JP2013031870A - Method for melting titanium ingot utilizing scrap and melting apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To melt a high quality ingot by obtaining the composition of recycled titanium scrap as a raw material and adding additives to the scrap.SOLUTION: The method comprises the steps of: storing individual recognition information and processing history information, which are made to pass a read means and attached to the scrap, in a server; predicting changed portions in chemical composition of the scrap from the processing history information and correcting the individual recognition information (chemical composition) by a computing means; in an initial stage of ingot production, calculating necessary combinations among the scrap, sponge titanium and additives of the raw materials and individual feed rates in the corrected individual recognition information stored in the server, so as to satisfy chemical composition and production rate of the aimed ingot; starting to feed by transmitting the signals corresponding to the calculation results to the feed rate control means of the individual feed means of these raw materials from the computing means; while after the initial stage of ingot production, reading actual production rate of ingot by a detection means of extraction site of ingot; and controlling each feed rate of these raw materials by the computing means based on the actual production rate.

Description

  The present invention relates to a metal melting method using metal titanium scrap, and more particularly, to a method for recovering the metal titanium scrap and a method and an apparatus for melting the recovered scrap.

  For titanium metal, the main demand is for aircraft, and the demand for titanium materials tends to increase due to an increase in replacement demand for aircraft. In addition, there is a tendency for demand for consumer titanium materials to increase, and there is a need for measures to meet the global demand for titanium materials.

  On the other hand, the supply of rutile and ilmenite, which are titanium ores as raw materials for producing titanium metal, is not necessarily catching up with the increase in demand, and improvement is required.

  On the other hand, paying attention to scrap generated after processing of metal titanium ingot, the remaining material of titanium material processed as a product is individually traded and recycled, but one of the metal titanium scrap generated in the entire market is one of them. Only part is recycled, and improvement is required from the viewpoint of resource conservation.

  An ingot melted by an ingot maker (refers to a person who manufactures and supplies an ingot from new raw materials or recycled materials, and may be simply referred to as a maker hereinafter) is a processing manufacturer (processes the supplied ingot to produce a semi-finished product) -Refers to a person who manufactures the final product, and may be simply referred to as a user hereinafter). The user processes the ingot to manufacture the product, and scrap is generated as a scrap. This scrap is collected and returned to the manufacturer again.

  Titanium scraps recycled from the user side to the manufacturer side are broadly divided into so-called pure titanium scraps and alloy scraps. These sorting operations are performed manually, and the alloy components are analyzed for each scrap. There is a need to improve the efficiency of the work.

  In addition, there is a risk of mistakes in manually sorting titanium scrap, and there is still room for improvement from the viewpoint of quality assurance of ingots that have been remelted using scraps that have been sorted incorrectly.

  In order to solve such a problem, a method of attaching an IC tag in which product information is described to a recycled resin product has been proposed (for example, see Patent Documents 1, 2, and 3).

  In this method, individual identification information of the resin from which the recycled material is generated is recorded on the IC tag. Therefore, by reading the individual identification information of the IC tag given to the recycled material, the characteristics of the recycled material can be grasped, and as a result, the resin product can be efficiently recycled. (See Patent Document 1).

  However, when melting an ingot as a product, not only recycled titanium scrap, but also titanium materials such as sponge titanium, titanium oxide, and additives such as iron oxide are also included in the product ingot. It is required to be blended so as to satisfy the composition, and it is required in the market only by specifying the characteristics of the recycled raw material by the method of imparting the IC tag according to the known document 1 to the recycled titanium and recycling it. High-quality ingots cannot be produced efficiently.

  Further, depending on the conditions of processing performed on the user side for the supplied ingot, the titanium scrap component may change during the processing of the ingot. For example, when an ingot is subjected to a treatment such as cutting or rolling in an atmospheric atmosphere at a high temperature, the surface of the material reacts with the atmosphere to generate oxides and nitrides, and finally recycled scrap In some cases, the oxide layer or nitride layer may remain on the surface. Therefore, even if the identity of the recycled material is appropriately given to the scrap as individual identification information by the succession technology of the individual identification information, the actual composition of the recovered scrap is different from the time of shipment to the user side. There was a case.

  Thus, in order to satisfy the quality of the ingot required as a product, in addition to accurately grasping and selecting the composition of the titanium scrap at the time of collection, the type of additive added to the titanium scrap, There is a need for a system that controls the feed rate of each additive in accordance with the feed rate of the scrap set to the melting furnace by appropriately setting and blending the amounts.

JP 2002-370257 A JP 2009-245298 A Japanese Patent Laying-Open No. 2005-066785

  The present invention has been made in view of the above situation, accurately grasping the composition of titanium scrap at the time of collection from the market, reusing it as a melting raw material, and adding other additives as appropriate. It aims at providing the method of melt | dissolving the titanium ingot excellent in quality by setting it as a melt | dissolution raw material.

  In view of this situation, we have intensively studied to solve the above problems, and record the individual identification information on the titanium ingot shipped to the user at the manufacturer, and the processing of the titanium ingot at the user's factory. In addition to passing on the above information to the titanium scrap produced as a by-product, and adding information on the processing performed on the ingot on the user side, information such as the composition and processing history of the titanium scrap returned to the manufacturer is accurately obtained As a result, it has been found that the chemical composition can be reused in the production of an ingot with a precisely controlled chemical composition, and the present invention has been completed.

  That is, the titanium ingot melting method according to the present invention is a titanium ingot melting method in which titanium scrap is melted as a part of the titanium ingot raw material. The titanium scrap has a chemical composition, a mass, and other titanium. Individual identification information consisting of one or a plurality of information selected from scrap-specific information and processing history information consisting of information on the type and number of times of processing already performed on titanium scrap are given. Multiple types of titanium scrap are passed through automatic reading means to acquire individual titanium scrap individual identification information and processing history information, and the acquired individual identification information and processing history information are transmitted to a data server computer for storage and processing. Based on changes in the chemical composition of titanium scrap predicted from historical information, The chemical composition information in the identification information is corrected by the arithmetic means, and in the first stage of ingot production, the chemical composition and production of the target ingot product from the corrected individual identification information stored in the data server computer. The required combination of titanium scrap, sponge titanium, and / or additive and the supply speed of each are calculated by the calculation means so as to satisfy the speed, and the electrical signal corresponding to the calculation result of the combination and the supply speed is calculated using titanium. Transmission from the calculation means to the supply speed control means of the respective supply means of scrap, sponge titanium, and / or additive material, and supply of these is started. At the stage after the start of ingot production, it is equipped at the ingot product extraction site. The actual production speed of the ingot product is read by the detected detection means. Take, calculating means, based on the actual production rate, it is characterized by controlling the feed rate of titanium scrap, titanium sponge, and / or additives.

  In the present invention, it is preferable that the individual identification information and the processing history information are recorded as a stamp, a two-dimensional figure directly formed on the scrap surface, or an IC chip mounted on the scrap.

  In the present invention, it is preferable that the two-dimensional figure is an image pattern or a character selected from a digital code, a QR code, and a barcode.

  In the present invention, the individual identification information is preferably recorded in the ingot in the manufacturing process of the original ingot that is the source of the scrap.

  In the present invention, it is preferable that the individual identification information is recorded in the scrap after the scrap is generated after the processing process of the original ingot which is the generation source of the scrap.

  In this invention, it is set as the preferable aspect that the titanium scrap in the state to which the said solid identification information and the said process history information were provided is melt | dissolved as it is.

  In the present invention, a plurality of types of titanium scrap having different individual identification information and processing history information are stored in the raw material warehouse corresponding to each species and the individual identification information and processing history information are stored in the data server computer, A preferred embodiment is that the necessary titanium scrap species calculated by the arithmetic device via the data server computer is automatically selected and carried out from the raw material warehouse to the raw material supply device.

  In the present invention, the titanium scrap is preferably a pure titanium material or a titanium alloy material.

  In the present invention, the additive is a single metal selected from Ti, Fe, Al, V, Sn, and Si, or one or more of Ti, Fe, Al, V, Sn, Si, O, and N It is a preferred embodiment that it is an alloy or oxide containing.

  Further, the titanium ingot melting apparatus of the present invention is a titanium ingot melting apparatus for melting titanium scrap as a part of the titanium ingot raw material, and its chemical composition applied to each of one or a plurality of types of titanium scrap. , Mass, and individual identification information consisting of one or more pieces of information selected from titanium scrap-specific information, and the processing history consisting of the type of processing already performed on the titanium scrap and accompanying information accompanying the processing Automatic reading means for acquiring information, data server computer for storing the acquired individual identification information and processing history information, and the chemistry in the individual identification information based on the change in the chemical composition of titanium scrap predicted from the processing history information While correcting the composition information, in the first stage of ingot production, Necessary combinations of titanium scrap, sponge titanium, and / or additives so as to satisfy the chemical composition and production rate of the target ingot product from the individual identification information stored in the data server computer. The calculation means for calculating the supply speed of the steel, the supply means for supplying titanium scrap, sponge titanium, and / or additive, and the electrical signal corresponding to the calculation result of the combination and the supply speed, titanium scrap, sponge titanium, and / or Or a supply speed control means for operating each supply means of the additive material, and a detection means for reading the actual production speed of the ingot product that is provided in the drawing portion of the ingot product at the stage after the start of ingot production. The device is based on the actual production speed, Scrap, is characterized by controlling the feed rate of titanium sponge, and / or additives.

  According to the present invention, since the individual identification information is given to the recovered scrap, it is possible to grasp the composition without going through a prior component analysis, and can be reused as it is as a raw material for ingots. Ingot manufacturing costs can be reduced. Furthermore, by taking into account the processing history information performed on the scrap, the amount of change can be estimated even when the composition changes from the original composition.

It is a figure which shows the flow of the recycling system of this invention. It is a figure which shows the ingot to which the individual identification information in this invention was provided. It is a figure which shows inheritance of the individual identification information in this invention, and provision of process history information. It is a figure which shows inheritance of the individual identification information in this invention, and provision of process history information. It is a figure which shows 1st Embodiment in the scrap recycling of this invention. It is a figure which shows 2nd Embodiment in the scrap recycling of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
1. Recovered scrap Scheme 1 from an ingot manufacturing process and user in manufacturers represents an example of a preferred overall flow of practicing the present invention. First, at an ingot maker (manufacturer), an ingot 11 is melted in an electron beam melting furnace or a known melting furnace using a new raw material 10 or a recycled raw material 13 described later. In the present invention, individual identification information 21 related to the ingot is given to the titanium ingot 11 melted by the manufacturer.

  The individual identification information 21 here is not particularly limited as long as it is information related to the ingot 11, such as the chemical composition, weight, lot number, shipping date, receipt date, and the like of the ingot 11. It means the information necessary when using this as a melting raw material after it becomes the scrap 13.

  In addition, to give the individual identification information 21 to the titanium ingot 11 here, specifically, to give the IC tag 20 in which the individual identification information 21 is recorded to the titanium ingot 11 as shown in FIG. Alternatively, although not shown, it means that marking information that can be optically recognized is given.

  When the individual identification information 21 is given to the titanium ingot 11 using the IC tag 20, the chemical composition, weight, lot number, shipping date, receipt date, etc. of the ingot 11 are given to the IC tag 20 to be given to the titanium ingot. It is preferable to record information necessary for specifying the ingot 11. The IC tag 20 in which the individual identification information 21 is recorded is then attached to the titanium ingot 11 as shown in FIG.

  The IC tag 20 used in the present invention does not require special specifications, and a commercially available product can be used. However, it is preferable to select an IC tag for metal attachment. Note that normal IC tags other than those for metal attachment may interfere with transmission and reception with radio waves from the reader.

  Further, the generated titanium ingot 11 may be stamped directly as the individual identification information 21. The stamp information is optically read by stamping the chemical composition, weight, lot number, shipment date, receipt date, and other information necessary for using titanium scrap as a melting raw material. As a result, the individual identification information 21 of the ingot can be acquired.

  The inscription may be recorded as pattern information such as QR code or bar code in addition to characters. By recording such information, it is possible to perform management with higher confidentiality than character information.

  Furthermore, the individual identification information 21 can be stamped on the ingot surface by a method called a digital mark. This information is for recording a pattern on the surface of the ingot if it is uneven, and it is a recording method with higher confidentiality than the above-mentioned character information as well as QR codes and bar codes.

  As the above-mentioned marking, not only a so-called normal stamping system but also a stamping system using a laser can be selected. The latter method has an effect that the individual identification information 21 with higher accuracy can be given to the ingot 11 as compared with the embossing method.

  As shown in FIG. 1 again, the ingot 11 to which the individual identification information 21 is given by the above-described method is sold to a processing manufacturer (user). The ingot 11 sold to the user is shipped as a product 12 such as a plate material, a bar material, or a pipe material after undergoing a hot forging process or a hot rolling process.

  On the other hand, in the hot forging process and the hot rolling process, scraps 13 that are not limited to various forms of scraps are often generated. In the present invention, the scrap 13 is assumed to be recycled to the manufacturer again.

  The individual identification information 21 given to the titanium ingot 11 that is the generation source of the scrap 13 is succeeded and given to the recycled scrap 13. As a result, information such as the composition of the original ingot 11 is carried over to the scrap 13 and is used during recycling.

  Furthermore, at this time, in the processing of the ingot in the atmosphere / high temperature such as the hot forging step, the hot rolling step, and the gas fusing step, the material to be processed comes into contact with the atmosphere in a heated state. Thus, an oxide or nitride layer 50 is formed on the surface, so that the composition of the scrap 13 as a whole is changed from the original composition of the ingot 11. Therefore, in order to estimate the composition change after the processing of the scrap 13, processing history information is added to the individual identification information 21 as information indicating what processing the scrap 13 has passed through. 22 is added.

  The processing history information 22 is information including the type of processing such as hot forging, hot rolling, gas fusing, processing temperature, time taken for processing, and the number of times processing has been performed.

  The method for giving the individual identification information 21 and the processing history information 22 to the scrap 13 may employ the same means as the method for giving the individual identification information 21 to the titanium ingot 11 performed on the manufacturer side. it can.

  As a method of inheriting the individual identification information 21 and giving the processing history information 22, first, when the individual identification information 21 is stored in the IC tag 20, as shown in FIG. Once IC tag 20 is removed and stored, and product 12 and scrap 13 are generated after processing, IC tag 20 to which processing history information 22 is added in addition to individual identification information 21 is again applied to scrap 13. The purpose can be achieved by wearing.

  Alternatively, as shown in FIG. 4, the individual identification information 21 given to the ingot 11 is read by the reading device 42 and stored in the data server, and the generated scrap 13 is stored. Then, the individual identification information 21 and the executed processing history information 22 stored in the data server are recorded on another IC tag by the writing device 43 as shown by the route in FIG. A method of newly giving to the scrap 13 may be used.

  Second, if the individual identification information 21 is pattern information directly stamped on the surface of the titanium ingot 11, the individual identification information 21 given to the ingot 11 is the titanium scrap as shown by the route in FIG. By processing on the maker side so as to remain up to the 13th stage, the individual identification information 21 of the titanium ingot 11 can be succeeded to the titanium scrap 13. In this case, as shown in FIG. 4B, in addition to the individual identification information 21, processing history information 22 is stamped after the processing is completed.

  In order to leave the individual identification information 21 up to the scrap 13, it is preferable that the individual identification information 21 formed of a pattern stamped on the titanium ingot 11 by a manufacturer is applied to as many locations as possible. Alternatively, when the usage and processing method after being supplied to the user are clear, it may be applied to a part that is known to be scrap by processing.

  Further, in the case of a processing method in which the stamp disappears due to heat treatment or deformation, the individual identification information 21 stamped before the processing is read by the user and stored in the server to generate the scrap 13 Later, the individual identification information 21 and the processing history information 22 can be again stamped with pattern information.

  As described above, the process for giving and succeeding the individual identification information 21 is completed by the manufacturer and / or the user, and the process for giving the process history information 22 is completed by the user. Therefore, the properties of the titanium scrap 13 recycled to the ingot maker will be clarified from the collection point by taking into account the composition change based on the processing history information in addition to the composition of this place. When dissolving the ingot, the component analysis can be omitted and the ingot can be processed efficiently.

2. Scrap Recycling Process in Manufacturer 2-1) Preliminary Experiment for Estimating Composition Change Prior to explaining the first embodiment and the second embodiment of the present invention, from the processing history information 22 given on the user side. A preliminary experiment for estimating the component change of the scrap 13 will be described.

  The processing history information 22 given to the scrap 13 includes the history of processing (processing type, condition, number of times, etc.) performed until the scrap 13 is generated and the weight of the processed scrap. Based on these pieces of information, it is possible to estimate the oxygen increase amount and the nitrogen increase amount for the scrap 13 as follows.

A. In the case of gas fusing, by setting the following specific preconditions, it is possible to estimate the oxygen rise amount ΔW _ox (ppm) and the nitrogen rise amount ΔW _ni (ppm) of the scrap 13 after gas fusing.
A-1) Preconditions Weight of scrap subject to gas fusing: W _s (Kg)
Total gas melt cross section: S (cm ² )
Oxygen increase per unit area of gas fusing: W _ox-gas (g / cm ² )
Nitrogen increase per unit area of gas fusing: W _ni-gas (g / cm ² )
A-2) Oxygen and nitrogen increase amounts By using the above preconditions, the oxygen increase amount ΔW _ox (ppm) and the nitrogen increase amount ΔW _ni (ppm) can be calculated as follows.
ΔW _ox = W _ox−gas · S / W _s × 10 ⁶ (1)
ΔW _ni = W _ni−gas · S / W _s × 10 ⁶ (2)

B. In the case of hot rolling, by setting specific preconditions in the same manner as in the case of gas cutting, the oxygen increase amount ΔW _ox (ppm) and the nitrogen increase amount ΔW _ni (ppm) of the scrap 13 after gas cutting are estimated. can do. Since the scrap 13 is a slab, it is called a slab here.
B-1) Precondition Weight of slab to be hot rolled: W _s (Kg)
Surface area of the slab before hot rolling: ΣS (cm ² )
Number of hot rolling: N (times)
Oxygen increase per slab unit surface area per hot rolling: W _ox-rol (g / cm ² · times)
Nitrogen increase per slab unit surface area per hot rolling: W _ni-rol (g / cm ² · times)
B-2) Oxygen and nitrogen increase amounts By using the above preconditions, the oxygen increase amount ΔW _ox (ppm) and the nitrogen increase amount ΔW _ni (ppm) can be calculated as follows.
ΔW _ox = W _ox−rol · ΣS · N / W _s × 10 ⁶ (3)
ΔW _ni = W _ni−rol · ΣS · N / W _s × 10 ⁶ (4)

C. In the case of hot forging, the oxygen increase amount ΔW _ox (ppm) and the nitrogen increase amount ΔW _ni (ppm) of the scrap 13 after hot forging can be estimated as in the case of the gas fusing.
C-1) Preconditions The weight of the slab as a target before hot forging: W _s (Kg)
Surface area of the slab before hot forging: ΣS (cm ² )
Number of hot forgings: N (times)
Oxygen increase per slab unit surface area per hot forging: W _ox-fog (g / cm ² · times)
Nitrogen increase per slab unit surface area per hot forging: W _ni-fog (g / cm ² · times)
C-2) Oxygen and nitrogen increase amounts By using the above preconditions, the oxygen increase amount ΔW _ox (ppm) and the nitrogen increase amount ΔW _ni (ppm) can be calculated as follows.
ΔW _ox = W _ox−fog · ΣS · N / W _s × 10 ⁶ (5)
ΔW _ni = W _ni−fog · ΣS · N / W _s × 10 ⁶ (6)

  Specific values can be determined by preliminary tests for the oxygen increase amount and the nitrogen increase coefficient when the above-described gas fusing, hot rolling, and hot forging processes are performed.

  For example, when the metal lump delivered to the processing manufacturer is a cylindrical ingot, all the processing steps described above are performed. Therefore, in this case, the oxygen increase amount and the nitrogen increase amount added to the titanium scrap are obtained by adding the increase amounts associated with the respective processes of hot forging, hot rolling, and gas fusing.

  On the other hand, when the metal lump delivered to the processing manufacturer is a rectangular slab, only the increments associated with each process of hot rolling and gas fusing among the above processes are added.

  By combining the arithmetic expression as described above in the scrap processing process and combining it with the information given to the scrap 13, the oxygen increase amount and nitrogen increase amount of the scrap 13 brought into the melting plant can be calculated each time. It can be estimated without analysis.

  The correspondence between the processing method and the component change obtained by this preliminary experiment (Table 1) is preferably stored in a data server computer to be described later and a database is constructed.

2-2) 1st Embodiment Next, 1st Embodiment of this invention for manufacturing an ingot using the collect | recovered scrap is described.
FIG. 5 shows an example of a preferable process after the titanium scrap 13 that has been subjected to the pre-processing of inheritance / granting of individual identification information and processing history information as described above is recycled to an ingot maker. That is, as shown in FIG. 5 (a), the titanium scrap 13 to which the individual identification information 21 and the processing history information 22 are given is transferred on the transfer line and is transferred to the automatic reading device 40 arranged in the transfer line. Thus, the individual identification information 21 and the processing history information 22 given to the titanium scrap 13 are read.

  The individual identification information 21 and the processing history information 22 read by the automatic reading device 40 are then transmitted to the data server computer. In the data server computer, a database of chemical composition and the like associated with the individual identification information 21 is configured. By collating the read individual identification information 21 with the database, the titanium scrap is transferred to the user side. Necessary information such as the original chemical composition before shipment can be read out. In addition, since the data server computer is also configured with a database indicating the relationship between the type of processing obtained by the above-described preliminary experiment and the component change, the scraped processing history information 22 and the database can be checked by collating It is also possible to read information on the composition change according to the processing history.

  Next, the read information on the original chemical composition of the scrap and the information on the composition change are transmitted to the arithmetic unit and added to calculate an estimated value of the current chemical composition of the scrap. Furthermore, based on the estimated value of the current chemical composition, the supply speed of the scrap 13 necessary to satisfy the ingot information (chemical composition and manufacturing speed) input in advance for the manufacturing purpose. If necessary, the type and supply speed of the additive 14 can be calculated and determined.

  The additive 14 includes a plurality of types of additives such as those containing a high concentration of alloy components such as Fe, Al, O, and N and those not containing an alloy component such as sponge titanium. , And supplied independently according to the calculation result by the arithmetic unit.

  The information on the supply speed of the scrap 13 calculated by the arithmetic device is transmitted from the arithmetic device to the control device 1A that controls the supply speed of the titanium scrap 13 filled in the supply hopper 42 of the titanium scrap 13, and the control device 1A By controlling the supply hopper 42, the scrap 13 is supplied at a speed according to the calculation result. Similarly, information on the type and supply speed of the additive 14 such as a material containing an alloy component or sponge titanium is transmitted to the control device 1B, and the supply hopper 43 is controlled by the control device 1B. Is supplied at a speed corresponding to

  In this way, the titanium scrap 13 and the additive 14 are supplied to the hearth 30, and the molten metal that has been melted and formed is poured into the mold 31 and cooled and solidified to produce the ingot 11. Furthermore, the information on the manufacturing speed of the ingot inputted in advance is transmitted to the control device 1C that controls the drawing speed of the generated titanium ingot 11, and the ingot 11 is drawn at that speed.

  In FIG. 5, the supply system of the additive 14 (additive 14, supply hopper 43, and control device 1 </ b> B) is shown by representing only one row, but a plurality of supply systems are arranged as necessary. Thus, a plurality of additives can be supplied independently as necessary.

  Further, if the individual identification information 21 and the processing history information 22 are directly stamped on the scrap 13, no special action is required, but if the individual identification information 21 and the processing history information 22 are recorded on the IC tag 20, the automatic reading device 40 is used. The process of removing the IC tag 20 from the scrap 13 is necessary from the time when it is read until the supply hopper 42 is filled.

The necessary raw material type and supply speed in the arithmetic unit are calculated as follows, for example. For example, information on the target ingot to be entered in advance
Titanium concentration: C _I ^Ti (constant)
Oxygen _{concentration: C} ^{I O} (constant)
Nitrogen concentration: C _I ^N (constant)
Production rate: V _I (constant)
The current information that takes into account the component changes of a certain scrap,
Titanium concentration: C _S ^Ti (constant)
Oxygen concentration: C _S ^O (constant)
Nitrogen concentration: C _S ^N (constant)
Supply speed: V _S (variable)
And information on oxygen-added materials (for example, titanium oxide)
Titanium concentration: C _A1 ^Ti (constant)
Oxygen concentration: C _A1 ^O (constant)
Supply speed: V _A1 (variable)
And the information of the nitrogen additive (for example, titanium nitride) is
Titanium concentration: C _A2 ^Ti (constant)
Nitrogen concentration: C _A2 ^N (constant)
Supply speed: V _A2 (variable)
The information on titanium sponge is
Titanium concentration: C _Ti ^Ti (= 100%, constant)
Supply speed: V _Ti (variable)
If so, the following formula is established.

V _Ti · C _Ti ^Ti + V _A1 · C _A1 ^Ti + V _A2 · C _A2 ^Ti + V _S · C _S ^Ti = V _I · C _I ^Ti (equation for titanium)
V _A1 · C _A1 ^O + V _S · C _S ^O = V _I · C _I ^O (equation for oxygen)
V _A2 · C _A2 ^N + V _S · C _S ^N = V _I · C _I ^N (equation for nitrogen)

  Since the speed V and concentration C of the target ingot and the concentration C of the scrap and additive are known as constants, the optimum scrap can be obtained by solving the speed V of the scrap and additive as a variable of simultaneous equations in these equations. The feed rate and additive feed rate can be determined and controlled.

  At that time, depending on the combination of materials, the solution may not be determined in a single way, but in that case, the determination is made with priority given to the supply rate of the titanium scrap 13 and the supply rate of the additive 14. The case can be selected and the solution can be determined in an arbitrary manner, but this point can be appropriately used depending on the stock situation of the raw material.

  By incorporating the control logic as described above into the arithmetic device, the supply speed of each additive can be controlled in accordance with the supply speed of the titanium scrap to the melting furnace.

  Reference numeral 41 is a device for detecting the production rate of the ingot 11. In the ingot production process based on the above control, the actual production rate of the ingot is detected based on fluctuation factors such as raw material supply errors and molten metal volatilization. This can be fed back to the apparatus to contribute to control of the feed rate of the raw material and the pulling rate of the ingot 11.

  By adopting the apparatus control configuration as described above, there is an effect that an ingot having a target composition can be efficiently produced.

2-3) Second Embodiment FIG. 6 shows another preferred aspect of the present invention.
In this embodiment, unlike the case of the first embodiment, the titanium scrap 13 from which the individual identification information 21 and the processing history information 22 are read by the automatic reading device 40 is temporarily transferred to the warehouse S via the carry-in device 44. It is brought in. This process is repeated for a plurality of types of scraps and stored independently in warehouses S1, S2,.

  At this time, each scrap is carried into the warehouse, and the individual identification information 21 and the processing history information 22 read by the automatic reading device 40 are transmitted to the data server computer, and further, the warehouse number into which each titanium scrap is carried. The information of (S1, S2,..., SN) is also stored in a form added to the individual identification information 21 and the processing history information 22.

  Subsequently, as in the first embodiment, the chemical composition and the production rate of the target ingot to be melted are input, and in response to this, the arithmetic unit first calculates the current composition component considering the scrap processing history. Estimated values are calculated, necessary scrap types and supply speeds, additive material types and supply speeds are calculated, and the calculation results are transmitted to the unloader 45, where appropriate preferred titanium scrap is automatically selected from the warehouse. The specific titanium scrap and additive are supplied to Hearth.

  Also in this embodiment, as in the first embodiment, there are cases where the solution of the simultaneous equations of the chemical composition concentration and the supply rate may not be fixed, but in this case as well, priority is given to the scraps stored in the warehouse. The types to be used can be determined and the variables for the remaining scrap and additives can be determined.

  By setting it as the above aspect, compared with 1st Embodiment, there exists an effect that the ingot which has a wide specification can be melted.

2-4) Other Modifications In the present invention, as described above, the individual identification information 21 and the processing history information 22 can be separately stored in the server computer to configure the database. However, as another aspect, The component change can be added to the individual identification information 21 at the time when the processing history information 22 is read, and both can be integrated as a database of the individual identification information 21.

  Titanium scraps, titanium chips, or titanium crops can be suitably used for the titanium scrap used in the present invention. Here, the titanium crop is a relatively thick titanium block produced in the rolling process of the titanium ingot, and becomes a rectangular parallelepiped titanium scrap. Such a shaped titanium crop has the effect that it can be suitably melted by using an electron beam melting furnace having a rectangular parallelepiped shaped transport device.

  Furthermore, the additive used in the present invention is a single metal selected from Ti, Fe, Al, V, Sn, and Si, or one of Ti, Fe, Al, V, Sn, Si, O, and N. Alternatively, a preferred embodiment is an alloy or oxide containing a plurality.

  Specifically, not only oxygen sources added to pure titanium such as titanium oxide and iron oxide, but also titanium sponge is included. The latter sponge titanium can be an effective additive when titanium scrap alone cannot keep up with the required amount of titanium ingot produced or when it is necessary to satisfy the required characteristics in the titanium ingot produced.

  By appropriately selecting and combining these elements, it is possible to produce a titanium ingot having a wide range of specifications.

  In the present invention, it is preferable to select as fine an IC tag as possible for recording the solid identification information and the processing history information to be given to the titanium scrap. As a result, even when the IC tag is melted without being removed from the titanium scrap prior to melting, quality contamination of the melted titanium ingot can be minimized.

  In addition, when quality requirement characteristics for ingots to be melted are strict, by recording solid identification information and processing history information on the titanium scrap itself by a technique such as laser engraving, quality contamination due to melting of the IC tag is effective. The effect that it can suppress automatically is produced.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
Titanium ingots were melted using an electron beam melting furnace using titanium scraps with individual identification information as raw materials.
1. Dissolved raw material 1) Titanium scrap: Titanium crop 2) Additives Titanium source: Sponge titanium Oxygen source: Powdered titanium oxide
2. Individual identification information recording medium IC tag: IC tag attached to the surface of the titanium crop Here, the processing history of the titanium crop is described, and using the above formulas (1) to (6), the titanium crop The oxygen content rate and nitrogen content rate were calculated and added to the original titanium ingot composition.
3. Melting furnace 1) Electron beam melting furnace with hearth: Output 400kW
2) Mold diameter: 100mm
4). Ingot Evaluation After the melted ingot was hot forged and processed into a billet, it was processed into a sheet having a thickness of 1 mm. The titanium material processed into a sheet shape was examined by transmission X-ray, EPMA and optical microscope for the presence or absence of LDI of the sheet-like titanium material and the segregation status of oxygen and iron.

[Example 1]
Using the apparatus and control system shown in FIG. 5, a titanium ingot was melted using a block-like titanium crop as titanium scrap. Analytical values of oxygen, nitrogen and iron of the melted titanium ingot were examined by EPMA for each of the ingots TOP, Middle and Bottom by the above method.

  The survey results are shown in Table 1. As shown in Table 1, the segregation of iron, oxygen and nitrogen concentration components in the produced ingot was negligible. In addition, LDI was not observed in the produced ingot.

[Example 2]
Using the apparatus and control system shown in FIG. 3, a titanium ingot was melted using a block-like titanium crop as titanium scrap. The melted titanium ingot was evaluated for the quality of the ingot by the same method as in the examples. The results are shown in Table 2.
Here, the processing history of the titanium crop is described, and the oxygen content and nitrogen content of the titanium crop are added to the composition of the original titanium ingot using the above formulas (1) to (6). The calculation process was performed.

[Example 3]
In Example 1, the quality of the titanium ingot melted under the same conditions was investigated except that the individual identification information was replaced with an IC tag and a titanium crop provided with a digital mark using a laser was used. The results are shown in Table 3.

  Here, the processing history of the titanium crop is described, and the oxygen content and nitrogen content of the titanium crop are added to the composition of the original titanium ingot using the above formulas (1) to (6). The calculation process was performed.

  As shown in Table 3, LDI was not detected in the melted ingot, and it was confirmed that iron, oxygen, and nitrogen were uniformly distributed.

[Example 4]
In Example 1, a titanium ingot was melted under the same conditions except that powdered iron oxide was used as an additive. As shown in Table 4, the distribution of iron, oxygen and nitrogen in the melted titanium ingot was extremely uniform.

[Example 5]
In Example 1, a 6Al-4V alloy was melted under the same conditions except that an Al-V mother alloy was used as an additive. The distribution of Al and V in the melted ingot was analyzed, and the results are shown in Table 5.

[Comparative Example 1]
In Example 1, a titanium ingot was melted using a recycled material of titanium scrap to which individual identification information was not given. In this comparative example, oxygen and nitrogen of the titanium scrap used as the melting raw material were analyzed and the weight of the individual titanium scrap was also measured. Based on the measured information, the average values of oxygen and nitrogen of the titanium scrap used for melting were determined, and this value was used as a representative value for the entire titanium scrap. Furthermore, the weight of the titanium scrap was melted in advance so as to be substantially the same.

  After following the above procedure, a titanium ingot was melted using an electron beam melting apparatus. The composition of the melted titanium ingot is shown in Table 6. The composition of the melted ingot is generally inferior to that of Example 1, and there is no segregation of oxygen and nitrogen in the melted ingot, and an ingot having a uniform composition is melted. It was. However, compared with Example 1, various steps were required before the melting operation, and the ingot productivity was reduced by 5.9% compared to Example 1 using the present invention.

  This contributes to improving the efficiency of the titanium alloy ingot manufacturing process and is promising.

10 ... Raw material 11 ... Ingot,
12 ... Product,
13 ... scrap,
20 ... IC tag,
21 ... Individual identification information,
22 ... processing history information,
30 ... Haas,
31 ... mold,
40 ... automatic reading device,
41. Detection device,
42, 43 ... supply hopper,
44. Reading device,
45. Writing device,
50. Composition change portion (oxide / nitride)
1A-1C ... control device,
2A-2C ... control device,
S1-SN ... Warehouse.

Claims (10)

A titanium ingot melting method for melting titanium scrap as part of a titanium ingot raw material,
The titanium scrap includes individual identification information including one or a plurality of pieces of information selected from the chemical composition, mass, and other information unique to the titanium scrap, and the processing already performed on the titanium scrap. Processing history information consisting of the type and incidental information accompanying the processing is given,
Passing one or more types of titanium scrap through an automatic reading means to obtain the individual identification information and the processing history information of each titanium scrap,
The acquired individual identification information and the processing history information are transmitted to and stored in a data server computer,
Based on the amount of change in the chemical composition of the titanium scrap predicted from the processing history information, the information on the chemical composition in the individual identification information is corrected by the calculation means,
In the first stage of ingot production, the titanium scrap, sponge titanium, so as to satisfy the chemical composition and production rate of the target ingot product from the corrected individual identification information stored in the data server computer. And / or calculating the required combination of the additives and their respective feed rates by means of computing means,
An electric signal corresponding to the calculation result of the combination and the supply speed is transmitted from the calculation means to the supply speed control means of the supply means of each of the titanium scrap, the sponge titanium, and / or the additive material, and supplied. Start
In the stage after the start of the ingot production, the actual production speed of the ingot product is read by the detection means equipped in the drawing portion of the ingot product,
The said calculating means controls the supply rate of the said titanium scrap, the said sponge titanium, and / or the said additive based on the said actual production rate, The melting method of the titanium ingot characterized by the above-mentioned.   2. The device according to claim 1, wherein the individual identification information and the processing history information are recorded as a stamp, a two-dimensional figure directly formed on the scrap surface, or an IC chip attached to the scrap. Of melting titanium ingot.   The method for melting a titanium ingot according to claim 2, wherein the two-dimensional figure is an image pattern or a character selected from a digital code, a QR code, and a barcode.   2. The titanium ingot melting method according to claim 1, wherein the individual identification information is recorded in an ingot in a manufacturing process of an original ingot which is a generation source of the scrap.   The method for melting a titanium ingot according to claim 1, wherein the individual identification information is recorded on the scrap after processing the original ingot which is a generation source of the scrap. A plurality of types of titanium scrap having different individual identification information and the processing history information are stored in a raw material warehouse corresponding to each type and the individual identification information and the processing history information are stored in the data server computer,
2. The titanium according to claim 1, wherein the necessary titanium scrap species calculated by the calculation means via the data server computer is automatically selected and carried out from the raw material warehouse to the raw material supply means. Ingot melting method.   A titanium ingot melting method, wherein the titanium scrap in a state to which the solid identification information and the processing history information according to claim 1 are given is melted as it is.   The method for melting a titanium ingot according to claim 1, wherein the titanium scrap is a pure titanium material or a titanium alloy material.   The additive is a single metal selected from Ti, Fe, Al, V, Sn, and Si, or an alloy or oxidation containing one or more of Ti, Fe, Al, V, Sn, Si, O, or N The method for melting a titanium ingot according to claim 1, wherein the titanium ingot is melted. A titanium ingot melting device for melting titanium scrap as part of a titanium ingot raw material,
The individual identification information consisting of one or a plurality of information selected from the chemical composition, mass, and other information unique to the titanium scrap, and the titanium scrap assigned to each of one or a plurality of types of titanium scrap Automatic reading means for acquiring processing history information consisting of information on the type and number of times of processing already performed,
A data server computer for storing the acquired individual identification information and processing history information;
The chemical composition information in the individual identification information is corrected based on the change in chemical composition of the titanium scrap predicted from the processing history information, and stored in the data server computer in the first stage of ingot production. An operation for calculating a necessary combination of the titanium scrap, sponge titanium, and / or additive materials and a supply rate of each so as to satisfy the chemical composition and production rate of the target ingot product from the individual identification information. Means,
Supply means for supplying the titanium scrap, the sponge titanium, and / or the additive;
Supply speed control means for operating each supply means of the titanium scrap, the sponge titanium, and / or the additive material by an electrical signal corresponding to the calculation result of the combination and the supply speed;
In the stage after the start of ingot production, it is equipped with a detecting means that is equipped at a drawing site of the ingot product and reads the actual production speed of the ingot product,
The said arithmetic unit controls the supply speed of the said titanium scrap, the said sponge titanium, and / or the said additive based on the said actual production rate, The melting device of the titanium ingot characterized by the above-mentioned.

Images