JPH093575A - Seamless titanium alloy tube and its production - Google Patents

Abstract

PURPOSE: To produce a large-sized, thick-walled Ti alloy tube having superior surface quality, minimal in die wear, excellent in flattening test characteristics, and applicable, in particular, to a large-sized structure. CONSTITUTION: This seamless Ti alloy tube has a composition consisting of, by weight, <=10%, in total, of one or >=2 kinds among 0.01-10% S, 0.01-10% Se, and 0.01-10% Te, <=10%, in total, of one or two kinds among 0.01-10% REM and 0.01-10% Ca, and the balance essentially Ti and further containing, if necessary, <=30%, in total, of one or >=2 kinds among <=10% Al, <=25% V, <=15% Sn, <=10% Co, <=10% Cu, <=15% Ta, <=10% Mn, =10% Hf, <=10% W, <=0.5% Si, <=20% Nb, <=10% Zr, <=15% Mo, and <=0.1% 0 and is formed by being extruded into seamless tubular shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless Ti alloy pipe used in industrial fields such as aerospace, chemistry, oil drilling and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In general, Ti alloys are widely used in industrial fields such as aerospace, chemistry, oil drilling, etc. because of their high strength per weight (that is, specific strength) and excellent corrosion resistance. It's being used.

In order to further exhibit and utilize the excellent properties of Ti alloys in these industrial fields, the manufacture of Ti alloy pipes is indispensable. In the prior art, Ti alloys are formed into a thin plate shape. Then, a method of joining the U-O bent joints and a method of directly manufacturing a Ti alloy tube from a Ti alloy mass by a machining method have been put into practical use.

[0004]

However, in the case of a welded pipe for joining seams formed by U-O bending of a Ti alloy plate, there is a limit to the forming process of the Ti alloy plate, and the production of thick-walled pipes. There was a problem that it was difficult.

Further, in the case of a Ti alloy pipe formed by a machining method, although the degree of freedom in size and shape is large, there are problems that the material yield and the manufacturing efficiency are extremely low and the cost is high.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has good surface quality, little wear of the mold, and excellent flatness test characteristics. In particular, it is an object of the present invention to provide a large and thick Ti alloy pipe applicable to a large structure and a method for manufacturing the same.

[0007]

The seamless Ti alloy pipe according to the present invention has, as described in claim 1, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: 0.01 to 10% of one or two kinds in total of 10% or less, and the composition having a balance of substantially Ti, and extruded to form a seamless tubular shape. It is characterized by having the configuration.

A seamless Ti alloy pipe according to the present invention which achieves the same object has a weight% of S: 0.01 to 10% and Se: 0.01.
-10%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10
%, Ca: 0.01 to 10%, one or two kinds in total of 10% or less, Al: 10% or less, V: 25% or less, Sn: 15% or less, Co: 10% or less, Cu : 10
% Or less, Ta: 15% or less, Mn: 10% or less, Hf:
10% or less, W: 10% or less, Si: 0.5% or less, N
b: 20% or less, Zr: 10% or less, Mo: 15% or less, O: 0.1% or less, and 30% or less in total of one or more kinds, and the balance is substantially Ti. It is characterized in that it has a composition of and is extruded to form a seamless tubular shape.

Further, in the embodiment of the seamless Ti alloy pipe according to the present invention, as described in claim 3, the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe. ) Is preferably 0.01 or more and 0.40 or less in some cases.

In the method for manufacturing a seamless Ti alloy pipe according to the present invention, as described in claim 4, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: a composition in which one or two kinds out of 0.01 to 10% is contained in a total amount of 10% or less, and the balance is made by extruding a Ti alloy material having a composition substantially made of Ti to form a tubular shape. It is characterized by having done.

Furthermore, a method for producing a seamless Ti alloy pipe according to the present invention which achieves the same object, as described in claim 5, has a weight percentage of S: 0.01-10.
%, Se: 0.01 to 10%, Te: 0.01 to 10%
10% or less in total of one or more of these, RE
One or two of M: 0.01 to 10% and Ca: 0.01 to 10% in total, 10% or less, Al: 10% or less, V: 25% or less, Sn: 15% or less, Co: 10%
Below, Cu: 10% or less, Ta: 15% or less, Mn: 1
0% or less, Hf: 10% or less, W: 10% or less, Si:
0.5% or less, Nb: 20% or less, Zr: 10% or less,
A Ti alloy material containing Mo: 15% or less and O: 0.1% or less, 30% or less in total of one kind or two or more kinds, and the balance substantially consisting of Ti is extruded. The feature is that it is formed into a tubular shape.

In the embodiment of the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 6, the ratio of the wall thickness (t) to the outer diameter (D) of the pipe ( t / D) is set to 0.01 or more and 0.40 or less for extrusion processing, or as described in claim 7,
In some cases, it is desirable to carry out extrusion at a temperature of 900 ° C. or higher and 1150 ° C. or lower.

[0013]

The seamless Ti alloy pipe and the method for producing the same according to the present invention have the above-mentioned constitution. However, when a seamless pipe is formed by hot extrusion of a Ti alloy, the working temperature is in the β range. If so, the deformation resistance decreases and the work becomes easy, but the crystal grains become coarse and the toughness and ductility of the Ti alloy material as the work material decreases.

On the other hand, when REM is added to the Ti alloy, the sulfides or inclusions in the Ti alloy containing S are granulated and finely dispersed, so that the nuclei of crystal grain growth are widely dispersed. Therefore, since it has an effect of suppressing coarsening of crystal grains in a high temperature range of α-β transition temperature or higher, it significantly acts to prevent coarsening of crystal grains when hot-extruding a Ti alloy tube. Therefore, it was confirmed that such S and Ti alloys can be easily extruded to produce a seamless Ti alloy tube having excellent characteristics.

Further, the above-mentioned sulfides or inclusions finely and uniformly dispersed effectively act to prevent the oxidation of the Ti alloy during the hot extrusion process, and have an affinity with the glass-based material used for lubrication. Since it has good properties, it has the effect of suppressing the peeling of the lubricant during the hot extrusion process, which improves the surface texture of the Ti alloy tube and prevents wear or damage to the mold. The effect of reducing is great.

These actions and effects are similarly observed in Ca in addition to REM and in Se and Te in addition to S.

Therefore, the reasons for limiting the chemical composition (% by weight) of the Ti alloy applied in the seamless Ti alloy pipe and the method for producing the same according to the present invention will be described in more detail together with their respective functions.

S: 0.01 to 10%, Se: 0.01 to
10%, Te: 0.01 to 10%, or 2
10% or less in total of species or more S, Se, and Te are all 0.01% or more in content of T
It forms inclusions in the i-alloy and acts as nuclei for crystal grain formation during α-β transformation and prevents coarsening of crystal grains. However, if it is contained in excess, the transformation ability at high temperature is significantly deteriorated and extrusion processing is performed. Therefore, the upper limit is limited to 10%,
Even when two or more kinds are contained, the upper limit of the total amount is limited to 10%.

REM: 0.01 to 10%, Ca: 0.0
One or two of 1 to 10% are 10% or less in total. REM in the present invention refers to Sc, Y and lanthanide rare earth metal (atomic number: 57 to 71). And
These rare earth metals combine with S, Se and Te to form a stable compound, and the inclusions are granulated and dispersed, whereby the Ti alloy is hot extruded to form a Ti alloy tube. It has an effect of suppressing coarsening of crystal grains. And
All of these effects are obtained by containing 0.01% or more. However, if the content is excessive, the strength and corrosion resistance decrease, so the upper limit was made 10%.

Further, Ca, like REM, has S, S
Since it has a function of forming a stable compound by binding to e and Te and granulating and dispersing inclusions, Ca is also set to 0.01% or more. However, if contained too much,
As in the case of REM, the strength and corrosion resistance decrease, so the upper limit is set to 10%, and the total amount also has an upper limit of 10%.
Regulated to.

Al: 10% or less, V: 25% or less, S
n: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10% or less, Hf: 10
% Or less, W: 10% or less, Si: 0.5% or less, Nb:
20% or less, Zr: 10% or less, Mo: 15% or less,
O: 1% or more of 0.1% or less, and 30% or less in total, all of these elements are useful elements for improving the strength of the Ti alloy. And of these, Al, S
Although n, Co, Cu, Ta, Mn, Hf, W, Si, and Nb combine with Ti to form a compound, the strength is improved, but if it exceeds the limit, the plastic deformability of Ti is impaired. As a result, extrusion processability and toughness (flatness) will be reduced, so the upper limit values of the above-mentioned respective elements were made.

Zr, Mo and V are added in order to suppress the crystal grains of the Ti alloy and to obtain appropriate strength and plastic deformability, but if each of the components exceeds the upper limit, β
Since the phases are stabilized, the upper limit values of the above elements are set.

Further, O improves the strength of the Ti alloy as described above, but if it is excessive, it makes the Ti alloy brittle, so it is made 1% or less.

Then, these Al, V, Sn, Co, C
u, Ta, Mn, Hf, W, Si, Nb, Zr, Mo,
If the total amount of O is too large, the plastic deformability of the Ti alloy is impaired, the toughness is reduced, and cracks due to the flatness test are likely to occur, so these total amounts should be 30% or less. Limited

The ratio of the wall thickness (t) to the outer diameter (D) of the pipe (t /
D): 0.01 or more and 0.40 or less The smaller the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe, the greater the required extrusion force and the equipment Since the equipment cost increases due to the large size, the lower limit is set to 0.01. Further, a Ti alloy pipe having a large t / D can be manufactured by a machining method, and a Ti alloy pipe having an excessively large t / D is industrially meaningless, so the upper limit is set to 0.40. .

Extrusion processing temperature: 900 ° C. or more and 1150 ° C.
Below, when the extrusion temperature for Ti alloy material is low, T
The i-alloy material has a large deformation resistance, and even if a lubricant is used, the friction with the die becomes large, resulting in wear of the die and deterioration of the surface quality of the extruded material. ℃ was made. Further, when the extrusion processing temperature is high, although the coarsening of the crystal grains is suppressed by adding various elements, the adverse effect of the coarsening of the crystal grains becomes large, so the upper limit of the processing temperature was set to 1150 ° C. .

[0027]

EXAMPLES Examples 1 to 9 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having a composition of 1 to 9, a mandrel having an outer diameter of 60 mm was used to obtain a temperature of 1000.
Each seamless Ti alloy tube was manufactured by carrying out a hot extrusion process at ℃.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It shows in the column of 1-9.

[0029]

[Table 1]

[0030]

[Table 2]

As is clear from the results shown in the table, Invention Example No. In Comparative Examples Nos. 3 to 8, the manufacturing efficiency was good and no cracks were generated in the flatness test, while Comparative Example No. 3 having a small S and REM content. Comparative Example No. 1 containing no REM and Ca. The result of 2 was not so good. In addition, Comparative Example N having too much S content and REM content
o. In No. 9 as well, the deformability was lowered and cracks were generated in the flatness test.

Examples 10 to 21 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having compositions of 10 to 21, a mandrel having an outer diameter of 50 mm was used to obtain a temperature of 100.
Each seamless Ti alloy tube was manufactured by performing a hot extrusion process at 0 degreeC.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It shows in the column of 10-21.

[0034]

[Table 3]

[0035]

[Table 4]

As is clear from the results shown in the table, Invention Example No. In Nos. 13 to 20, the production efficiency was good, and cracks were not generated in the flattening test, whereas in Comparative Example No. 3 having a low S, Se, Te content and a low REM, Ca content. 1
In Nos. 1, 12, and 13, cracks were generated by the flattening test, and conversely, the total content of S, Se, and Te was too large. 20 and Comparative Example N with too much Ca content
o. Also in No. 21, cracks were generated by the flatness test.

Examples 22 to 38 Nos. After coating a glass-based lubricant on the surface of various Ti alloy ingots having a composition of 22 to 38 (diameter 100 mm), a mandrel having an outer diameter of 40 mm was used to obtain a temperature of 100.
Each seamless Ti alloy tube was manufactured by performing a hot extrusion process at 0 degreeC.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy tube, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It is shown in columns 22 to 38.

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

As is clear from the results shown in the table, Invention Example No. In Nos. 22 to 31, the production efficiency was good, and cracks were not generated in the flatness test, whereas in Comparative Example No. 3 in which the Al + V content was too large. 32, comparative example No. 32 having too much V + Sn content. 33, Comparative Example N containing too much Co + Ta
o. 34, comparative example No. 3 having too much Cu + Mn content. 3
5, Hf + W and Si content is too high. 36,
Nb + Zr content is too high. 37, Comparative Example No. 3 having too much Mo content. In No. 38, cracks were generated in the flatness test.

Examples 39 to 47 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having a composition of 39 to 47, a mandrel having various outer diameters was used for temperature 8
Each seamless Ti alloy tube was manufactured by carrying out a hot extrusion process at 80 to 1250 ° C.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It is shown in columns 39 to 47.

[0045]

[Table 8]

[0046]

[Table 9]

As is clear from the results shown in the table, Invention Example No. In Nos. 41 to 45, the production efficiency was good, and cracks did not occur in the flatness test, while Comparative Example No. 4 having a low extrusion temperature. In Comparative Example No. 39, since the deformation resistance is large, the manufacturability is not so good, and t / D is large. Also in Comparative Example No. 40, the manufacturability is not so good and the extrusion temperature is 1200 ° C. or higher. In Nos. 46 and 47, a tendency of coarsening of crystal grains was observed, and microcracks or cracks were generated in the flatness test.

[0048]

EFFECTS OF THE INVENTION The seamless Ti alloy pipe according to the present invention has, as described in claim 1, S:% by weight.
0.01-10%, Se: 0.01-10%, Te:
One or two or more of 0.01 to 10% are 10% or less in total, REM: 0.01 to 10%, Ca: 0.0
1 to 10% of one or two kinds in total of 10% or less is contained, and the balance substantially has a composition consisting of Ti,
Since it is extruded and formed into a seamless tubular shape, it has good surface quality, little die wear, and excellent flatness test characteristics, making it particularly applicable to large structures. The remarkable effect of being able to provide a large and thick Ti alloy tube is brought about.

The seamless T according to the present invention is also provided.
The i-alloy tube has a weight percentage as defined in claim 2.
, S: 0.01 to 10%, Se: 0.01 to 10%,
Te: 0.01 to 10% of one or more kinds in total of 10% or less, REM: 0.01 to 10%, Ca:
1 or 2 of 0.01 to 10% in total 10
% Or less, Al: 10% or less, V: 25% or less, Sn: 1
5% or less, Co: 10% or less, Cu: 10% or less, T
a: 15% or less, Mn: 10% or less, Hf: 10% or less, W: 10% or less, Si: 0.5% or less, Nb: 20
% Or less, Zr: 10% or less, Mo: 15% or less, O:
30% of one or more of 0.1% or less
% Or less, and has a composition consisting essentially of Ti as the balance, and is extruded to form a seamless tubular shape. Therefore, the strength of the seamless Ti alloy pipe according to claim 1 is improved. The remarkable effect that it can be further improved is provided.

In the embodiment of the seamless Ti alloy pipe according to the present invention, as described in claim 3, the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe. ) Is 0.01 or more and 0.40 or less, thereby providing a large-sized / thick-walled Ti alloy pipe applicable to large-scale structures without increasing the required extrusion force. It is possible to achieve the remarkably excellent effect.

In the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 4, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: A Ti alloy material containing 0.01 to 10% of one or two kinds in total of 10% or less, and the balance being substantially Ti, so as to be extruded into a tubular shape. Therefore, the surface quality is good, the wear of the mold is small, and the flatness test characteristics are also excellent. In particular, it is possible to provide a large and thick Ti alloy pipe applicable to large structures. The remarkably excellent effect of

Further, as described in claim 5, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: One or two of 0.01 to 10% in total, 10% or less, Al: 10% or less, V: 25% or less, S
n: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10% or less, Hf: 10
% Or less, W: 10% or less, Si: 0.5% or less, Nb:
20% or less, Zr: 10% or less, Mo: 15% or less,
O: a Ti alloy material containing 0.1% or less and one or more kinds of 30% or less in total, and the balance being substantially Ti is extruded to form a tubular shape. Therefore, the remarkably excellent effect that it is possible to manufacture a seamless Ti alloy pipe having further improved strength as compared with the seamless Ti alloy pipe manufactured in claim 4 is brought about.

In the embodiment of the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 6, the ratio between the wall thickness (t) and the outer diameter (D) of the pipe ( t / D) is set to 0.01 or more and 0.40 or less so that the extrusion processing is performed, so that a large-sized / thick-walled structure applicable to a large-scale structure without increasing the required extrusion force. The remarkable advantage is that it is possible to produce Ti alloy tubes.

Further, as described in claim 7, by extruding at a temperature of 900 ° C. or more and 1150 ° C. or less, the deformation resistance in the hot extrusion of the Ti alloy material is small. In addition, it is possible to produce a seamless Ti alloy tube while preventing coarsening of crystal grains, which is a remarkable advantage.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 11, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Title: Seamless Ti alloy tube and method for producing the same

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless Ti alloy pipe used in industrial fields such as aerospace, chemistry, oil drilling and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In general, Ti alloys are widely used in industrial fields such as aerospace, chemistry, oil drilling, etc. because of their high strength per weight (that is, specific strength) and excellent corrosion resistance. It's being used.

In order to further exhibit and utilize the excellent properties of Ti alloys in these industrial fields, the manufacture of Ti alloy pipes is indispensable. In the prior art, Ti alloys are formed into a thin plate shape. Then, a method of joining the U-O bent joints and a method of directly manufacturing a Ti alloy tube from a Ti alloy mass by a machining method have been put into practical use.

[0004]

However, in the case of a welded pipe for joining seams formed by U-O bending of a Ti alloy plate, there is a limit to the forming process of the Ti alloy plate, and the production of thick-walled pipes. There was a problem that it was difficult.

Further, in the case of a Ti alloy pipe formed by a machining method, although the degree of freedom in size and shape is large, there are problems that the material yield and the manufacturing efficiency are extremely low and the cost is high.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has good surface quality, little wear of the mold, and excellent flatness test characteristics. In particular, it is an object of the present invention to provide a large and thick Ti alloy pipe applicable to a large structure and a method for manufacturing the same.

[0007]

The seamless Ti alloy pipe according to the present invention has, as described in claim 1, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: 0.01 to 10% of one or two kinds in total of 10% or less, and the composition having a balance of substantially Ti, and extruded to form a seamless tubular shape. It is characterized by having the configuration.

A seamless Ti alloy pipe according to the present invention which achieves the same object has a weight% of S: 0.01 to 10% and Se: 0.01.
-10%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10
%, Ca: 0.01 to 10%, one or two kinds in total of 10% or less, Al: 10% or less, V: 25% or less, Sn: 15% or less, Co: 10% or less, Cu : 10
% Or less, Ta: 15% or less, Mn: 10% or less, Hf:
10% or less, W: 10% or less, Si: 0.5% or less, N
b: 20% or less, Zr: 10% or less, Mo: 15% or less, O: 0.1% or less, and 30% or less in total of one or more kinds, and the balance is substantially Ti. It is characterized in that it has a composition of and is extruded to form a seamless tubular shape.

Further, in the embodiment of the seamless Ti alloy pipe according to the present invention, as described in claim 3, the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe. ) Is preferably 0.01 or more and 0.40 or less in some cases.

In the method for manufacturing a seamless Ti alloy pipe according to the present invention, as described in claim 4, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: a composition in which one or two kinds out of 0.01 to 10% is contained in a total amount of 10% or less, and the balance is made by extruding a Ti alloy material having a composition substantially made of Ti to form a tubular shape. It is characterized by having done.

Furthermore, a method for producing a seamless Ti alloy pipe according to the present invention which achieves the same object, as described in claim 5, has a weight percentage of S: 0.01-10.
%, Se: 0.01 to 10%, Te: 0.01 to 10%
10% or less in total of one or more of these, RE
One or two of M: 0.01 to 10% and Ca: 0.01 to 10% in total, 10% or less, Al: 10% or less, V: 25% or less, Sn: 15% or less, Co: 10%
Below, Cu: 10% or less, Ta: 15% or less, Mn: 1
0% or less, Hf: 10% or less, W: 10% or less, Si:
0.5% or less, Nb: 20% or less, Zr: 10% or less,
A Ti alloy material containing Mo: 15% or less, O: 0.1% or less, 30% or less in total of 1 type or 2 types or more, and the balance substantially consisting of Ti is extruded. The feature is that it is formed into a tubular shape.

In the embodiment of the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 6, the ratio of the wall thickness (t) to the outer diameter (D) of the pipe ( t / D) is set to 0.01 or more and 0.40 or less for extrusion processing, or as described in claim 7,
In some cases, it is desirable to carry out extrusion at a temperature of 900 ° C. or higher and 1150 ° C. or lower.

[0013]

The seamless Ti alloy pipe and the method for producing the same according to the present invention have the above-mentioned constitution. However, when a seamless pipe is formed by hot extrusion of a Ti alloy, the working temperature is in the β range. If so, the deformation resistance decreases and the work becomes easy, but the crystal grains become coarse and the toughness and ductility of the Ti alloy material as the work material decreases.

On the other hand, when REM is added to the Ti alloy, the sulfides or inclusions in the Ti alloy containing S are granulated and finely dispersed, so that the nuclei of crystal grain growth are widely dispersed. Therefore, since it has an effect of suppressing coarsening of crystal grains in a high temperature range of α-β transition temperature or higher, it significantly acts to prevent coarsening of crystal grains when hot-extruding a Ti alloy tube. Therefore, it was confirmed that such S and Ti alloys can be easily extruded to produce a seamless Ti alloy tube having excellent characteristics.

Further, the above-mentioned sulfides or inclusions finely and uniformly dispersed effectively act to prevent the oxidation of the Ti alloy during the hot extrusion process, and have an affinity with the glass-based material used for lubrication. Since it has good properties, it has the effect of suppressing the peeling of the lubricant during the hot extrusion process, which improves the surface texture of the Ti alloy tube and prevents wear or damage to the mold. The effect of reducing is great.

These actions and effects are similarly observed in Ca in addition to REM and in Se and Te in addition to S.

Therefore, the reasons for limiting the chemical composition (% by weight) of the Ti alloy applied in the seamless Ti alloy pipe and the method for producing the same according to the present invention will be described in more detail together with their respective functions.

S: 0.01 to 10%, Se: 0.01 to
10%, Te: 0.01 to 10%, or 2
10% or less in total of species or more S, Se, and Te are all 0.01% or more in content of T
It forms inclusions in the i-alloy and acts as nuclei for crystal grain formation during α-β transformation and prevents coarsening of crystal grains. However, if it is contained in excess, the transformation ability at high temperature is significantly deteriorated and extrusion processing is performed. Therefore, the upper limit is limited to 10%,
Even when two or more kinds are contained, the upper limit of the total amount is limited to 10%.

REM: 0.01 to 10%, Ca: 0.0
One or two of 1 to 10% are 10% or less in total. REM in the present invention refers to Sc, Y and lanthanide rare earth metal (atomic number: 57 to 71). And
These rare earth metals combine with S, Se and Te to form a stable compound, and the inclusions are granulated and dispersed, whereby the Ti alloy is hot extruded to form a Ti alloy tube. It has an effect of suppressing coarsening of crystal grains. And
All of these effects are obtained by containing 0.01% or more. However, if the content is excessive, the strength and corrosion resistance decrease, so the upper limit was made 10%.

Further, Ca, like REM, has S, S
Since it has a function of forming a stable compound by binding to e and Te and granulating and dispersing inclusions, Ca is also set to 0.01% or more. However, if contained too much,
As in the case of REM, the strength and corrosion resistance decrease, so the upper limit is set to 10%, and the total amount also has an upper limit of 10%.
Regulated to.

Al: 10% or less, V: 25% or less, S
n: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10% or less, Hf: 10
% Or less, W: 10% or less, Si: 0.5% or less, Nb:
20% or less, Zr: 10% or less, Mo: 15% or less,
O: 1% or more of 0.1% or less, and 30% or less in total, all of these elements are useful elements for improving the strength of the Ti alloy. And of these, Al, S
Although n, Co, Cu, Ta, Mn, Hf, W, Si, and Nb combine with Ti to form a compound, the strength is improved, but if it exceeds the limit, the plastic deformability of Ti is impaired. As a result, extrusion processability and toughness (flatness) will be reduced, so the upper limit values of the above-mentioned respective elements were made.

Zr, Mo and V are added in order to suppress the crystal grains of the Ti alloy and to obtain appropriate strength and plastic deformability, but if each of the components exceeds the upper limit, β
Since the phases are stabilized, the upper limit values of the above elements are set.

Further, O improves the strength of the Ti alloy as described above, but if it is excessive, it makes the Ti alloy brittle, so it is made 1% or less.

Then, these Al, V, Sn, Co, C
u, Ta, Mn, Hf, W, Si, Nb, Zr, Mo,
If the total amount of O is too large, the plastic deformability of the Ti alloy is impaired, the toughness is reduced, and cracks due to the flatness test are likely to occur, so these total amounts should be 30% or less. Limited

The ratio of the wall thickness (t) to the outer diameter (D) of the pipe (t /
D): 0.01 or more and 0.40 or less The smaller the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe, the greater the required extrusion force and the equipment Since the equipment cost increases due to the large size, the lower limit is set to 0.01. Further, a Ti alloy pipe having a large t / D can be manufactured by a machining method, and a Ti alloy pipe having an excessively large t / D is industrially meaningless, so the upper limit is set to 0.40. .

Extrusion processing temperature: 900 ° C. or more and 1150 ° C.
Below, when the extrusion temperature for Ti alloy material is low, T
The i-alloy material has a large deformation resistance, and even if a lubricant is used, the friction with the die becomes large, resulting in wear of the die and deterioration of the surface quality of the extruded material. ℃ was made. Further, when the extrusion processing temperature is high, although the coarsening of the crystal grains is suppressed by adding various elements, the adverse effect of the coarsening of the crystal grains becomes large, so the upper limit of the processing temperature was set to 1150 ° C. .

[0027]

EXAMPLES Examples 1 to 9 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having a composition of 1 to 9, a mandrel having an outer diameter of 60 mm was used to obtain a temperature of 1000.
Each seamless Ti alloy tube was manufactured by carrying out a hot extrusion process at ℃.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It shows in the column of 1-9.

[0029]

[Table 1]

[0030]

[Table 2]

As is clear from the results shown in the table, Invention Example No. In Comparative Examples Nos. 3 to 8, the manufacturing efficiency was good and no cracks were generated in the flatness test, while Comparative Example No. 3 having a small S and REM content. Comparative Example No. 1 containing no REM and Ca. The result of 2 was not so good. In addition, Comparative Example N having too much S content and REM content
o. In No. 9 as well, the deformability was lowered and cracks were generated in the flatness test.

Examples 10 to 21 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having compositions of 10 to 21, a mandrel having an outer diameter of 50 mm was used to obtain a temperature of 100.
Each seamless Ti alloy tube was manufactured by performing a hot extrusion process at 0 degreeC.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It shows in the column of 10-21.

[0034]

[Table 3]

[0035]

[Table 4]

As is clear from the results shown in the table, Invention Example No. In Nos. 13 to 20, the production efficiency was good, and cracks were not generated in the flattening test, whereas in Comparative Example No. 3 having a low S, Se, Te content and a low REM, Ca content. 1
In Nos. 1, 12, and 13, cracks were generated by the flattening test, and conversely, the total content of S, Se, and Te was too large. 20 and Comparative Example N with too much Ca content
o. Also in No. 21, cracks were generated by the flatness test.

Examples 22 to 38 Nos. After coating a glass-based lubricant on the surface of various Ti alloy ingots having a composition of 22 to 38 (diameter 100 mm), a mandrel having an outer diameter of 40 mm was used to obtain a temperature of 100.
Each seamless Ti alloy tube was manufactured by performing a hot extrusion process at 0 degreeC.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy tube, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It is shown in columns 22 to 38.

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

As is clear from the results shown in the table, Invention Example No. In Nos. 22 to 31, the production efficiency was good, and cracks were not generated in the flatness test, whereas in Comparative Example No. 3 in which the Al + V content was too large. 32, comparative example No. 32 having too much V + Sn content. 33, Comparative Example N containing too much Co + Ta
o. 34, comparative example No. 3 having too much Cu + Mn content. 3
5, Hf + W and Si content is too high. 36,
Nb + Zr content is too high. 37, Comparative Example No. 3 having too much Mo content. In No. 38, cracks were generated in the flatness test.

Examples 39 to 47 Nos. After applying a glass-based lubricant to the surface of various Ti alloy lumps (diameter 100 mm) having a composition of 39 to 47, a mandrel having various outer diameters was used for temperature 8
Each seamless Ti alloy tube was manufactured by carrying out a hot extrusion process at 80 to 1250 ° C.

Then, a flatness test (JIS) was carried out for each seamless Ti alloy pipe, and the productivity was evaluated by the production efficiency. Then, a penetration flaw detection test was carried out on the inner and outer surfaces of the seamless Ti alloy tube subjected to the flatness test to investigate the presence or absence of cracks. These results are also shown in No. of the table. It is shown in columns 39 to 47.

[0045]

[Table 8]

[0046]

[Table 9]

As is clear from the results shown in the table, Invention Example No. In Nos. 41 to 45, the production efficiency was good, and cracks did not occur in the flatness test, while Comparative Example No. 4 having a low extrusion temperature. In Comparative Example No. 39, the deformation resistance is large and the manufacturability is not so good, and t / D is large. Also in Comparative Example No. 40, the manufacturability is not so good and the extrusion temperature is 1200 ° C. or higher. In Nos. 46 and 47, a tendency of coarsening of crystal grains was observed, and microcracks or cracks were generated in the flatness test.

[0048]

EFFECTS OF THE INVENTION The seamless Ti alloy pipe according to the present invention has, as described in claim 1, S:% by weight.
0.01-10%, Se: 0.01-10%, Te:
One or two or more of 0.01 to 10% are 10% or less in total, REM: 0.01 to 10%, Ca: 0.0
1 to 10% of one or two kinds in total of 10% or less is contained, and the balance substantially has a composition consisting of Ti,
Since it is extruded and formed into a seamless tubular shape, it has good surface quality, little die wear, and excellent flatness test characteristics, making it particularly applicable to large structures. The remarkable effect of being able to provide a large and thick Ti alloy tube is brought about.

The seamless T according to the present invention is also provided.
The i-alloy tube has a weight percentage as defined in claim 2.
, S: 0.01 to 10%, Se: 0.01 to 10%,
Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, Ca:
1 or 2 of 0.01 to 10% in total 10
% Or less, Al: 10% or less, V: 25% or less, Sn: 1
5% or less, Co: 10% or less, Cu: 10% or less, T
a: 15% or less, Mn: 10% or less, Hf: 10% or less, W: 10% or less, Si: 0.5% or less, Nb: 20
% Or less, Zr: 10% or less, Mo: 15% or less, O:
30% of one or more of 0.1% or less
% Or less and has a composition consisting essentially of Ti as the balance, and is extruded to form a seamless tubular shape. Therefore, the strength of the seamless Ti alloy pipe according to claim 1 The remarkable effect that it can be further improved is provided.

In the embodiment of the seamless Ti alloy pipe according to the present invention, as described in claim 3, the ratio (t / D) of the wall thickness (t) to the outer diameter (D) of the pipe. ) Is 0.01 or more and 0.40 or less, thereby providing a large-sized / thick-walled Ti alloy pipe applicable to large-scale structures without increasing the required extrusion force. It is possible to achieve the remarkably excellent effect.

In the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 4, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: A Ti alloy material containing 0.01 to 10% of one or two kinds in total of 10% or less, and the balance being substantially Ti, so as to be extruded into a tubular shape. Therefore, the surface quality is good, the wear of the mold is small, and the flatness test characteristics are also excellent. In particular, it is possible to provide a large and thick Ti alloy pipe applicable to large structures. The remarkably excellent effect of

Further, as described in claim 5, S: 0.01 to 10% and Se: 0.01 to 10% by weight.
%, Te: 0.01 to 10%, one or more of which is 10% or less in total, REM: 0.01 to 10%, C
a: One or two of 0.01 to 10% in total, 10% or less, Al: 10% or less, V: 25% or less, S
n: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10% or less, Hf: 10
% Or less, W: 10% or less, Si: 0.5% or less, Nb:
20% or less, Zr: 10% or less, Mo: 15% or less,
O: a Ti alloy material containing 0.1% or less and one or more kinds of 30% or less in total, and the balance being substantially Ti is extruded to form a tubular shape. Therefore, the remarkably excellent effect that it is possible to manufacture a seamless Ti alloy pipe having further improved strength as compared with the seamless Ti alloy pipe manufactured in claim 4 is brought about.

In the embodiment of the method for producing a seamless Ti alloy pipe according to the present invention, as described in claim 6, the ratio between the wall thickness (t) and the outer diameter (D) of the pipe ( t / D) is set to 0.01 or more and 0.40 or less so that the extrusion processing is performed, so that a large-sized / thick-walled structure applicable to a large-scale structure without increasing the required extrusion force. The remarkable advantage is that it is possible to produce Ti alloy tubes.

Further, as described in claim 7, by extruding at a temperature of 900 ° C. or more and 1150 ° C. or less, the deformation resistance in the hot extrusion of the Ti alloy material is small. In addition, it is possible to produce a seamless Ti alloy tube while preventing coarsening of crystal grains, which is a remarkable advantage.

Claims (7)

[Claims] 1. By weight%, S: 0.01 to 10%, S
e: 0.01 to 10%, Te: 0.01 to 10%, one or more kinds in total of 10% or less, REM:
0.01 to 10%, Ca: 1 out of 0.01 to 10%
A seamless Ti alloy pipe containing at least 10% in total of two or more kinds, and having a composition consisting essentially of Ti for the balance, and being extruded to form a seamless tube. 2. By weight%, S: 0.01 to 10%, S
e: 0.01 to 10%, Te: 0.01 to 10%, one or more kinds in total of 10% or less, REM:
0.01 to 10%, Ca: 1 out of 0.01 to 10%
Or less than 10% in total, Al: 10% or less,
V: 25% or less, Sn: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10
% Or less, Hf: 10% or less, W: 10% or less, Si:
0.5% or less, Nb: 20% or less, Zr: 10% or less,
Mo: 15% or less, O: 0.1% or less, one kind or two or more kinds in total, 30% or less is contained, and the balance has a composition substantially made of Ti. Seamless Ti alloy tube characterized by being formed into a tubular shape without. 3. The ratio (t) between the wall thickness (t) and the outer diameter (D) of the pipe.
/ D) is 0.01 or more and 0.40 or less, The seamless Ti alloy pipe according to claim 1 or 2. 4. By weight%, S: 0.01 to 10%, S
e: 0.01 to 10%, Te: 0.01 to 10%, one or more kinds in total of 10% or less, REM:
0.01 to 10%, Ca: 1 out of 0.01 to 10%
A method for producing a seamless Ti alloy pipe, which comprises extruding a Ti alloy material having a composition of 10% or less in total, or 10% or less in total, with the balance being substantially Ti to form a tubular shape. 5. By weight%, S: 0.01 to 10%, S
e: 0.01 to 10%, Te: 0.01 to 10%, one or more kinds in total of 10% or less, REM:
0.01 to 10%, Ca: 1 out of 0.01 to 10%
Or less than 10% in total, Al: 10% or less,
V: 25% or less, Sn: 15% or less, Co: 10% or less, Cu: 10% or less, Ta: 15% or less, Mn: 10
% Or less, Hf: 10% or less, W: 10% or less, Si:
0.5% or less, Nb: 20% or less, Zr: 10% or less,
A Ti alloy material containing Mo: 15% or less and O: 0.1% or less, 30% or less in total of one kind or two or more kinds, and the balance substantially consisting of Ti is extruded. A method for producing a seamless Ti alloy tube, which is characterized by being formed into a tubular shape. 6. The ratio (t) between the wall thickness (t) and the outer diameter (D) of the pipe.
/ D) is 0.01 or more and 0.40 or less, and extruding is carried out, The manufacturing method of the seamless Ti alloy pipe of Claim 4 or 5. 7. The method for producing a seamless Ti alloy pipe according to claim 4, wherein the extrusion is carried out at a temperature of 900 ° C. or more and 1150 ° C. or less.