Aluminum-molybdenum-iron intermediate alloy, preparation method and application thereof

Abstract

The application provides an aluminum-molybdenum-iron intermediate alloy, wherein the mass percentage of each element in the aluminum-molybdenum-iron intermediate alloy is as follows: molybdenum: 55.0-60.0%, iron: 30.0-35.0%, oxygen: 0.01-0.1%, nitrogen: 0.001-0.05%, silicon: 0.01-0.2%, carbon: 0.01-0.05%, and the balance is aluminum. The application also provides a preparation method of the aluminum-molybdenum-iron intermediate alloy. The application also provides a method for preparing a titanium alloy ingot by using the aluminum-molybdenum-iron intermediate alloy. The application uses the aluminum-molybdenum-iron intermediate alloy as a raw material for vacuum self-consumption smelting, so that the content of iron and molybdenum in a high-iron and high-molybdenum titanium alloy ingot with a diameter of Ф550mm- Ф750mm is less than or equal to 0.2wt% in different regions, and the composition uniformity is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy and relates to a processing method for titanium alloys, specifically an aluminum-molybdenum-iron master alloy, its preparation method, and its application. Background Technology

[0002] The molybdenum in high-molybdenum titanium alloys enhances heat resistance and corrosion resistance, while iron, as an inexpensive β-stabilizing element, improves alloy strength. The synergistic effect of these elements results in high strength, good high-temperature stability, and excellent corrosion resistance, making it suitable for demanding and rigorous working environments. Furthermore, the addition of iron reduces alloy costs while maintaining performance, thus enhancing market competitiveness.

[0003] High-molybdenum titanium alloys for high-speed rail are now widely used in a variety of complex applications, including aero-engine parts and fuselage structural components, corrosion-resistant pipes and reactors for chemical applications, structural components for offshore platforms, and deep-sea equipment.

[0004] Due to the significant differences in melting points and diffusion rates among molybdenum, iron, and titanium, high-iron, high-molybdenum titanium alloys are prone to segregation during the solidification stage of ingot smelting. This segregation manifests as the enrichment of molybdenum and iron at grain boundaries or between dendrites, forming regions of non-uniform composition. This segregation leads to localized brittleness, reduces plasticity and toughness, and increases the difficulty of processing and forming. Furthermore, the overall properties of the material, such as strength, high-temperature stability, and corrosion resistance, will also decrease due to the non-uniform composition. It may even cause localized failure under heavy loads or harsh environments, shortening the service life of components and posing a threat to safe applications in critical fields such as aerospace and chemical engineering.

[0005] Using intermediate alloys as raw materials in the preparation of titanium alloy ingots can refine the solidification structure, shorten the diffusion distance, promote uniform dissolution of elements, regulate solidification kinetics, and thus optimize the element distribution state, effectively improving the unevenness of composition. This is an effective and key means to improve the quality of modern titanium alloy products.

[0006] Chinese patent application CN202010967632.0 discloses a method for preparing an aluminum-molybdenum-chromium-iron-silicon master alloy, comprising the following components by mass fraction: Mo: 22.0–24.0%, Fe: 3.0–5.0%, Cr: 13.0–15.0%, Si: 2.0–4.0%, with Al as the balance. This invention utilizes a combination of aluminothermic and vacuum melting, controlling the melting process in a medium-frequency vacuum induction furnace to ensure uniform distribution of aluminum, molybdenum, chromium, iron, and silicon in the alloy, reducing the content of gaseous impurities such as O and N. This contributes to the homogenization of the titanium alloy composition during the melting of TC6 titanium alloy. The master alloy described in this patent differs from the one described in this invention in terms of the mass ratio of metallic elements, with lower iron and molybdenum content and increased inclusion of chromium and silicon. When used to prepare titanium alloys with high iron and high molybdenum content, in order to meet the alloy composition requirements, it is still necessary to use more other intermediate alloys or raw materials in the form of elemental metals to incorporate iron and molybdenum. This results in the iron and molybdenum content in large-size ingots having a deviation of >0.2wt% in different regions and cannot be applied to materials that do not contain chromium and silicon.

[0007] Chinese Patent Application No. CN201711002703.8 discloses a molybdenum-iron-aluminum-silicon-titanium master alloy and its preparation method. The master alloy, by weight ratio, contains 30-45 parts Mo, 20-30 parts Fe, 6-10 parts Al, 0-3 parts Si, and 25-40 parts Ti. This molybdenum-iron-aluminum-silicon-titanium master alloy is mainly used for the production of low-cost β-type titanium alloys containing molybdenum, iron, aluminum, and silicon. It helps eliminate the large density differences between molybdenum, iron, aluminum, and titanium elements during alloy smelting. The semi-suspension melting process produces a stable chemical composition in the molybdenum-iron-aluminum-titanium master alloy, which is beneficial for the subsequent smelting and preparation of high-quality ingots of low-cost titanium alloys. The master alloy described in this patent has a different metal element mass ratio than that of this invention. It has lower iron and molybdenum content and increased silicon content. Furthermore, the preparation process involves only one induction melting and natural fracture using thermal stress cracking, resulting in a larger particle size in the final master alloy. When used to prepare high-iron, high-molybdenum titanium alloys, in order to meet the alloy composition requirements, it is still necessary to use other intermediate alloys or raw materials in the form of elemental metals to incorporate iron and molybdenum. Moreover, the compositional uniformity of intermediate alloys is insufficient, resulting in a deviation of >0.2wt% in the iron content and molybdenum content in different regions of large-sized ingots.

[0008] The current method for preparing large-sized titanium alloy ingots with high molybdenum content for high-speed rail involves mixing and stirring aluminum-molybdenum master alloy, iron nails, elemental aluminum, and sponge titanium, pressing them into electrodes, and then splicing them together. These electrodes are then vacuum welded and vacuum arc remelted to produce titanium alloy ingots with diameters ranging from Ф550mm to Ф750mm. When the prepared ingot size is small (diameter ≤ Ф400mm), the existing method can produce products with less segregation and higher compositional uniformity. However, for large-sized ingots with diameters exceeding Ф550mm, this leads to significant compositional deviations in different regions, with localized segregation of high-content iron and molybdenum elements, thus affecting the quality and stability of the final product. Summary of the Invention

[0009] To address the aforementioned technical problems in the prior art, this invention provides an aluminum-molybdenum-iron master alloy, its preparation method, and its application. This aluminum-molybdenum-iron master alloy and its preparation method and application aim to solve the technical problem in the prior art where the preparation method of large-diameter ingots with a diameter of Ф550mm or more leads to large compositional deviations in different regions and local segregation of high-content iron and molybdenum elements, thereby affecting the quality and stability of the final product.

[0010] This invention provides an aluminum-molybdenum-iron master alloy, wherein the mass percentages of each element in the aluminum-molybdenum-iron master alloy are as follows:

[0011] Molybdenum: 55.0%–60.0%

[0012] Iron: 30.0%–35.0%

[0013] Oxygen: 0.01–0.1%,

[0014] Nitrogen: 0.001–0.05%,

[0015] Silicon: 0.01–0.2%,

[0016] Carbon: 0.01–0.05%,

[0017] The balance is aluminum and unavoidable impurities, and the total amount of all elements is 100%.

[0018] Furthermore, the mass percentages of each element in the aforementioned aluminum-molybdenum-iron master alloy are as follows:

[0019] Molybdenum: 58.0%–60.0%

[0020] Iron: 30.0%–32.0%

[0021] Oxygen: 0.01–0.1%,

[0022] Nitrogen: 0.001–0.005%,

[0023] Silicon: 0.01–0.15%,

[0024] Carbon: 0.01–0.02%,

[0025] The balance is aluminum and unavoidable impurities, and the total amount of all elements is 100%.

[0026] This invention also provides a method for preparing the above-mentioned aluminum-molybdenum-iron master alloy, comprising the following steps:

[0027] Step S1: The first aluminum bean, the second aluminum bean, the iron oxide powder, the molybdenum trioxide powder, the molybdenum dioxide powder, the auxiliary heating agent, the flux, and the reaction regulator are baked separately for drying.

[0028] Step S2: After mixing the first aluminum granule, iron oxide powder, auxiliary heating agent, flux, and reaction regulator, a binder solution is sprayed onto the surface and the mixture is stirred and pressed to form a raw material metal block. The mass ratio of iron oxide powder, first aluminum granule, reaction regulator, flux, and auxiliary heating agent is (8.80~10.20):(0.78~1.32):(1.10~1.65):(3.79~4.65):(1.80~2.42).

[0029] Step S3: Ignite the raw material metal block to carry out the aluminothermic reaction and obtain an aluminum-iron primary metal alloy;

[0030] Step S4: Crush the aluminum-iron primary metal alloy to make aluminum-iron primary metal alloy blocks.

[0031] Step S5: Following the order of "molybdenum trioxide powder - molybdenum dioxide powder - the aforementioned aluminum-iron primary metal alloy block - the second aluminum bean", each raw material is placed into a vacuum induction furnace and melted and cast. After cooling, an aluminum-molybdenum-iron secondary alloy ingot is obtained. The mass ratio of molybdenum trioxide powder, molybdenum dioxide powder, aluminum-iron primary metal alloy block, and the second aluminum bean is (3.88~4.61):(3.49~4.13):(3.80~4.40):(0.20~0.65).

[0032] Step S6: Refine and crush the aluminum-molybdenum-iron secondary alloy ingot, and obtain aluminum-molybdenum-iron intermediate alloy with a particle diameter of 1-6 mm through fine selection.

[0033] Furthermore, the auxiliary heating agent is ammonium perchlorate powder, the flux is silicon dioxide powder, the reaction regulator is pure iron powder, the binder is ethyl silicate solution, and the concentration of the ethyl silicate solution is 3.5–4.5 mol / L; the baking temperature of the iron oxide powder, molybdenum trioxide powder, and molybdenum dioxide powder is 600℃–800℃, the baking temperature of the flux, the first aluminum briquette, and the second aluminum briquette is 80℃–120℃, and the baking temperature of the auxiliary heating agent is 40℃–60℃.

[0034] Furthermore, in steps S1, S2, and S5, the particle size of the first aluminum bean, the second aluminum bean, the iron tetroxide powder, the molybdenum trioxide powder, and the molybdenum dioxide powder is 0-5 mm.

[0035] Furthermore, in step S2, the density of the pressed raw material metal block is 3.35 g / cm³. 3 ~3.65g / cm 3 .

[0036] Furthermore, in step S3, the aluminothermic reaction temperature is 2100℃~2200℃, and the reaction time is 50s~60s.

[0037] Furthermore, in step S4, the particle size of the crushed aluminum-iron primary metal alloy block is 1-8 mm.

[0038] Furthermore, in step S5, the melting power of vacuum induction melting is 150kW to 160kW, the refining power is 90kW to 100kW, the vacuum degree of the melting environment is ≤1Pa, and argon gas is introduced for cooling after melting is completed.

[0039] The present invention also provides a method for preparing titanium alloy ingots using an intermediate alloy, comprising the following steps:

[0040] Step P1: Place the aluminum-molybdenum-iron intermediate alloy obtained above into a closed cavity for baking;

[0041] Step P2: According to the composition requirements of the ingot, the aluminum-molybdenum-iron intermediate alloy, other raw materials and sponge titanium are stirred and mixed and then pressed into electrode blocks with a diameter of Ф300mm~Ф400mm.

[0042] Step P3: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding.

[0043] Step P4: Place the aforementioned consumable electrode into a crucible and perform vacuum consumable smelting at least three times to produce a large-scale ingot of high-iron and high-molybdenum titanium alloy with a diameter of Ф550mm~Ф750mm.

[0044] Step P5: Finish the ingot and take samples for inspection.

[0045] Furthermore, in step P1, the baking temperature is 60℃~100℃.

[0046] Furthermore, the other raw materials mentioned are aluminum wire, aluminum-molybdenum-vanadium master alloy, or titanium-chromium master alloy.

[0047] Furthermore, in step P3, the vacuum level inside the plasma welding furnace during vacuum welding is 5 Pa to 10 Pa.

[0048] Furthermore, in step P4, during the final vacuum self-consumption smelting, the vacuum level during the arc stabilization stage is ≤5Pa, the smelting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

[0049] In steps S1 to S6 of this invention, a method for preparing an aluminum-molybdenum-iron master alloy is described, and this method is applied to manufacture large-scale titanium alloy ingots with high iron and high molybdenum content using the methods described in steps P1 to P4, in order to improve the compositional segregation phenomenon. The principle is as follows:

[0050] The densities of molybdenum and iron are 10.2 g / cm³. 3 and 7.8g / cm 3 All are higher than those of the titanium matrix (density 4.5 g / cm³). 3 Furthermore, because molybdenum has a melting point above 2600℃ while titanium's is only above 1600℃, it easily settles as unmelted particles to the bottom of the ingot in the molten pool, thus forming molybdenum-rich and molybdenum-poor zones in different areas. Iron, as the strongest β-stabilizing element, tends to aggregate towards the core and top of the ingot during the smelting and solidification stage, resulting in uneven compositional distribution across regions and potentially forming β-spot defects. Simultaneously, the interaction between the two elements exacerbates this segregation trend. Molybdenum sedimentation accelerates the aggregation and migration of iron caused by convective disturbances, while iron promotes β-phase formation and reduces melt viscosity, further intensifying the molybdenum sedimentation tendency. Ultimately, this leads to composite segregation bands in the axial and radial directions of the ingot, which is the basic mechanism for the uneven composition of molybdenum and iron. For large-sized ingots, the large size increases the molybdenum sedimentation effect and iron aggregation and migration tendency during smelting, and the heavier mass also means that more raw materials are required. When the raw material composition or particle size is uneven, the ingot compositional segregation phenomenon will be exacerbated.

[0051] The aluminum-molybdenum-iron master alloy of this invention is manufactured using an aluminothermic reduction reaction combined with vacuum induction melting, and uses iron(III) oxide as an oxide to enhance reaction efficiency and controllability. When applied to the preparation of titanium alloy ingots, this aluminum-molybdenum-iron master alloy makes the melting points of molybdenum and iron closer to the titanium matrix, reducing the temperature gradient during melting, suppressing element precipitation and coarse dendrite growth; it also refines the casting microstructure to shorten element diffusion paths, thereby reducing the tendency for element aggregation and migration, and decreasing the interdendritic enrichment of molybdenum and iron. Furthermore, the high content and alloyed form of molybdenum and iron in this master alloy lowers their dissolution activation energy in the titanium melt, avoiding excessively high local concentrations of a single metal caused by the addition of multiple different raw materials, reducing the formation of element agglomeration nuclei, making the manufacturing process more controllable, and resulting in more uniform composition in each region.

[0052] Compared with existing technologies, the technical effects of this invention are positive and significant. Large-sized titanium alloy ingots with high iron and molybdenum content and diameters ranging from Ф550mm to Ф750mm, prepared using existing technologies, exhibit significant variations in elemental content across different regions, with molybdenum reaching 0.4wt% to 0.8wt% and iron 0.5wt% to 0.9wt%. This invention, by employing an aluminum-molybdenum-iron master alloy and applying it to vacuum arc remelting, ensures that the variations in iron and molybdenum content across different regions of the prepared ingots are both ≤0.2wt%, thereby effectively improving compositional uniformity. Attached Figure Description

[0053] Figure 1 A schematic cross-sectional sampling diagram of the chemical composition of the ingot in this invention.

[0054] Figure 2 A schematic diagram of longitudinal sampling of the chemical composition of the ingot in this invention. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0056] The main parameters and analysis and test results of the embodiments and comparative examples of this invention are shown in Table 1.

[0057] Example 1

[0058] A Ti-LCB titanium alloy ingot has an outer diameter of Φ700mm and a height of 2700mm. The required composition of its main metallic elements is as follows:

[0059] Aluminum: 1.0wt%–2.0wt%, Iron: 4.0wt%–5.0wt%, Molybdenum: 6.3wt%–7.3wt%.

[0060] First, the preparation steps of the aluminum-molybdenum-iron master alloy raw material are as follows:

[0061] Step S1: The aluminum granules, iron oxide powder, molybdenum trioxide powder, molybdenum dioxide powder, auxiliary heating agent, flux, and reaction regulator are baked separately for drying.

[0062] Step S2: After mixing aluminum briquettes, iron oxide powder, auxiliary heating agent, flux, and reaction regulator, a binder solution is sprayed onto the surface and the mixture is stirred and pressed to form a raw material metal block. The mass ratio of iron oxide powder, aluminum briquettes, reaction regulator, flux, and auxiliary heating agent is 10.00:1.12:1.45:4.45:2.22.

[0063] Specifically, the auxiliary heating agent is ammonium perchlorate powder, the flux is silicon dioxide powder, the reaction regulator is pure iron powder, and the binder is ethyl silicate solution with a concentration of 4.5 mol / L.

[0064] Step S3: Ignite the raw material metal block to carry out the aluminothermic reaction and obtain an aluminum-iron primary metal alloy;

[0065] Step S4: Crush the aluminum-iron primary metal alloy to make aluminum-iron primary metal alloy blocks.

[0066] Step S5: Following the order of "molybdenum trioxide powder - molybdenum dioxide powder - the aforementioned aluminum-iron primary metal alloy block - aluminum granules", place each raw material into a vacuum induction furnace for melting and casting. After cooling, an aluminum-molybdenum-iron secondary alloy ingot is obtained, wherein the mass ratio of molybdenum trioxide powder, molybdenum dioxide powder, aluminum-iron primary metal alloy block, and aluminum granules is 4.08:3.69:4.00:0.45.

[0067] Step S6: Refine and crush the aluminum-molybdenum-iron secondary alloy ingot, and obtain aluminum-molybdenum-iron master alloy with 1-6mm particles through fine selection. The mass ratio of iron, molybdenum and aluminum elements in the aluminum-molybdenum-iron master alloy is 35:55:9.

[0068] The process of manufacturing an ingot using an intermediate alloy includes the following steps:

[0069] Step P1: Place the aluminum-molybdenum-iron intermediate alloy into a closed cavity for baking;

[0070] Step P2: According to the composition requirements of the ingot, the aluminum-molybdenum-iron master alloy, aluminum wire and sponge titanium are mixed in sequence at a mass ratio of 1.22:0.06:8.72 and then pressed into an electrode block with a diameter of Ф390mm.

[0071] Step P3: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding.

[0072] Step P4: Place the consumable electrode into a crucible and perform vacuum consumable smelting at least three times to produce a large-sized ingot of high-iron and high-molybdenum titanium alloy with a diameter of Ф700mm; In step P4, during the last vacuum consumable smelting, the vacuum degree of the arc stabilization stage is ≤5Pa, the melting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

[0073] Step P5: Finish the ingot and take samples for inspection.

[0074] Example 2

[0075] A BT22 titanium alloy ingot has an outer diameter of Φ580mm and a height of 2400mm. The required composition of its main metallic elements is as follows:

[0076] Aluminum: 4.5wt%–5.5wt%, Iron: 0.8wt%–1.5wt%, Molybdenum: 4.0wt%–5.5wt%, Chromium: 0.8wt%–1.5wt%, Vanadium: 4.5wt%–5.5wt%.

[0077] First, the preparation steps of the aluminum-molybdenum-iron master alloy raw material are as follows:

[0078] Step S1: The aluminum granules, iron oxide powder, molybdenum trioxide powder, molybdenum dioxide powder, auxiliary heating agent, flux, and reaction regulator are baked separately for drying.

[0079] Step S2: After mixing aluminum briquettes, iron oxide powder, auxiliary heating agent, flux, and reaction regulator, a binder solution is sprayed onto the surface and the mixture is stirred and pressed to form a raw material metal block. The mass ratio of iron oxide powder, aluminum briquettes, reaction regulator, flux, and auxiliary heating agent is 9.00:0.98:1.30:3.99:2.00.

[0080] Specifically, the auxiliary heating agent is ammonium perchlorate powder, the flux is silicon dioxide powder, the reaction regulator is pure iron powder, and the binder is ethyl silicate solution with a concentration of 3.5 mol / L.

[0081] Step S3: Ignite the raw material metal block to carry out the aluminothermic reaction and obtain an aluminum-iron primary metal alloy;

[0082] Step S4: Crush the aluminum-iron primary metal alloy to make aluminum-iron primary metal alloy blocks.

[0083] Step S5: Following the order of "molybdenum trioxide powder - molybdenum dioxide powder - the aforementioned aluminum-iron primary metal alloy block - aluminum granules", place each raw material into a vacuum induction furnace and melt and cast it. After cooling, an aluminum-molybdenum-iron secondary alloy ingot is obtained, wherein the mass ratio of molybdenum trioxide powder, molybdenum dioxide powder, aluminum-iron primary metal alloy block, and aluminum granules is 4.41:3.93:4.10:0.40.

[0084] Step S6: Refine and crush the aluminum-molybdenum-iron secondary alloy ingot, and obtain aluminum-molybdenum-iron master alloy with 1-6 mm particles through fine selection. The mass ratio of iron, molybdenum and aluminum elements in the aluminum-molybdenum-iron master alloy is 32:59:8.

[0085] The process of manufacturing an ingot using an intermediate alloy includes the following steps:

[0086] Step P1: Place the aluminum-molybdenum-iron intermediate alloy into a closed cavity for baking;

[0087] Step P2: According to the composition requirements of the ingot, the aluminum-molybdenum-iron master alloy, aluminum wire, aluminum-molybdenum-vanadium master alloy (the mass ratio of aluminum, molybdenum and vanadium elements is 22:27:50), titanium-chromium master alloy (the mass ratio of titanium and chromium elements is 1:1) and sponge titanium are mixed in sequence at a mass ratio of 0.36:0.26:1:0.24:8.14 and then pressed into an electrode block with a diameter of Ф330mm.

[0088] Step P3: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding.

[0089] Step P4: Place the aforementioned consumable electrode into a crucible and perform at least three vacuum consumable smelting processes to produce a large-sized ingot of high-iron and high-molybdenum titanium alloy with a diameter of Ф580mm. Specifically, in step P4, during the last vacuum consumable smelting process, the vacuum degree during the arc stabilization stage is ≤5Pa, the melting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

[0090] Step P5: Finish the ingot and take samples for inspection.

[0091] Comparative Example 1

[0092] A Ti-LCB titanium alloy ingot has an outer diameter of Φ700mm and a height of 2700mm. The required composition of its main metallic elements is as follows:

[0093] Aluminum: 1.0wt%–2.0wt%, Iron: 4.0wt%–5.0wt%, Molybdenum: 6.3wt%–7.3wt%.

[0094] Its manufacturing method includes the following steps:

[0095] Step P1: Mix aluminum-molybdenum master alloy (aluminum and molybdenum in a mass ratio of 1:9), aluminum wire, iron nails and sponge titanium in a mass ratio of 0.78:0.10:0.46:8.66 and press them into electrode blocks with a diameter of Ф390mm.

[0096] Step P2: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding.

[0097] Step P3: Place the consumable electrode into a crucible and perform vacuum consumable smelting at least three times to produce a Ti-LCB titanium alloy ingot with a diameter of Ф700mm; in step P3, during the last vacuum consumable smelting, the vacuum degree of the arc stabilization stage is ≤5Pa, the melting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

[0098] Step P4: Finish the ingot and take samples for inspection.

[0099] Comparative Example 2

[0100] A certain BT22 titanium alloy ingot has an outer diameter of Φ580mm and a height of 2400mm. The main metal element composition requirements are: aluminum: 4.5wt%~5.5wt%, iron: 0.8wt%~1.5wt%, molybdenum: 4.0wt%~5.5wt%, chromium: 0.8wt%~1.5wt%, and vanadium: 4.5wt%~5.5wt%.

[0101] Its manufacturing method includes the following steps:

[0102] Step P1: Mix aluminum-molybdenum master alloy (aluminum to molybdenum elemental composition mass ratio of 2:8), aluminum wire, iron nail, aluminum-molybdenum-vanadium master alloy (aluminum to molybdenum to vanadium elemental composition mass ratio of 22:27:50), titanium-chromium master alloy (titanium to chromium elemental composition mass ratio of 1:1) with sponge titanium in a mass ratio of 0.29:0.23:0.12:1:0.24:8.24, and then press it into an electrode block with a diameter of Ф330mm.

[0103] Step P2: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding.

[0104] Step P3: Place the consumable electrode into a crucible and perform vacuum consumable smelting at least three times to produce a BT22 titanium alloy ingot with a diameter of Ф580mm; specifically, in step P3, during the last vacuum consumable smelting, the vacuum degree of the arc stabilization stage is ≤5Pa, the melting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

[0105] Step P4: Finish the ingot and take samples for inspection.

[0106] Table 1

[0107]

[0108] As can be seen from the above examples and comparative examples in conjunction with Table 1, the titanium alloy ingots of "Comparative Example 1 and Example 1" and "Comparative Example 2 and Example 2" have the same composition requirements, outer diameter and height dimensions, and basic preparation process routes. However, the ingots of Comparative Example 1 and Comparative Example 2 did not contain aluminum-molybdenum-iron master alloy and used 4 to 6 different raw materials, while Example 1 and Example 2 used aluminum-molybdenum-iron master alloy and only used 3 to 5 different raw materials.

[0109] The ingots manufactured in all comparative examples and embodiments were analyzed and tested separately:

[0110] The Ti-LCB titanium alloy ingot with a diameter of Ф700mm manufactured in Comparative Example 1 was processed according to... Figure 1 and Figure 2 Sampling and composition analysis revealed that the iron content ranged from 4.43 wt% to 5.21 wt%, and the molybdenum content ranged from 6.65 wt% to 7.38 wt%. The iron content varied by up to 0.78 wt% in different regions, and the molybdenum content varied by up to 0.73 wt% in different regions.

[0111] The BT22 titanium alloy ingot with a diameter of Φ580mm manufactured in Comparative Example 2 was processed according to... Figure 1 and Figure 2 Sampling and composition analysis revealed that the iron content ranged from 0.91 wt% to 1.52 wt%, and the molybdenum content ranged from 4.94 wt% to 5.47 wt%. The iron content varied by up to 0.61 wt% in different regions, and the molybdenum content varied by up to 0.53 wt% in different regions.

[0112] The Ti-LCB titanium alloy ingot with a diameter of Ф700mm manufactured in Example 1 was processed according to... Figure 1 and Figure 2 Sampling and composition analysis revealed that the iron content ranged from 4.51 wt% to 4.68 wt%, and the molybdenum content ranged from 6.77 wt% to 6.93 wt%. The deviations in the iron and molybdenum content in different regions were all ≤0.2 wt%.

[0113] The BT22 titanium alloy ingot with a diameter of Φ580mm manufactured in Example 2 was processed according to... Figure 1 and Figure 2 Sampling and composition analysis revealed that the iron content ranged from 1.14 wt% to 1.27 wt%, and the molybdenum content ranged from 5.02 wt% to 5.17 wt%. The deviations in the iron and molybdenum content in different regions were all ≤0.2 wt%.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an aluminum-molybdenum-iron master alloy, characterized in that, Includes the following steps: Step S1: The first aluminum bean, the second aluminum bean, the iron oxide powder, the molybdenum trioxide powder, the molybdenum dioxide powder, the auxiliary heating agent, the flux, and the reaction regulator are baked separately for drying. Step S2: After mixing the first aluminum granule, iron oxide powder, auxiliary heating agent, flux, and reaction regulator, a binder solution is sprayed onto the surface and the mixture is stirred and pressed to form a raw material metal block. The mass ratio of iron oxide powder, first aluminum granule, reaction regulator, flux, and auxiliary heating agent is (8.80~10.20):(0.78~1.32):(1.10~1.65):(3.79~4.65):(1.80~2.42). Step S3: Ignite the raw material metal block to carry out the aluminothermic reaction and obtain an aluminum-iron primary metal alloy; Step S4: Crush the aluminum-iron primary metal alloy to make aluminum-iron primary metal alloy blocks. Step S5: Following the order of "molybdenum trioxide powder - molybdenum dioxide powder - the aforementioned aluminum-iron primary metal alloy block - second aluminum bean", place each raw material into a vacuum induction furnace and melt and cast it. After cooling, an aluminum-molybdenum-iron secondary alloy ingot is obtained. The mass ratio of molybdenum trioxide powder, molybdenum dioxide powder, aluminum-iron primary metal alloy block, and second aluminum bean is (3.88~4.61):(3.49~4.13):(3.80~4.40):(0.20~0.65). Step S6: Refine and crush the aluminum-molybdenum-iron secondary alloy ingot, and obtain an aluminum-molybdenum-iron intermediate alloy with a particle diameter of 1-6 mm through fine selection.

2. The method for preparing an aluminum-molybdenum-iron master alloy according to claim 1, characterized in that, The auxiliary heating agent is ammonium perchlorate powder, the flux is silicon dioxide powder, the reaction regulator is pure iron powder, and the binder is ethyl silicate solution with a concentration of 3.5–4.5 mol / L. The baking temperature of the iron oxide powder, molybdenum trioxide powder, and molybdenum dioxide powder is 600℃–800℃, the baking temperature of the flux, the first aluminum briquette, and the second aluminum briquette is 80℃–120℃, and the baking temperature of the auxiliary heating agent is 40℃–60℃.

3. The method for preparing an aluminum-molybdenum-iron master alloy according to claim 1, characterized in that, In steps S1, S2, and S5, the particle size of the first aluminum bean, the second aluminum bean, the iron tetroxide powder, the molybdenum trioxide powder, and the molybdenum dioxide powder is 0-5 mm.

4. The method for preparing an aluminum-molybdenum-iron master alloy according to claim 1, characterized in that, In step S2, the density of the pressed raw material metal block is 3.35 g / cm³. 3 ~3.65g / cm 3 In step S3, the aluminothermic reaction temperature is 2100℃~2200℃, and the reaction time is 50s~60s; in step S4, the particle size of the crushed aluminum-iron primary metal alloy block is 1~8mm; in step S5, the melting power of vacuum induction melting is 150kW~160kW, the refining power is 90kW~100kW, the vacuum degree of the melting environment is ≤1Pa, and argon gas is introduced for cooling after melting is completed.

5. A method for preparing titanium alloy ingots using a master alloy, characterized in that, Includes the following steps: Step P1: Place the aluminum-molybdenum-iron master alloy obtained in claim 1 into a closed cavity for baking; Step P2: According to the composition requirements of the ingot, the aluminum-molybdenum-iron intermediate alloy, other raw materials and sponge titanium are stirred and mixed and then pressed into electrode blocks with a diameter of Ф300mm~Ф400mm. Step P3: After connecting the electrode block with the auxiliary electrode, place it in a plasma welding furnace and manufacture a consumable electrode by vacuum welding. Step P4: Place the aforementioned consumable electrode into a crucible and perform vacuum consumable smelting at least three times to produce a high-iron, high-molybdenum titanium alloy ingot with a diameter of Ф550mm~Ф750mm. Step P5: Finish the ingot and take samples for inspection.

6. The method for preparing titanium alloy ingots using intermediate alloys according to claim 5, characterized in that: in step P1, the baking temperature is 60℃~100℃.

7. The method for preparing titanium alloy ingots using a master alloy according to claim 5, characterized in that: In step P3, the vacuum level inside the plasma welding furnace during vacuum welding is 5 Pa to 10 Pa.

8. The method for preparing titanium alloy ingots using a master alloy according to claim 5, characterized in that, In step P4, during the final vacuum self-consumption smelting, the vacuum level during the arc stabilization stage is ≤5Pa, the smelting temperature is 1600℃~1700℃, and the melting rate is 13kg / min~20kg / min.

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