A method for preparing high-quality refractory metal ingots

Abstract

The present application belongs to the technical field of non-ferrous metal smelting, and relates to a preparation method of high-quality refractory metal ingot, comprising the following steps: firstly, preparing a primary ingot of refractory metal or refractory metal alloy by using an electron beam cold hearth furnace smelting method; secondly, obtaining a secondary ingot by vacuum consumable arc smelting the primary ingot; thirdly, welding a plurality of machined secondary ingots in a vacuum consumable arc furnace to form a finished product smelting electrode; and finally, performing finished product smelting on the finished product smelting electrode in the vacuum consumable arc furnace to obtain a high-quality refractory metal ingot. The present application effectively solves the problems of the existing electron beam cold hearth furnace smelting method, such as the metallurgical defects of the surface of the ingot being not smooth, cold shut and transverse cracks, and the risk of high-density inclusions being difficult to remove in the vacuum consumable arc furnace smelting; and the purpose of purifying and homogenizing the refractory metal ingot is achieved, the longitudinal main element composition deviation of the ingot is controlled within 0.3%, and the present application has the advantages of simple operation process and low cost.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal smelting technology and relates to a method for preparing high-quality refractory metal ingots. Background Technology

[0002] Refractory metals generally refer to metals with melting points above 1650℃ and a certain amount of reserves, including tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium, and titanium. They have advantages such as good high-temperature strength and corrosion resistance, and have broad application prospects in metallurgical industry, petrochemical industry, electronic light source and machinery manufacturing.

[0003] Currently, with the continuous expansion of the application range of refractory metals, their production and preparation technologies are also diverse, mainly including powder metallurgy (PM), electron beam cold hearth furnace melting (EBM), vacuum arc remelting (VAR), plasma beam cold hearth furnace melting (PAM), and electroslag remelting (ESR). Among them, vacuum arc remelting carries the risk of difficulty in removing high-density inclusions; while metal ingots prepared by electron beam cold hearth furnace melting have high purity and good as-cast structure, thus possessing high mechanical properties, especially high toughness, plasticity, and isotropy. Moreover, the melting process has a significant removal effect on high and low density inclusions in the alloy, improving the utilization rate of residual material during the melting process. However, electron beam melting ingots are prone to some surface metallurgical defects, such as surface roughness, cold shuts, and transverse cracks.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing high-quality refractory metal ingots. This method effectively solves the problems of metallurgical defects such as uneven surface, cold shuts and transverse cracks in ingots produced by the existing electron beam cold hearth furnace melting method, as well as the risk of high-density inclusions being difficult to remove in vacuum consumable arc furnace melting.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The method for preparing this high-quality refractory metal ingot includes: firstly, preparing a primary ingot of refractory metal or refractory metal alloy using an electron beam cold hearth furnace melting method; then, subjecting the primary ingot to vacuum arc remelting to obtain a secondary ingot; next, welding multiple machined secondary ingots in a vacuum arc remelting furnace to form an electrode for finished product smelting; and finally, smelting the electrode for finished product smelting in a vacuum arc remelting furnace to obtain a high-quality refractory metal ingot.

[0008] Furthermore, the head and tail ends of the secondary ingot are provided with concave-convex connecting parts that facilitate welding.

[0009] Furthermore, the preparation method specifically includes the following steps:

[0010] Step 1: Determine the crucible specifications required for different smelting methods based on the smelting capacity and feed amount of the electron beam cold hearth furnace and the vacuum consumable arc furnace.

[0011] Step 2: Determine the composition ratio of the raw materials for the ingots based on the chemical composition of the finished ingots;

[0012] Step 3: Calculate the required raw material weight based on the component ratio determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a single ingot.

[0013] Step 4: Clean the surface of the primary ingot and chamfer it at the head and tail. Then, use a vacuum arc furnace to perform secondary melting to obtain a secondary ingot.

[0014] Step 5: After flattening the secondary spindle head and tail end face described in Step 4, machine it to form a concave-convex connection that is easy to weld.

[0015] Step 6: Weld multiple secondary ingots after machining using a vacuum arc furnace, then inspect the welds, clean the weld beads, and continue vacuuming to form electrodes for finished product smelting;

[0016] Step 7: Melt the electrodes for smelting the finished product using a vacuum consumable arc furnace;

[0017] Step 8: After melting, cool and remove from the furnace to obtain a high-quality refractory metal ingot.

[0018] Furthermore, the relevant process parameters for the secondary melting in step 4 are as follows: melting current is 5-12KA, melting voltage is 28-35V, arc stabilization current is (5-12)A / (30-60)s, pre-melting vacuum degree is ≤0.5Pa, and leakage rate is ≤0.3Pa / min.

[0019] Furthermore, in step 4, the chamfer is 10mm × 45°.

[0020] Furthermore, the welding parameters in step 6 are: vacuum degree ≤ 1.0 Pa, leakage rate ≤ 1 Pa / min, welding current 2~12 kA, and welding voltage 20~40 V.

[0021] Furthermore, the melting parameters in step 7 are as follows: melting current 8-13KA, melting voltage 28-35V, arc stabilization current (8-12)A / (30-60)s, pre-melting vacuum degree ≤0.5Pa, and leakage rate ≤0.3Pa / min.

[0022] Furthermore, step 8 specifically includes:

[0023] Step 8.1: After smelting, three ingots are obtained and cooled to below 400°C under vacuum conditions before being removed from the furnace;

[0024] Step 8.2: After the three ingot peeling and flaw detection in step 8.1, the riser is removed to obtain a high-quality finished ingot.

[0025] Furthermore, the compositional deviation of the main elements in the longitudinal direction of the refractory metal ingot is ≤0.3%.

[0026] Furthermore, when using a vacuum consumable arc furnace for melting, a bottom pad is placed at the bottom of each crucible, and the thickness of the bottom pad is ≥30mm.

[0027] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0028] 1) This invention optimizes the existing smelting method for single refractory metals. The primary ingot is smelted in an electron beam cold hearth furnace, and the secondary / tertiary ingots are smelted in a vacuum consumable furnace. The secondary ingots of the electrodes used for smelting the finished product are welded in the furnace in the form of concave-convex contact. On the one hand, this increases the contact area between the electrodes and improves the welding strength. On the other hand, the molten refractory metal will not overflow, and the weld beads or weld chips formed will be reduced, which reduces the risk of high-density inclusions in refractory metals and alloys and improves the compositional uniformity of the alloy.

[0029] 2) This invention combines two processes: electron beam cold hearth furnace melting (EBM) and vacuum arc melting (VAR), providing a standard industrial-grade production method for producing high-quality rotor blade-grade refractory metal bars, ensuring the stability of ingot product quality and appearance quality.

[0030] 3) This invention can achieve the purpose of cleaning and homogenizing refractory alloy ingots, and the longitudinal main element composition deviation of the ingot is controlled within 0.3%. The operation process is simple and the cost is low, which is conducive to the large-scale preparation of refractory metal ingots. Attached Figure Description

[0031] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A flowchart illustrating a method for preparing a high-quality refractory metal ingot provided by the present invention;

[0034] Figure 2 The diagram shows the positional distribution of multiple secondary ingots welded in a vacuum consumable arc furnace, as provided by this invention. Detailed Implementation

[0035] Exemplary embodiments will be described in detail below. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of methods consistent with some aspects of the present invention as detailed in the appended claims.

[0036] This invention provides a method for preparing high-quality refractory metal ingots, comprising: firstly, preparing a primary ingot of a refractory metal or refractory metal alloy using an electron beam cold hearth furnace melting method; then, subjecting the primary ingot to vacuum arc remelting to obtain a secondary ingot; subsequently, welding multiple machined secondary ingots in a vacuum arc remelting furnace to form a melting electrode; and finally, melting the melting electrode in a vacuum arc remelting furnace to obtain a high-quality refractory metal ingot.

[0037] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] Example 1

[0039] This example uses the preparation of a 200 kg Nb-1.0%W alloy ingot as an example, combined with... Figure 1 As shown, the specific preparation process is as follows:

[0040] Step 1: Based on the melting capacity and melting process scheme of the electron beam cold hearth furnace and the vacuum consumable arc furnace, determine the crucible sizes required for different melting processes, which are Φ100mm for primary melting (electron beam cold hearth furnace melting), Φ160mm for secondary melting (vacuum consumable arc furnace melting), and Φ220mm for finished product melting (vacuum consumable arc furnace melting).

[0041] Step 2: Using niobium rods (Nb1), tungsten plates or bars as raw materials, based on a tungsten content of 1%, the required weight of tungsten plates or bars is 2 kg, and the number of niobium rods is 3, with each rod weighing 66 kg.

[0042] Step 3: Calculate the required raw material weight based on the proportion determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a primary ingot (Φ100mm). The process parameters for electron beam cold hearth furnace smelting are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, smelting current 2~12A, and smelting voltage 25~40KV.

[0043] Step 4: Clean the surface of the primary ingot from Step 3, machine the head and tail ends flat, and chamfer the head by 10mm×45°. Manually weld it to the Φ80mm auxiliary electrode outside the furnace, and then use a vacuum consumable arc furnace for secondary melting to obtain a secondary ingot. The crucible used for secondary melting is Φ160mm in size. A base pad must be placed during melting. The base pad is made of the same alloy and has a thickness ≥30mm. The melting current is 5~7KA, the melting voltage is controlled at 25~40V, the arc stabilizing current (AC) is 6~8A, the stirring cycle is 30~60s, the cooling time is ≥3h, the vacuum degree before melting is ≤0.5Pa, and the leakage rate is ≤0.3Pa / min.

[0044] Step 5: After flattening the end face of the secondary spindle head from Step 4, machine it into a convex and concave platform of a certain size, weigh it, and clearly mark the grade. Figure 2 As shown.

[0045] Step 6: Weld the machined secondary ingot in a vacuum arc furnace, then inspect the weld, clean the weld beads, and continue evacuation to obtain electrodes for smelting; the welding parameters are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, welding current: 2~12KA, welding voltage: 20~40V.

[0046] Step 7: Use a vacuum consumable arc furnace to melt the finished ingot. The crucible size is Φ220mm. A bottom pad must be placed during melting. The bottom pad material is this alloy and the thickness is ≥30mm. The melting current is 7~9KA, the melting voltage is 28~35V, the arc stabilizing current (AC) is 8~10A, the stirring cycle is 30~60s, the vacuum degree before melting is ≤0.5Pa, and the air leakage rate is ≤0.3Pa / min.

[0047] Step 8: After melting is completed, the ingot from Step 7 is cooled to below 400°C under vacuum conditions and then removed from the furnace.

[0048] Step 9: After peeling and inspecting the ingot from Step 8, cut off the riser to obtain the finished ingot.

[0049] Step 10: Samples were taken from the head, middle and tail of the finished ingot prepared in step 9 for chemical composition analysis. The analysis results of the main element W were 0.95% to 1.06%, and the longitudinal composition deviation of the ingot was 0.11%.

[0050] Example 2

[0051] This example uses the preparation of a 200 kg Nb-3.0%W alloy ingot as an example. The specific preparation process is as follows:

[0052] Step 1: Based on the melting capacity and melting process scheme of the electron beam cold hearth furnace and the vacuum consumable arc furnace, determine the crucible sizes required for different melting processes, which are Φ100mm for primary melting (electron beam cold hearth furnace melting), Φ160mm for secondary melting (vacuum consumable arc furnace melting), and Φ220mm for finished product melting (vacuum consumable arc furnace melting).

[0053] Step 2: Using niobium rods (Nb1), tungsten plates or bars as raw materials, based on a tungsten content of 1%, the required weight of tungsten plates or bars is 6 kg, and the number of niobium rods is 4, with each rod weighing 48.5 kg.

[0054] Step 3: Calculate the required raw material weight based on the proportion determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a primary ingot (Φ100mm). The electron beam cold hearth furnace smelting process parameters are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, smelting current: 2~12A, smelting voltage 25~40KV.

[0055] Step 4: Clean the surface of the primary ingot from Step 3, machine the head and tail ends flat and chamfer the head 10mm×45°, and manually weld it to the Φ80mm auxiliary electrode outside the furnace. Then, use a vacuum self-consuming electric arc furnace for secondary melting to obtain a secondary ingot. The crucible used for secondary melting is Φ160mm. A base pad must be placed during melting. The base pad is made of the same alloy and has a thickness ≥30mm. The melting current is 6~8KA, the melting voltage is controlled at 25~40V, the arc stabilizing current (AC) is 6~8A, the stirring cycle is 30~60s, the cooling time is ≥3h, the vacuum degree before melting is ≤0.5Pa, and the leakage rate is ≤0.3Pa / min.

[0056] Step 5: After flattening the head and tail ends of the secondary casting ingot from Step 4, machine it into a convex and concave platform of a certain size, weigh it, and clearly mark the grade.

[0057] Step 6: Weld the machined secondary ingot in a vacuum arc furnace. Then, inspect the weld, clean the weld beads, and continue evacuation to obtain electrodes for smelting. The welding parameters are: vacuum degree ≤ 1.0 Pa, leakage rate ≤ 1 Pa / min, welding current 2~12 kA, and welding voltage 20~40 V.

[0058] Step 7: Use a vacuum self-consuming electric arc furnace to melt the finished ingot. The crucible size is Φ220mm. A bottom pad must be placed during melting. The bottom pad material is this alloy and the thickness is ≥30mm. The melting current is 8~9KA, the melting voltage is 28~35V, the arc stabilizing current (AC) is 8~10A, the stirring cycle is 30~60s, the vacuum degree before melting is ≤0.5Pa, and the air leakage rate is ≤0.3Pa / min.

[0059] Step 8: After melting is completed, the ingot from Step 7 is cooled to below 400°C under vacuum conditions and then removed from the furnace.

[0060] Step 9: After peeling and inspecting the ingot from Step 8, cut off the riser to obtain the finished ingot.

[0061] Step 10: Samples were taken from the head, middle, and tail sections of the ingot prepared in Step 9 for chemical composition analysis. The analysis results for the main element W were 2.96%–3.14%, and the longitudinal composition deviation of the ingot was 0.18%.

[0062] Example 3

[0063] This example uses the preparation of a 200 kg Nb-5.0%W alloy ingot as an example. The specific preparation process is as follows:

[0064] Step 1: Based on the melting capacity and melting process scheme of the electron beam cold hearth furnace and the vacuum consumable arc furnace, determine the crucible sizes required for different melting processes, which are Φ100mm for primary melting (electron beam cold hearth furnace melting), Φ160mm for secondary melting (vacuum consumable arc furnace melting), and Φ220mm for finished product melting (vacuum consumable arc furnace melting).

[0065] Step 2: Using niobium rods (Nb1), tungsten plates or bars as raw materials, based on a tungsten content of 1%, the required weight of tungsten plates or bars is 10 kg, and the number of niobium rods is 4, with each rod weighing 47.5 kg.

[0066] Step 3: Calculate the required raw material weight based on the proportion determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a primary ingot (Φ100mm). The process parameters for electron beam cold hearth furnace smelting are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, smelting current 2~12A, and smelting voltage 25~40KV.

[0067] Step 4: Clean the surface of the primary ingot from Step 3, machine the head and tail ends flat, and chamfer the head by 10mm×45°. Manually weld it to the Φ80mm auxiliary electrode outside the furnace, and then use a vacuum consumable arc furnace for secondary melting to obtain a secondary ingot. The crucible used for secondary melting is Φ160mm in size. A base pad must be placed during melting. The base pad is made of the same alloy and has a thickness ≥30mm. The melting current is 8~10KA, the melting voltage is controlled at 25~40V, the arc stabilizing current (AC) is 6~8A, the stirring cycle is 30~60s, the cooling time is ≥3h, the vacuum degree before melting is ≤0.5Pa, and the leakage rate is ≤0.3Pa / min.

[0068] Step 5: After flattening the end face of the secondary spindle head from Step 4, machine it into a convex and concave platform of a certain size, weigh it, and clearly mark the grade.

[0069] Step 6: Weld the machined secondary ingot in a vacuum arc furnace, then inspect the weld, clean the weld beads, and continue evacuation to obtain electrodes for smelting; the welding parameters are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, welding current: 2~12KA, welding voltage: 20~40V.

[0070] Step 7: Use a vacuum self-consuming electric arc furnace to melt the finished ingot. The crucible size is Φ220mm. A bottom pad must be placed during melting. The bottom pad material is this alloy and the thickness is ≥30mm. The melting current is 9~11KA, the melting voltage is 28~35V, the arc stabilizing current (AC) is 8~10A, the stirring cycle is 30~60s, the vacuum degree before melting is ≤0.5Pa, and the air leakage rate is ≤0.3Pa / min.

[0071] Step 8: After melting is completed, the ingot from step 7 is cooled to below 400°C under vacuum conditions and then removed from the furnace.

[0072] Step 9: After peeling and inspecting the ingot from Step 8, cut off the riser to obtain the finished ingot.

[0073] Step 10: Samples were taken from the head, middle and tail of the finished ingot prepared in step 9 for chemical composition analysis. The analysis results of the main element W were 4.82% to 5.04%, and the longitudinal composition deviation of the ingot was 0.22%.

[0074] Example 4

[0075] This example uses the preparation of a 200 kg Nb-7.0%W alloy ingot as an example. The specific preparation process is as follows:

[0076] Step 1: Based on the melting capacity and melting process scheme of the electron beam cold hearth furnace and the vacuum consumable arc furnace, determine the crucible sizes required for different melting processes, which are Φ100mm for primary melting (electron beam cold hearth furnace melting), Φ160mm for secondary melting (vacuum consumable arc furnace melting), and Φ220mm for finished product melting (vacuum consumable arc furnace melting).

[0077] Step 2: Using niobium rods (Nb1), tungsten plates or bars as raw materials, based on a tungsten content of 1%, the required weight of tungsten plates or bars is 14 kg, and the number of niobium rods is 4, with each rod weighing 46.5 kg.

[0078] Step 3: Calculate the required raw material weight based on the proportion determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a primary ingot (Φ100mm). The process parameters for electron beam cold hearth furnace smelting are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, smelting current 2~12A, and smelting voltage 25~40KV.

[0079] Step 4: Clean the surface of the primary ingot from Step 3, machine the head and tail ends flat, and chamfer the head by 10mm×45°. Manually weld it to the Φ80mm auxiliary electrode outside the furnace, and then use a vacuum self-consuming electric arc furnace for secondary melting to obtain a secondary ingot. The crucible used for secondary melting is Φ160mm in size. A bottom pad must be placed during melting. The bottom pad is made of the same alloy and has a thickness ≥30mm. The melting current is 10~12KA, the melting voltage is controlled at 25~40V, the arc stabilizing current (AC) is 6~8A, the stirring cycle is 30~60s, the cooling time is ≥3h, the vacuum degree before melting is ≤0.5Pa, and the leakage rate is ≤0.3Pa / min.

[0080] Step 5: After flattening the end face of the secondary spindle head from Step 4, machine it into a convex and concave platform of a certain size, weigh it, and clearly mark the grade.

[0081] Step 6: Weld the machined secondary ingot in a vacuum arc furnace, then inspect the weld, clean the weld beads, and continue evacuation to obtain electrodes for smelting. The welding parameters are: vacuum degree ≤1.0Pa, leakage rate ≤1Pa / min, welding current 2~12KA, and welding voltage 20~40V.

[0082] Step 7: Use a vacuum self-consuming electric arc furnace to melt the finished ingot. The crucible size is Φ220mm. A bottom pad must be placed during melting. The bottom pad material is this alloy and the thickness is ≥30mm. The melting current is 12~13KA, the melting voltage is 28~35V, the arc stabilizing current (AC) is 8~10A, the stirring cycle is 30~60s, the vacuum degree before melting is ≤0.5Pa, and the air leakage rate is ≤0.3Pa / min.

[0083] Step 8: After melting is completed, the ingot from step 7 is cooled to below 400°C under vacuum conditions and then removed from the furnace.

[0084] Step 9: After peeling and inspecting the ingot from Step 8, cut off the riser to obtain the finished ingot.

[0085] Step 10: Samples were taken from the head, middle and tail of the finished ingot prepared in step 9 for chemical composition analysis. The analysis results of the main element W were 6.93% to 7.12%, and the longitudinal composition deviation of the ingot was 0.19%.

[0086] In summary, the method for preparing high-quality refractory metal ingots provided by this invention employs a combination of electron beam cold hearth furnace melting (EBM) and vacuum arc remelting (VAR) to synergistically prepare refractory metal ingots. Ingots prepared by electron beam cold hearth furnace melting possess high purity and excellent as-cast microstructure, resulting in high mechanical properties, particularly high toughness, plasticity, and isotropy. Furthermore, the melting process significantly removes high- and low-density inclusions in the alloy, improving the utilization rate of residual material. Ingots prepared by vacuum arc remelting exhibit excellent crystalline structure, uniform chemical composition, and good appearance quality. The combination of these two processes can produce high-quality refractory metal ingots, facilitating the large-scale production of refractory metal ingots.

[0087] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0088] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a high-quality refractory metal ingot, characterized in that, include: First, a primary ingot of refractory metal or refractory metal alloy is prepared by electron beam cold hearth furnace melting; then, the primary ingot is subjected to vacuum consumable arc melting to obtain a secondary ingot; then, multiple secondary ingots after machining are welded in a vacuum consumable arc furnace to form an electrode for finished product melting; finally, the electrode for finished product melting is melted in a vacuum consumable arc furnace to obtain a high-quality refractory metal ingot. The head and tail ends of the secondary ingot are provided with concave and convex connecting parts that facilitate welding. The preparation method specifically includes the following steps: Step 1: Determine the crucible specifications required for different smelting methods based on the smelting capacity and feed amount of the electron beam cold hearth furnace and the vacuum consumable arc furnace. Step 2: Determine the composition ratio of the raw materials for the ingots based on the chemical composition of the finished ingots; Step 3: Calculate the required raw material weight based on the component ratio determined in Step 2. After the raw materials are removed from the warehouse, they are weighed and their dimensions are measured. Then, they are smelted in an electron beam cold hearth furnace to obtain a single ingot. Step 4: Clean the surface of the primary ingot and chamfer it at the head and tail. Then, use a vacuum arc furnace to perform secondary melting to obtain a secondary ingot. Step 5: After flattening the secondary spindle head and tail end face described in Step 4, machine it to form a concave-convex connection that is easy to weld. Step 6: Weld multiple secondary ingots after machining using a vacuum arc furnace, then inspect the welds, clean the weld beads, and continue vacuuming to form electrodes for finished product smelting; Step 7: Use a vacuum consumable arc furnace to melt the electrodes used for melting the finished product; Step 8: After melting, cool and remove from the furnace to obtain a high-quality refractory metal ingot; The compositional deviation of the main elements in the longitudinal direction of the refractory metal ingot is ≤0.3%.

2. The method for preparing high-quality refractory metal ingots according to claim 1, characterized in that, The relevant process parameters for the secondary melting in step 4 are as follows: melting current is 5~12KA, melting voltage is 28~35V, arc stabilization current is (5~12)A / (30~60)s, vacuum degree before melting is ≤0.5Pa, and leakage rate is ≤0.3Pa / min.

3. The method for preparing high-quality refractory metal ingots according to claim 1, characterized in that, In step 4, the chamfer is 10mm × 45°.

4. The method for preparing high-quality refractory metal ingots according to claim 1, characterized in that, The welding parameters in step 6 are: vacuum degree ≤ 1.0 Pa, leakage rate ≤ 1 Pa / min, welding current 2~12 KA, and welding voltage 20~40V.

5. The method for preparing high-quality refractory metal ingots according to claim 1, characterized in that, The melting parameters in step 7 are as follows: melting current 8~13KA, melting voltage 28~35V, arc stabilization current (8~12)A / (30~60)s, pre-melting vacuum degree ≤0.5Pa, and leakage rate ≤0.3Pa / min.

6. The method for preparing high-quality refractory metal ingots according to claim 1, characterized in that, Step 8 specifically involves: Step 8.1: After smelting, three ingots are obtained and cooled to below 400°C under vacuum conditions before being removed from the furnace; Step 8.2: After the three ingot peeling and flaw detection in step 8.1, the riser is removed to obtain a high-quality refractory metal ingot.

7. The method for preparing high-quality refractory metal ingots according to any one of claims 1 to 6, characterized in that, When using a vacuum consumable arc furnace for melting, a bottom pad is placed at the bottom of the crucible, and the thickness of the bottom pad is ≥30mm.

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