particle size of 1-6 mm, and powdered titanium dioxide are selected. These intermediate alloys are mixed evenly with 0A grade sponge titanium with a particle size range of 3-12.7 mm and Ti-40Cu alloy with a particle size of 1-6 mm by a mixer, and pressed into electrode blocks with uniform distribution of various intermediate alloys.

[0043] In some embodiments, the step of welding the consumable electrode includes: performing argon filling welding on the consumable electrode through a plasma welding box, the argon filling pressure is 15000-25000Pa, the welding voltage is 60~90V, the welding current is 460~600A, and the cooling time after welding is 30~60min.

[0044] In the plasma welding box, high-frequency current ionizes argon gas to form a plasma arc. The plasma arc has extremely high temperature and energy density, which can reach 10,000-30,000°C. During welding, the plasma arc locally heats the consumable electrode to a molten state. As the plasma arc moves, the melted consumable electrode area gradually cools and solidifies, forming a strong weld. The argon filling pressure is maintained at 15,000-25,000Pa. As an inert gas, argon can form an effective protective gas layer in the welding area, isolating the welding area from oxygen, thereby preventing the consumable electrode from oxidizing during the welding process. This not only ensures the purity and quality of the welding area, but also improves the mechanical properties of the weld and enhances the structural strength of the consumable electrode.

[0045] In the post-weld cooling phase, the cooling time is set to 30-60 minutes. On the one hand, sufficient cooling time can ensure that the weld is fully cooled, so that the metal structure at the weld can be stabilized, avoiding internal stress concentration caused by too fast cooling, thereby reducing the occurrence of welding defects such as cracks, etc., and ensuring welding quality. On the other hand, the cooling time will not be too long, effectively avoiding the reduction of welding efficiency caused by too long cooling time.

[0046] In some embodiments, such as Fig. 9 As shown, the step of welding the consumable electrode also includes: 6-10 welds are evenly arranged along the axial circumferential surface of the consumable electrode, each weld has a width of 20-30 mm, and a weld depth greater than 10 mm.

[0047] 6-10 welds are evenly arranged along the axial circumferential surface of the consumable electrode, which is equivalent to adding multiple reinforcing ribs to the consumable electrode, greatly enhancing the structural strength of the consumable electrode. When the consumable electrode is subjected to various complex external stresses, these evenly distributed welds can effectively disperse the stress, thereby significantly improving the consumable electrode's ability to resist fracture and effectively preventing the consumable electrode from breaking during the smelting process. Specifically, when 6 welds are evenly arranged along the axial circumferential surface of the consumable electrode, a weld is arranged at every 60° angle along the circumference of the consumable electrode; when 10 welds are evenly arranged along the axial circumferential surface of the consumable electrode, a weld is arranged at every 36° angle along the circumference of the consumable electrode.

[0048] A specific embodiment of the present application is described below: Step 1: Determine the raw material ratio according to the mass percentage requirement range of each element in Ti662 ingot. The mass percentage requirement range is Al: 5.5%-5.9%, V: 5.5%-5.9%, Sn: 2.1%-2.4%, Cu: 0.35%-1.00%, Fe: 0.35%-1.00%, O: 0.15%-0.19%, and the rest is Ti and trace impurity elements. The raw material ratio is Ti-5.8Al-5.75V-2.3Sn-0.50Cu-0.50Fe-0.155O.

[0049] Step 2: Select aluminum beans with a particle size of 5-11mm, Ti-32Fe alloy with a particle size of 1-6mm, Ti-80Sn alloy with a particle size of 2-10mm, Al-65V alloy with a particle size of 1-6mm, and powdered titanium dioxide. Mix these master alloys with 0A grade sponge titanium with a particle size range of 3-12.7mm and Ti-40Cu alloy with a particle size of 1-6mm in a mixer for 20-60S.

[0050] Step 3: Use an 8000T hydraulic press to press an electrode block with a specification of Φ480mm (1 / 2 circle), with a pressure range of 6000-7000T and a holding time of 10~20s. Two electrode blocks are spliced ​​to form a single consumable electrode, and multiple consumable electrodes are spliced ​​to form a whole consumable electrode, with a diameter of Φ480mm. The consumable electrode is argon-filled and welded by a plasma welding box, with an argon filling pressure of 15000-25000Pa, a welding voltage of 60~90V, a welding current of 460~600A, and a cooling time after welding of 30~60min. The consumable electrode to be smelted is taken out of the furnace, with each electrode block weighing 46.53kg, a total of 72 electrode blocks, and a whole consumable electrode weighing 3350kg.

[0051] Step 4: Place the consumable electrode to be smelted in a Φ580mm water-cooled copper crucible for vacuum consumable arc smelting to obtain a first smelting ingot, and the vacuum degree before melting is ≤5Pa. During the smelting process, the smelting voltage is 30~36V, the smelting current is 10~15kA, the arc stabilization current is 5~12A AC, the arc stabilization change cycle is 4~8s, and the ingot cooling time after the smelting is not less than 5 hours. Invert the first ingot as a consumable electrode for secondary smelting, and place it in a Φ650mm water-cooled copper crucible for secondary vacuum consumable arc smelting to obtain a finished ingot, the vacuum degree before melting is ≤5Pa, the smelting voltage is 30~36V, and the smelting current is 16~20kA. The arc stabilization current is 8-14A, and the arc stabilization stirring cycle is 4-8S. The shrinkage feeding time is not less than 3 hours, and the high cooling rate water flow of the smelting process is continued during the shrinkage feeding stage, and the crucible water flow is 80~100m 3During the primary and secondary smelting, argon gas with a purity greater than 99.99% is introduced into the water-cooled copper crucible, with a gas flow rate of 5-20L / min and a pressure of 0.1-0.5MPa.

[0052] Step 5: After smelting, the furnace is filled with argon for cooling. The argon filling pressure is 4000~6000Pa, and the ingot cooling time is not less than 6 hours.

[0053] After the ingot is machine-skinned, samples are taken from the head, middle and bottom of the ingot axial direction for testing. The Cu element test results of Ti662 ingot are as follows: Fig.10 The ingot head and bottom were sampled and tested at 9 points in the radial direction (4 points on the circumference, 4 points at 1 / 2R, and 1 point at the center). The Cu element test results of Ti662 ingot are as follows: Fig.11 shown.

[0054] from Fig.10 It can be seen that the extreme difference of Cu element in the axial direction of Ti662 ingot is within 0.003%. Fig.11 and Fig.12 It can be seen that the extreme difference of Cu element in the head and bottom of Ti662 ingot is within 0.02%. Figures 10 to 12 It can be seen that the uniformity of the Cu element in the Ti662 ingot prepared by the method of the present application is good. Figures 10 to 12 All are mass percentages.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a copper-containing titanium alloy ingot, characterized in that: The following steps are involved: Selecting a master alloy according to the raw material ratio of the copper-containing titanium alloy ingot; the master alloy includes a titanium-copper master alloy and / or a titanium-copper-aluminum master alloy; The titanium sponge and the master alloy are uniformly mixed to form a raw material to be melted, Pressing the raw material to be melted into an electrode block; splicing the electrode blocks into consumable electrodes, and welding the consumable electrodes; The consumable electrode is subjected to vacuum consumable arc melting; during the vacuum consumable arc melting process, an inert gas is introduced into a water-cooled copper crucible used for vacuum consumable arc melting to prepare a titanium alloy ingot containing copper.

2. The method for preparing a copper-containing titanium alloy ingot according to claim 1, characterized in that: The titanium-copper master alloy is a Ti-40Cu alloy, and the titanium-copper-aluminum master alloy is a Ti-Cu40-Al40.

3. The method for preparing a copper-containing titanium alloy ingot according to claim 1, characterized in that: The step of splicing the electrode blocks into consumable electrodes comprises: The axial cross-section of the electrode block is 1 / 2-1 circle, one or more electrode blocks form a single section of the consumable electrode, and multiple sections of the consumable electrode are spliced ​​into a whole consumable electrode. The consumable electrode is in the shape of a cylinder with a diameter of 400-700 mm.

4. The method for preparing a copper-containing titanium alloy ingot according to claim 3, characterized in that: A recessed portion is provided on one side of the single-section consumable electrode along the axial direction, and a protruding portion is provided on the other side of the single-section consumable electrode along the axial direction; the recessed portion of one of the two adjacent consumable electrodes is connected to the protruding portion of the other of the two adjacent consumable electrodes by snapping.

5. The method for preparing a copper-containing titanium alloy ingot according to claim 1, characterized in that: The step of performing vacuum consumable arc melting on the consumable electrode comprises: The consumable electrode is placed in a water-cooled copper crucible with a diameter of 580-650 mm for a smelting operation to prepare an ingot; and the inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible.

6. The method for preparing a copper-containing titanium alloy ingot according to claim 5, characterized in that: The step of performing vacuum consumable arc melting on the consumable electrode further includes: The primary ingot is inverted and placed in a water-cooled copper crucible with a diameter of 650-720 mm for secondary smelting to prepare a titanium alloy ingot containing copper elements; similarly, the inert gas is introduced into the water-cooled copper crucible through a gas nozzle at the bottom of the side wall of the water-cooled copper crucible.

7. The method for preparing a copper-containing titanium alloy ingot according to any one of claims 1 to 6, characterized in that: The vacuum degree inside the water-cooled copper crucible is less than 1000Pa.

8. The method for preparing a copper-containing titanium alloy ingot according to any one of claims 1 to 6, characterized in that: The inert gas is argon or helium, and the purity of the argon or helium is greater than 99.99%.

9. The method for preparing a copper-containing titanium alloy ingot according to any one of claims 1 to 6, characterized in that: The gas flow rate of the inert gas is 5-20 L / min, and the pressure is 0.1-0.5 MPa.

10. The method for preparing a copper-containing titanium alloy ingot according to any one of claims 1 to 6, characterized in that: The step of welding the consumable electrode also includes: evenly arranging 6-10 welds along the axial circumferential surface of the consumable electrode, each weld having a width of 20-30 mm and a weld depth greater than 10 mm.

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