High-homogeneity double-phase titanium alloy VAR cast ingot and preparation method thereof

Abstract

The invention discloses a high-homogeneity double-phase titanium alloy VAR cast ingot and a preparation method thereof.The preparation method comprises the steps that a consumable electrode is prepared from cast ingot raw materials, the consumable electrode and an auxiliary electrode are welded, and a first to-be-smelted electrode is obtained; the first to-be-smelted electrode is smelted for the first time, and a primary smelted cast ingot is obtained; the primary smelting cast ingot is turned around and then welded with the auxiliary electrode, and a second to-be-smelted electrode is obtained; the second electrode to be smelted is smelted for the second time, and a secondary smelted cast ingot is obtained; and the secondary smelting cast ingot is subjected to aftertreatment and detection, and the high-homogeneity double-phase titanium alloy VAR cast ingot is obtained. According to the method, the two-phase titanium alloy cast ingots are prepared through the two-time VAR smelting technology for electrodes of different specifications, the optimal arc stabilizing current input mode, size and period are matched according to the characteristics of different smelting stages, the size and morphology of a molten pool and the like, and the obtained titanium alloy cast ingots are uniform in component, high in yield and free of metallurgical defects such as shrinkage cavities and looseness.

Description

Technical Field

[0001] The present invention relates to the technical field of VAR ingot production, and particularly to a highly homogeneous duplex titanium alloy VAR ingot and a preparation method thereof. Background Art

[0002] Duplex titanium alloy is an α+β two-phase heat-resistant titanium alloy with excellent properties, having excellent creep resistance, thermal stability, corrosion resistance and workability, and is widely used in structural parts such as compressor disks, blades, and centrifuge impellers of aerospace engines. At present, the main method for industrial production of duplex titanium alloy ingots is the vacuum consumable melting method (VAR method), generally with three meltings, which has problems such as long process and low efficiency, and with the increase of the number of meltings, the compositional uniformity of the ingot becomes worse. The input mode and magnitude of the stabilizing arc current are significant factors affecting the impurity removal effect during the melting process, the health state of the molten pool, and the elemental distribution uniformity of the ingot. Therefore, in order to meet the demand for highly homogeneous duplex titanium alloy in high-end fields, it is necessary to further optimize the VAR melting process.

[0003] Based on this, the existing technology still needs to be improved. Summary of the Invention

[0004] To solve the above technical problems, an embodiment of the present invention provides a highly homogeneous duplex titanium alloy VAR ingot and a preparation method thereof to solve the technical problem that the existing duplex titanium alloy cannot meet the requirements of high-end fields.

[0005] To solve the above technical problems, some embodiments of the present invention disclose a preparation method of a highly homogeneous duplex titanium alloy VAR ingot, which includes: Step 1: Prepare a consumable electrode from the ingot raw materials, and weld the consumable electrode with an auxiliary electrode to obtain a first electrode to be melted; Step 2: Melt the first electrode to be melted for the first time to obtain a first-melted ingot; Step 3: After turning the first-melted ingot around, weld it with an auxiliary electrode to obtain a second electrode to be melted; Step 4: Melt the second electrode to be melted for the second time to obtain a second-melted ingot; Step 5: Perform post-treatment and detection on the second-melted ingot to obtain a highly homogeneous duplex titanium alloy VAR ingot. Further, in Step 1, the preparation of the consumable electrode includes: weighing sponge titanium and the required intermediate alloys according to the batching ratio, mixing the materials, pressing electrode blocks, and welding multiple electrode blocks to obtain a consumable electrode.

[0006] Further, in Step 1, the ratio of the consumable electrode to the crucible diameter is 0.78 - 0.92; Alternatively, in Step 1, after welding, evacuate the air to check the weld seam. After the weld seam is qualified, evacuate to a vacuum of ≤1 Pa, and the leak rate for leak detection is ≤0.8 Pa / min.

[0007] Further, in Step 2, the first melting includes an arc starting stage, a stable melting stage, and a feeding stage; And, the control time of the arc starting stage is not more than 25 min, the melting current increases linearly, and the current is input with direct current of 10 - 15 A; the ratio of the melting rate to the diameter of the consumable electrode in the stable melting stage is 0.015 - 0.035, the current is input with alternating current of 5 - 10 A, and the ratio of the alternating current period to the crucible diameter is 0.08 - 0.14; the duration of the feeding stage is not less than 30 min; Wherein, the unit of the melting rate is kg / min, the unit of the diameter of the consumable electrode is mm, the unit of the crucible diameter is mm, and the unit of the alternating current period is s.

[0008] Further, in Step 2, at the initial stage of the feeding stage, the current is input with direct current of 5 - 10 A. After the molten pool diameter is not greater than 2 / 3 of the crucible diameter, the current is input with direct current of 10 - 15 A.

[0009] Further, Step 2 also includes: after the feeding stage ends, maintain the vacuum for a predetermined time, then perform argon filling for cooling. After the cooling ends, perform surface treatment and feeding end treatment on the ingot to obtain a first - melted ingot.

[0010] Further, in Step 3, when welding the first - melted ingot after turning it around with the auxiliary electrode, the vacuum degree is ≤0.5 Pa and the leak rate is ≤0.5 Pa / min.

[0011] Further, in Step 4, the second melting includes an arc starting stage, a stable melting stage, and a feeding stage; And, the control time of the arc starting stage is not more than 25 min, the melting current increases linearly, and the current is input with direct current of 10 - 15 A; the ratio of the melting rate to the diameter of the consumable electrode in the stable melting stage is 0.027 - 0.032, the current is input with alternating current, and the ratio of the current magnitude to the crucible diameter is 0.015 - 0.02, and the alternating current period is 10 - 30 s; the feeding weight in the feeding stage satisfies 5% - 8% of the ingot weight, and the feeding duration is ≥120 min; Wherein, the unit of the melting rate is kg / min, the unit of the diameter of the consumable electrode is mm, the unit of the crucible diameter is mm, and the unit of the current is A.

[0012] Further, in Step 4, at the initial stage of the feeding stage, the current is input with direct current of 10 - 15 A. After the molten pool diameter is not greater than 2 / 3 of the crucible diameter, the current is input with direct current of 15 - 20 A.

[0013] On the other hand, the embodiments of the present invention also disclose a highly homogeneous dual-phase titanium alloy VAR ingot, which is prepared by the aforementioned method.

[0014] By adopting the above technical solutions, the present invention has at least the following beneficial effects: A highly homogeneous dual-phase titanium alloy VAR ingot and a preparation method thereof provided by the present invention prepare a dual-phase titanium alloy ingot by adopting a two-stage VAR melting process for electrodes of different specifications through measures such as dynamically adjusting the arc stabilizing current magnitude, input mode, and alternating period in different melting stages. According to the characteristics of different melting stages, the size and morphology of the molten pool, etc., the optimal arc stabilizing current input mode, magnitude, and period are matched, and the obtained titanium alloy ingot has uniform composition, high yield, and no metallurgical defects such as shrinkage cavities and porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a flowchart of a preparation method of a highly homogeneous dual-phase titanium alloy VAR ingot disclosed in some embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following will further describe the embodiments of the present disclosure in detail in conjunction with the drawings. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms, not limited to the specific embodiments disclosed herein, but including all technical solutions falling within the scope of the claims.

[0018] These embodiments are provided by the present disclosure to make the present disclosure thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, the components of materials, numerical expressions, and values described in these embodiments should be construed as merely exemplary, rather than as limitations.

[0019] It should be noted that in the description of the present disclosure, unless otherwise specified, the meaning of "a plurality of" is greater than or equal to two; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0020] In addition, the "first", "second" and similar terms used in the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. Terms such as "including" or "comprising" mean that the elements before the term cover the elements listed after the term, and do not exclude the possibility of also covering other elements.

[0021] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances. When it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0022] All terms used in the present disclosure have the same meaning as understood by those of ordinary skill in the art to which the present disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such here.

[0023] Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the specification.

[0024] As Figure 1 shown, some embodiments of the present invention disclose a highly homogeneous duplex titanium alloy VAR ingot and a preparation method thereof. The highly homogeneous duplex titanium alloy VAR ingot simplifies the traditional three - time melting to two - time melting. Specifically, it includes: Step 1: Prepare the ingot raw material into a consumable electrode, and weld the consumable electrode with an auxiliary electrode to obtain a first electrode to be melted. The ingot raw material can be sponge titanium and other required intermediate alloys. After weighing and mixing the required raw materials according to the batching ratio, press them into electrode blocks of appropriate specifications, and then weld multiple electrode blocks to obtain a consumable electrode. Then weld the consumable electrode with the auxiliary electrode for vacuum consumable melting. The auxiliary electrode can preferably be of the same grade. When there is no auxiliary electrode of the same grade, TA1 grade can be used instead. The ratio of the consumable electrode to the crucible diameter is between 0.78 and 0.92. After welding, break the vacuum to check the weld. After the weld is qualified, re-pump the vacuum to ≤1 Pa, and the leak rate should be ≤0.8 Pa / min.

[0025] Step 2: Melt the first electrode to be melted for the first time to obtain an ingot after the first melting. The first melting process can be divided into an arc starting stage, a stable melting stage, and a feeding stage. The arc starting stage is controlled for a time ≤25 min, and the melting current increases linearly. After the edge of the molten pool reaches the crucible wall, it enters the stable melting stage. To accelerate the formation and reaching the edge of the molten pool, a stable arc current is input with direct current of 10 - 15 A; during the stable melting stage, the ratio of the melting rate (kg / min) to the diameter (mm) of the consumable electrode is between 0.015 and 0.035. To improve the removal effect of volatile impurity elements and the migration effect of inclusions to the edge of the ingot during the first melting process, the stable arc current can be input in an alternating current mode of 5 - 10 A, and the ratio of the alternating current cycle (s) to the crucible diameter (mm) is between 0.08 and 0.14; during the feeding stage, the feeding time is ≥30 min, and the melting current decreases linearly. To reduce the heat loss rate during the feeding stage and the depth of the riser shrinkage cavity, the stable arc current is input with direct current of 5 - 10 A at the initial stage of feeding. When the diameter of the molten pool ≤2 / 3 of the crucible diameter, input with direct current of 10 - 15 A.

[0026] After the power is cut off during the first melting, generally, it is necessary to continue to maintain the vacuum ≥1 h, and then fill with argon ≥800 Pa for cooling, and the cooling time is ≥6 h; after the ingot is taken out of the furnace, peel 2 - 5 mm according to the surface condition of the ingot to ensure that the surface impurities and oxidized parts are completely removed; level the riser end (feeding end) of the ingot to obtain a qualified ingot after the first melting.

[0027] Step 3: Turn the ingot after the first melting and weld it with the auxiliary electrode to obtain a second electrode to be melted; that is, weld the arc starting end of the ingot after the first melting with the auxiliary electrode, and the vacuum degree should be ≤0.5 Pa and the leak rate should be ≤0.5 Pa / min.

[0028] Step 4: Perform secondary melting on the second electrode to be melted to obtain a secondary melted ingot. The secondary melting also includes three stages: arc starting, stabilization, and feeding. In the arc starting stage, the control time is ≤25 min, the melting current increases linearly, and the arc stabilizing current is input with direct current of 10 - 15 A. In the stable melting stage, the ratio of the melting rate (kg / min) to the diameter of the consumable electrode (mm) is between 0.027 - 0.032. The arc stabilizing current is input in an alternating current mode, and the ratio of the arc stabilizing current magnitude (A) to the crucible diameter (mm) is between 0.015 - 0.02, and the alternating current period is between 10 - 30 s. In the feeding stage, the feeding weight should meet 5% - 8% of the ingot weight, the feeding duration should be ≥120 min, the melting current decreases linearly, and the arc stabilizing current at the initial stage of feeding can be input with direct current of 10 - 15 A. When the molten pool diameter ≤2 / 3 of the crucible diameter, direct current of 15 - 20 A can be used for input.

[0029] Step 5: Perform post - treatment and detection on the secondary melted ingot to obtain a highly homogeneous duplex titanium alloy VAR ingot. The post - treatment detection specifically includes turning the surface of the secondary melted ingot smooth, then using a 2 - MHz high - frequency probe to perform ultrasonic flaw detection on the ingot. After cutting off the unqualified parts at the head and tail of the flaw detection, take ≥8 points at the head, middle, and tail on the side of the ingot for composition detection. The range of alloy elements in the ingot is ≤0.2%, and the range of gas elements Fe and O is ≤0.02%.

[0030] Through measures such as dynamically adjusting the arc stabilizing current magnitude, input mode, and alternating period in different melting stages, the above - mentioned embodiments use a two - stage VAR melting process to prepare a duplex titanium alloy ingot for electrodes of different specifications. According to the characteristics of different melting stages, the size and morphology of the molten pool, etc., the optimal arc stabilizing current input mode, magnitude, and period are matched. The obtained titanium alloy ingot has uniform composition, high yield rate, and no metallurgical defects such as shrinkage cavities and porosity.

[0031] Example 1 Produce a typical duplex TC11 titanium alloy ingot with a specification of φ600 mm.

[0032] Step 1: Weigh, mix, and press electrode blocks with 0 - grade sponge titanium (Ti: the balance), sponge zirconium (Zr: 1.55 wt.%), aluminum - molybdenum alloy (Mo: 3.50 wt.%), ferro - titanium alloy (Fe: 3.50 wt.%), aluminum - silicon alloy (Si: 0.30 wt.%), aluminum beans (proportion and weigh according to the Al content in the remaining raw materials to ensure that the Al content ratio is: 6.50 wt.%), and TiO2 powder (proportion and weigh according to the O content in the remaining raw materials to ensure that the O content ratio is: 0.11 wt.%). After welding multiple electrode blocks, a consumable electrode is obtained.

[0033] Step 2: Weld the consumable electrode TC11 in Step 1 to the vacuum consumable melting auxiliary electrode. The grade of the auxiliary electrode is TC11. The ratio of the consumable electrode (420 mm) to the crucible diameter (520 mm) is 0.81. After welding, break the vacuum to check the weld seam. After the weld seam is qualified, re-pump the vacuum to 0.8 Pa, and the leak rate during leak detection ≤ 0.5 Pa / min.

[0034] Step 3: If the leak rate in Step 2 is qualified, perform the first melting. The arc starting stage lasts for 20 min, and the melting current linearly increases at 3 + 0.6t kA / min. The stable arc current is input with direct current 10 A. After the molten pool reaches the edge, enter the stable melting stage; in the stable melting stage, the melting rate is 12 kg / min, the stable arc current is input with alternating current 6 A, and the alternating current cycle is 40 s; in the feeding stage, the feeding duration is 60 min, the melting current linearly decreases, and the stable arc current at the beginning of feeding is input with direct current 8 A. When the molten pool diameter is 2 / 3 of the crucible diameter, input with direct current 12 A.

[0035] Step 4: After power-off of the first melting in Step 3, continue to pump the vacuum for 1 h, then fill with argon at 1000 Pa for cooling, and the cooling duration is 6 h; after the ingot is taken out of the furnace, peel off 2 mm, and perform flat-head treatment on the feeding end of the ingot.

[0036] Step 5: Turn the primary ingot obtained in Step 4 for welding. After checking that the weld seam is qualified, re-pump the vacuum. After the vacuum degree is 0.2 Pa and the leak rate ≤ 0.2 Pa / min, perform the second melting. The arc starting stage of the second melting controls the time at 25 min, and the melting current linearly increases at 3 + 0.85·t kA / min. The stable arc current is input with direct current 12 A; in the stable melting stage, the melting rate is 15 kg / min, the stable arc current is input in an alternating current mode, the current magnitude is 8 A, and the alternating current cycle is 15 s; in the feeding stage, the feeding weight is 6% of the ingot weight, the feeding duration is 120 min, the melting current linearly decreases, and the stable arc current at the beginning of feeding is input with direct current 12 A. When the molten pool diameter is 2 / 3 of the crucible diameter, input with direct current 15 A.

[0037] Step 6: After turning the surface of the secondary melting ingot obtained in Step 5 smooth, use a 2MHz high-frequency probe to perform ultrasonic flaw detection on the ingot. After cutting off the unqualified parts at the head and tail during flaw detection, take 8 points each at the head, middle, and tail on the side of the ingot for composition detection. The ranges of various elements in the ingot are as follows: Al = 0.12%, V = 0.10%, Mo = 0.13%, Zr = 0.14%, Si = 0.009%, Fe = 0.011%, O = 0.012%. When using the three-time melting process, the control levels of the ranges of various elements are: Al: 0.6% - 0.9%, V: 0.5% - 0.7%, Mo: 0.5% - 0.8%, Zr: 0.5% - 0.8%, Si: 0.01% - 0.1%; Fe: 0.06% - 0.1%, O: 0.07% - 0.12%. Compared with the three-time melting process, after adopting this new secondary melting process, the compositional uniformity of the TC11 titanium alloy ingot has been significantly improved.

[0038] The present invention prepares a φ600mm-class TC11 titanium alloy ingot by adopting a two-time VAR melting process through dynamically adjusting the input mode, magnitude, and period of the arc starting, stabilizing, and feeding stage stabilizing arc currents during the first and second melting processes. The melting process is shortened, the impurity removal effect is significantly improved, the molten pool states at each stage are improved, and the obtained φ600mm-class typical duplex TC11 titanium alloy ingot has a uniform composition and no metallurgical defects such as shrinkage cavities and porosities.

[0039] Example 2 Produce a φ1200mm-class typical duplex large-size TC4 titanium alloy ingot.

[0040] Step 1: Weigh, mix, and press into electrode blocks 0A-grade small granular sponge titanium (Ti: the balance), high-purity AlV55 alloy with a particle size of 1 - 5mm (V: 4.1wt.%), TiFe32 alloy (Fe: 0.15wt.%), aluminum beans (proportion and weigh according to the Al content in the remaining raw materials to ensure that the Al content ratio is: 6.15wt.%), and 3N high-purity TiO2 powder (proportion and weigh according to the O content in the remaining raw materials to ensure that the O content ratio is: 0.15wt.%). After welding multiple electrode blocks, obtain a consumable electrode.

[0041] Step 2: Weld the TC4 consumable electrode in Step 1 with a vacuum consumable melting auxiliary electrode. The grade of the auxiliary electrode is TC4, and the ratio of the consumable electrode (1030mm) to the crucible diameter (1120mm) is 0.92. After welding, break the vacuum to check the weld seam. After the weld seam is qualified, re-pump the vacuum to 0.5Pa, and the leak rate ≤ 0.5Pa / min.

[0042] Step 3: If the leak rate in Step 2 is qualified, conduct the first smelting. The starting arc stage lasts for 25 minutes, and the smelting current increases linearly at a rate of 5 + 0.8t kA / min. The stable arc current is input with a DC of 15 A. After the molten pool reaches the edge, it enters the stable smelting stage. The melting rate in the stable smelting stage is 18 kg / min, the stable arc current is input with an AC of 10 A, and the AC cycle is 120 s. In the feeding stage, the feeding duration is 90 minutes, and the smelting current decreases linearly. At the beginning of feeding, the stable arc current is input with a DC of 10 A. When the diameter of the molten pool is 2 / 3 of the crucible diameter, a DC of 15 A is input.

[0043] Step 4: After the power-off of the first smelting in Step 3, continue to maintain vacuum pumping for 1 hour, then fill with argon at 1000 Pa for cooling, and the cooling duration is 10 hours. After the ingot is taken out of the furnace, peel off 3 mm, and perform flat head treatment on the feeding end of the ingot.

[0044] Step 5: Turn the primary ingot obtained in Step 4 for welding. After checking that the weld is qualified, re-pump the vacuum. When the vacuum degree is 0.1 Pa and the leak rate ≤ 0.1 Pa / min, conduct the second smelting. The control time for the starting arc stage of the second smelting is 25 minutes, and the smelting current increases linearly at a rate of 5 + 1.12·t kA / min. The stable arc current is input with a DC of 15 A. The melting rate in the stable smelting stage is 30 kg / min, the stable arc current is input in an AC mode, the current magnitude is 20 A, and the AC cycle is 30 s. In the feeding stage, the feeding weight is 6% of the ingot weight, the feeding duration is 210 minutes, the smelting current decreases linearly. At the beginning of feeding, the stable arc current is input with a DC of 15 A. When the diameter of the molten pool is 2 / 3 of the crucible diameter, a DC of 20 A is input.

[0045] Step 6: After turning the surface of the secondary smelting ingot obtained in Step 5 smooth, use a 2 MHz high-frequency probe to conduct ultrasonic flaw detection on the ingot. After cutting off the unqualified parts at the head and tail of the flaw detection, take 12 points each at the head, middle, and tail on the side of the ingot for composition detection. The range of each element in the ingot is Al = 0.13%, V = 0.12%, Fe = 0.012%, O = 0.012%. When adopting the three-time smelting process, the control level of the range of each element is: Al: 0.6% - 0.9%, V: 0.5% - 0.7%, Fe: 0.06% - 0.1%, O: 0.07% - 0.12%. Comparing with the three-time smelting process, after adopting this new secondary smelting process, the composition uniformity of the TC4 titanium alloy ingot has been significantly improved.

[0046] The present invention prepares a large-sized TC4 titanium alloy ingot with a diameter of φ1200mm by dynamically adjusting the input mode, magnitude and period of the arc-stabilizing current in the arc starting, stabilizing and feeding stages of the VAR melting process, adopting a two-step VAR melting process. The melting process is shortened, the impurity removal effect is significantly improved, the molten pool state in each stage is improved, and the component uniformity is significantly enhanced. The obtained typical dual-phase large-sized TC4 titanium alloy ingot with a diameter of φ1200mm has uniform components and no metallurgical defects such as shrinkage cavities and porosity.

[0047] So far, the embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0048] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in each of the embodiments can be combined in any manner.

Claims

1. A method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot, characterized in that: include: Step 1: preparing the ingot raw material into a consumable electrode, welding the consumable electrode with an auxiliary electrode to obtain a first electrode to be smelted; Step 2: Smelting the first electrode to be smelted for the first time to obtain a primary smelting ingot; Step 3: Turning the first smelting ingot around and welding it with the auxiliary electrode to obtain a second electrode to be smelted; Step 4: Smelting the second electrode to be smelted for a second time to obtain a secondary smelted ingot; Step 5: Post-processing and testing the secondary smelting ingot to obtain a high-homogeneity dual-phase titanium alloy VAR ingot.

2. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step 1, the preparation of the consumable electrode includes: weighing, mixing, and pressing sponge titanium and the required master alloy into an electrode block according to a proportion, and welding a plurality of the electrode blocks to obtain a consumable electrode.

3. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step 1, the ratio of the diameter of the consumable electrode to the crucible is 0.78-0.92; Alternatively, in step one, after welding is completed, the weld is inspected through air, and after the weld is qualified, the vacuum is ≤1Pa, and the leak detection rate is ≤0.8Pa / min.

4. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step 2, the first smelting includes an arc starting stage, a stable smelting stage and a feeding stage; In addition, the control time of the arc starting stage is no more than 25 minutes, the melting current increases linearly, and the current is input by DC 10~15A; the ratio of the melting rate to the diameter of the consumable electrode in the stable melting stage is 0.015~0.035, the current is input by AC 5~10A, and the ratio of the AC cycle to the crucible diameter is 0.08~0.14; the duration of the feeding stage is no less than 30 minutes; The unit of melting rate is kg / min, the unit of consumable electrode diameter is mm, the unit of crucible diameter is mm, and the unit of AC cycle is s.

5. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 4, characterized in that: In step 2, the current is input as DC 5~10A at the initial stage of the shrinkage feeding stage. After the diameter of the molten pool is no larger than 2 / 3 of the diameter of the crucible, the current is input as DC 10~15A.

6. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 4, characterized in that: Step 2 also includes: after the feeding stage is finished, vacuuming is maintained for a predetermined time, followed by argon-filling cooling, and after cooling, the ingot is subjected to surface treatment and feeding end treatment to obtain a primary smelting ingot.

7. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step three, when the primary smelting ingot is turned around and welded with the auxiliary electrode, the vacuum degree is ≤0.5Pa and the leakage rate is ≤0.5Pa / min.

8. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step 4, the second smelting includes an arc starting stage, a stable smelting stage and a feeding stage; In addition, the control time of the arc starting stage is no more than 25 minutes, the melting current increases linearly, and the current is input by DC 10~15A; the ratio of the melting rate to the diameter of the consumable electrode in the stable melting stage is 0.027~0.032, the current is input by AC, the ratio of the current size to the crucible diameter is 0.015~0.02, and the AC cycle is 10~30s; the feeding weight in the feeding stage meets 5%~8% of the ingot weight, and the feeding time is ≥120min; The unit of melting rate is kg / min, the unit of consumable electrode diameter is mm, the unit of crucible diameter is mm, and the unit of current is A.

9. The method for preparing a highly homogeneous dual-phase titanium alloy VAR ingot according to claim 1, characterized in that: In step 4, the initial current of the shrinkage feeding stage is input with a DC current of 10-15A. After the diameter of the molten pool is no larger than 2 / 3 of the diameter of the crucible, the current is input with a DC current of 15-20A.

10. A highly homogeneous dual-phase titanium alloy VAR ingot, characterized in that: The method is prepared by the method described in any one of claims 1 to 9.

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