Method for preparing low-cost Ti52 titanium alloy cast ingot from TA15 and TC6 return scraps

Abstract

The invention discloses a method for preparing a low-cost Ti52 titanium alloy cast ingot from TA15 and TC6 return scraps, which comprises the following steps: step 1, smelting raw materials in an electron beam cold bed furnace to obtain a primary cast ingot; the raw materials comprise an intermediate alloy, a TA15 return scrap and a TC6 return scrap; and secondly, vacuum self-consuming electric arc melting is conducted on the primary cast ingot, and the Ti52 titanium alloy cast ingot is obtained after cooling. According to the preparation method, TA15 return scrap, TC6 return scrap, sponge titanium and intermediate alloy are used as raw materials, advantages and disadvantages of electron beam cold bed furnace smelting and vacuum self-consuming electric arc smelting are integrated, the low-cost and high-quality Ti52 titanium alloy cast ingot is prepared through a duplex smelting process, the phenomenon that chemical components of the Ti52 titanium alloy cast ingot are not uniform is avoided, and the quality of the Ti52 titanium alloy cast ingot is improved. And the method is suitable for the technical field of titanium alloy cast ingot preparation.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy ingot preparation, and in particular relates to a method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials. Background Art Titanium alloys have the characteristics of high specific strength, low density, corrosion resistance, and non-magnetic properties. They have very important applications in aerospace, weapons and ships, petrochemicals and other fields, and have the potential to expand their applications. However, due to the high cost of titanium alloy raw materials and the long processing process, their prices are higher than those of metals such as steel and aluminum, which limits their further widespread application. Therefore, reducing costs has been the research focus and hot topic of titanium alloy researchers in recent years. There are two common methods: (1) by adding low-priced elements such as Fe to replace expensive elements such as V; (2) by adding titanium alloy return materials to reduce raw material costs. Russia's Avisma Company reported that for every 1% increase in titanium return materials, the cost of titanium alloy ingots can be reduced by 0.7%; if the amount of titanium return materials added reaches 50%, the cost of titanium alloy ingots can be reduced by at least one-third.

[0002] Titanium alloy recycled materials include ingot risers, ingot bottoms, rod tips, plate edges, and turnings. During the production process, there is a risk of contamination with other raw materials or inclusions, ultimately leading to abnormal ingot composition or the presence of inclusions. The vacuum consumable arc furnace is currently one of the most widely used methods for smelting titanium alloys. Its advantage is the uniformity of the composition of the ingots produced, but due to its simultaneous melting and solidification process, its impurity removal capability is limited. The vacuum electron beam cooling hearth (EB) furnace is another commonly used smelting method. The molten titanium melt is placed on a cooling hearth for a period of time, effectively removing inclusions introduced by the titanium alloy return material. However, due to the melting characteristics of the EB cooling hearth furnace, it can lead to severe burnout of low-saturated vapor pressure elements (such as Al and Cr), making it difficult to control the uniformity of the ingot composition.

[0003] Ti52 alloy (nominal composition: Ti-6.7Al-2V-1Zr-1.5Mo-2Cr-0.5Fe) is a titanium alloy grade independently developed and designed in my country. Existing technology uses titanium sponge and master alloys to produce Ti52 alloy, but this is costly. Furthermore, removing inclusions and controlling the composition uniformity of conventional titanium alloy return materials are difficult, severely limiting their widespread use. Summary of the Invention

[0004] The present invention aims to overcome the deficiencies in the prior art by providing a method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials. This method reduces the production cost of Ti52 titanium alloy ingots by replacing some of the raw materials with TA15 and TC6 return materials. Furthermore, the method combines a dual melting process of electron beam cold hearth furnace melting and vacuum consumable arc melting to improve the uniformity of the Ti52 titanium alloy ingots and produce high-quality Ti52 titanium alloy ingots, thereby addressing the high cost of preparing Ti52 alloys using the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials, characterized in that the method comprises the following steps: Step 1: Smelting the raw materials in an electron beam cold hearth furnace to obtain a primary ingot; the raw materials include master alloy, TA15 return material and TC6 return material; Step 2: The primary ingot obtained in step 1 is subjected to vacuum consumable arc melting, and after cooling, a Ti52 titanium alloy ingot is obtained.

[0006] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that the intermediate alloy in step one is one or more of an aluminum-vanadium alloy, an aluminum-chromium alloy, a titanium-iron alloy, and an aluminum-molybdenum alloy; the particle size of the aluminum-vanadium alloy is 0.83 mm to 3 mm, the particle size of the aluminum-chromium alloy is 1 mm to 3 mm, the particle size of the titanium-iron alloy is 1 mm to 6 mm, and the particle size of the aluminum-molybdenum alloy is not greater than 0.5 mm.

[0007] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials is characterized in that the raw materials in step one also include one or more of sponge titanium, sponge zirconium and aluminum, and the sponge titanium is selected from grade 1 or above.

[0008] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that the total mass of the TA15 return material and the TC6 return material in step one accounts for 60% to 80% of the total mass of the raw materials.

[0009] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that, when the TA15 return material and TC6 return material in step one are in block form, the TA15 return material and TC6 return material are pickled, alkali washed and shot blasted before smelting in an electron beam cooling hearth furnace, and then the raw materials other than the TA15 return material and TC6 return material are mixed and pressed into electrode blocks, and the TA15 return material, TC6 return material and electrode blocks are layered in the material box of the electron beam cooling hearth furnace to form a TA15 return material layer, a TC6 return material layer and an electrode block layer; the size of the block is: length greater than 100 mm, width greater than 100 mm, and thickness greater than 15 mm.

[0010] The present invention can control the smooth movement of raw materials during the electron beam cooling hearth furnace smelting process by laying out the block-shaped TA15 return material, TC6 return material and electrode blocks in layers, and at the same time can make the raw material composition during the electron beam cooling hearth furnace smelting process more uniform, thereby improving the composition uniformity of the primary ingot.

[0011] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that when the TA15 return material and TC6 return material in step one are in the form of chips, the TA15 return material and TC6 return material are crushed, cleaned, and screened before electron beam cold hearth furnace smelting, and then all the raw materials are mixed and pressed into electrode blocks; the size of the chips is: length 5mm~12mm, width 5mm~12mm, and thickness not more than 1mm.

[0012] The present invention mixes the chip-like TA15 return material and TC6 return material with other raw materials and presses them into electrode blocks, thereby avoiding the scattering of the chip-like materials during movement due to their small size during the electron beam cold hearth furnace smelting process. At the same time, the raw material composition during the electron beam cold hearth furnace smelting process is more uniform, thereby improving the composition uniformity of the primary ingot.

[0013] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that the electron beam cold hearth furnace smelting in step one includes bottom making and smelting processes, the electron gun current of the bottom making process is 1A~6A, the melting rate of the smelting process is 150kg / h~900kg / h, and the crucible diameter of the electron beam cold hearth furnace smelting is 300mm~890mm.

[0014] The present invention is used to ensure the composition uniformity of a primary ingot by controlling the electron gun current in the bottom making process and the melting rate in the melting process.

[0015] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that the parameters of the vacuum consumable melting in step 2 are: melting current 8kA~36kA, melting voltage 22V~34V, arc stabilization current 5A~30A, arc stabilization period 5s~30s; the crucible diameter of the vacuum consumable melting is 380mm~1020mm.

[0016] The present invention is used to ensure the composition uniformity of Ti52 titanium alloy ingots by controlling the parameters of vacuum consumable melting; by controlling the crucible diameters of electron beam cold hearth furnace melting and vacuum consumable melting, the size of the obtained Ti52 titanium alloy ingot can be freely adjusted, and at the same time, the crucible diameter of the electron beam cold hearth furnace melting is controlled to be smaller than the crucible diameter of the vacuum consumable melting crucible, so as to ensure production safety and the surface quality of the ingots.

[0017] The above-mentioned method for preparing low-cost Ti52 titanium alloy ingots using TA15 and TC6 return materials is characterized in that the cross-sectional area ratio of the primary ingot in step one to the Ti52 titanium alloy ingot in step two is 0.62~0.88.

[0018] The present invention is used to ensure production safety and surface quality of the ingot by controlling the cross-sectional area ratio of the primary ingot and the Ti52 titanium alloy ingot.

[0019] Compared with the prior art, the present invention has the following advantages: 1. The present invention adopts TA15 return material and TC6 return material to replace part of the raw materials to reduce the preparation cost of Ti52 titanium alloy ingots, and combines the electron beam cold hearth furnace melting + vacuum consumable arc melting method to avoid the occurrence of uneven chemical composition of Ti52 titanium alloy ingots and improve the quality of Ti52 titanium alloy ingots.

[0020] 2. Among the raw materials for preparing Ti52 titanium alloy ingots according to the present invention, the total mass proportion of TA15 return material and TC6 return material can reach more than 60%, which significantly reduces the preparation cost of Ti52 titanium alloy ingots.

[0021] 3. The present invention divides TA15 return material and TC6 return material into block and chip shapes according to size, lays the block material and the electrode blocks pressed by the remaining raw materials in layers, and then performs electron beam cold hearth furnace melting. The chip material is mixed with the remaining raw materials and pressed into electrode blocks, which are then subjected to electron beam cold hearth furnace melting. Combined with controlling the speed of the electron beam cold hearth furnace melting, the present invention can effectively control the uniformity of the composition of the primary ingot; and through subsequent vacuum consumable arc melting, further ensure that the composition of each part of the Ti52 titanium alloy ingot is uniform.

[0022] 4. The preparation method of the present invention has a simple process, low production cost, and is easy to industrialize. The diameter of the prepared Ti52 titanium alloy ingot can reach 1020 mm. At the same time, the method of preparing low-cost titanium alloy by "heterogeneous grade return material + intermediate alloy" proposed in the present invention is also applicable to the preparation of other grades of titanium alloy ingots.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a physical picture of the Ti52 titanium alloy ingot prepared in Example 1. DETAILED DESCRIPTION

[0025] Example 1 The nominal composition of the Ti52 titanium alloy ingot in this embodiment is Ti-6.0Al-2.6V-1Zr-1.5Mo-1.6Cr-0.5Fe-0.09O. The method for preparing the Ti52 titanium alloy ingot comprises the following steps: Step 1: 170kg of aluminum-vanadium alloy with a particle size of 0.83mm~3mm, 115kg of aluminum-chromium alloy with a particle size of 1mm~3mm, 55kg of titanium-iron alloy with a particle size of 1mm~6mm, 22kg of aluminum-molybdenum alloy with a particle size not greater than 0.5mm, 46kg of aluminum beans, 22kg of sponge zirconium, and 1580kg of grade 1 or above sponge titanium are mixed evenly through an automatic mixing system and pressed into 25 pieces with a density of not less than 3.2g / cm 3 The electrode blocks are prepared, and 1400 kg of lump TA15 return material and 1600 kg of lump TC6 return material are pickled, alkali washed and shot blasted. The electrode blocks, lump TA15 return material and lump TC6 return material are then layered in a material box to form a layer of TA15 return material, a layer of TC6 return material and a layer of electrode blocks, so that they are evenly distributed in the material box for electron beam cold hearth furnace smelting to obtain a primary ingot. The dimensions of the lump TA15 return material and the lump TC6 return material are as follows: a length greater than 100 mm, a width greater than 100 mm, and a thickness greater than 15 mm. The nominal composition of the TA15 return material is Ti-6.5Al-1Mo-1V-2Zr, and the nominal composition of the TC6 return material is Ti-6Al-1.5Cr-2.5Mo-0.5Fe-0.3Si. The process of electron beam cold hearth furnace melting is as follows: vacuuming to 1.0×10 0 Pa is used to make the bottom, and the electron gun current is maintained at 1A~6A during the bottom making process. When the molten metal covers the bottom of the crucible, the melting rate is 700kg / h~900kg / h, and the crucible is taken out of the furnace after cooling for 10 hours. The diameter of the crucible for melting in the electron beam cooling hearth furnace is 890mm; Step 2: The primary ingot obtained in step 1 is subjected to vacuum consumable arc melting, cooled for 11 hours and then taken out of the furnace to obtain Figure 1 The 5000kg Ti52 titanium alloy ingot shown is shown; the parameters of the vacuum consumable melting are: melting current 10kA~36kA, melting voltage 27V~34V, arc stabilization current 5A~30A, arc stabilization period 10s~30s; the crucible diameter of the vacuum consumable melting is 1020mm.

[0026] The upper, middle and lower parts of the Ti52 titanium alloy ingot prepared in this embodiment were turned and sampled for composition inspection, and the results are shown in Table 1; the upper part is 200mm~300mm away from the ingot head, and the lower part is 200mm~300mm away from the ingot bottom.

[0027] Table 1 Component mass percentage of each part of the Ti52 titanium alloy ingot prepared in Example 1

[0028] The preparation method of this embodiment was used for repeated preparation and composition testing, and the composition results of various parts of the obtained Ti52 titanium alloy ingot are shown in Table 2.

[0029] Table 2 Component mass percentage of each part of the Ti52 titanium alloy ingots repeatedly prepared in Example 1

[0030] It can be seen from Table 1 and Table 2 that the preparation method of this embodiment can prepare a Ti52 titanium alloy ingot with uniform overall composition and in compliance with the nominal composition.

[0031] Example 2 The nominal composition of the Ti52 titanium alloy ingot in this embodiment is Ti-6.0Al-2.6V-1Zr-1.5Mo-1.6Cr-0.5Fe-0.10O. The method for preparing the Ti52 titanium alloy ingot comprises the following steps: Step 1: Mix 10.7kg of aluminum-vanadium alloy with a particle size of 0.83mm~3mm, 10kg of aluminum-chromium alloy with a particle size of 1mm~3mm, 4.6kg of titanium-iron alloy with a particle size of 1mm~6mm, 4.6kg of aluminum beans, and 90kg of grade 1 or above titanium sponge through an automatic mixing system and press them into 15 pieces with a density of not less than 3.2g / cm 3The electrode blocks are prepared, and 189 kg of TA15 return block material and 112 kg of TC6 return block material are pickled, alkali washed and shot blasted. The electrode blocks, TA15 return block material and TC6 return block material are then layered in a material box to form a layer of TA15 return material, a layer of TC6 return material and a layer of electrode blocks, so that they are evenly distributed in the material box for electron beam cold hearth furnace smelting to obtain a primary ingot. The dimensions of the TA15 return block material and the TC6 return block material are as follows: a length greater than 100 mm, a width greater than 100 mm and a thickness greater than 15 mm. The nominal composition of the TA15 return material is Ti-6.5Al-1Mo-1V-2Zr, and the nominal composition of the TC6 return material is Ti-6Al-1.5Cr-2.5Mo-0.5Fe-0.3Si. The process of electron beam cold hearth furnace melting is as follows: vacuuming to 1.0×10 0 Pa is used to make the bottom, and the electron gun current is maintained at 1A~6A during the bottom making process. When the molten metal covers the bottom of the crucible, the melting rate is 150kg / h~300kg / h, and the crucible is taken out of the furnace after cooling for 4 hours. The diameter of the crucible for melting in the electron beam cooling hearth furnace is 390mm; Step 2: The primary ingot obtained in step 1 is subjected to vacuum consumable arc melting, cooled for 5 hours and then taken out of the furnace to obtain a 400 kg Ti52 titanium alloy ingot; the parameters of the vacuum consumable melting are: melting current 8kA~20kA, melting voltage 22V~30V, arc stabilization current 5A~20A, and arc stabilization period 5s~20s; the crucible diameter of the vacuum consumable melting is 480 mm.

[0032] The upper and lower parts of the Ti52 titanium alloy ingot prepared in this embodiment were turned and sampled for composition inspection, and the results are shown in Table 3; the upper part is 200mm~300mm away from the ingot head, and the lower part is 200mm~300mm away from the ingot bottom.

[0033] Table 3 Mass percentage of components of each part of the Ti52 titanium alloy ingot prepared in Example 2

[0034] As can be seen from Table 3, the preparation method of this embodiment can prepare a Ti52 titanium alloy ingot with uniform overall composition and in compliance with the nominal composition.

[0035] Example 3 The nominal composition of the Ti52 titanium alloy ingot in this embodiment is Ti-6.0Al-2.6V-1Zr-1.5Mo-1.6Cr-0.5Fe-0.10O. The method for preparing the Ti52 titanium alloy ingot comprises the following steps: Step 1: Crushing, cleaning, and screening 189 kg of TA15 return material and 112 kg of TC6 return material to obtain contamination-free TA15 return material and TC6 return material; the size of the chips is: length 5 mm to 12 mm, width 5 mm to 12 mm, and thickness not greater than 1 mm; 11kg of aluminum-vanadium alloy with a particle size of 0.83mm~3mm, 10.5kg of aluminum-chromium alloy with a particle size of 1mm~3mm, 5.0kg of titanium-iron alloy with a particle size of 1mm~6mm, 5.2kg of aluminum beans, 105kg of grade 1 or above titanium sponge, 205kg of shavings of pollution-free TA15 return material and 124kg of shavings of pollution-free TC6 return material were mixed evenly by an automatic mixing and distributing system and then pressed into 20 pieces with a density of not less than 3.2g / cm 3 The electrode block is then placed in a material box and smelted in an electron beam cold hearth furnace to obtain a primary ingot; the nominal composition of the TA15 return material is Ti-6.5Al-1Mo-1V-2Zr, and the nominal composition of the TC6 return material is Ti-6Al-1.5Cr-2.5Mo-0.5Fe-0.3Si; The process of electron beam cold hearth furnace melting is as follows: vacuuming to 1.0×10 0 Pa is used to make the bottom, and the electron gun current is maintained at 1A~6A during the bottom making process. When the molten metal covers the bottom of the crucible, the melting rate is 150kg / h~250kg / h, and the crucible is taken out of the furnace after cooling for 4 hours. The diameter of the crucible for melting in the electron beam cooling hearth furnace is 300mm; Step 2: The primary ingot obtained in step 1 is subjected to vacuum consumable arc melting, cooled for 5 hours and then taken out of the furnace to obtain a 460kg Ti52 titanium alloy ingot; the parameters of the vacuum consumable melting are: melting current 8kA~15kA, melting voltage 22V~30V, arc stabilization current 5A~20A, and arc stabilization period 5s~20s; the crucible diameter of the vacuum consumable melting is 380mm.

[0036] The upper and lower parts of the Ti52 titanium alloy ingot prepared in this embodiment were turned and sampled for composition inspection, and the results are shown in Table 4; the upper part is 200mm~300mm away from the ingot head, and the lower part is 200mm~300mm away from the ingot bottom.

[0037] Table 4 Mass percentage of components of each part of the Ti52 titanium alloy ingot prepared in Example 3

[0038] As can be seen from Table 4, the preparation method of this embodiment can prepare a Ti52 titanium alloy ingot with uniform overall composition and in compliance with the nominal composition.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials, characterized in that: The method comprises the following steps: Step 1: Smelting the raw materials in an electron beam cold hearth furnace to obtain a primary ingot; the raw materials include master alloy, TA15 return material and TC6 return material; Step 2: The primary ingot obtained in step 1 is subjected to vacuum consumable arc melting, and after cooling, a Ti52 titanium alloy ingot is obtained.

2. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: The intermediate alloy in step 1 is one or more of an aluminum-vanadium alloy, an aluminum-chromium alloy, a titanium-iron alloy, and an aluminum-molybdenum alloy; the particle size of the aluminum-vanadium alloy is 0.83 mm to 3 mm, the particle size of the aluminum-chromium alloy is 1 mm to 3 mm, the particle size of the titanium-iron alloy is 1 mm to 6 mm, and the particle size of the aluminum-molybdenum alloy is not greater than 0.5 mm.

3. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: The raw materials in step 1 further include one or more of titanium sponge, zirconium sponge and aluminum, and the titanium sponge is selected from grade 1 or above.

4. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: When the total mass of the TA15 return material and the TC6 return material in step 1 accounts for 60% to 80% of the total mass of the raw materials.

5. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: When the TA15 return material and TC6 return material described in step one are in block form, before smelting in the electron beam cooling hearth furnace, the TA15 return material and TC6 return material are pickled, alkali washed and shot blasted, and then the raw materials other than the TA15 return material and TC6 return material are mixed and pressed into electrode blocks, and the TA15 return material, TC6 return material and electrode blocks are layered in the material box of the electron beam cooling hearth furnace to form a TA15 return material layer, a TC6 return material layer and an electrode block layer; the size of the block is: length greater than 100 mm, width greater than 100 mm, and thickness greater than 15 mm.

6. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: When the TA15 return material and TC6 return material in step 1 are in the form of chips, the TA15 return material and TC6 return material are crushed, cleaned, and screened before electron beam cold hearth furnace smelting, and then all the raw materials are mixed and pressed into electrode blocks; the size of the chips is: length 5mm~12mm, width 5mm~12mm, and thickness not more than 1mm.

7. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: The electron beam cold hearth furnace smelting in step 1 includes bottom making and smelting processes, the electron gun current of the bottom making process is 1A~6A, the melting rate of the smelting process is 150kg / h~900kg / h, and the crucible diameter of the electron beam cold hearth furnace smelting is 300mm~890mm.

8. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: The parameters of the vacuum consumable melting in step 2 are: melting current 8kA~36kA, melting voltage 22V~34V, arc stabilization current 5A~30A, arc stabilization period 5s~30s; the crucible diameter of the vacuum consumable melting is 380mm~1020mm.

9. The method for preparing low-cost Ti52 titanium alloy ingots from TA15 and TC6 return materials according to claim 1, characterized in that: The cross-sectional area ratio of the primary ingot in step 1 to the Ti52 titanium alloy ingot in step 2 is 0.62-0.88.

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