JP2003221626A - Method for manufacturing pure titanium ingot, and pure titanium ingot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily and inexpensively manufacturing a large pure-titanium ingot by using cut scrap and cut pieces generated in a working process for a titanium material, and a titanium sponge containing relatively high contents of oxygen, nitrogen, and iron, namely, relatively low purity of titanium, and to provide a pure titanium ingot. <P>SOLUTION: The method for manufacturing the pure titanium ingot comprises a step of forming a consumable electrode by arranging the first titanium material containing an O content of 0.07 wt.% or less, an N content of 0.009 wt.% or less, and an Fe content of 0.05 wt.% or less, on a periphery, and arranging the second titanium material containing the O content of 0.08-0.3 wt.%, the N content of 0.01-0.1 wt.%, and the Fe content of 0.06-5.0 wt.%, inside the first titanium material, and a step of melting the consumable electrode obtained in the above step, by vacuum arc. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a pure titanium ingot and a pure titanium ingot, and in particular,
The present invention relates to a method for producing a pure titanium ingot and a pure titanium ingot, which utilizes sponge titanium having a relatively low purity, and cutting scraps and cut pieces generated in a processing step of a titanium material.

[0002]

2. Description of the Related Art Titanium materials have high strength and can be used at high temperatures, so they are used for various purposes. However, when used for aircraft, they are of high quality and have sufficient reliability. The material with the property is provided.

Therefore, as a titanium material for aircraft, a sponge titanium having a low content rate of oxygen, iron, nitrogen, etc. is selected from sponge titanium produced by the Kroll method, and pure sponge titanium is used as a raw material. Titanium ingots were being manufactured.

As described above, when a high quality pure titanium ingot is manufactured, scrap materials such as cutting chips and cut pieces are generated in the manufacturing process. This scrap material and titanium sponge containing a relatively large amount of impurities have been used, for example, as a steel additive, but they have not always been utilized sufficiently.

On the other hand, recently, titanium materials have come to be used also in the field of consumer products such as mufflers for automobiles and motorcycles, golf club heads, and tennis rackets. It is possible to deal with these consumer products even if they do not have high quality as compared with the above titanium material for aircraft. For this reason, the range of utilization of scrap materials, which have not been effectively utilized up to now, and so-called B-grade titanium sponge, which has a relatively high content of oxygen, iron, or nitrogen, has expanded.

[0006]

Normally, a pure titanium ingot is formed by forming a briquette from a raw material such as titanium sponge, welding the briquettes to form a consumable electrode, and melting the consumable electrode by vacuum arc (VAR) melting. It is formed by

However, when the B-grade sponge titanium having a relatively low purity is used, since the briquette contains oxygen and nitrogen at a high content rate, there is a problem that the welding strength is lowered. Furthermore, when using scrap materials,
There is a problem that it is difficult to form briquettes because the shape of scrap material is not constant.

Further, since raw materials having different impurity contents are used, there are problems that the content ratio of impurities is different or the content of impurities is high depending on the site of the ingot obtained as a product. It was

The object of the present invention is to utilize sponge titanium having a relatively high content of cutting chips and chips, oxygen, nitrogen and iron, that is, a relatively low purity, generated in the processing step of titanium material, An object of the present invention is to provide a method for manufacturing a large-sized pure titanium ingot and a pure titanium ingot at a simple and low cost.

Another object of the present invention is to utilize oxygen, nitrogen and iron components contained in these raw materials by utilizing cutting scraps and chips generated in the processing step of titanium material and titanium sponge having a relatively low purity. The purpose is to provide a method for producing a pure titanium ingot having excellent elongation, tensile strength, and workability, and a pure titanium ingot.

Another object of the present invention is to provide oxygen, nitrogen,
It is an object of the present invention to provide a method for producing a pure titanium ingot in which an iron component is distributed as close as possible to a target value and evenly distributed over the entire ingot, and a pure titanium ingot.

[0012]

According to the method for producing a pure titanium ingot according to claim 1 of the present invention,
O content is 0.07 wt% or less, N content is 0.009
A first titanium material having a Fe content of 0.05% by weight or less and a Fe content of 0.05% by weight or less is disposed on the outer peripheral portion, and the O content is 0.08 to 0.3% by weight inside the first titanium material. %, N content is 0.01 to 0.1% by weight, Fe content is 0.06 to
A consumable electrode forming step of forming a consumable electrode by disposing a second titanium material of 5.0% by weight; and a step of vacuum-arc melting the consumable electrode obtained by the consumable electrode forming step.
It is solved by having.

Further, according to the method for producing a pure titanium ingot according to claim 2 of the present invention, the above-mentioned problem is that the O content is 0.07% by weight or less, the N content is 0.009% by weight or less, and the Fe content is 0.009% by weight or less. A first titanium material having a content of 0.05% by weight or less, an O content of 0.08 to 0.3% by weight, an N content of 0.01 to 0.1% by weight, and an Fe content of 0. .06-5.
A briquette forming step of forming a briquette by using 0% by weight of the second titanium material, arranging the first titanium material on the outer peripheral portion and arranging the second titanium material inside, and a briquette forming step And a step of forming a consumable electrode by assembling and welding the briquette obtained in 1. to form a consumable electrode, and a step of vacuum-arc melting the consumable electrode obtained in the consumable electrode forming step. .

As described above, according to the method for producing a pure titanium ingot of the present invention, the pure titanium ingot is formed by using two kinds of titanium materials having different purities, and it has not been effectively utilized in the past. In addition, it is possible to effectively utilize titanium material having low purity.

The pure titanium ingot is obtained by vacuum arc melting the consumable electrode, and the consumable electrode is formed by assembling and welding a plurality of briquettes. According to the manufacturing method of this example, since the highly pure first titanium material is located on the outer peripheral portion of the briquette, the briquette is welded at the first titanium material portion,
Briquettes can be welded with high joint strength. Therefore, a large-sized consumable electrode can be formed, and as a result, a large-sized pure titanium ingot can be manufactured.

As the second titanium material, specifically, either or both of B-grade sponge titanium having low purity and scrap material generated in the processing step of the titanium material are used. In order to contain oxygen (represented by O), nitrogen (represented by N), and iron (represented by Fe) in a good balance, the second titanium material may include class A sponge titanium. Further, in order to adjust the balance of O, N and Fe, the second titanium material is made of titanium oxide or metallic iron.
One kind or two or more kinds may be added. Titanium oxide can be used as the titanium oxide, and electrolytic iron or the like can be used as the metallic iron.

In the step of forming the consumable electrode, a plurality of briquettes are connected in the horizontal direction, usually 2 to 8 pieces,
By stacking and assembling in a plurality of stages in the vertical direction, usually 5 to 20 stages, and assembling and welding, the first titanium material is placed on the outer peripheral portion of the electrode, and the second titanium material is disposed inside the electrode, so that long wear is caused. Electrodes are formed. Moreover, the first titanium material and the second titanium material
The titanium material and the titanium material are alternately arranged.

As described above, in the consumable electrode, if the first titanium material and the second titanium material are alternately arranged, when the consumable electrode is melted to obtain the ingot, the first titanium material is obtained. Material and the second titanium material can be homogenized, a minute amount of O, N, Fe contained in the raw material titanium material can be uniformly distributed, and pure titanium containing O, N, Fe having a uniform composition It becomes possible to obtain an ingot.

The pure titanium ingot obtained by the manufacturing method of the present invention has an O content of 0.07% by weight or less, an N content of 0.005% by weight or less, and an Fe content of 0.3% by weight.
The following first titanium material and O content of 0.08 to 0.3
% By weight, N content is 0.01 to 0.1% by weight, Fe content is 0.06 to 0.3% by weight, and the second titanium material is used. A pure titanium ingot formed by forming a briquette in which the second titanium material is placed, assembling and welding the briquette to form a consumable electrode, and vacuum-melting the consumable electrode. Therefore, O content is 0.07 to 0.4% by weight, N content is 0.005 to 0.03% by weight, Fe content is 0.15 to 0.4% by weight, and other unavoidable components are contained. The Ti content is 99% or more, and the balance is substantially composed of Ti.

The pure titanium ingot of the present invention is C
The r or Ni content is 0.1 wt% or less, the C content is 0.05 wt% or less, and the H content is 100 ppm or less.

As described above, the pure titanium ingot obtained by the manufacturing method of the present invention uses sponge titanium having a relatively low purity as the raw material titanium material and scrap material generated in the processing step of the titanium material. Thus, a pure titanium ingot containing each of the components of oxygen, nitrogen and iron contained in these raw titanium materials can be obtained. By containing these oxygen, nitrogen, and iron components, it is possible to obtain a pure titanium ingot having excellent elongation, tensile strength, and workability.

In the present specification, the "pure titanium ingot" contains trace amounts of oxygen, iron and nitrogen,
99% or more is a titanium material composed of titanium and having excellent mechanical strength and workability, and is expressed as a pure titanium ingot to distinguish it from conventional alloy titanium.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.

FIGS. 1 to 19 show an embodiment of the present invention, FIG. 1 is a block diagram showing an example of a method for producing a pure titanium ingot, and FIGS. 2 to 13 show the structure and joining state of briquettes. FIG. 14 is an explanatory view showing a briquette as a reference example, FIGS. 15 to 17 are explanatory views showing a briquette forming method, and FIG. 18 is an explanatory view showing a part of a consumable electrode formed by assembling the briquette. FIG. 19 is an explanatory view showing the entire consumable electrode.

As shown in FIG. 1, the method for producing a pure titanium ingot according to the present invention is a titanium material (first titanium material; hereinafter referred to as "A grade") having a very small content of O (oxygen) and N (nitrogen). A briquette composed of a titanium material) and a titanium material (second titanium material; hereinafter referred to as "B-class titanium material") having a slightly higher content of O (oxygen), N (nitrogen), and Fe (iron). Then, a plurality of these briquettes are combined to form a columnar consumable electrode, and the consumable electrode is vacuum arc melted to obtain a pure titanium ingot.

The pure titanium ingot obtained by the manufacturing method of this example has an O content of 0.07 to 0.4% by weight, an N content of 0.005 to 0.03% by weight, and an Fe content of 0.
15 to 0.4% by weight, other unavoidable components are contained, and the balance is composed of Ti.

Grade A titanium material has a Ti purity of substantially 9
It means a titanium material of 9.8% or more, and in terms of impurity purity, O content is 0.07% by weight or less, N content is 0.01% by weight or less, and the balance is substantially Ti. The following titanium materials are applicable.

As the A-class titanium material, sponge titanium for general wrought materials, or high-purity titanium scrap generated when an ingot manufactured using high-purity A-class sponge titanium is processed, or these Titanium material of equivalent purity is used.

The B content titanium material has an O content of 0.08-
0.3 wt%, N content 0.01-0.1 wt%, F
e content is 0.06 to 5.0% by weight, and the balance is substantially T
The titanium material of i is applicable.

As impurities that are unavoidable components,
Cr (chromium), Ni (nickel), Al (aluminum), V (vanadium) should not be substantially contained, and if not intentionally contained, it does not affect the properties of the manufactured ingot. The limit, specifically 0.
The allowable amount is not more than 05% by weight.

The grade B titanium material is a grade having a lower purity than the grade A sponge titanium among the titanium sponge lumps obtained by the reduction of TiCl ₄ , and specifically, it is collected from the outer peripheral portion or the bottom of the titanium sponge lump. Sponge titanium (hereinafter referred to as "B-class sponge titanium") and scrap material (hereinafter referred to as "B-class scrap material").

The B-class sponge titanium is specifically Fe.
The content is 0.5 to 2.0% by weight, and the N content is 0.01 to
0.5% by weight, O content 0.05 to 0.3% by weight, T
i: Titanium sponge having a purity of 98% or more is applicable. If necessary, the B-grade titanium material may be used in combination of two or more kinds adjusted to have the above composition.

The class B scrap material corresponds to cutting chips and cut pieces generated in the process of processing an ingot manufactured from class A sponge titanium, and specifically, when grinding the surface of an ingot or the surface of a rolled material. It includes a black skin that is generated, a white skin (cutting powder) that is generated when the forged slab surface is ground, and a cut piece (chip) that is generated when processing a rolled plate, a rod, and a wire.

All of the above scrap materials were high-purity titanium materials, but their O and N contents were generally high because they were contacted with air at high temperature during the processing. The Fe content is low.

It is preferable that both raw titanium materials are sized by cutting, crushing or the like to have a shape suitable for briquette molding. Specifically, it is preferable that both the A-class titanium material and the B-class titanium material be cut into pieces having a particle size of 4 to 30 mm or 30 mm square or less. When using two or more kinds of materials, it is advisable to thoroughly mix them with a mixer.

When a scrap material is used as the B-grade titanium material, cutting oil and water are often attached to the scrap material, and therefore it is preferable to remove it sufficiently before briquette molding.

The cutting oil can be removed by washing with an organic solvent or the like. It is preferable that the oil content in the titanium material after washing is 0.02% by weight or less and the water content is 0.01% by weight or less.

As the sponge titanium constituting the B-grade titanium material, in addition to the B-grade sponge titanium, a portion containing more O, N, or Fe than the B-grade sponge titanium, especially containing Fe. The amount is 2.0-4.0
It is also possible to use titanium sponge collected from a site having a high percentage by weight.

When the above titanium sponge is used,
It is advisable to mix it with a raw material titanium material having a low O, N and Fe content and adjust it so that the impurity purity is within an allowable range before use. Therefore, if necessary, class A sponge titanium may be mixed.

Further, when the predetermined values of O, N and Fe cannot be adjusted by the mixing ratio of various materials, titanium oxide such as TiO, TiO ₂ , Ti ₃ O ₅ or electrolysis is used as the O source or the Fe source. The briquette may be formed by adding metallic iron such as iron or iron nail to the second titanium material, that is, class B sponge titanium or class B scrap material.

A briquette is formed from the above titanium material. The briquette is the minimum unit of the electrode configuration, and the outside is made of class A titanium material and the inside is made of class B titanium material. Briquette is based on the analysis value of each raw material,
It is created by defining the raw material composition (raw material used, ratio, amount used) necessary to obtain the target pure titanium ingot.

In this example, as a result, the O content was 0.07.
.About.0.4 wt%, N content is 0.005 to 0.03 wt%, Fe content is 0.15 to 0.4 wt%, other unavoidable components are contained, and the balance is substantially Ti. The raw material composition is such that a pure titanium ingot composed of the above is produced.

Specifically, the proportion of the B-grade titanium material is preferably 80% by weight or less from the viewpoint of the briquette preparation and the tensile strength of the completed briquette, and from the viewpoint of cost, 30% by weight or more. Preferably.

The briquettes are, for example, 20 to 40c in length.
m, width 30 to 50 cm, height 20 to 30 cm, mass 3
It is formed so as to have a weight of 0 to 100 kg, but is not limited to this. The briquette is made by putting a raw material titanium material into a mold and compression-molding it at a pressure of about 3000 tons.

2 to 13 show the structure of the briquette 1 used in the production of a pure titanium ingot. FIG. 2 is an external perspective view of the briquette 1, and FIG. 3 is a front view of the briquette 1. 4 to 13 are cross-sectional views of a briquette used in the present invention or a consumable electrode formed by joining briquettes (hereinafter, referred to as "briquet unit"). As shown in the drawing, the briquette 1 has a rectangular outer shape, and some of the briquettes 1 have rounded corners.

The briquette 1 shown in FIG. 4 and FIG.
The area of the grade-A titanium material 3 is completely contained in the area of the Grade-A titanium material 2, and the cross-section shows the grade-A titanium material 2
Is configured so as to have a rectangular shape or an O shape (hereinafter referred to as “O type briquette”).

As shown in FIG. 5, the corners may not be rounded. Further, as shown in FIGS. 8 and 9, the inside may be composed of a B-grade titanium material 3 and two types of A-grade titanium material 2 may be used on the outside thereof.

The O-type briquette 1 is, as shown in FIG.
The corners are joined inside. By further joining the O-shaped briquette 1 to the two joined O-shaped briquettes 1, a briquette unit 5 as shown in FIG. 7 is formed. At this time, the size of each briquette 1 can be appropriately selected.

FIG. 10 shows a briquette 1 of another mode. By combining two or more briquettes 1, a briquette unit 5 as shown in FIG. 11 is obtained.
Is formed. The briquette 1 has a structure in which the region of the B-grade titanium material 3 is included in the region of the A-grade titanium material 2 except for a part, and the region of the A-grade titanium material 2 is U-shaped in cross section. (Hereinafter referred to as "U-shaped briquette").

FIG. 12 also shows another embodiment of the briquette 1. The cross section of the briquette 1 is configured such that the region of the class A titanium material 2 is L-shaped (hereinafter referred to as "L-shaped briquette").

The briquette 1 used in the present invention is shown in FIG.
As shown in FIGS. 8, 10 and 12, a class A titanium material 2 is arranged on the outside, and a class B titanium material 3 is arranged on the inside so as to be surrounded by the class A titanium material 2. ing. The briquette shown in FIG. 14 is a reference example,
As described above, in the briquette 1 having a shape in which both sides of the B-grade titanium material 3 are sandwiched by the A-grade titanium material 2, a part of the B-grade titanium material 3 is exposed at the outer peripheral portion, so that it is assembled into a large electrode. In this case, a difficulty remains in terms of welding strength.

15 to 17 show, by way of example, the U
It shows a method of forming a mold briquette. First, it is formed by filling the mold 11 with the class A titanium material 2 and the class B titanium material 3 and compressing from above. As a molding step, as shown in FIG. 15, a core 12 is arranged in a mold 11, and a class A titanium is placed outside the core 12, that is, in a space surrounded by the mold 11 and the core 12. Material 2 is filled.

The class B titanium material 3 is filled inside the core 12. After that, the core 12 is pulled out, as shown in FIG.
As shown in 6, the A-class titanium material 2 is additionally charged in the upper portion. Then, the both titanium materials 2 and 3 thus filled are compression-press molded by using the pressing means 13 to obtain the structure shown in FIG.
The briquette 1 is completed as shown in FIG. Then, two or more briquettes 1 are combined and welded to form a briquette unit 5 as shown in FIG. 11 (an example in which four briquettes are joined in the horizontal direction in FIG. 11).

FIG. 7 shows an example in which five O type briquettes are connected, and FIG. 13 shows another example of the briquette unit 5 in which eight L type briquettes are connected in the same manner. The cross section of these briquette units 5 coincides with the cross section of the electrodes.

As shown in FIGS. 7, 11, and 13, a briquette unit 5 formed by joining a plurality of briquettes 1
The cross section, that is, the cross section of the electrode, is configured such that the class A titanium material 2 is arranged on the outer peripheral portion and the class B titanium material 3 is arranged inside.

Further, in the area of the B-class titanium material 3, two or more areas (5 areas A to E in FIG. 7, two areas A and B in FIGS. 11 and 13) are A-class titanium material areas. It is surrounded.

Regarding other briquettes such as O-type briquette and L-type briquette, how to arrange the cores,
By changing the way of filling the raw material, it is possible to obtain the same as the above-mentioned molding method.

The bulk density of briquette 1 is 3 to 4 g / cm.
³ , preferably 3.2 to 3.8 g / cm ³ . If the bulk density of the briquette 1 is below the lower limit of the above range, the strength of the consumable electrode becomes insufficient, which is not preferable.

When the bulk density of the briquette 1 is equal to or higher than the upper limit of the above range, volatile components such as magnesium chloride contained in the briquette are less likely to dissipate, and impurities such as chlorine and oxygen are contained in the ingot after melting. The concentration may be difficult to decrease, which is not preferable.

Next, an example of a method of forming the consumable electrode 6 will be described. As shown in FIG. 18, the consumable electrodes 6 are 2 to
About eight briquettes 1 are welded and joined in the horizontal direction to form a briquette unit 5, and then the briquette units 5 are stacked in a plurality of stages in the vertical direction, and welded at a joint 7 by plasma arc welding means to form a columnar shape. To be done.

In the briquette 1 of this example, an A-class titanium material 2 containing almost no O and N is located on the outer side, and B is on the inner side.
Since the grade titanium material 3 is formed so as to be positioned and the welding is performed in the region of the grade A titanium material 2, high welding strength can be maintained in welding when forming the briquette unit 5 and the consumable electrode 6. Therefore, as shown in FIG. 19, the consumable electrode 6 in which a large number of briquettes 1 are joined can be formed, and as a result, a large ingot can be manufactured.

The size of the consumable electrode 6 is selected based on the size of the target pure titanium ingot. For example, when manufacturing a pure titanium ingot of about 5 to 15 tons, the consumable electrode 6 is usually formed by stacking 5 to 30 layers of the briquette units 5, depending on the structure of the briquette unit.

When the consumable electrode 6 is melted, a stub is joined to the top of the electrode by welding and mounted in a vacuum arc (VAR) melting furnace. In order to securely join the stubs, it is preferable from the viewpoint of load resistance to join a briquette made of only the class A titanium material 2 to the top of the consumable electrode 6.

The consumable electrode 6 is mounted in a vacuum arc melting furnace in a suspended state. The inside of the furnace is evacuated, and when a predetermined degree of vacuum is reached, an arc is generated between the consumable electrode 6 and the bottom of the melting furnace to start melting.

As time elapses, the consumable electrode 6 is gradually lowered to dissolve almost all of the consumable electrode 6 in the VAR.
In this way, a pure titanium ingot is produced. According to the manufacturing method of this example, it is also possible to produce a large ingot of 15 tons. If necessary, the obtained ingot is inverted and redissolved. Thus, by remelting the ingot, a pure titanium ingot having a more uniform composition can be obtained.

As described above, the consumable electrode 6 in this example.
As shown in FIGS. 7, 11, 13 and 18.
Looking at the cross section, the B-class titanium material 3 is distributed continuously or intermittently, and the periphery thereof is surrounded by the A-class titanium material 2.

Therefore, when the consumable electrode 6 is melted in the vacuum arc melting furnace, the A-class titanium material 2 and the B-class titanium material 3 can be made uniform, and a small amount of O, contained in the raw titanium material,
N and Fe can be uniformly distributed, and it becomes possible to obtain a pure titanium ingot containing O, N and Fe having a uniform composition.

In this example, the O content is 0.07 to 0.4% by weight, the N content is 0.005 to 0.03% by weight, and the Fe content is 0.15 to 0.4% by weight. A pure titanium ingot containing other unavoidable components and the balance being substantially Ti is prepared.

Specific examples of briquettes and ingots produced by the method for producing a pure titanium ingot of this example are shown below.

(Specific Example) As a specific example,
The specific example of the briquette used in manufacture of a pure titanium ingot is shown. Here, a briquette was prepared using class A sponge titanium as the class A titanium material and class B sponge titanium and class B scrap material (cutting powder) as the class B titanium material.

The raw material titanium material used is, specifically, A-class sponge titanium; particles having an average particle diameter of 12 mm; (component) O content; 0.05 wt%; N content; 0.003
% By weight, Fe content; 0.04% by weight, Ti purity; 9
9.8% or more. Class B sponge titanium; particles having an average particle diameter of 25 mm, (component) O content; 0.085% by weight, N content; 0.03
3% by weight, Fe content; 0.6% by weight, Ti purity; 99
%that's all. Cutting chips; (component) O content; 0.16% by weight, N content; 0.02% by weight, Fe content; 0.08% by weight, T
i Purity: 99% or more. Is.

The briquette has a square shape and a height of 18
The size is 5 mm × width 260 mm × depth 407 mm. The weight is 65 kg.

Table 1 shows the arrangement of materials (type of briquette) and the ratio of raw material titanium material. Here, briquette 1 (Example 1), briquette 2 (Example 2), and briquette 3 (Reference example) were created.

Example 1 A briquette 1 is an O type briquette as shown in FIG.
It is formed at a rate of 30% of grade titanium material.

(Embodiment 2) The briquette 2 is a U-shaped briquette as shown in FIG.
It is formed of a B-grade sponge titanium of 30% and a cutting powder of 13%.

(Reference Example) The briquette 3 is a sandwich type briquette as shown in FIG. 14, and is formed of a class A titanium material of 50% and a class B titanium material of 50%.

After filling the raw material titanium material into a mold,
A briquette 1, a briquette 2 and a briquette 3 were produced by compression molding with a pressing machine at a press pressure of 3200 tons, and two briquettes of each were subjected to argon seal plasma arc welding. As the state of each briquette after welding, the results shown in Table 1 below were obtained.

[0078]

[Table 1]

The briquettes 1 and 2 shown in Examples 1 and 2 were impacted with a hammer, but the briquettes did not collapse. In addition, the welded part of the welded briquette and the base metal were also well bonded.

(Embodiment 3) Two briquettes produced by the method of Embodiment 2 are back-to-back and spot-welded by plasma arc welding means to form a two-joint briquette unit (substantially the same shape as in FIG. 6). Then, the unit was welded and joined in 13 steps in the lengthwise direction in the same manner to prepare a VAR columnar consumable electrode having a mass of 3.7 tons.

Next, a stub was plasma arc welded to the top of the consumable electrode, the consumable electrode was suspended in a VAR melting furnace, and VAR was melted twice under the following melting conditions to obtain 3.7 tons of pure. Titanium ingot A was manufactured. Regarding the load resistance of the consumable electrode, the consumable electrode had a load of 3.7 tons, but could be melted without dropping the electrode due to breakage of the briquette.

Dissolution conditions: (First dissolution) Vacuum degree: 6 × 10 ⁻³ torr. , Current; 15 KA (second melting) vacuum degree; 2 × 10 ⁻³ torr. , Current; 25KA

Example 4 An O type briquette was prepared using the following raw material titanium materials. At this time, the ratio of the raw material titanium material is 29% by weight of the class A sponge titanium, and the mixture of the class B sponge titanium / cutting powder (2: 1 by weight).
It was set to% by weight. Also, a small amount of TiO ₂ powder was added to the mixture of class B sponge titanium / cutting powder.

Class A sponge titanium; particles having an average particle size of 12 mm, (component) O content; 0.05% by weight, N content;
0.003% by weight, Fe content; 0.04% by weight, Ti
Purity: 99.8% or more. Class B sponge titanium; particles having an average particle size of 25 mm, (component) O content; 0.080% by weight, N content; 0.03
3% by weight, Fe content; 0.6% by weight, Ti purity; 99
%that's all. Cutting chips; (component) O content; 0.16% by weight, N content; 0.02% by weight, Fe content; 0.08% by weight, T
i Purity: 99% or more.

Five briquettes thus prepared were spot-welded in the plane direction by a plasma arc welding means as shown in FIG. 7 to produce a 5-joint briquette unit. Then
The unit was welded in a stack of 29 steps in the length direction, and a mass of 9.
A 4-ton VAR columnar consumable electrode was prepared.

Next, a stub was plasma-arc welded to the top of the consumable electrode, the consumable electrode was suspended in a VAR melting furnace, and VAR was melted twice under the following melting conditions to obtain 9.4 tons of pure. A titanium ingot B was manufactured. Regarding the load bearing capacity of the consumable electrode, it was possible to suitably dissolve the electrode without breaking a part of the electrode during melting.

Dissolution conditions: (First dissolution) Vacuum degree: 6 × 10 ⁻³ torr. , Current; 25 KA (second melting) vacuum degree; 2 × 10 ⁻³ torr. , Current; 40KA

Table 2 shows the properties of the pure titanium ingots A and B obtained in the above Examples 3 and 4.

[0089]

[Table 2]

As shown in Table 2, in the third embodiment, O,
A pure titanium ingot was produced in which N and Fe were uniformly contained throughout the ingot according to the target contents. Further, in Example 4, a large-sized pure titanium ingot of 9.4 tons in which O, N, and Fe were uniformly contained in the entire ingot according to the target contents was manufactured.

[0091]

As described above, according to the method for producing a pure titanium ingot of the present invention, the briquette is formed by using two kinds of titanium materials having different purities, and the second titanium having a low purity is used. As the material, it is possible to use titanium sponge with low purity, which has not been effectively used in the past, and scrap material generated in the processing step of the titanium material.

At this time, since the first titanium material having high purity is located outside the briquette and the second titanium material having low purity is contained inside the briquette, a plurality of briquettes are welded. When the consumable electrode is formed by using the first titanium material having high purity, the briquette can be welded with high joint strength. Therefore, a large consumable electrode can be formed, and as a result, a large ingot can be manufactured.

Further, since the consumable electrode is formed by assembling and welding the briquettes in a plurality of stages in the horizontal direction, the vertical direction, or both, and assembling and welding the briquette, the consumable electrode can be formed in a long direction or a short direction. In either or both, the first titanium material alternates with the second titanium material.

Therefore, when the consumable electrode is melted and an ingot is obtained, the first titanium material and the second titanium material can be made uniform, and a small amount of O, N, and N contained in the raw titanium material can be achieved.
Fe can be uniformly distributed, and O, which has a uniform composition,
It is possible to obtain a pure titanium ingot containing N and Fe.

The pure titanium ingot obtained by the manufacturing method of the present invention uses sponge titanium having a relatively low purity as a raw material titanium material and scrap material generated in the processing step of titanium material. A pure titanium ingot containing each of the components of oxygen, nitrogen, and iron contained in these raw titanium materials is obtained. At this time, oxygen,
Nitrogen and iron are uniformly contained in proper amounts, and it becomes possible to obtain a pure titanium ingot which is excellent in extensibility, tensile strength and workability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a method for producing a pure titanium ingot according to the present invention.

FIG. 2 is a perspective view of a briquette.

FIG. 3 is a front view of a briquette.

FIG. 4 is an explanatory view showing a cross section of an O-type briquette.

FIG. 5 is an explanatory view showing a cross section of an O-type briquette.

FIG. 6 is an explanatory view showing a cross section of a briquette unit when two O-shaped briquettes are joined together.

FIG. 7 is an explanatory diagram showing a cross section of a briquette unit when eight O-type briquettes are joined together.

FIG. 8 is an explanatory diagram showing another example of an O-type briquette.

FIG. 9 is an explanatory diagram showing another example of an O-type briquette.

FIG. 10 is an explanatory view showing a cross section of a U-shaped briquette.

FIG. 11 is an explanatory view showing a cross section of a briquette unit when four U-shaped briquettes are joined together.

FIG. 12 is an explanatory view showing a cross section of an L-shaped briquette.

FIG. 13 is an explanatory view showing a cross section of a briquette unit in which eight L-shaped briquettes are joined.

FIG. 14 is an explanatory view showing a sandwich type briquette.

FIG. 15 is an explanatory diagram showing a briquette forming method.

FIG. 16 is an explanatory diagram showing a briquette forming method.

FIG. 17 is an explanatory diagram showing a briquette forming method.

FIG. 18 is an explanatory diagram showing a consumable electrode.

FIG. 19 is an example of a long consumable electrode manufactured by joining the briquettes of the present invention.

[Explanation of symbols]

1 briquette 2 Class A titanium material (first titanium material) 3 Class B titanium material (second titanium material) 5 briquette unit 6 Consumable electrodes 7 joints 11 Formwork 12 core 13 Pressing means A to E class B titanium material (second titanium material) area

Continued front page    (72) Inventor Yoshihiro Hatta             Kanagawa Prefecture Chigasaki City Chigasaki 3-3-5 Toho             Titanium Co., Ltd. (72) Inventor Ken Takayoshi             Kanagawa Prefecture Chigasaki City Chigasaki 3-3-5 Toho             Titanium Co., Ltd. F term (reference) 4K001 AA27 BA23 DA01 EA02 FA11                       GA16

Claims (8)

[Claims] 1. A first titanium material having an O content of 0.07% by weight or less, an N content of 0.009% by weight or less, and an Fe content of 0.05% by weight or less is arranged on an outer peripheral portion. , O content of 0.08 to 0.3% by weight, N content of 0.01 to 0.1% by weight, and Fe content of 0.06 to 5.0 inside the first titanium material. And a consumable electrode forming step of forming a consumable electrode by arranging a second titanium material of which weight% is present, and a step of vacuum arc melting the consumable electrode obtained by the consumable electrode forming step. Method for producing pure titanium ingot. 2. A first titanium material having an O content of 0.07% by weight or less, an N content of 0.009% by weight or less, and an Fe content of 0.05% by weight or less, and an O content of 0. 0.08-0.3 wt%, N content 0.0
A second titanium material having a Fe content of 1 to 0.1% by weight and an Fe content of 0.06 to 5.0% by weight is used, the first titanium material is arranged on the outer peripheral portion, and the second titanium material is provided inside. A briquette forming step of arranging materials to form a briquette, a consumable electrode forming step of assembling and welding the briquette obtained in the briquette forming step to form a consumable electrode, and a consumable electrode obtained in the consumable electrode forming step A method of manufacturing a pure titanium ingot, comprising: a step of melting an electrode in a vacuum arc. 3. The method for producing a pure titanium ingot according to claim 1, wherein one or both of class B sponge titanium and titanium scrap material is used as the second titanium material. 4. The method for producing a pure titanium ingot according to claim 1, wherein the second titanium material contains class A sponge titanium. 5. The method for producing a pure titanium ingot according to claim 1, wherein one or more kinds of titanium oxide or metallic iron is added to the second titanium material. 6. The consumable electrode according to claim 2, wherein in the briquette forming step, the consumable electrode is formed by stacking a plurality of the briquettes in a horizontal direction, a vertical direction, or both, assembling and welding. Manufacturing method of pure titanium ingot. 7. The O content is 0.07% by weight or less, the N content is 0.005% by weight or less, and the Fe content is 0.3% by weight.
The following first titanium material, O content of 0.08 to 0.3% by weight, N content of 0.0
The second titanium material having a Fe content of 1 to 0.1% by weight and an Fe content of 0.06 to 5.0% by weight is used. A pure titanium ingot formed by forming a briquette on which a titanium material is arranged, assembling and welding the briquette to form a consumable electrode, and vacuum-melting the consumable electrode. 07-0.4 wt%, N content 0.0
05-0.03% by weight, Fe content 0.15-0.4
A pure titanium ingot, characterized by containing wt% and other unavoidable components, and the balance being substantially composed of Ti. 8. The content of Cr or Ni is 0.1% by weight.
Hereinafter, the C content is 0.05% by weight or less and the H content is 10%.
The pure titanium ingot according to claim 7, which is 0 ppm or less.