Composite dummy bar head and manufacturing method thereof

Abstract

The invention relates to the technical field of tantalum ingot preparation, and discloses a composite dummy bar head and a manufacturing method thereof.The composite dummy bar head comprises an upper ingot body and a lower ingot body, the upper ingot body is made of tantalum, the lower ingot body is made of niobium, and the upper ingot body and the lower ingot body are connected to form the composite dummy bar head. The preparation method comprises the following steps: preparing a tantalum ingot, processing a niobium ingot to obtain an upper ingot head with a convex part, processing the niobium ingot to obtain a lower ingot head with a concave part, and welding the upper ingot head and the lower ingot head to obtain the composite dummy bar head. And in addition, the manufacturing cost of the dummy bar head needed by tantalum ingot electron beam melting can be reduced through the compounding mode.

Description

Technical Field

[0001] The invention relates to the technical field of tantalum ingot preparation, in particular to a composite ingot starter and a manufacturing method thereof. Background Art

[0002] Tantalum is an important metal material in industry, and tantalum target is prepared through tantalum ingots. In the preparation of tantalum ingots, electron beam melting is the most important preparation method because of its high melting point. When tantalum is melted by electron beam, the molten metal tantalum liquid flows into a copper crucible and gradually solidifies into a tantalum ingot under the action of cooling water. In this process, there is an ingot starter inside the crucible. During melting, the head of the ingot starter is melted first, and the melted part is a molten pool with a depth of about 30 to 50 mm. Then the tantalum material is melted, and the tantalum liquid drips onto the ingot starter and solidifies. Under the pulling action of the ingot starter, the ingot is gradually pulled into shape to finally obtain a tantalum ingot.

[0003] In the prior art, the invention patent (CN106925734A) discloses a method for manufacturing an ingot starter head for sealing the bottom of a crystallizer having a bottom diameter, comprising: providing a first component having a first diameter and a first thickness and being a cylinder, the first component containing a first center hole penetrating its thickness and having a first aperture, the first diameter being smaller than the bottom diameter; providing a second component, comprising a first cylinder and a second cylinder located on top of the first cylinder, the first cylinder having a second diameter, the second cylinder having a third diameter and a third thickness, the third diameter being smaller than the first aperture, and the third thickness being equal to the first thickness; sleeve the first center hole of the first component on the second cylinder of the second component, and then perform a smelting process. The cost of the ingot starter head is relatively high when used in the preparation of tantalum ingots.

[0004] Based on this, the technical problem to be solved in this case is: how to reduce the preparation cost of the ingot head. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a composite ingot starter head and a manufacturing method thereof. The composite ingot starter head is formed by combining an upper ingot body and a lower ingot body, and the material of the upper ingot body is tantalum, and the material of the lower ingot body is niobium. The combination of tantalum and niobium can reduce the manufacturing cost of the tantalum material ingot starter head required for the preparation of tantalum ingots. During manufacturing, the combination of the convex part of the upper ingot body and the concave part of the lower ingot body can improve the welding strength and ensure the ingot starter strength. On the other hand, it can also ensure that the lower ingot body will not be affected during electron beam melting.

[0006] The technical solution of the present invention is:

[0007] A composite ingot starter comprises an upper ingot body and a lower ingot body. The upper ingot body is made of tantalum, and the lower ingot body is made of niobium. The upper ingot body and the lower ingot body are connected to form the composite ingot starter.

[0008] In the above-mentioned composite ingot starter, a convex portion is provided at the bottom of the upper ingot body, a concave portion matching the convex portion is provided at the top of the lower ingot body, and the upper ingot body and the lower ingot body are connected via the convex portion and the concave portion to form a composite ingot starter.

[0009] Preferably, the height of the upper ingot body is at least 100 mm, and the height of the upper ingot body may be 100 mm, 110 mm, or 120 mm. More preferably, the height of the upper ingot body is 100 mm.

[0010] A method for preparing a composite ingot starter head comprises processing a tantalum ingot to obtain an upper ingot head with a convex portion, processing a niobium ingot to obtain a lower ingot head with a concave portion, and welding the upper ingot head and the lower ingot head to obtain the composite ingot starter head.

[0011] Preferably, the welding is performed by electron beam welding, wherein the electron beam current is 200-260 mA; more preferably, the electron beam current can be selected as 200 mA, 210 mA, 220 mA, 230 mA, 240 mA, 250 mA, 260 mA;

[0012] Preferably, the acceleration voltage is 80-120 kV, more preferably, the acceleration voltage can be selected from 80 kV, 90 kV, 100 kV, 110 kV, 120 kV;

[0013] Preferably, the welding speed is 250-300 mm / min, and more preferably, the welding speed can be selected as 250 mm / min, 260 mm / min, 270 mm / min, 280 mm / min, 290 mm / min, or 300 mm / min.

[0014] Preferably, during EB welding in step 2, the bottom of the upper ingot and the top of the lower ingot are melted, and the melting depth is 10 to 20 mm. The melting depth can be selected as 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or 20 mm. More preferably, the melting depth can be selected as 12 to 18 mm. The melting depth can be selected as 12 mm, 14 mm, 16 mm, or 18 mm.

[0015] Preferably, the concave portion matches the convex portion, and the distance between one side of the convex portion and the same side of the upper ingot body is 10 to 20 mm, and the distance can be selected as 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or 20 mm. More preferably, the distance between one side of the convex portion and the same side of the upper ingot body is 14 to 16 mm, and the distance between one side of the convex portion and the same side of the upper ingot body can be selected as 14 mm, 15 mm, or 16 mm.

[0016] Preferably, the height of the convex portion is 5 to 10 mm, and the height of the convex portion can be selected as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm. More preferably, the height of the convex portion is 6 to 8 mm, and the height of the convex portion can be selected as 6 mm, 7 mm, and 8 mm.

[0017] One of the above technical solutions of the present invention has at least one of the following advantages or beneficial effects:

[0018] The present invention forms a composite ingot starter by combining an upper ingot body and a lower ingot body, and the material of the upper ingot body is tantalum, and the material of the lower ingot body is niobium. The combination of tantalum and niobium can reduce the manufacturing cost of the tantalum ingot starter head required for the preparation of tantalum ingots. During manufacturing, the distance between one side of the convex portion of the upper ingot body and the same side of the upper ingot body can ensure the welding strength of electron beam welding. On the other hand, the height of the convex portion can ensure the ingot starter strength of electron beam melting. On the other hand, the height of the upper ingot body can ensure that the lower ingot body is not affected during electron beam melting, thereby ensuring the integrity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the composite ingot starter of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the upper ingot body of the present invention;

[0021] Figure 3 It is a structural schematic diagram of the lower ingot body of the present invention.

[0022] Among them, the figure markings of each figure are as follows: 1, upper ingot body; 2, lower ingot body; 11, convex part; 12, height of upper ingot body 21, concave part; 111, height of convex part; 112, distance between one side of the convex part and the same side of the upper ingot body. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] First, the equipment to which the present invention is applicable is explained. Specifically, the present invention relates to vacuum electron beam melting equipment, which is mainly used for the melting of metals. More specifically, the present invention mainly relates to the melting of tantalum metal. When melting tantalum metal, it is necessary to melt a part of the ingot starter, specifically the upper part of the ingot starter. The melting depth is called the molten pool depth, and the tantalum metal is melted and dripped into the melting part of the ingot starter, and after cooling, the ingot starter (hereinafter referred to as the pulled ingot) is pulled out, thereby completing the preparation of the tantalum ingot.

[0025] Example 1

[0026] See also Figures 1 to 3 A composite ingot starter comprises an upper ingot body 1 and a lower ingot body 2, wherein the upper ingot body 1 is made of tantalum, and the lower ingot body 2 is made of niobium, and the upper ingot body 1 and the lower ingot body 2 are connected to form a composite ingot starter.

[0027] When preparing tantalum ingots by vacuum electron beam melting, tantalum metal is melted by electron beam melting equipment, and tantalum liquid is drained to the ingot starter. Specifically, the composite ingot starter is installed on the crucible of the electron beam melting equipment, and the upper part of the composite ingot starter, specifically the upper part of the upper ingot body 1, is first melted by electron beam, and then the tantalum liquid is drained into the melting part of the ingot starter. After cooling, the tantalum liquid combines with the melting part of the upper ingot body 1, and then the tantalum ingot is prepared by pulling out the composite ingot starter. Among them, the material of the upper ingot body 1 is tantalum, which is conducive to the preparation of tantalum ingots, specifically, it is conducive to the crystallization of tantalum liquid and can avoid impurities. On the other hand, the material of the lower ingot body 2 is niobium, which is conducive to reducing the manufacturing cost of the ingot starter. Moreover, since the metal properties of niobium and tantalum are similar, after a part of the upper ingot body 1 is melted, the heat conduction will not cause the lower ingot body 2 to also melt, thereby causing the composite ingot starter to split.

[0028] Furthermore, a convex portion 11 is provided at the bottom of the upper ingot body 1, and a concave portion 21 matching the convex portion 11 is provided at the top of the lower ingot body 2. The upper ingot body 1 and the lower ingot body 2 are connected via the convex portion 11 and the concave portion 21 to form a composite ingot starter.

[0029] In the present invention, the convex portion 11 of the upper ingot body 1 is connected with the concave portion 21 of the lower ingot body 2 to form a composite ingot starter. Specifically, the connection between the convex portion 11 and the concave portion 21 is more conducive to the bonding strength between the upper ingot body 1 and the lower ingot body 2.

[0030] Preferably, the height 12 of the upper ingot body is at least 100 mm.

[0031] Through the above design, the height 12 of the upper ingot body is at least 100 mm. Specifically, when the composite ingot head is used to prepare the tantalum ingot, the depth of the melting of the upper part of the upper ingot body 1 is generally 30 to 50 mm. When the tantalum ingot is prepared by electron beam melting, the melting depth of the upper ingot body 1 is 50 mm, and sufficient heat conduction distance is retained. Since the melting point of tantalum is 3036°C and the melting point of niobium is 2477°C, this can ensure that when preparing the tantalum ingot, niobium will not melt due to the heat conduction of tantalum, and even cause the upper ingot body 1 and the lower ingot body 2 to separate. Therefore, the height 12 of the upper ingot body is at least 100 mm to prevent the lower ingot body 2 from melting and separating from the upper ingot body 1 when preparing the tantalum ingot.

[0032] A method for preparing a composite ingot starter head comprises processing a tantalum ingot to obtain an upper ingot body 1 with a protrusion 11, processing a niobium ingot to obtain a lower ingot body 2 with a concave portion 21, and welding the upper ingot body 1 and the lower ingot body 2 to obtain a composite ingot starter head.

[0033] Preferably, the welding is performed by electron beam welding, the electron beam current of the electron beam welding is 200-260 mA, the acceleration voltage is 80-120 KV, and the welding speed is 250-300 mm / min.

[0034] In this embodiment, the electron beam current of electron beam welding is 230 mA; the acceleration voltage is 100 kV; and the welding speed is 280 mm / min. Specifically, the electron beam current, the acceleration voltage, and the welding speed are determined according to different materials to be welded.

[0035] More preferably, when the welding is electron beam welding, the bottom of the upper ingot 1 and the top of the lower ingot 2 are both melted, and the melting depth is 10 to 20 mm.

[0036] The welding in the preparation method is electron beam welding, which is beneficial to improving the bonding strength between the upper ingot body 1 and the lower ingot body 2 and the ingot guide strength of the subsequent composite ingot guide head. On the other hand, during electron beam welding, the connecting part of the upper ingot body 1 and the lower ingot body 2 will melt, and the melting depth is 10 to 20 mm. The deeper the melting depth, the stronger the penetration of the welding. However, if the melting depth is too deep, it may cause thermal damage or deformation.

[0037] More preferably, the concave portion 21 matches the convex portion 11 , and a distance 112 between one side of the convex portion and the same side of the upper ingot body is 10 to 20 mm.

[0038] In the present invention, the distance 112 between one side of the protrusion and the same side of the upper ingot body is 10 to 20 mm, which can be conducive to stronger welding and ensure the welding effect. When the distance is reduced, when preparing the tantalum ingot, the ingot leading process may cause the upper ingot body 1 and the lower ingot body 2 to separate; when the distance is increased, during electron beam welding, the welding effect will be reduced.

[0039] More preferably, the height 111 of the protrusion is 5 to 10 mm.

[0040] In the present invention, the protrusion height 111 is 5 to 10 mm, which is conducive to the welding of the upper ingot body 1 and the lower ingot body 2. Specifically, before welding, the upper ingot body 1 and the lower ingot body 2 need to be assembled and then electron beam welded. Therefore, when the protrusion height 111 is too shallow, it will affect the assembly effect; when the protrusion height 111 is too deep, it will increase the cost.

[0041] It should be noted that the present embodiment adopts electron beam melting equipment to prepare the composite ingot head, the material of the upper ingot body 1 is tantalum, and the material of the lower ingot body 2 is niobium, wherein the height 12 of the upper ingot body in the present embodiment is 100 mm, and the height 111 of the convex part of the upper ingot body is 8 mm; the distance 112 between one side of the convex part and the same side of the upper ingot body is 15 mm.

[0042] Example 2

[0043] The difference between the second embodiment and the first embodiment is that the height 12 of the upper ingot body is 120 mm; the height 111 of the convex part of the upper ingot body is 10 mm; and the distance 112 between one side of the convex part and the same side of the upper ingot body is 20 mm.

[0044] Example 3

[0045] The difference between the present embodiment 3 and the embodiment 1 is that the height 111 of the convex part of the upper ingot body is 5 mm; and the distance 112 between one side of the convex part and the same side of the upper ingot body is 10 mm.

[0046] Example 4

[0047] The difference between this embodiment 4 and embodiment 1 is that the welding method adopted is laser welding.

[0048] Example 5

[0049] The difference between Comparative Example 5 and Example 1 is that the height 12 of the upper ingot body is 80 mm.

[0050] Example 6

[0051] The difference between this comparative example 6 and the example 1 is that the distance 112 between one side of the protrusion and the same side of the upper ingot body is 8 mm.

[0052] Example 7

[0053] The difference between this comparative example 7 and the example 1 is that the distance 112 between one side of the protrusion and the same side of the upper ingot body is 22 mm.

[0054] Example 8

[0055] The difference between the present embodiment 8 and the embodiment 1 is that the height 111 of the protrusion is 4 mm.

[0056] Example 9

[0057] The difference between the present embodiment 9 and the embodiment 1 is that the height 111 of the protrusion is 11 mm.

[0058] Comparative Example 1

[0059] The difference between Comparative Example 1 and Example 1 is that the entire ingot starter head is made of tantalum.

[0060] In order to further reflect the advantages of the present invention, the present invention uses Examples 1 to 9 to prepare composite ingot starters, and Comparative Example 1 to prepare pure tantalum ingot starters. Finally, the material costs of the two ingot starters are calculated respectively, and the phenomena before and after the preparation of metal tantalum using the prepared ingot starters are observed, as shown in Table 1. It should be noted that the present invention uses electron beam melting to prepare metal tantalum, wherein when the ingot starter is needed to pull the ingot, a part of the top of the ingot starter will melt as a molten pool to receive the molten metal tantalum liquid, wherein the molten pool depth used is 50 mm, and before and after the electron beam melting to prepare the tantalum ingot, the phenomenon of the ingot starter can be obtained by direct observation, and the material cost is based on the size of the ingot starter. It is calculated that it should be noted that the specific parameters of the electron beam melting equipment used in Examples 1 to 3 and Examples 5 to 9 are as follows: the electron beam current is 230 mA; the acceleration voltage is 100 KV; and the welding speed is 280 mm / min.

[0061] Table 1 Table of ingot head and ingot head cost before and after the preparation of tantalum metal

[0062]

[0063]

[0064] Result analysis:

[0065] 1. It can be seen from Example 1, Example 2, and Example 9 that the increase in the height 12 of the upper ingot and the increase in the height 111 of the protrusion will lead to an increase in material cost, and the effects achieved by Example 1, Example 2, and Example 9 before and after preparing tantalum metal by electron beam melting are normal, so it is best to use Example 1 with the lowest cost to achieve the same effect.

[0066] 2. It can be seen from Example 1, Example 3, and Example 8 that the height 111 of the convex portion of the upper ingot body is reduced. Since it is not convenient for the workers to assemble the upper ingot body 1 and the lower ingot body 2 before welding, the quality of electron beam welding deteriorates, especially manifested as offset after assembly, resulting in a break at the welding point between the upper ingot body 1 and the lower ingot body 2 after welding. Although the ingot pulling is normal, there is a safety hazard.

[0067] 3. It can be seen from Examples 1 and 4 that when laser welding is used, the welding strength of the upper ingot body 1 and the lower ingot body 2 is insufficient because laser welding can only weld the surface of the metal, resulting in the upper ingot body 1 and the lower ingot body 2 being pulled apart when the composite ingot head is used to pull the ingot.

[0068] 4. It can be seen from Examples 1 and 5 that when the height 12 of the upper ingot is too low, since the melting point of tantalum is 3036°C and the melting point of niobium is 2477°C, when using an ingot guide to prepare metallic tantalum, the molten pool depth of the upper ingot 1 is 50 mm. Since the height 12 of the upper ingot is too low, the temperature generated by the molten pool is transferred to the lower ingot 2, causing partial melting of niobium, which is specifically manifested as partial cracks after cooling. When used as a composite ingot guide to pull ingots, there is a safety hazard.

[0069] 5. It can be seen from Examples 1, 6 and 7 that when the distance 112 between one side of the protrusion and the same side of the upper ingot body is too close, when the ingot is pulled using the ingot guide head, the bonding strength between tantalum and niobium is insufficient, resulting in the tantalum and niobium being pulled apart, causing a safety accident; when the distance 112 between one side of the protrusion and the same side of the upper ingot body is too far, the welding effect between tantalum and niobium is not good, and partial cracks appear after welding. When the composite ingot guide head is used to pull the ingot, although the ingot is pulled normally, there is a safety hazard.

[0070] 6. It can be seen from Example 1 and Comparative Example 1 that when pure tantalum is used as the ingot starter, the ingot pulling is normal, but because the price of tantalum is much higher than that of niobium, the material cost of pure tantalum is much higher than the material cost of the composite ingot starter of tantalum and niobium, and the composite ingot starter can also achieve the ingot pulling effect of the pure tantalum ingot starter.

[0071] To sum up, when the height 12 of the upper ingot is less than 100 mm, when the tantalum ingot is prepared by electron beam melting, the lower ingot 2 will partially melt, and some cracks will appear after the ingot is cooled, posing a safety hazard; when the height 111 of the convex portion of the upper ingot is less than 5 mm, it is not conducive to the staff to combine and assemble the upper ingot 1 and the lower ingot 2 before electron beam welding, which is specifically manifested in the presence of a break in the composite ingot head. Although the ingot pulling is normal for a short time, there will be safety hazards if used for a long time; when the height 111 of the convex portion of the upper ingot exceeds 10 mm, the cost will increase. In order to ensure the convenience of the staff to combine and assemble the upper ingot 1 and the lower ingot 2 and control the cost, the convex portion height 111 of the upper ingot is 111 is most preferably 8mm; when the distance 112 between one side of the protrusion and the same side of the upper ingot body is less than 10mm, when electron beam melting is used to prepare tantalum, the upper ingot body 1 and the lower ingot body 2 may be pulled apart; when the distance 112 between one side of the protrusion and the same side of the upper ingot body exceeds 20mm, during electron beam welding, the welding effect is reduced, and there are partial cracks at the welding points of tantalum and niobium, resulting in a decrease in the strength of the composite ingot head. Although the ingot can be pulled normally for a short time, there will be safety hazards if used for a long time. In order to ensure the effect of electron beam welding and the strength of the composite ingot head for preparing tantalum by electron beam melting, the distance 112 between one side of the protrusion and the same side of the upper ingot body is most preferably 15mm.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A composite ingot starter, comprising an upper ingot body and a lower ingot body, characterized in that: The material of the upper ingot body is tantalum, the material of the lower ingot body is niobium, and the upper ingot body and the lower ingot body are connected to form a composite ingot starter.

2. A composite ingot starter according to claim 1, characterized in that: A convex portion is provided at the bottom of the upper ingot body, a concave portion matching the convex portion is provided at the top of the lower ingot body, and the upper ingot body and the lower ingot body are connected through the convex portion and the concave portion to form a composite ingot starter.

3. A composite ingot starter according to claim 1, characterized in that: The height of the upper ingot body is at least 100 mm.

4. A method for preparing a composite starter head, characterized in that: The tantalum ingot is processed to obtain an upper ingot head with a convex portion, and the niobium ingot is processed to obtain a lower ingot head with a concave portion. The upper ingot head and the lower ingot head are welded to obtain a composite ingot head.

5. The method for preparing a composite starter head according to claim 4, characterized in that: The welding adopts electron beam welding, the electron beam current of the electron beam welding is 200-260mA; the acceleration voltage is 80-120KV; and the welding speed is 250-300mm / min.

6. The method for preparing a composite starter head according to claim 5, characterized in that: When the upper ingot and the lower ingot are welded by electron beam welding, the bottom of the upper ingot and the top of the lower ingot are melted, and the melting depth is 10 to 20 mm.

7. The method for preparing a composite starter head according to claim 4, characterized in that: The concave portion matches the convex portion, and the distance between one side of the convex portion and the same side of the upper ingot body is 10 to 20 mm.

8. The method for preparing a composite starter head according to claim 7, characterized in that: The height of the convex portion is 5 to 10 mm.

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