WO2023128361A1

WO2023128361A1 - Apparatus for manufacturing titanium ingot and method for manufacturing titanium ingot using same

Info

Publication number: WO2023128361A1
Application number: PCT/KR2022/019755
Authority: WO
Inventors: 노윤경; 이초롱; 염종택; 홍재근; 박찬희; 장근; 유재섭
Original assignee: (주)동아특수금속; 한국재료연구원; 한국인닥타썸(주)
Priority date: 2021-12-30
Filing date: 2022-12-06
Publication date: 2023-07-06

Abstract

An apparatus for manufacturing a titanium ingot according to exemplary embodiments of the present invention may comprise: a plasma arc melting unit for melting metal scrap with a plasma arc; an induction skull melting unit for melting the molten metal melted by the plasma with an induced current; and an ingot drawing unit for withdrawing the metal ingot that is solidified after being melted by the induced current, wherein the plasma arc melting unit and the induction skull melting unit may be disposed in one chamber in the order named.

Description

Titanium ingot manufacturing apparatus and manufacturing method of titanium ingot using the same

The present invention relates to a titanium ingot manufacturing apparatus and a method for manufacturing a titanium ingot using the same, and more particularly, to a titanium ingot to which PAM (Plasma Arc Melting) and ISM (Induction Skull Melting) are continuously applied. The invention relates to a method for manufacturing a high-purity titanium ingot, a titanium alloy ingot, for example, a titanium alloy ingot for biomaterials using a manufacturing apparatus.

Biomaterials for plastic surgery or dentistry require excellent strength, toughness, wear resistance, and corrosion resistance, as well as biocompatibility that is harmless to the human body and combines with living bone. Representative metal materials for living organisms that exhibit these characteristics include Ni-Cr-based stainless steel (316L), Co-Cr-Mo alloy developed under the trade name of vitalium, and titanium (Ti) alloy, and these metal materials are currently It accounts for more than 70% of implant materials for implantation in the body. Stainless steel and Co-Cr-Mo alloys have been used for biomedical purposes since the 1930s and 1940s, respectively, and Ti alloys have been reported in 1952 by Per-Ingvar Brεnemark of Sweden for the osseointegration phenomenon in which Ti surfaces combine with bone tissue. Afterwards, it was first applied to dental implants in 1965, and full-scale commercialization took place in the mid-1970s. Ti alloy is light, non-magnetic, and has excellent biocompatibility as well as mechanical properties such as corrosion resistance, strength, and toughness. Today, it is used in dentistry as inlays, crowns, and tooth roots, in orthopedics, fracture fixation materials, artificial joints, etc., and in circulatory surgery. It is widely used in pacemakers and stents. Although Ti metal and Ti alloy are not bioactive, they are evaluated to have better biocompatibility than other biomaterials (stainless steel, vitallium) or polymer materials (PMMA, polymethyl metaacrylate) in bone formation patterns. Currently, Ti-6Al4V alloy (composition: wt.%), which is most commonly used for biomedical purposes, is an alloy with a (α + β) type two-phase structure. come. Therefore, high-quality titanium alloy powder and ingot manufacturing technology is required.

In the case of Korea, the infrastructure for manufacturing titanium alloy powder and titanium alloy ingot is not established, so most of the titanium rods and alloy powder are dependent on foreign countries, so the price is expensive and it is difficult to activate the market.

As an example for solving the above problems, in Korean Patent Registration No. 10-1751794, titanium scrap is melted using a heating means including induction heating and plasma to form titanium molten metal, and the titanium molten metal is formed by the heating means. It relates to a titanium refining and melting furnace that refines titanium scrap by removing various metal impurities and oxygen, including titanium scrap, and cools the refined material to produce titanium ingots and a titanium refining method using the same. a titanium molten metal part for processing, a main chamber part including the titanium molten metal part therein, a heating source part having a first function of removing metallic impurities and a second function of removing oxygen, and a scrap supplying titanium scrap to the titanium molten metal part. It includes a supply unit and an ingot take-out unit for withdrawing molten titanium from the titanium molten metal unit, and the heating source unit includes an induction coil unit performing the first function and a plasma generating unit performing the first function and the second function. A technology related to a titanium refining melting furnace, characterized in that it comprises, is disclosed, and also, in Korean Patent No. 10-1441654, a step of washing titanium alloy scrap, a tungsten electrode so that an arc occurs in a certain direction A method for manufacturing a titanium bar using a continuous non-consumable vacuum arc melting method comprising the step of processing the tip into a sharp point and installing it in a vacuum arc melting furnace, and the step of charging scrap into the inside of the hearth installed inside the vacuum arc melting furnace. This is disclosed, and Korean Patent Registration No. 10-1370029 discloses a titanium scrap refining method capable of removing oxygen contained in the molten metal by supplying hydrogen plasma to the surface of the molten metal for refining the titanium scrap.

Conventional titanium scrap refining technology applies plasma and induction melting to titanium alloy at the same time to melt titanium scrap to form titanium molten metal, and the heat applied at this time removes various metal impurities and oxygen contained in the molten metal. is to refine Melting of metal by plasma increases the melting property of the metal as the distance between the metal material and the plasma torch decreases. However, since the distance between the metal material and the plasma torch is relatively long, complete melting is difficult and high-density impurities are not removed, making it not suitable for refining and manufacturing titanium alloys for application to high-quality fields such as biomaterials. not.

One of the various problems of the present invention is to provide a titanium ingot manufacturing apparatus capable of greatly improving purity while increasing meltability.

One of the various problems of the present invention is to provide a method for manufacturing a titanium ingot using the titanium ingot manufacturing apparatus.

One of the various tasks of the present invention, in order to solve the above problems, is to shorten the distance between the plasma arc and the titanium alloy to completely melt the metal material and completely remove impurities to refine the titanium alloy and to obtain titanium through an induction skull melting process To provide a method for manufacturing a titanium alloy ingot for biomaterials by manufacturing an alloy ingot.

Titanium ingot manufacturing apparatus according to exemplary embodiments of the present invention includes a plasma arc melting unit for melting metal scrap with a plasma arc; an induction skull melting unit for melting the molten metal melted by the plasma with an induction current; and an ingot drawing unit for drawing out the metal ingot melted and solidified by the induction current, and the plasma arc melting unit and the induction skull melting unit may be disposed in one chamber in this order.

A disposition height of the plasma arc melting unit may be higher than a disposition height of the induction skull melting unit.

The plasma arc melting unit may include a cold hearth and a plasma torch, the induction skull melting unit may include a cold crucible and an induction coil, and one end of the cold hearth may be disposed above the cold crucible. .

A method for manufacturing a titanium ingot according to exemplary embodiments of the present invention includes melting titanium scrap with a plasma arc; melting the molten titanium scrap by an induction skull method; and casting a titanium ingot with molten titanium sequentially through the plasma arc and the induction skull method.

The titanium scrap may be in the form of rods, chunks, chips, clips, or sponges.

The plasma arc melting step may include inputting the titanium scrap into a plasma arc melting unit; Melting titanium scrap into primary titanium molten metal by driving a plasma torch; and separating inclusions by flowing the primary titanium molten metal on a cold hearth or vaporizing the inclusions into vapor.

The cold hearth may be made of a water-cooled copper vessel.

The melting by the induction skull method may include introducing the primary titanium molten metal into an induction skull melting unit; melting the primary titanium molten metal into a secondary titanium molten metal by driving an induction coil; and purifying the secondary titanium molten metal in a cold crucible.

The plasma arc melting step and the melting step by the induction skull method may be performed independently of each other.

The plasma arc melting step and the melting step by the induction skull method may be continuously performed.

The method for manufacturing a titanium ingot according to exemplary embodiments of the present invention solves both economic effects and environmental problems at the same time by using scrap, and also reduces production costs and improves productivity due to the use of copper melting instead of ceramic refractories It is characterized by the melting of metal materials and the production of high-purity titanium ingots by independently applying two heating processes.

1 is a view for explaining a titanium ingot manufacturing apparatus according to exemplary embodiments of the present invention.

2 is a flowchart illustrating a method for manufacturing a titanium ingot according to exemplary embodiments of the present invention.

3 is a diagram for explaining a step of melting titanium using a plasma arc melting unit according to exemplary embodiments of the present invention.

4 is a view for explaining a step of melting titanium using an induction skull melting unit according to exemplary embodiments of the present invention.

Hereinafter, specific embodiments of the present invention will be described. The detailed descriptions that follow are provided to provide a comprehensive understanding of the methods, devices and/or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification. Terminology used in the detailed description is only for describing the embodiments of the present invention and should in no way be limiting. Unless expressly used otherwise, singular forms of expression include plural forms. In this description, expressions such as "comprising" or "comprising" are intended to indicate any characteristic, number, step, operation, element, portion or combination thereof, one or more other than those described. It should not be construed to exclude the existence or possibility of any other feature, number, step, operation, element, part or combination thereof.

Also, terms such as first, second, A, B, (a), and (b) may be used to describe components of an embodiment of the present invention. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term.

Meanwhile, in the following, the term “titanium” may be used as “titanium”, and conversely, the term “titanium” may be used as “titanium”, and both “titanium” and “titanium” correspond to the element symbol Ti (Titanium). It can be interpreted as meaning a metal that In addition, both “melting” and “melting” may mean that a material in a solid state absorbs thermal energy and changes into a material in a liquid state.

Referring to FIG. 1 , a titanium ingot manufacturing apparatus 1 according to exemplary embodiments of the present invention may include a plasma arc melting unit 10, an induction skull melting unit 20, and an ingot drawing unit 30. can

The plasma arc melting unit 10 may include a plasma arc melting furnace (PAM Furnace), and may include a cold hearth 13 and a plasma torch 15.

The metal introduced into the plasma arc melting unit 10 may be titanium scrap 100, and the titanium scrap 100 may be made of various types of raw materials such as rods, lumps, chips, clips, and sponges.

The cold hearth 13 may be made of, for example, a water-cooled copper container, and may precipitate High Density Inclusions (HDIs) and Low Density Inclusions (LDIs) from molten metal or vaporize them into vapor. By removing it, it can play a role of increasing the purity of the cast metal. For example, the water-cooled copper container may be a reusable copper crucible, and in this case, the copper crucible that may be destroyed or lost due to a high melting temperature may be controlled by a metal skull formed on the inner wall of the crucible. Therefore, a reaction with molten metal due to the use of a conventional ceramic crucible can be prevented.

High-density inclusions may be, for example, metal compounds such as WC and TaC, low-density inclusions may be metal compounds such as TiN and TiC, and high-density inclusions may be deposited on the bottom surface of the cold hearth 13 and low-density inclusions can be vaporized.

Meanwhile, although FIG. 1 shows that the bottom surface of the cold hearth 13 has a flat shape, the concept of the present invention is not necessarily limited thereto, and the cold hearth 13 may have a non-flat bottom surface. Or, it may have a bottom surface having a step difference of different heights. That is, the bottom surface of the cold hearth 13 may be configured to have a different shape for more efficiently removing high-density inclusions and/or low-density inclusions.

The plasma torch 15 is configured to generate a plasma arc to melt metal scrap and may be referred to as a plasma arc generator. Meanwhile, the plasma arc may be replaced with an electron beam. Although not shown, the movement of the plasma torch 15 up and down and/or left and right on the cold hearth 13 may be controlled, and the rotation of the plasma torch 15 may be controlled so that the spraying direction of the plasma arc may be adjusted. there is.

In exemplary embodiments, the titanium scrap 100 injected into the plasma arc melting unit 10 may be melted into the primary titanium molten metal 110 by a plasma arc generated from the plasma torch 15 and sprayed, Inclusions 105 included in the primary titanium molten metal 110 may be precipitated and removed as the primary titanium molten metal 110 flows on the cold hearth 13 .

The induction skull melting unit 20 may include an induction skull melting furnace (ISM Furnace) and may include a cold crucible 23 and an induction coil 25 .

The cold crucible 23 may provide a space for accommodating the metal primarily melted through the plasma arc melting unit 10, and may be formed of, for example, a water-cooled copper crucible.

The induction coil 25 may be configured to induction-heat molten metal by generating a magnetic field by generating a current, and may be formed in a wound form of, for example, a high-frequency coil made of copper. The induction coil 25 may also be referred to as a high frequency coil. The magnetic field generated by the induction coil 25 can be adjusted by controlling the frequency of a power supply (not shown), and the molten metal can be secondarily melted by the magnetic field.

In exemplary embodiments, the primary titanium molten metal 110 injected into the induction skull melting unit 20 may be remelted into the secondary titanium molten metal 120 by a magnetic field formed by the induction coil 25, Thereafter, the secondary titanium molten metal 120 may be solidified on the cold crucible 23 and cast into a titanium ingot 150 . At this time, the secondary titanium molten metal 120 may be formed by additionally removing impurities or gases included in the primary titanium molten metal 110, and thus the purity and quality of the finally cast titanium ingot 150 are greatly improved. It can be.

In one embodiment, the arrangement height of the plasma arc melting unit 10 may be higher than the arrangement height of the induction skull melting unit 20, and one end of the cold hearth 13 may be disposed above the cold crucible 23. there is.

In exemplary embodiments, the molten metal, that is, the primary titanium molten metal 110 charged into the induction skull melting unit 20 is completely transformed into a uniform phase by convection in the cold crucible 23 through induction heating. By melting, secondary titanium molten metal 120 may be formed. At this time, the secondary titanium molten metal 120 in contact with the cold crucible 23 may be solidified by a water-cooled segment (not shown), and then the cold crucible 23 and the secondary titanium melt due to the generated skull. A boundary layer of thin metal is formed between the molten metal 120, and the boundary layer acts as thermal resistance to reduce the heat transferred from the secondary titanium molten metal 120 to the cold crucible 23, extending the life of the cold crucible 23. can fulfill its role.

In addition, the melting method by the induction skull melting unit 20 may be performed by melting the metal in a metal-to-metal manner in a cold crucible 23, that is, a water-cooled copper crucible, without a refractory material in a vacuum state, and melting with the absence of a refractory material. A reaction between the metal, that is, the secondary titanium molten metal 120 and oxygen may be suppressed.

In addition, the side surface of the secondary titanium molten metal 120 may be pushed inward from the inner side wall of the cold crucible 23, which means that the side surface of the secondary titanium molten metal 120 does not form a contact with the inner side wall of the cold crucible 23. Since there is no physical contact, it is possible to prevent the water-cooled segment from being short-circuited and reduce heat loss to the cold crucible 23 .

The ingot drawing unit 30 may be configured to draw a metal ingot formed by ingoing primary and secondary melted molten metal, that is, the titanium ingot 150 . In one embodiment, the ingot drawing unit 30 may be controlled so that the metal ingot is drawn through an up-and-down motion.

In exemplary embodiments, the plasma arc melting unit 10 and the induction skull melting unit 20 may be disposed in one chamber in this order, and thus the plasma arc melting (PAM) process and the induction skull melting ( ISM) process may be performed sequentially and continuously.

As described above, the titanium ingot manufacturing apparatus 1 according to exemplary embodiments of the present invention may be configured by sequentially disposing the plasma arc melting unit 10 and the induction skull melting unit 20, and metal scrap A plasma arc melting (PAM) process and an induction skull melting (ISM) process are sequentially and continuously performed through the silver titanium ingot manufacturing apparatus 1 to be cast into a metal ingot, thereby improving the meltability of metal scrap and The purity of the finally cast metal ingot can be increased.

Referring to FIG. 2, a method for manufacturing a titanium ingot according to exemplary embodiments of the present invention includes melting titanium scrap 100 with a plasma arc (S-1), melting the molten titanium scrap by an induction skull method It may include a step (S-2), and a step (S-3) of casting a titanium ingot with molten titanium sequentially through the plasma arc and the induction skull method.

Referring to FIGS. 1 and 2 together, the titanium scrap 100 may be melted into primary titanium molten metal 110 through a plasma arc melting step (S-1), and the primary titanium molten metal 110 is an induction skull. It may be re-melted into the secondary titanium molten metal 120 through the melting step (S-2). Thereafter, the secondary titanium molten metal 120 may be solidified and cast into a titanium ingot 150 .

3 is a view for explaining a step of melting titanium using the plasma arc melting unit 10 according to exemplary embodiments of the present invention.

Referring to FIG. 3, in the plasma arc melting step (S-1), the titanium scrap 100 is put into the plasma arc melting unit 10 (S11), and the titanium scrap 100 is driven by driving the plasma torch 15. ) into primary titanium molten metal 110 (S12), and flowing the primary titanium molten metal 110 on the cold hearth 13 to separate the inclusions 105 by precipitating them or vaporizing them into steam. (S13) may be included.

4 is a view for explaining a step of melting titanium using the induction skull melting unit 20 according to exemplary embodiments of the present invention.

Referring to FIG. 4 , the induction skull melting step (S-2) includes the step of inputting the primary titanium molten metal 110 into the induction skull melting unit 20 (S21) and driving the induction coil 25 to It may include melting the titanium molten metal 110 into the secondary titanium molten metal 120 (S22), and purifying the secondary titanium molten metal 120 on the cold crucible 23 (S23).

In exemplary embodiments, the plasma arc melting step (S-1) and the induction skull melting step (S-2) may be performed independently of each other, and the plasma arc melting step (S-1) and the induction skull melting step (S-2) may be performed continuously.

As described above, the method for manufacturing a titanium ingot according to the present invention is performed by independently and continuously applying two different melting processes to improve the meltability of titanium scrap 100 and minimize inclusions 105. can

That is, a process of removing impurities in the raw material using PAM (Plasma Arc Melting) can be applied first, and then, only pure molten metal molten metal from which low-density and high-density inclusions are removed can be used for ISM (Induction Skull Melting) Induction skull melting) may be charged into a cold crucible, and the purity of the finally manufactured metal ingot may be further improved by additionally remelting the pure molten metal.

However, the concept of the present invention is not necessarily limited thereto, and the titanium ingot manufacturing apparatus and the titanium ingot manufacturing method according to exemplary embodiments of the present invention can be used in various technical fields other than the above-described technical fields, for example, titanium alloy ingots. It can be applied to the manufacturing method of.

In one embodiment, in the case of the titanium alloy ingot manufacturing method, titanium scrap 100 may be used as a titanium alloy scrap, and accordingly, the primary titanium molten metal 110 and the secondary titanium molten metal 120 are also 1 It may be referred to as a primary titanium alloy molten metal and a secondary titanium alloy molten metal.

Unlike this, in the method of manufacturing a titanium alloy ingot, the titanium scrap 100 is melted into a primary titanium molten metal 110 and a secondary titanium molten metal 120 through a plasma arc melting unit 10 and an induction skull melting unit 20. Melting may be performed through substantially the same or similar steps as the above-described titanium ingot manufacturing method, and additionally, the step of injecting alloy components into the primary titanium molten metal 110 or the secondary titanium molten metal 120 is further performed. can include

Although various embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications are possible to the above-described embodiments without departing from the scope of the present invention. . Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

Claims

a plasma arc melting unit for melting metal scrap with a plasma arc;

an induction skull melting unit for melting the molten metal melted by the plasma with an induction current; and

Including; an ingot drawing unit for withdrawing a solidified metal ingot after being melted by the induced current,

The titanium ingot manufacturing apparatus, characterized in that the plasma arc melting unit and the induction skull melting unit are arranged in one chamber in this order.
According to claim 1,

Titanium ingot manufacturing apparatus, characterized in that the arrangement height of the plasma arc melting unit is higher than the arrangement height of the induction skull melting unit.
According to claim 1,

The plasma arc melting unit includes a cold hearth and a plasma torch,

The induction skull melting unit includes a cold crucible and an induction coil,

Titanium ingot manufacturing apparatus, characterized in that one end of the cold hearth is disposed on the upper part of the cold crucible.
melting titanium scrap with a plasma arc;

melting the molten titanium scrap by an induction skull method; and

Casting a titanium ingot with molten titanium sequentially through the plasma arc and the induction skull method.
According to claim 4,

The titanium scrap is a method for producing a titanium ingot, characterized in that in the form of rods, lumps, chips, clips, sponges.
According to claim 4,

The plasma arc melting step,

Injecting the titanium scrap into a plasma arc melting unit;

Melting titanium scrap into primary titanium molten metal by driving a plasma torch; and

A method for manufacturing a titanium ingot, comprising the step of precipitating inclusions by flowing the primary titanium molten metal on a cold hearth or vaporizing and separating inclusions.
According to claim 6,

The method of manufacturing a titanium ingot, characterized in that the cold hearth is made of a water-cooled copper container.
According to claim 6,

The step of melting by the induction skull method,

Injecting the primary titanium molten metal into an induction skull melting unit;

melting the primary titanium molten metal into a secondary titanium molten metal by driving an induction coil; and

A method for manufacturing a titanium ingot, comprising: purifying the secondary titanium molten metal on a cold crucible.
According to claim 8,

The method of manufacturing a titanium ingot, characterized in that the plasma arc melting step and the melting step by the induction skull method are performed independently of each other.
According to claim 9,

The method of manufacturing a titanium ingot, characterized in that the plasma arc melting step and the melting step by the induction skull method are performed continuously.