Preparation method of Ti65 titanium alloy cast ingot

Abstract

The invention discloses a preparation method of a Ti65 titanium alloy cast ingot, and relates to the technical field of titanium alloys. According to the target component range of the Ti65 titanium alloy cast ingot, the proportion range of each alloy element is determined as follows: 6.0-7.2% of Al; 3.2 to 4.3 percent of Sn; 3.2% to 4.8% of Zr; 0.3% to 0.9% of Mo; 0.25 to 0.45 percent of Si; 0.3% to 0.6% of Nb; 0.7 to 2.3 percent of Ta; 0.4 to 1.1 percent of W; and 0.03 to 0.07 percent of C. The raw materials to be smelted are subjected to primary smelting through the electron beam cold bed furnace, and primary cast ingots are subjected to secondary smelting through the vacuum consumable electrode arc furnace. Alloy elements are preliminarily homogenized and part of impurities are removed by using the high energy density and good refining capacity of the electron beam cold bed furnace, and then the components are further adjusted through the vacuum consumable electric arc furnace, so that the component uniformity of the Ti65 titanium alloy cast ingot is effectively improved, and the quality of the Ti65 titanium alloy cast ingot is improved. The application of the titanium alloy material in the fields of petrochemical industry, aviation industry, nuclear power generation, hydrogen storage industry, military industry and the like is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium alloys, and particularly to a method for preparing a Ti65 titanium alloy ingot. Background Art

[0002] Ti65 is a titanium alloy material with specific composition and performance characteristics. Ti65 has an excellent strength-to-weight ratio, with a tensile strength of up to 800 - 1000 MPa and a yield strength that can also reach 700 - 900 MPa, while maintaining good toughness. This makes it perform excellently in the application of structural components that bear large loads, such as aeroengine components, aircraft landing gears, etc. In a variety of corrosive media, Ti65 exhibits excellent corrosion resistance. Whether in acidic, alkaline, or seawater and other complex environments, a stable oxide film can form on its surface, effectively preventing the corrosive medium from eroding the alloy matrix. Ti65 can also maintain good mechanical properties and chemical stability at relatively high temperatures. Therefore, Ti65 titanium alloy is widely used in fields such as petrochemical industry, aviation industry, nuclear power generation, hydrogen storage industry, and military industry.

[0003] In the prior art, a Ti65 titanium alloy ingot is prepared by vacuum consumable arc melting, and then the Ti65 titanium alloy ingot is processed and applied. On the one hand, due to the huge differences in the densities, volatilization characteristics, and melting points of various alloying elements in the Ti65 titanium alloy ingot, it is difficult for various elements of Ti65 titanium alloy to achieve synchronous melting and uniform distribution within a limited melting time, resulting in segregation of the element composition of Ti65 titanium alloy. On the other hand, compared with other titanium alloy ingots, the addition amount of titanium sponge in the Ti65 titanium alloy ingot is less, while the addition amount of master alloy is more, resulting in insufficient strength of the pressed consumable electrode during the vacuum consumable arc melting process of the Ti65 titanium alloy ingot. Intermediate alloy spillage or block dropping is likely to occur during the melting process, and then inclusions, segregation, or uneven melting of high-melting-point metals occur in the Ti65 titanium alloy ingot, seriously affecting the metallurgical quality of the Ti65 titanium alloy ingot. Summary of the Invention

[0004] The present invention provides a method for preparing a Ti65 titanium alloy ingot to solve the problem that various elements of Ti65 titanium alloy in the prior art are difficult to achieve synchronous melting and uniform distribution within a limited melting time, resulting in segregation of the element composition of Ti65 titanium alloy.

[0005] The present invention provides a method for preparing a Ti65 titanium alloy ingot, comprising the following steps: According to the target composition range of Ti65 titanium alloy ingot, the ratio of each alloy element is determined, and the type of alloy raw material is determined; the target composition range is Al: 5.5-6.5%; Sn: 3.0-4.5%; Zr: 3.0-5.0%; Mo: 0.2-1.0%; Si: 0.2-0.5%; Nb: 0.2-0.7%; Ta: 0.5-2.5%; W: 0.3-1.2%; C: 0.02-0.08%. According to the target composition range of Ti65 titanium alloy ingot, the ratio of the alloy elements is determined to be Al: 6.0-7.2%; Sn: 3.2-4.3%; Zr: 3.2-4.8%; Mo: 0.3-0.9%; Si: 0.25-0.45%; Nb: 0.3-0.6%; Ta: 0.7-2.3%; W: 0.4-1.1%; C: 0.03-0.07%; Mixing the titanium sponge and the alloy raw material evenly to form a raw material to be melted; Melting the raw material to be melted by an electron beam cooling furnace to prepare a primary ingot; The primary ingot is melted by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot.

[0006] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of determining the type of alloy raw material comprises: The types of alloy raw materials are determined to be sponge zirconium, aluminum beans, aluminum-molybdenum master alloy, aluminum-tungsten master alloy, aluminum-tantalum master alloy, aluminum-silicon master alloy, carbon powder, titanium-tin master alloy and aluminum-niobium master alloy.

[0007] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of uniformly mixing the titanium sponge and the alloy raw material to form a raw material to be melted comprises: The titanium sponge, the zirconium sponge, the aluminum beans, the aluminum-molybdenum master alloy, the aluminum-tungsten master alloy, the aluminum-tantalum master alloy, the aluminum-silicon master alloy, the carbon powder, the titanium-tin master alloy and the aluminum-niobium master alloy are mixed evenly by an automatic mixing machine to form a first raw material to be pressed, and the first raw material to be pressed is pressed by a hydraulic press to prepare the block-shaped raw material to be melted.

[0008] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of determining the type of alloy raw material comprises: The types of the alloy raw materials are determined to be zirconium sponge, aluminum beans, aluminum-molybdenum master alloys, aluminum-molybdenum-tungsten-titanium master alloys, aluminum-tantalum master alloys, aluminum-silicon master alloys, carbon powder, titanium-tin master alloys and aluminum-niobium master alloys.

[0009] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of uniformly mixing titanium sponge and alloy raw materials to form a raw material to be melted comprises: The titanium sponge, the zirconium sponge, the aluminum beans, the aluminum-molybdenum master alloy, the aluminum-molybdenum-tungsten-titanium master alloy, the aluminum-tantalum master alloy, the aluminum-silicon master alloy, the titanium-tin master alloy and the aluminum-niobium master alloy are mixed evenly by an automatic mixing machine to form a second raw material to be pressed, the carbon powder is prepared into a carbon powder bag, the carbon powder bag is mixed evenly with the second raw material to be pressed to form a third raw material to be pressed, the third raw material to be pressed is pressed by an oil press to prepare a block raw material; the block raw material is evenly arranged in the feed trough of the electron beam cooling hearth furnace to form the raw material to be melted.

[0010] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of smelting the raw material to be melted by an electron beam cooling hearth furnace comprises: According to the specifications and dimensions of the feed trough of the electron beam cooling hearth furnace and the specifications and dimensions of the block-shaped raw materials to be melted, the quantity and weight of the raw materials to be melted are determined so that the raw materials to be melted can adapt to the loading space of the feed trough; the raw materials to be melted are placed in the loading space, and the raw materials to be melted located in the loading space are melted by the electron gun of the electron beam cooling hearth furnace to prepare a primary ingot.

[0011] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of melting the raw material to be melted located in the charging space by the electron gun of the electron beam cooling hearth furnace comprises: The electron gun includes a first electron gun group, a second electron gun group and a third electron gun group; the first electron gun group is used to melt the raw material to be melted into titanium liquid; the second electron gun group is used to refine the titanium liquid; the titanium liquid enters the crystallizer of the electron beam cooling hearth furnace to form a molten pool, and the third electron gun group is used to heat the surface of the molten pool.

[0012] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the total melting power of the electron beam cooling hearth furnace is 1800KW-3150KW; wherein the melting power of the first electron gun group accounts for 60-70% of the total melting power; the melting power of the second electron gun group accounts for 10-15% of the total melting power; and the melting power of the third electron gun group accounts for 20-25% of the total melting power.

[0013] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, the step of melting the primary ingot by a vacuum consumable arc furnace to prepare the Ti65 titanium alloy ingot comprises: The primary ingot is melted by a vacuum consumable arc furnace with a crucible diameter of 650 mm - 720 mm to prepare a Ti65 titanium alloy ingot.

[0014] According to a method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, after the step of melting the raw materials to be melted by an electron beam cold hearth furnace to prepare a primary ingot, the method further includes: The two primary ingots are butt-welded by an electron beam welding box, and the two butt-welded primary ingots are melted by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot.

[0015] Compared with the prior art, the beneficial effects of the present invention are: In the method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention, according to the target composition range of the Ti65 titanium alloy ingot, the proportion range of each alloy element in the Ti65 titanium alloy ingot is determined as follows: Al: 6.0 - 7.2%; Sn: 3.2 - 4.3%; Zr: 3.2 - 4.8%; Mo: 0.3 - 0.9%; Si: 0.25 - 0.45%; Nb: 0.3 - 0.6%; Ta: 0.7 - 2.3%; W: 0.4 - 1.1%; C: 0.03 - 0.07%. The raw materials to be melted that meet the above proportion ranges of each alloy element are weighed and mixed evenly. The raw materials to be melted are subjected to primary melting by an electron beam cold hearth furnace, and the primary ingot is subjected to secondary melting by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot. On the one hand, by first utilizing the high energy density and good refining ability of the electron beam cold hearth furnace, the alloy elements are preliminarily homogenized and part of the impurities are removed, and then the composition is further adjusted by a vacuum consumable arc furnace, effectively improving the composition uniformity of the Ti65 titanium alloy ingot. On the other hand, it avoids the insufficient strength of the consumable electrode caused by excessive master alloy, or the master alloy is likely to spill or drop during the melting process, resulting in abnormal melting or the occurrence of inclusions, segregation and uneven melting of high melting point metals. In addition, the melting point and density of the aluminum-molybdenum-tungsten-titanium master alloy are lower. Using the aluminum-molybdenum-tungsten-titanium quaternary master alloy can effectively reduce the deviation of the content of high melting point and high density elements tungsten and molybdenum and the risk of generating inclusions, and improve the product quality. Description of the Drawings

[0016] Figure 1 It is a process flow diagram of the method for preparing a Ti65 titanium alloy ingot provided by an embodiment of the present invention; Figure 2 It is one of the schematic diagrams of the bulk raw materials to be melted provided by an embodiment of the present invention; Figure 3 It is another schematic diagram of the bulk raw materials to be melted provided by an embodiment of the present invention; Figure 4Schematic diagram of the punch of the hydraulic press extruding the third raw material to be pressed in the mold cavity provided by the embodiment of the present invention; Figure 5 Schematic diagram of the scanning areas of the first electron gun group, the second electron gun group, and the third electron gun group provided by the embodiment of the present invention; Figure 6 Schematic diagram of butt welding of two primary ingots provided by the embodiment of the present invention; 1. Block-shaped raw material to be melted; 2. Carbon powder package; 3. Punch of the hydraulic press; 4. Mold cavity; 5. Primary ingot; 6. Circumferential weld; 7. Schematic diagram of the scanning of the first electron gun group; 8. Schematic diagram of the scanning of the second electron gun group; 9. Schematic diagram of the scanning of the third electron gun group; 91. Scanning image of the second electron gun; 92. Scanning image of the third electron gun. Detailed implementation manners

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0018] Figure 1 Schematic flow chart of the method for preparing a Ti65 titanium alloy ingot provided by the embodiment of the present invention, as Figure 1 shown, a method for preparing a Ti65 titanium alloy ingot includes the following steps: S1: Determine the proportioning values of each alloy element according to the target composition range of the Ti65 titanium alloy ingot, and determine the types of alloy raw materials; the target composition range is Al: 5.5 - 6.5%; Sn: 3.0 - 4.5%; Zr: 3.0 - 5.0%; Mo: 0.2 - 1.0%; Si: 0.2 - 0.5%; Nb: 0.2 - 0.7%; Ta: 0.5 - 2.5%; C: 0.02 - 0.08%; W: 0.3 - 1.2%. According to the target composition range of the Ti65 titanium alloy ingot, the alloy element proportioning range is determined as Al: 6.0 - 7.2%; Sn: 3.2 - 4.3%; Zr: 3.2 - 4.8%; Mo: 0.3 - 0.9%; Si: 0.25 - 0.45%; Nb: 0.3 - 0.6%; Ta: 0.7 - 2.3%; W: 0.4 - 1.1%; C: 0.03 - 0.07%; S2: Mix the sponge titanium and the alloy raw materials evenly to form the raw material to be melted; S3: Melting the raw material to be melted by an electron beam cold hearth furnace to prepare a primary ingot; S4: Melting the primary ingot by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot.

[0019] The preparation method of the Ti65 titanium alloy ingot provided by the embodiment of the present invention determines the ratio of each alloy element in the Ti65 titanium alloy ingot according to the target composition range of the Ti65 titanium alloy ingot as follows: Al: 7.2%, Sn: 4.05%; Zr: 3.5%; Mo: 0.5%; Si: 0.415%; Nb: 0.3%; Ta: 1.0%; W: 0.8%; C: 0.055%. Weigh and mix evenly the raw materials to be melted that meet the above ratio ranges of each alloy element. Conduct primary melting on the raw materials to be melted through an electron beam cold hearth furnace, and conduct secondary melting on the primary ingot through a vacuum consumable arc furnace to prepare the Ti65 titanium alloy ingot. On the one hand, first utilize the high energy density and good refining ability of the electron beam cold hearth furnace to preliminarily homogenize the alloy elements and remove some impurities, and then further adjust the composition through the vacuum consumable arc furnace, effectively improving the composition uniformity of the Ti65 titanium alloy ingot. On the other hand, it avoids the insufficient strength of the consumable electrode caused by excessive master alloy, or the easy spilling or dropping of the master alloy during the melting process, resulting in abnormal melting or the occurrence of inclusions, segregation and uneven melting of high melting point metals.

[0020] In the prior art, due to the small addition amount of titanium sponge in the Ti65 titanium alloy ingot and the large addition amount of master alloy, the strength of the consumable electrode pressed in the production of the Ti65 titanium alloy ingot is insufficient, and the master alloy is prone to spill or drop during the melting process, thereby resulting in inclusions, segregation or uneven melting of high melting point metals in the Ti65 titanium alloy ingot, seriously affecting the metallurgical quality of the Ti65 titanium alloy ingot. In this application, the raw materials to be melted are melted through an electron beam cold hearth furnace, avoiding the insufficient strength of the consumable electrode caused by excessive master alloy, or the easy spilling or dropping of the master alloy during the melting process, resulting in abnormal melting or the occurrence of inclusions, segregation and uneven melting of high melting point metals.

[0021] It should be noted that since the increase in Fe content will significantly reduce the creep properties of the high-temperature titanium alloy, the Fe content needs to be strictly controlled not to exceed 0.25%. Specifically, use aviation-grade low-Fe titanium sponge with a particle size of 3 - 12.7 mm, and the Fe content of the titanium sponge is less than 0.015% to ensure the quality of the ingot.

[0022] It should be noted that determining the ratio range according to the target composition range can, on the one hand, ensure that the content of each alloy element in the Ti65 titanium alloy ingot meets the requirements of the target range, and on the other hand, can improve the uniformity of the alloy elements and enhance the material properties of the Ti65 titanium alloy.

[0023] In the embodiment of the present invention, the steps of determining the types of alloy raw materials include: Determine that the types of alloy raw materials are zirconium sponge, aluminum beans, aluminum-molybdenum master alloy, aluminum-tungsten master alloy, aluminum-tantalum master alloy, aluminum-silicon master alloy, carbon powder, titanium-tin master alloy and aluminum-niobium master alloy.

[0024] In the embodiment of the present invention, the step of mixing titanium sponge and alloy raw materials evenly to form the raw materials to be melted includes: Mix zirconium sponge, aluminum beans, aluminum-molybdenum master alloy, aluminum-tungsten master alloy, aluminum-tantalum master alloy, aluminum-silicon master alloy, carbon powder, titanium-tin master alloy and aluminum-niobium master alloy evenly through an automatic batching and mixing machine to form the first raw material to be pressed, and press the first raw material to be pressed through a hydraulic press to prepare the massive raw materials to be melted.

[0025] In the embodiment of the present invention, the step of determining the types of alloy raw materials includes: Determine that the types of alloy raw materials are zirconium sponge, aluminum beans, aluminum-molybdenum master alloy, aluminum-molybdenum-tungsten-titanium master alloy, aluminum-tantalum master alloy, aluminum-silicon master alloy, carbon powder, titanium-tin master alloy and aluminum-niobium master alloy. Preferably, the mass ratio of each element in the aluminum-molybdenum-tungsten-titanium master alloy is Al: 50%; Mo: 14%; W: 26%; Ti: 10%.

[0026] Since tungsten and molybdenum are high-melting-point and high-density elements, they have a high melting point during the smelting process, are difficult to melt and evenly disperse in the melt, and are prone to local enrichment or depletion, resulting in a large deviation in the content of tungsten and molybdenum in the ingot. The aluminum-molybdenum-tungsten-titanium master alloy has a low melting point itself, which can promote the more uniform dissolution and dispersion of tungsten and molybdenum, thereby effectively reducing their segregation in each region of the ingot and making the composition of the ingot more uniform and stable. In addition, using the quaternary aluminum-molybdenum-tungsten-titanium master alloy, its good fluxing and dispersing effects can reduce the appearance of unmelted tungsten and molybdenum particles, thereby reducing the risk of inclusions and improving the quality of the ingot.

[0027] Compared with the aluminum-tungsten master alloy, the quaternary aluminum-molybdenum-tungsten-titanium master alloy has additional molybdenum and titanium elements. On the one hand, the molybdenum element acts synergistically with other elements to further optimize the dissolution and dispersion effects on high-melting-point and high-density elements; on the other hand, the titanium element combines with impurity elements such as oxygen to purify the melt, further reducing the possibility of inclusions.

[0028] In the embodiment of the present invention, the step of mixing titanium sponge and alloy raw materials evenly to form the raw materials to be melted includes: Mix sponge titanium, sponge zirconium, aluminum beans, aluminum-molybdenum master alloy, aluminum-molybdenum-tungsten-titanium master alloy, aluminum-tantalum master alloy, aluminum-silicon master alloy, titanium-tin master alloy and aluminum-niobium master alloy evenly through an automatic batching machine to form a second raw material to be pressed. Prepare carbon powder into carbon powder packets, mix the carbon powder packets evenly with the second raw material to be pressed to form a third raw material to be pressed, and press the third raw material to be pressed through a hydraulic press to prepare a massive raw material; Arrange the massive raw materials evenly in the feeding trough of an electron beam cold hearth furnace to form raw materials to be melted.

[0029] Carbon powder usually has fine particle size and light mass. When mixing with other alloy raw materials, it is easy to agglomerate together under the action of van der Waals force and the like. During the melting process, this agglomeration phenomenon will hinder the uniform dispersion of carbon powder in the liquid alloy. In the melting of titanium alloy, the particle size and density of raw materials such as sponge titanium are quite different from those of carbon powder. Simple mixing is difficult to make the carbon powder evenly adhere to or distribute on the surface of other raw material particles, resulting in that carbon elements cannot be evenly incorporated into the alloy matrix during melting, affecting the uniformity of alloy composition. In this application, by making carbon powder packets and arranging the carbon powder packets evenly in the massive raw materials to be melted, the carbon powder can be evenly incorporated into the Ti65 titanium alloy ingot, improving the uniformity of ingot composition.

[0030] Figure 2 One of the schematic diagrams of the massive raw materials to be melted provided by the embodiment of the present invention Figure 3 Another schematic diagram of the massive raw materials to be melted provided by the embodiment of the present invention Figure 4 A schematic diagram of the hydraulic press punch extruding the third raw material to be pressed in the mold cavity provided by the embodiment of the present invention, as Figures 2 to 4 shown, in the embodiment of the present invention, a single massive raw material to be melted has multiple carbon powder packets. The multiple carbon powder packets are evenly distributed inside the massive raw material to be melted. Specifically, first pour 1 / 2 weight of the second raw material to be pressed of a single massive raw material to be melted into the mold cavity of the hydraulic press, then arrange multiple carbon powder packets evenly along the cross-section of the massive raw material to be melted, and then pour the remaining 1 / 2 weight of the second raw material to be pressed of a single massive raw material to be melted into the mold cavity of the hydraulic press. Extrude the third raw material to be pressed in the mold cavity through the punch of the hydraulic press to complete the preparation of a single massive raw material to be melted.

[0031] In the embodiment of the present invention, the steps of melting the raw materials to be melted through an electron beam cold hearth furnace include: According to the specification dimensions of the feeding trough of the electron beam cold hearth furnace and the specification dimensions of the massive raw materials to be melted, determine the quantity and weight of the raw materials to be melted so that the raw materials to be melted are adapted to the loading space of the feeding trough; Place the raw materials to be melted in the loading space, and melt the raw materials to be melted located in the loading space through the electron gun of the electron beam cold hearth furnace to prepare a primary ingot.

[0032] For example, an 8000-ton hydraulic press is used to press the third raw material to be pressed that is uniformly mixed to prepare a block-shaped raw material to be melted, and the number of block-shaped raw materials to be melted is determined according to the length of the feeding trough. When the length of the block-shaped raw material to be melted is 400 mm, the width is 300 mm, the length of the feeding trough is 4500 mm, and the width of the feeding trough is 600 mm, 80 block-shaped raw materials to be melted need to be prepared. 40 block-shaped raw materials are placed in each of the feeding troughs on both sides of the cooling bed. Two columns of block-shaped raw materials are placed in each feeding trough, with 20 block-shaped raw materials in each column. Two layers of raw materials to be melted can be arranged in the height direction to increase the feeding amount, increase the ingot specification size, and improve the production efficiency.

[0033] In an embodiment of the present invention, the step of melting the raw material to be melted located in the loading space by the electron gun of the electron beam cold hearth furnace includes: The electron gun includes a first electron gun group, a second electron gun group, and a third electron gun group; the first electron gun group is used to melt the raw material to be melted into titanium liquid; the second electron gun group is used to refine the titanium liquid; the titanium liquid enters the crystallizer of the electron beam cold hearth furnace to form a molten pool, and the third electron gun group is used to heat the surface of the molten pool.

[0034] Figure 5 The schematic diagram of the scanning areas of the first electron gun group, the second electron gun group, and the third electron gun group provided for the embodiment of the present invention is as Figure 5 shown. In an embodiment of the present invention, the first electron gun group includes four first electron guns, and the scanning pattern of the first electron gun is in a zigzag shape. The scanning patterns of the four first electron guns are symmetrically arranged with respect to the cold hearth of the electron beam cold hearth furnace.

[0035] In an embodiment of the present invention, the third electron gun group includes a second electron gun and a third electron gun. The scanning pattern of the second electron gun is a circle, and the center of the circle coincides with the center of the crystallizer. The scanning pattern of the third electron gun is an annulus, and the annulus is located between the circle and the edge of the crystallizer.

[0036] In the setting of the electron gun of the electron beam cold hearth furnace, the third electron gun group is jointly composed of the second electron gun and the third electron gun. Among them, the scanning area of the second electron gun presents a circle, and the center of the circle coincides with the center of the crystallizer. In this way, when the second electron gun heats the surface of the molten pool, it can transfer heat more evenly to the surrounding area with the center of the crystallizer as the center, playing a role in heating the central area of the molten pool.

[0037] The scanning area of the third electron gun is an annulus, and its position is between the edge of the crystallizer and the scanning area of the second electron gun, that is, it surrounds the outside of the central area of the molten pool. This annular scanning area forms a clever combination with the circular scanning area of the second electron gun.

[0038] During the actual heating of the molten pool surface, by combining such annular and circular scanning areas, compared with heating only relying on the circular scanning area alone, it can cover the entire molten pool surface more comprehensively and evenly, enabling each part of the molten pool surface to receive appropriate and uniform heat supply, thereby effectively improving the uniformity of the molten pool surface temperature, creating a good and stable thermal environment for the crystallization process of titanium alloy in the molten pool, and helping to ensure uniform crystallization speed and uniform and dense ingot microstructure.

[0039] Specifically, the electron beam cold hearth furnace has a total of seven electron guns, numbered 1-7 respectively. During the smelting process, guns 1-4 are the first electron guns, used to melt the raw materials in the left and right feeding troughs into titanium liquid. Gun 5 is the second electron gun group, used to refine the titanium liquid in the cold hearth. Gun 6 is the second electron gun, and gun 7 is the third electron gun. Guns 6 and 7 are used for heating the molten pool surface in the crystallizer to enable the continuous solidification of the titanium liquid in the molten pool.

[0040] In the embodiment of the present invention, the total smelting power of the electron beam cold hearth furnace is 1800KW - 3150KW; among them, the smelting power of the first electron gun group accounts for 60 - 70% of the total smelting power; the smelting power of the second electron gun group accounts for 10 - 15% of the total smelting power; the smelting power of the third electron gun group accounts for 20 - 25% of the total smelting power. By reasonably allocating the smelting power of the first electron gun group, the second electron gun group, and the third electron gun group, the melting speed, refining speed, and crystallization speed of the raw materials to be melted are matched, ensuring the compositional uniformity of various elements in the Ti65 titanium alloy ingot and effectively reducing inclusions and segregation phenomena in the alloy.

[0041] In the embodiment of the present invention, the steps of smelting the primary ingot through a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot include: Smelting the primary ingot through a vacuum consumable arc furnace with a crucible diameter of 650mm - 720mm to prepare a Ti65 titanium alloy ingot. When the diameter of the primary ingot is 580mm, smelt the primary ingot through a vacuum consumable arc furnace with a crucible diameter of 650mm. When the diameter of the primary ingot is 650mm, smelt the primary ingot through a vacuum consumable arc furnace with a crucible diameter of 720mm. During the vacuum consumable arc melting process, AC arc stabilizing stirring is carried out, with an arc stabilizing current of 12 - 16A and an arc stabilizing stirring time of 6 - 8S. Through arc stabilizing stirring, the volume and shape of the molten pool are changed, which is more conducive to the uniform distribution of elements. The convection and diffusion effects of the liquid metal in the molten pool can be more fully exerted, enabling various alloy elements such as Al, Sn, Zr, Mo, W, Si, Nb, Ta, C, etc. to be uniformly mixed in the melt, reducing segregation phenomena, and more effectively improving the microstructure uniformity of the ingot, thereby improving the overall quality of the ingot.

[0042] Figure 6 A schematic diagram of butt welding of two primary ingots provided in an embodiment of the present invention is shown in FIG. Figure 6 As shown, in an embodiment of the present invention, after the step of melting the raw material to be melted by the electron beam cooling hearth furnace to prepare a primary ingot, the step further includes: The two primary ingots are butt-welded by an electron beam welding box, and the two primary ingots that have been butt-welded are melted by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot. Since the weight of the Ti65 titanium alloy ingot is twice that of the primary ingot, the specifications of the Ti65 titanium alloy ingot are increased, and the production efficiency is improved. The welding current is 1-3A, the welding voltage is 30KV, and the welding speed is 15-40mm / min. When the electron beam welding box is used for welding, the electron beam can be focused to a very small diameter due to the very high energy density of the electron beam. This high energy density can achieve high-precision welding, which can make the weld very narrow and have a large aspect ratio, which helps to improve production efficiency and greatly shorten the welding time. The width of the annular weld is 80-100mm and the depth is 30-50mm. Since the other parts of the primary ingot are less affected by heat during the welding process, thermal deformation and thermal stress can be reduced, and the annular weld can be prevented from cracking due to thermal stress after welding.

[0043] The first specific embodiment of the present invention is described below, as follows: The raw materials are shown in Table 1, with a total of 72 block raw materials to be melted, and the weight of a single block raw material to be melted is 46.53 kg. According to the ratio range of each alloy element in the Ti65 titanium alloy ingot: Al: 6.0-7.2%; Sn: 3.2-4.3%; Zr: 3.2-4.8%; Mo: 0.3-0.9%; Si: 0.25-0.45%; Nb: 0.3-0.6%; Ta: 0.7-2.3%; W: 0.4-1.1%; C: 0.03-0.07%; determine the ratio of each alloy element: Al: 7.2%, Sn: 4.05%; Zr: 3.5%; Mo: 0.5%; Si: 0.415%; Nb: 0.3%; Ta: 1.0%; W: 0.8%; C: 0.055%.

[0044] Table 1

[0045] The titanium sponge and the alloy raw material are weighed by an automatic mixer, and the titanium sponge and the alloy raw material are evenly mixed by a mixer, and the mixing time of the mixer is 30-90S.

[0046] The sponge titanium and alloy raw materials are pressed by an 8000-ton oil press to prepare block-shaped raw materials to be melted. The block-shaped raw materials to be melted are 400 mm in length and 300 mm in width. 36 block-shaped raw materials are placed in each of the feeding troughs on both sides of the cold bed. The feeding troughs on each side place two columns of block-shaped raw materials, with 18 block-shaped raw materials in each column.

[0047] The feeding troughs are placed into the feeding system of the electron beam cold hearth furnace. When the left and right feeding chambers and the melting chamber are evacuated to a vacuum degree ≤ 0.6 Pa, melting starts. During the melting process, the vacuum degree in the melting chamber meets ≤ 1.0 Pa. After the raw materials are bombarded by the electron beam and melted into titanium liquid, they flow through the melting cold bed and the refining cold bed, and then flow into the crystallizer crucible to solidify. Then, through the ingot pulling system, the ingot is pulled to the ingot pulling chamber and cooled in the furnace before being taken out, obtaining a primary ingot with a diameter of 650 mm.

[0048] The electron beam cold hearth furnace has a total of seven electron guns, numbered 1-7 respectively. During the melting process, guns 1-4 are the first electron guns, used to melt the raw materials in the left and right feeding troughs into titanium liquid; gun 5 is the second electron gun group, used to refine the titanium liquid in the cold bed; guns 6-7 are the second electron gun and the third electron gun, used to heat the surface of the molten pool in the crystallizer so that the titanium liquid in the molten pool solidifies continuously.

[0049] The primary ingot is melted through a crucible with a diameter of 720 mm to prepare a Ti65 titanium alloy ingot. The melting current is 25-29 KA, and the melting voltage is 30-35 V.

[0050] Samples of the ingot chemical composition are taken for testing, and the test results are shown in Table 2. It can be seen from Table 2 that the deviation of Al element is ≤ 0.20%, the deviation of Mo element is ≤ 0.05%, the deviation of Si element is ≤ 0.05%, the deviation of Sn element is ≤ 0.20%, the deviation of Zr element is ≤ 0.20%, the deviation of Nb element is ≤ 0.05%, the deviation of Ta element is ≤ 0.20%, the deviation of C element is ≤ 0.02%, and the deviation of W element is ≤ 0.05%. The composition uniformity of various alloy elements of the Ti65 titanium alloy is good.

[0051] Table 2

[0052] The second specific embodiment of the present invention is described below as follows: The raw materials are shown in Table 3. There are a total of 72 block-shaped raw materials to be melted, and the weight of each block-shaped raw material to be melted is 46.53 kg. According to the proportion range of each alloy element in the Ti65 titanium alloy ingot: Al: 6.0 - 7.2%; Sn: 3.2 - 4.3%; Zr: 3.2 - 4.8%; Mo: 0.3 - 0.9%; Si: 0.25 - 0.45%; Nb: 0.3 - 0.6%; Ta: 0.7 - 2.3%; W: 0.4 - 1.1%; C: 0.03 - 0.07%; the proportion values of each alloy element are determined as follows: Al: 7.0%, Sn: 3.9%; Zr: 3.6%; Mo: 0.6%; Si: 0.42%; Nb: 0.4%; Ta: 1.5%; W: 0.9%; C: 0.065%.

[0053] Table 3

[0054] The sponge titanium and alloy raw materials are weighed by an automatic batching and mixing machine, and the sponge titanium and alloy raw materials are evenly mixed by a mixer. The mixing time of the mixer is 30 - 90S.

[0055] The sponge titanium and alloy raw materials are pressed by an 8000-ton hydraulic press to prepare block-shaped raw materials to be melted. The length of the block-shaped raw materials to be melted is 400 mm, and the width is 300 mm. 36 block-shaped raw materials are placed in each feeding groove on both sides of the cold bed. Two columns of block-shaped raw materials are placed in each feeding groove on each side, with 18 block-shaped raw materials in each column.

[0056] The feeding groove is placed into the feeding system of the electron beam cold hearth furnace. When the left and right feeding chambers and the melting chamber are evacuated to a vacuum degree ≤ 0.6 Pa, melting starts. During the melting process, the vacuum degree in the melting chamber meets ≤ 1.0 Pa. After the raw materials are bombarded by the electron beam and melted into titanium liquid, they flow through the melting cold hearth and the refining cold hearth, flow into the crystallizer crucible and solidify, and then the ingot is pulled to the ingot pulling chamber by the ingot pulling system and cooled in the furnace and then taken out of the furnace to obtain a primary ingot with a diameter of 650 mm.

[0057] The electron beam cold hearth furnace has a total of seven electron guns, numbered 1 - 7. During the melting process, guns 1 - 4 are the first electron guns, used to melt the raw materials in the left and right feeding grooves into titanium liquid. Gun 5 is the second electron gun group, used to refine the titanium liquid in the cold hearth. Guns 6 - 7 are the second electron gun and the third electron gun, used to heat the surface of the molten pool in the crystallizer so that the titanium liquid in the molten pool solidifies continuously.

[0058] The primary ingot is melted by a crucible with a diameter of 720 mm to prepare a Ti65 titanium alloy ingot. The melting current is 25 - 29 KA, and the melting voltage is 30 - 35 V.

[0059] Samples were taken from the ingot for chemical composition testing, and the test results are shown in Table 4. It can be seen from Table 4 that the deviation of Al element is ≤0.20%, the deviation of Mo element is ≤0.05%, the deviation of Si element is ≤0.05%, the deviation of Sn element is ≤0.20%, the deviation of Zr element is ≤0.20%, the deviation of Nb element is ≤0.05%, the deviation of Ta element is ≤0.20%, the deviation of C element is ≤0.02%, and the deviation of W element is ≤0.05%. The composition uniformity of various alloying elements of Ti65 titanium alloy is good.

[0060] Table 4

[0061] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A method for preparing a Ti65 titanium alloy ingot, characterized in that: The following steps are involved: Determine the ratio of each alloy element according to the target composition range of Ti65 titanium alloy ingot, and determine the type of alloy raw material; the target composition range is Al: 5.5-6.5%; Sn: 3.0-4.5%; Zr：3.0-5.0%； Mo: 0.2-1.0%; Si: 0.2-0.5%; Nb: 0.2-0.7%; Ta: 0.5-2.5%; W：0.3-1.2%； C: 0.02-0.08%, according to the target composition range of Ti65 titanium alloy ingot, the alloy element ratio range is determined to be Al: 6.0-7.2%; Sn: 3.2-4.3%; Zr: 3.2-4.8%; Mo: 0.3-0.9%; Si: 0.25-0.45%; Nb: 0.3-0.6%; Ta: 0.7-2.3%; W：0.4-1.1%； C：0.03-0.07%； Mixing the titanium sponge and the alloy raw material evenly to form a raw material to be melted; Melting the raw material to be melted by an electron beam cooling furnace to prepare a primary ingot; The primary ingot is melted by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot.

2. The method for preparing the Ti65 titanium alloy ingot according to claim 1, characterized in that: The step of determining the type of alloy raw material comprises: The types of the alloy raw materials are determined to be zirconium sponge, aluminum beans, aluminum-molybdenum master alloys, aluminum-tungsten master alloys, aluminum-tantalum master alloys, aluminum-silicon master alloys, carbon powder, titanium-tin master alloys and aluminum-niobium master alloys.

3. The method for preparing the Ti65 titanium alloy ingot according to claim 2, characterized in that: The step of uniformly mixing the titanium sponge and the alloy raw material to form a raw material to be melted comprises: The titanium sponge, the zirconium sponge, the aluminum beans, the aluminum-molybdenum master alloy, the aluminum-tungsten master alloy, the aluminum-tantalum master alloy, the aluminum-silicon master alloy, the carbon powder, the titanium-tin master alloy and the aluminum-niobium master alloy are mixed evenly by an automatic mixing machine to form a first raw material to be pressed, and the first raw material to be pressed is pressed by a hydraulic press to prepare the block-shaped raw material to be melted.

4. The method for preparing the Ti65 titanium alloy ingot according to claim 1, characterized in that: The step of determining the type of alloy raw material comprises: The types of the alloy raw materials are determined to be zirconium sponge, aluminum beans, aluminum-molybdenum master alloys, aluminum-molybdenum-tungsten-titanium master alloys, aluminum-tantalum master alloys, aluminum-silicon master alloys, carbon powder, titanium-tin master alloys and aluminum-niobium master alloys.

5. The method for preparing the Ti65 titanium alloy ingot according to claim 4, characterized in that: The step of uniformly mixing the titanium sponge and the alloy raw material to form the raw material to be melted comprises: The titanium sponge, the zirconium sponge, the aluminum beans, the aluminum-molybdenum master alloy, the aluminum-molybdenum-tungsten-titanium master alloy, the aluminum-tantalum master alloy, the aluminum-silicon master alloy, the titanium-tin master alloy and the aluminum-niobium master alloy are mixed evenly by an automatic mixing machine to form a second raw material to be pressed, the carbon powder is prepared into a carbon powder bag, the carbon powder bag is mixed evenly with the second raw material to be pressed to form a third raw material to be pressed, the third raw material to be pressed is pressed by an oil press to prepare a block raw material; the block raw material is evenly arranged in the feed trough of the electron beam cooling hearth furnace to form the raw material to be melted.

6. The method for preparing a Ti65 titanium alloy ingot according to any one of claims 1 to 5, characterized in that: The step of smelting the raw material to be melted by an electron beam cooling furnace comprises: According to the specifications and dimensions of the feed trough of the electron beam cooling hearth furnace and the specifications and dimensions of the block-shaped raw materials to be melted, the quantity and weight of the raw materials to be melted are determined so that the raw materials to be melted can adapt to the loading space of the feed trough; the raw materials to be melted are placed in the loading space, and the raw materials to be melted located in the loading space are melted by the electron gun of the electron beam cooling hearth furnace to prepare a primary ingot.

7. The method for preparing the Ti65 titanium alloy ingot according to claim 6, characterized in that: The step of melting the raw material to be melted located in the charging space by the electron gun of the electron beam cooling hearth furnace comprises: The electron gun includes a first electron gun group, a second electron gun group and a third electron gun group; the first electron gun group is used to melt the raw material to be melted into titanium liquid; the second electron gun group is used to refine the titanium liquid; the titanium liquid enters the crystallizer of the electron beam cooling hearth furnace to form a molten pool, and the third electron gun group is used to heat the surface of the molten pool.

8. The method for preparing the Ti65 titanium alloy ingot according to claim 7, characterized in that: The total melting power of the electron beam cooling hearth furnace is 1800KW-3150KW; wherein, the melting power of the first electron gun group accounts for 60-70% of the total melting power; the melting power of the second electron gun group accounts for 10-15% of the total melting power; and the melting power of the third electron gun group accounts for 20-25% of the total melting power.

9. The method for preparing a Ti65 titanium alloy ingot according to claim 8, characterized in that: The step of melting the primary ingot by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot comprises: The primary ingot is melted in a vacuum consumable arc furnace with a crucible diameter of 650 mm to 720 mm to prepare a Ti65 titanium alloy ingot.

10. The method for preparing a Ti65 titanium alloy ingot according to claim 9, characterized in that: After the step of melting the raw material to be melted by the electron beam cooling furnace to prepare a primary ingot, the method further includes: The two primary ingots are butt-welded by an electron beam welding box, and the two butt-welded primary ingots are melted by a vacuum consumable arc furnace to prepare a Ti65 titanium alloy ingot.

Images