A method for preparing a titanium-tin intermediate alloy for inhibiting tin segregation and a cooling device

Abstract

This invention provides a method for preparing a titanium-tin master alloy with tin segregation suppression and a cooling device. The preparation method includes: (1) pressing a molten blank; (2) smelting and refining to obtain an alloy melt; (3) casting and cooling: after turning on the cooling device, the alloy melt is poured into the cooling device, cooled, and then demolded to obtain a titanium-tin master alloy; the outer surface and the interior of the cooling device are equipped with water-cooling units. This invention utilizes the raw material structure of "titanium-tin core" to effectively reduce the occurrence of tin seepage in the crucible, reduce tin raw material loss, and improve the accuracy of alloy composition; combined with the cooling device to achieve internal and external synergistic cooling, it can effectively suppress tin atom diffusion, prevent the occurrence of tin element anti-segregation in the traditional smelting process, enhance the uniform distribution of tin element in the titanium-tin alloy ingot, and control the tin element content deviation in the titanium-tin alloy ingot within 2wt%.

Description

Technical Field

[0001] This invention belongs to the field of intermediate alloy smelting technology, and relates to a method for preparing titanium-tin intermediate alloy, specifically a method for preparing titanium-tin intermediate alloy and a cooling device for suppressing tin segregation. Background Technology

[0002] Tin is an important element commonly added to titanium alloys. Through solid solution strengthening, stabilizing the α phase, and refining the microstructure, it can significantly improve the strength, plasticity, heat resistance, and biocompatibility of titanium alloys. Tin-added titanium alloys are widely used in key industrial fields such as aerospace, marine engineering, and biomedicine. During the titanium alloy smelting process, due to the low melting point of tin (approximately 231.9℃), which differs significantly from the melting point of sponge titanium, it is difficult to add tin in its elemental form. Therefore, the industry generally adds it as a titanium-tin master alloy.

[0003] Currently, there are two methods for preparing titanium-tin master alloys. For example, CN 105624735A discloses a method for preparing titanium-tin alloys, which specifically discloses the molten salt electrolysis method; CN101376930A discloses a Ti-Sn master alloy and its preparation method, and CN 102329974A discloses a method for preparing titanium-tin master alloys for superconducting wires, which specifically discloses the induction melting method.

[0004] The aforementioned molten salt electrolysis method suffers from slow preparation speed and small production scale, thus hindering its large-scale application. Induction melting is currently the mainstream method for preparing titanium-tin master alloys. However, during the induction melting process, due to the typical anti-segregation characteristics of Sn, the Sn content in the alloy ingot increases from the core to the edge, reaching as high as 15 wt.%. This level of segregation does not meet the requirements of downstream customers, forcing master alloy manufacturers to refine the ingots and select the best for supply, resulting in persistently high production costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and cooling device for preparing titanium-tin master alloys that suppress tin segregation. By constructing the raw materials into a "titanium-shell tin-core" structure, the present invention effectively reduces tin seepage into the crucible, minimizes tin raw material loss, and ensures a more accurate final alloy composition. Combined with a cooling device, it achieves synergistic internal and external cooling, effectively suppressing tin atom diffusion, preventing tin re-segregation during traditional smelting processes, and enhancing the uniform distribution of tin within the titanium-tin alloy ingot. This allows the tin content deviation within the ingot to be controlled within 2 wt%.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a titanium-tin master alloy that suppresses tin segregation, the method comprising the following steps: (1) Pressing of smelted blanks: The smelted blanks include hollow frustum-shaped blanks and frustum-shaped blanks built into the hollow frustum-shaped blanks; the raw material of the hollow frustum-shaped blanks is sponge titanium, and the raw material of the frustum-shaped blanks is metallic tin. (2) Melting and refining: The molten blank is placed in a crucible, vacuumed and then smelted by electric current, followed by refining and cooling to obtain an alloy melt; (3) Casting and cooling: After turning on the cooling device, the alloy molten liquid is poured into the cooling device, cooled and then demolded to obtain the titanium-tin intermediate alloy. The cooling device is equipped with water-cooling units on both its outer surface and inside.

[0007] The smelting blank of this invention has a "titanium-coated tin core" structure. The advantages of this structure are as follows: In traditional charging methods, due to the low melting point of tin, it tends to seep into the bottom of the crucible after melting, resulting in a low tin content in the final alloy. However, the "titanium-coated tin core" structure of this invention allows the tin to be contained in a titanium bowl made of pressed titanium sponge after melting, thus avoiding tin seepage. At the same time, utilizing this material structure, the molten tin can diffuse from the inside out to the surrounding sponge, increasing the contact area between the two compared to traditional charging methods. This efficiently promotes alloying, significantly shortens the melting time, and enhances the uniformity of element distribution. The traditional charging method involves placing metallic tin at the bottom of the crucible first, and then piling titanium sponge on top of the metallic tin without pressing it down.

[0008] Furthermore, traditional processes cool the alloy unidirectionally from the outer surface to the interior, resulting in a large radial temperature gradient within the alloy. The high-temperature melt in the core remains liquid for an extended period, driving the accumulation of low-melting-point, high-density Sn elements at the solidification front. These Sn elements are ultimately pushed towards the cooled alloy ingot edge by contraction and feeding flows, leading to reverse segregation of Sn in the titanium-tin alloy ingot. This invention, however, achieves simultaneous cooling of the alloy's outer surface and core using a cooling device with water-cooling units on both the outer and inner surfaces. This allows the high-temperature melt to dissipate heat rapidly from both interfaces simultaneously, significantly reducing the radial temperature gradient and weakening the convection driving force of the hot solute that drives long-distance Sn migration. Simultaneously, this cooling device not only increases the effective cooling surface area but also enables faster overall solidification along the ingot wall thickness, significantly shortening the solidification time. This prevents Sn atoms from fully diffusing and segregating before being fixed in the solid solution. Moreover, rapid, simultaneous internal and external cooling promotes the formation of fine equiaxed crystals, further hindering the formation of macroscopic segregation channels. Ultimately, rapid and uniform solidification of the titanium-tin alloy ingot was achieved, effectively curbing the reverse segregation problem of Sn element and controlling the deviation of tin element content in the titanium-tin alloy ingot within 2wt%.

[0009] As a preferred technical solution of the present invention, the mass ratio of metallic tin and sponge titanium in step (1) is (4.0~4.5):1, for example, it can be 4.0:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1 or 4.5:1, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] Preferably, the sponge titanium is in granular form with a particle size range of 5 to 20 mm, such as 5 mm, 10 mm, 15 mm or 20 mm, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] Preferably, the tin metal is in an irregular shape.

[0012] Preferably, the pressing pressure in step (1) is 200~300MPa, for example, it can be 200MPa, 220MPa, 240MPa, 260MPa, 280MPa or 300MPa, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] As a preferred technical solution of the present invention, the temperature of the electric melting process in step (2) is 1250~1350℃, for example, it can be 1250℃, 1270℃, 1290℃, 1310℃, 1330℃ or 1350℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the refining temperature in step (2) is 1400~1450℃, for example, it can be 1400℃, 1410℃, 1420℃, 1430℃, 1440℃ or 1450℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the refining process in step (2) takes 5 to 15 minutes, for example, 5 minutes, 7 minutes, 9 minutes, 11 minutes, 13 minutes or 15 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Preferably, the final temperature of the cooling process in step (2) is 1250~1300℃, for example, it can be 1250℃, 1260℃, 1270℃, 1280℃, 1290℃ or 1300℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] As a preferred technical solution of the present invention, the cooling medium used in the casting cooling in step (3) includes distilled water.

[0018] Preferably, the inlet temperature of the distilled water is -10~25℃, for example, it can be -10℃, -5℃, 0℃, 5℃, 10℃, 15℃, 20℃ or 25℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the water pressure of the distilled water in step (3) is 0.2~0.25MPa, for example, it can be 0.2MPa, 0.21MPa, 0.22MPa, 0.23MPa, 0.24MPa or 0.25MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the cooling time in step (3) is 2 to 4 hours, for example, it can be 2 hours, 2.4 hours, 2.8 hours, 3.2 hours, 3.6 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] It is worth noting that the cooling medium used in the casting cooling process described in this invention is distilled water, which can avoid corrosion of the cooling device and extend its service life. It is not recommended to use other cooling water, such as tap water, which contains too many impurities and scale. In addition, when the temperature is low in winter, an appropriate amount of antifreeze can be added to the distilled water for antifreeze treatment.

[0022] In a second aspect, the present invention provides a cooling device for use in the method for preparing a titanium-tin master alloy to suppress tin segregation provided in the first aspect.

[0023] As a preferred embodiment of the present invention, the cooling device includes an ingot mold, a plurality of fixing holes and a sealing ring; the water cooling unit includes a cooling sleeve and a cooling core; the cooling sleeve is fitted over the outer periphery of the ingot mold; the cooling core is welded and fixed to the bottom of the ingot mold; the fixing holes are used to fix the ingot mold and the cooling sleeve; a groove is provided on the upper surface of the cooling sleeve near the ingot mold; the sealing ring is embedded in the groove.

[0024] In this invention, the ingot mold and the cooling sleeve are fixed by a threaded connection through a screw passing through a fixing hole, and after fixing, a sealing structure is formed by a sealing ring set between the ingot mold and the cooling sleeve.

[0025] Preferably, the ingot mold, cooling jacket, and cold core are all frustum-shaped.

[0026] Preferably, the ingot mold, cooling jacket, and cold core have the same axis and the cone angle is 5~10°, for example, it can be 5°, 6°, 7°, 8°, 9° or 10°, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the volume of the cold core accounts for 10-25% of the internal volume of the ingot mold, for example, it can be 10%, 13%, 16%, 19%, 22% or 25%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] It is worth noting that the height of the cold core described in this invention is 10% higher than the designed alloy ingot height to ensure sufficient cooling effect. In addition, in order to better suppress tin segregation in the core, the volume of the cold core accounts for 10-25% of the internal volume of the ingot mold. If the volume occupied by the cold core is too small, sufficient cooling of the core of the titanium-tin alloy ingot cannot be achieved, and the tin element in the core still has a strong tendency to diffuse outward, resulting in a large degree of tin segregation in the alloy ingot and a low yield. Conversely, if the volume of the cold core is too large, although it can ensure an effective suppression of tin segregation, the output of alloy ingots per furnace is low, the equipment utilization rate is low, and the production cost will still be high.

[0029] Preferably, the cold core is hollow inside and has an opening at the bottom.

[0030] Preferably, a plurality of water outlet pipes are evenly arranged circumferentially on the upper part of the outer surface of the cooling jacket.

[0031] Preferably, a plurality of water inlet pipes are evenly arranged circumferentially on the lower part of the outer surface of the cooling jacket.

[0032] Preferably, the outlet end of the water inlet pipe is centrally located at the bottom of the cold core.

[0033] It is worth noting that the present invention has no fewer than two outlet pipes and two inlet pipes, and the inlet pipe has a right-angle bend to ensure that the outlet end of the inlet pipe is located at the bottom of the cold core, so as to achieve direct cooling of the inner cavity of the cold core.

[0034] Preferably, the distance between the outlet end of the water inlet pipe and the bottom horizontal plane of the ingot mold is 20~50mm, for example, it can be 20mm, 30mm, 40mm or 50mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the diameter of the water outlet pipe and the water inlet pipe is 20~60mm, for example, it can be 20mm, 30mm, 40mm, 50mm or 60mm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the wall thickness of the ingot mold is 20~40mm, for example, it can be 20mm, 25mm, 30mm, 35mm or 40mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the wall thickness of the cooling jacket is ≥15mm, for example, it can be 15mm, 16mm, 17mm, 18mm, 19mm or 20mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the gap width between the ingot mold and the cooling jacket is 30~50mm, for example, it can be 30mm, 35mm, 40mm, 45mm or 50mm, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0039] Preferably, the ingot mold and the cold core are each made of copper.

[0040] Preferably, the material of the cooling jacket includes mold steel.

[0041] It is worth noting that copper has excellent thermal conductivity, and when used in ingot molds and cold cores, it can improve the cooling rate and suppress segregation. When mold steel is used in cooling jackets, it can ensure both lower equipment manufacturing costs and higher water cooling jacket strength.

[0042] Preferably, the sealing ring is made of any one of fluororubber, silicone rubber, or perfluoroether rubber, with perfluoroether rubber being the most preferred.

[0043] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0044] Compared with the prior art, the present invention has the following beneficial effects: (1) By constructing the raw material into a "titanium-tin core" structure, the present invention can effectively reduce the occurrence of crucible tin diffusion, reduce the loss of tin raw material, and make the final alloy composition more accurate; at the same time, the structure effectively promotes the alloying efficiency of two elements, significantly reduces the melting temperature, shortens the melting time, and promotes the uniform distribution of elements. (2) The present invention achieves internal and external synergistic cooling through a cooling device, which can effectively suppress the diffusion of tin atoms, prevent the tin element reverse segregation phenomenon in the traditional smelting process, enhance the uniform distribution of tin element in titanium-tin alloy ingots, and control the tin element content deviation in titanium-tin alloy ingots to within 2wt%. (3) The present invention achieves internal and external synergistic cooling through the cooling device, which enhances the alloy cooling efficiency, shortens the alloy cooling time, reduces the production time of a single ingot, and also improves the equipment utilization rate. (4) The preparation method provided by the present invention has greatly improved the yield of titanium-tin master alloy and increased the benefits of production enterprises. Attached Figure Description

[0045] Figure 1 A three-dimensional model schematic diagram of the cooling device provided for a specific embodiment of the present invention; Figure 2 A half-sectional view of the cooling device provided for a specific embodiment of the present invention; Figure 3 A 1 / 4 cross-sectional view of the cooling device provided for a specific embodiment of the present invention; Figure 4 A 1 / 4 cross-sectional view of the smelting billet provided for a specific embodiment of the present invention; Figure 5 This is a schematic diagram of sampling the titanium-tin master alloys prepared in the embodiments and comparative examples of the present invention; Among them, 1 is the ingot mold, 2 is the cooling jacket, 3 is the water outlet pipe, 4 is the water inlet pipe, 5 is the cold core, 6 is the fixing hole, 7 is the sealing ring, 8 is the hollow frustum blank, and 9 is the frustum blank. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] In one specific embodiment, the present invention provides a method for preparing a titanium-tin master alloy to suppress tin segregation, the method comprising the following steps: (1) such as Figure 4 The pressing of the smelting blank shown: The smelting blank includes a hollow frustum-shaped blank 8 and a frustum-shaped blank 9 built inside the hollow frustum-shaped blank 8; the raw material of the hollow frustum-shaped blank 8 is sponge titanium, and the raw material of the frustum-shaped blank 9 is metallic tin. The mass ratio of metallic tin to sponge titanium is (4.0~4.5):1; (2) Melting and refining: The molten blank is placed in a high-purity graphite crucible, and after being evacuated to 20 Pa, it is subjected to electric melting treatment, followed by refining treatment and cooling treatment to 1250~1300℃ to obtain alloy melt. The temperature of the electric melting process is 1250~1350℃; the temperature of the refining process is 1400~1450℃, and the time is 5~15min. (3) Casting and cooling: After turning on the cooling device, the alloy melt is poured into the cooling device and cooled for 2-4 hours before demolding to obtain the titanium-tin intermediate alloy. The cooling device is equipped with water-cooling units on both its outer surface and inside. The cooling medium used in the casting cooling process includes distilled water with an inlet temperature of -10~25℃ and a water pressure of 0.2~0.25MPa.

[0048] In another specific embodiment, the present invention provides a cooling device for the casting cooling described in step (3) of the above preparation method; as Figure 1-3 The cooling device includes: a mold 1, several fixing holes 6 and a sealing ring 7; the water cooling unit includes a cooling jacket 2 and a cooling core 5. The cooling sleeve 2 is fitted around the outer periphery of the ingot mold 1; a cooling core 5 is welded and fixed to the bottom of the ingot mold 1; The fixing hole is used to fix the ingot mold 1 and the cooling jacket 2; The cooling jacket 2 has a groove on its upper surface near the ingot mold 1; the sealing ring 7 is embedded inside the groove. The ingot mold 1, cooling sleeve 2, and cold core 5 are all frustum-shaped; the ingot mold 1, cooling sleeve 2, and cold core 5 have the same axis and the cone angle is 5~10°; The volume of the cold core 5 accounts for 10-25% of the internal volume of the ingot mold 1; the cold core 5 is hollow inside and has an opening at the bottom; A plurality of water outlet pipes 4 are evenly arranged in the upper circumferential direction on the outer surface of the cooling jacket 2; a plurality of water inlet pipes 3 are evenly arranged in the lower circumferential direction on the outer surface of the cooling jacket 4. The outlet end of the water inlet pipe 4 is centrally located at the bottom of the cold core 5; the distance between the outlet end of the water inlet pipe 3 and the bottom horizontal plane of the mold 1 is 20~50mm; the diameter of the water outlet pipe 3 and the water inlet pipe 4 is 20~60mm. The wall thickness of the ingot mold 1 is 20~40mm; the wall thickness of the cooling sleeve 2 is ≥15mm; the gap width between the ingot mold 1 and the cooling sleeve 2 is 30~50mm; The materials of the ingot mold 1 and the cold core 5 are independently copper; the material of the cooling jacket 2 is mold steel; the material of the sealing ring 7 is any one of fluororubber, silicone rubber or perfluoroether rubber, preferably perfluoroether rubber.

[0049] Example 1 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation, the method comprising the following steps: (1) such as Figure 4 The pressing of the smelting blank shown: The smelting blank includes a hollow frustum-shaped blank 8 and a frustum-shaped blank 9 built inside the hollow frustum-shaped blank 8; the raw material of the hollow frustum-shaped blank 8 is sponge titanium, and the raw material of the frustum-shaped blank 9 is metallic tin. The mass ratio of metallic tin to sponge titanium is 4.5:1; the masses of metallic tin and sponge titanium are 65.4 kg and 14.6 kg, respectively. (2) Melting and refining: The molten blank is placed in a high-purity graphite crucible, vacuumed to 20 Pa and then subjected to electric melting treatment, followed by refining treatment and cooling treatment to 1280℃ to obtain alloy melt; The temperature of the electric melting process is 1300℃; the temperature of the refining process is 1425℃, and the time is 10 minutes. (3) Casting and cooling: After turning on the cooling device, the alloy melt is poured into the cooling device and cooled for 3 hours before demolding to obtain the titanium-tin intermediate alloy. The cooling device is equipped with water-cooling units on both its outer surface and inside. The cooling medium used in the casting cooling process includes distilled water with an inlet temperature of 0°C and a water pressure of 0.23 MPa.

[0050] like Figure 1-3 The cooling device in step (3) includes: a mold 1, several fixing holes 6 and a sealing ring 7; the water cooling unit includes a cooling jacket 2 and a cooling core 5. The cooling sleeve 2 is fitted around the outer periphery of the ingot mold 1; a cooling core 5 is welded and fixed to the bottom of the ingot mold 1; The fixing hole is used to fix the ingot mold 1 and the cooling jacket 2; The cooling jacket 2 has a groove on its upper surface near the ingot mold 1; the sealing ring 7 is embedded inside the groove. The ingot mold 1, cooling sleeve 2, and cold core 5 are all frustum-shaped; the ingot mold 1, cooling sleeve 2, and cold core 5 have the same axis and a cone angle of 8°; The volume of the cold core 5 accounts for 20% of the internal volume of the ingot mold 1; the cold core 5 is hollow inside and has an opening at the bottom; A plurality of water outlet pipes 4 are evenly arranged in the upper circumferential direction on the outer surface of the cooling jacket 2; a plurality of water inlet pipes 3 are evenly arranged in the lower circumferential direction on the outer surface of the cooling jacket 4. The outlet end of the water inlet pipe 4 is centrally located at the bottom of the cold core 5; the distance between the outlet end of the water inlet pipe 3 and the bottom horizontal plane of the ingot mold 1 is 35mm; the diameter of the water outlet pipe 3 and the water inlet pipe 4 is 40mm. The wall thickness of the ingot mold 1 is 30mm; the wall thickness of the cooling sleeve 2 is 20mm; the gap width between the ingot mold 1 and the cooling sleeve 2 is 40mm; The ingot mold 1 and the cold core 5 are each made of copper; the cooling jacket 2 is made of mold steel; and the sealing ring 7 is made of fluororubber.

[0051] Example 2 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation, the method comprising the following steps: (1) such as Figure 4 The pressing of the smelting blank shown: The smelting blank includes a hollow frustum-shaped blank 8 and a frustum-shaped blank 9 built inside the hollow frustum-shaped blank 8; the raw material of the hollow frustum-shaped blank 8 is sponge titanium, and the raw material of the frustum-shaped blank 9 is metallic tin. The mass ratio of metallic tin to sponge titanium is 4.0:1, and the weight of metallic tin is 64 kg; (2) Melting and refining: The molten blank is placed in a high-purity graphite crucible, vacuumed to 20 Pa and then subjected to electric melting treatment, followed by refining treatment and cooling treatment to 1250℃ to obtain alloy melt; The temperature of the electric melting process is 1250℃; the temperature of the refining process is 1400℃ and the time is 15min. (3) Casting and cooling: After turning on the cooling device, the alloy melt is poured into the cooling device, cooled for 2 hours, and then demolded to obtain the titanium-tin intermediate alloy. The cooling device is equipped with water-cooling units on both its outer surface and inside. The cooling medium used in the casting cooling process includes distilled water with an inlet temperature of 25°C and a water pressure of 0.25 MPa.

[0052] like Figure 1-3The cooling device in step (3) includes: a mold 1, several fixing holes 6 and a sealing ring 7; the water cooling unit includes a cooling jacket 2 and a cooling core 5. The cooling sleeve 2 is fitted around the outer periphery of the ingot mold 1; a cooling core 5 is welded and fixed to the bottom of the ingot mold 1; The fixing hole is used to fix the ingot mold 1 and the cooling jacket 2; The cooling jacket 2 has a groove on its upper surface near the ingot mold 1; the sealing ring 7 is embedded inside the groove. The ingot mold 1, cooling sleeve 2, and cold core 5 are all frustum-shaped; the ingot mold 1, cooling sleeve 2, and cold core 5 have the same axis and a cone angle of 5°; The volume of the cold core 5 accounts for 10% of the internal volume of the ingot mold 1; the cold core 5 is hollow inside and has an opening at the bottom; A plurality of water outlet pipes 4 are evenly arranged in the upper circumferential direction on the outer surface of the cooling jacket 2; a plurality of water inlet pipes 3 are evenly arranged in the lower circumferential direction on the outer surface of the cooling jacket 4. The outlet end of the water inlet pipe 4 is centrally located at the bottom of the cold core 5; the distance between the outlet end of the water inlet pipe 3 and the bottom horizontal plane of the ingot mold 1 is 20mm; the diameter of the water outlet pipe 3 and the water inlet pipe 4 is 20mm. The wall thickness of the ingot mold 1 is 20mm; the wall thickness of the cooling sleeve 2 is 15mm; the gap width between the ingot mold 1 and the cooling sleeve 2 is 30mm. The ingot mold 1 and the cold core 5 are each made of copper; the cooling jacket 2 is made of mold steel; and the sealing ring 7 is made of perfluoroether rubber.

[0053] Example 3 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation, the method comprising the following steps: (1) such as Figure 4 The pressing of the smelting blank shown: The smelting blank includes a hollow frustum-shaped blank 8 and a frustum-shaped blank 9 built inside the hollow frustum-shaped blank 8; the raw material of the hollow frustum-shaped blank 8 is sponge titanium, and the raw material of the frustum-shaped blank 9 is metallic tin. The mass ratio of metallic tin to sponge titanium is 4.2:1, and the weight of metallic tin is 75 kg; (2) Melting and refining: The molten blank is placed in a high-purity graphite crucible, and after being evacuated to 20 Pa, it is subjected to electric melting treatment, followed by refining treatment and cooling treatment to 1300℃ to obtain alloy melt. The temperature of the electric melting process is 1350℃; the temperature of the refining process is 1450℃, and the time is 5 minutes. (3) Casting and cooling: After turning on the cooling device, the alloy molten liquid is poured into the cooling device and cooled for 4 hours before demolding to obtain the titanium-tin intermediate alloy. The cooling device is equipped with water-cooling units on both its outer surface and inside. The cooling medium used in the casting cooling process includes distilled water with an inlet temperature of -10℃ and a water pressure of 0.2MPa.

[0054] like Figure 1-3 The cooling device in step (3) includes: a mold 1, several fixing holes 6 and a sealing ring 7; the water cooling unit includes a cooling jacket 2 and a cooling core 5. The cooling sleeve 2 is fitted around the outer periphery of the ingot mold 1; a cooling core 5 is welded and fixed to the bottom of the ingot mold 1; The fixing hole is used to fix the ingot mold 1 and the cooling jacket 2; The cooling jacket 2 has a groove on its upper surface near the ingot mold 1; the sealing ring 7 is embedded inside the groove. The ingot mold 1, cooling sleeve 2, and cold core 5 are all frustum-shaped; the ingot mold 1, cooling sleeve 2, and cold core 5 have the same axis and a cone angle of 10°; The volume of the cold core 5 accounts for 25% of the internal volume of the ingot mold 1; the cold core 5 is hollow inside and has an opening at the bottom; A plurality of water outlet pipes 4 are evenly arranged in the upper circumferential direction on the outer surface of the cooling jacket 2; a plurality of water inlet pipes 3 are evenly arranged in the lower circumferential direction on the outer surface of the cooling jacket 4. The outlet end of the water inlet pipe 4 is centrally located at the bottom of the cold core 5; the distance between the outlet end of the water inlet pipe 3 and the bottom horizontal plane of the ingot mold 1 is 50mm; the diameter of the water outlet pipe 3 and the water inlet pipe 4 is 60mm. The wall thickness of the ingot mold 1 is 40mm; the wall thickness of the cooling sleeve 2 is 22mm; the gap width between the ingot mold 1 and the cooling sleeve 2 is 50mm; The ingot mold 1 and the cold core 5 are each made of copper; the cooling jacket 2 is made of mold steel; and the sealing ring 7 is made of silicone rubber.

[0055] Example 4 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the mass ratio of metallic tin to sponge titanium is adjusted to 5:1.

[0056] Example 5 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the mass ratio of metallic tin to sponge titanium is adjusted to 3:1.

[0057] Example 6 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the temperature of the alloy melt in step (2) is adjusted to 1350℃.

[0058] Example 7 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the temperature of the alloy melt in step (2) is adjusted to 1200℃.

[0059] Example 8 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the volume ratio of the cold core 5 to the internal volume of the ingot mold 1 is adjusted to 8%.

[0060] Example 9 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the volume ratio of the cold core 5 to the internal volume of the ingot mold 1 is adjusted to 30%.

[0061] Example 10 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the gap width between the ingot mold 1 and the cooling sleeve 2 is adjusted to 20mm.

[0062] Example 11 This embodiment provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and that of Example 1 is that: In this embodiment, the gap width between the ingot mold 1 and the cooling sleeve 2 is adjusted to 60mm.

[0063] Comparative Example 1 This comparative example provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and Example 1 is that: In this comparative example, the pressing of the smelted blank in step (1) is adjusted as follows: the sponge titanium and metallic tin are no longer pressed into blocks by molds, but are mixed evenly and directly loaded into a high-purity graphite crucible.

[0064] Comparative Example 2 This comparative example provides a method for preparing a titanium-tin master alloy to suppress tin segregation. The only difference between this method and Example 1 is that: This comparative example modifies the cooling device to a conventional cooling device without a cooling core.

[0065] Experimental example: The titanium-tin master alloys provided in the above embodiments and comparative examples are according to Figure 5 The sampling diagram provided was used to sample and perform composition uniformity analysis. The products that met the composition requirements were then refined, and the yield per ingot was calculated. The results are shown in Table 1.

[0066] Table 1 According to Table 1, the following points can be observed: (1) Comprehensive analysis of Examples 1-3 shows that the tin element segregation in the titanium-tin master alloy prepared by the method provided by the present invention can be controlled between 1.02% and 1.88%, with an overall segregation degree of less than 2%. Moreover, thanks to the reduction in segregation degree, the product yield is significantly improved, with an average yield of more than 95%. (2) The melting point of the alloy prepared by the ratio of metallic tin to sponge titanium in the preparation method provided in Examples 4-5 is significantly different from that of sponge titanium, which does not meet the purpose of using titanium-tin intermediate alloy. The melting point is too high for sponge titanium, which increases power consumption and causes greater burn-off of other elements in the titanium alloy, such as aluminum. If the melting point is much lower than that of sponge titanium, the titanium-tin alloy itself will suffer greater burn-off. A comprehensive analysis of Examples 1 and 6-7 shows that if the temperature of the alloy melt is too high, the cooling time of the alloy melt in the cooling device will be longer, the tin diffusion time will be longer, and the amount of tin diffusion will be increased, resulting in a slight increase in tin segregation in the entire ingot; if the temperature is too low, the alloy melt will be more viscous during casting, and a large amount of alloy melt will adhere to the nozzle, making casting difficult, resulting in less alloy melt entering the ingot mold and a lower yield. (3) Comprehensive analysis of Examples 1 and 8-9 shows that a high volume ratio of the cold core in the cooling device will result in a low single utilization rate of the ingot mold, while a low volume ratio will result in insufficient cooling speed of the alloy ingot core, prolonged diffusion time of selenium from the core to the edge, and aggravated segregation of the main elements in the ingot. A comprehensive analysis of Examples 1 and 10-11 shows that a larger gap between the ingot mold 1 and the cooling sleeve 2 will result in a smaller ingot mold volume, a smaller effective cooling alloy ingot weight, and a lower single output. A smaller gap will result in a smaller cooling water volume, lower cooling efficiency, and increased segregation within the ingot. (4) Compared with Example 1, Comparative Example 1 adopted a conventional charging method, which achieved limited control over the degree of tin segregation in the alloy ingot, which was only 1.95%. However, due to the mixed charging, tin infiltration through the crucible caused the final alloy tin content to deviate significantly from the design value, resulting in a yield of only 79.3%. Compared to Example 1, Comparative Example 2 uses a conventional cooling device to cool the alloy melt. During the cooling process, the cooling and solidification can only be carried out gradually from the outer end of the ingot mold to the ingot core. The cooling effect is weak and the cooling time is long. This provides sufficient time for tin elements to diffuse outward, resulting in a tin element deviation of 12.94% in the entire alloy ingot and a product yield as low as 68.2%.

[0067] In summary, by constructing the raw material into a "titanium-coated tin core" structure, this invention can effectively reduce the occurrence of tin seepage in the crucible, reduce tin raw material loss, and make the final alloy composition more accurate. Combined with a cooling device, it achieves synergistic internal and external cooling, which can effectively suppress tin atom diffusion, prevent the tin element reverse segregation phenomenon in the traditional smelting process, enhance the uniform distribution of tin elements in the titanium-tin alloy ingot, and control the tin element content deviation in the titanium-tin alloy ingot within 2wt%.

[0068] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for producing a titanium-tin master alloy for suppressing tin segregation, characterized by, The preparation method comprises the following steps: (1) pressing of a smelting blank: the smelting blank comprises a hollow frustum blank and a frustum blank embedded in the hollow frustum blank; the raw material of the hollow frustum blank is titanium sponge, and the raw material of the frustum blank is metal tin; (2) smelting refining: the smelting blank is placed in a crucible, vacuumizing is performed, and then power feeding smelting treatment is performed, and then refining treatment and cooling treatment are performed to obtain an alloy melt; (3) pouring and cooling: after the cooling device is opened, the alloy melt is poured into the cooling device, and after cooling treatment, demolding treatment is performed to obtain the titanium-tin intermediate alloy; The outer surface and the inner part of the cooling device are provided with water cooling units.

2. The method for producing a titanium-tin master alloy for suppressing tin segregation according to claim 1, characterized by, In step (1), the mass ratio of the metal tin and the titanium sponge is (4.0-4.5):

1.

3. The method for producing a titanium-tin master alloy for suppressing tin segregation according to claim 1 or 2, characterized in that, In step (2), the temperature of the power feeding smelting treatment is 1250-1350℃; Preferably, in step (2), the temperature of the refining treatment is 1400-1450℃; Preferably, in step (2), the time of the refining treatment is 5-15 min; Preferably, in step (2), the end point temperature of the cooling treatment is 1250-1300℃.

4. The method of producing a titanium-tin master alloy for suppressing tin segregation according to any one of claims 1 to 3, characterized in that, In step (3), the cooling medium used in the pouring and cooling comprises distilled water; Preferably, the inlet temperature of the distilled water is -10-25℃; Preferably, in step (3), the water pressure of the distilled water is 0.2-0.25 MPa; Preferably, in step (3), the time of the cooling treatment is 2-4 h.

5. Cooling device, characterized in that The cooling device is used in the preparation method of the titanium-tin intermediate alloy for inhibiting tin segregation according to any one of claims 1-4.

6. Cooling device according to claim 5, characterized in that The cooling device comprises an ingot mold, a plurality of fixing holes and a sealing ring; the water cooling unit comprises a cooling sleeve and a cooling core; Preferably, the cooling sleeve is sleeved on the outer periphery of the ingot mold; Preferably, the bottom of the ingot mold is welded with the cooling core; Preferably, the fixing holes are used for fixing the ingot mold and the cooling sleeve; Preferably, the cooling sleeve is provided with a groove on the surface of the upper edge close to the ingot mold; Preferably, the sealing ring is embedded in the groove.

7. Cooling device according to claim 6, characterized in that The ingot mold, the cooling sleeve and the cooling core are all circular truncated cone-shaped; Preferably, the ingot mold, the cooling sleeve and the cooling core have the same axis, and the circular cone angle is 5-10°; Preferably, the volume of the cooling core accounts for 10-25% of the internal volume of the ingot mold; Preferably, the cooling core is hollow inside and has an open bottom.

8. Cooling device according to claim 7, characterized in that A plurality of water outlet pipes are circumferentially and uniformly arranged on the upper part of the outer surface of the cooling sleeve; Preferably, a plurality of water inlet pipes are circumferentially and uniformly arranged on the lower part of the outer surface of the cooling sleeve; Preferably, the outlet ends of the water inlet pipes are concentratedly arranged at the bottom of the cooling core; Preferably, the distance between the outlet ends of the water inlet pipes and the horizontal plane of the bottom of the ingot mold is 20-50 mm; Preferably, the pipe diameters of the water outlet pipes and the water inlet pipes are 20-60 mm.

9. Cooling device according to any of claims 6-8, characterized in that The wall thickness of the ingot mold is 20-40 mm; Preferably, the wall thickness of the cooling sleeve is ≥15 mm; Preferably, the gap width between the ingot mold and the cooling sleeve is 30-50 mm.

10. The cooling device of claim 6, wherein, The materials of the ingot mold and the cooling core are independently purple copper; Preferably, the material of the cooling sleeve comprises die steel; Preferably, the sealing ring is made of any one of fluororubber, silicone rubber, or perfluoroether rubber, with perfluoroether rubber being the most preferred.

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