JPH08224327A - Golf club head made of titanium alloy and its preparation - Google Patents

Abstract

PURPOSE: To provide a club head made of titanium alloys which is good at productivity, durability, and precision of its shape and size. CONSTITUTION: This club head is made of a main head unit (T1) containing hosel unit and a sole unit or a crown unit 2. The contact sections of These parts are welded. At least main head unit (T1) is made of a α+β type titanium alloys and its number of molybdenum equivalent is between 2-10. The chemical constituent of main head unit (T1) contains Al: 3-5, V: 2.1-3.7, Mo: 0.85-3.15, Fe: 0.85-3.15 and O: 0.06-0.2, and V, Fe, and Mo is 7<=0.67×V+2.9×Fe+Mo<=13. Each units is wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club head made of metal such as metal wood and a method for manufacturing the same, and in particular, a titanium alloy golf club head having few welding points and excellent in durability and manufacturability. And the manufacturing method thereof.

[0002]

2. Description of the Related Art A so-called metal wood golf club head (hereinafter referred to as a golf club head) has been manufactured by a precision casting method using a stainless alloy, an aluminum alloy, a titanium alloy or a beryllium-copper alloy as a raw material. In particular, titanium alloys have been put to practical use as golf club heads because they are lightweight and excellent in strength and have the so-called high specific strength. As a kind of titanium alloy used in the above precision casting method, for example, there is Ti-6Al-4V alloy which is an α + β type Ti alloy.

However, titanium alloys are inferior in castability represented by the fluidity of the molten metal. for that reason,
The titanium alloy golf club head manufactured by the precision casting method has fine casting defects such as porosity. If a certain amount or more of this casting defect exists, it is determined as a defective product. The golf club head made of a titanium alloy by the precision casting method has a high probability of becoming such a defective product and has a problem that the product yield decreases. The golf club head is brittle because the metal structure is a cast structure,
Further, it has a drawback that it is inferior in mechanical properties such as durability and tensile strength.

In order to solve the problem of the titanium alloy golf club head produced by such a precision casting method, a titanium golf club head formed by hot or cold plastic working has been proposed. However, titanium alloys generally have poor plastic workability. That is, the deformation resistance during plastic working is high and the ductility is low. Therefore, there is a problem that a large force is required for the plastic working of the titanium alloy, and a crack is likely to occur during the plastic working.

Certainly, the plastic workability of titanium alloys generally improves at high temperatures. That is, if the plastic working temperature is increased, the force required for the deformation is small and the ductility is increased. Therefore, when paying attention only to the plastically worked surface, it is possible to form a titanium alloy with a large degree of workability by subjecting the titanium alloy to plastic working at a high temperature, and to form a complex shape. it can. However, since titanium alloys are extremely active with respect to oxygen and nitrogen, it is not desirable to increase the heating temperature and the heat treatment temperature.

Therefore, for example, Japanese Patent Laid-Open No. 5-15620 discloses a titanium alloy golf club head manufactured by cold pressing (hereinafter referred to as prior art 1).

In the above-mentioned publication, a golf club head is divided into a plurality of constituent members, and these constituent members are formed by working a material made of β-type titanium alloy by cold pressing.
Then, a titanium alloy golf club head manufactured by assembling the above-mentioned components and welding the abutting portions is disclosed.

FIG. 3 is a schematic perspective view showing an assembled state of constituent members of the golf club head described in the prior art 1. As shown in FIG. In the figure, 1 is a face portion, 2 is a crown portion, 3 is a fosel portion, and 4 is a sole portion.

According to the prior art 1, the welding points of the constituent members of the golf club head are, for example, in the example of FIG. 3, the joint surface between the face portion 1, the crown portion 2 and the sole portion 4, The joint surface between the crown portion and the sole portion and the abutting portion between the fosel portion 3 and the face portion 1 and the crown portion 2 are provided at a total of 5 places.

Further, Japanese Patent Laid-Open No. 5-317467 discloses a metal golf golf club in which a face portion, a portion of a crown portion, a portion of a sole portion and a fusel portion are integrally formed by a forging method. A club head (hereinafter referred to as prior art 2) is described.

FIG. 4 is a schematic perspective view showing an assembled state of the constituent members of the golf club head described in the above publication. In the figure, 7 is a face side member, which comprises a face portion 1, a portion 2a of the crown portion 2, a portion 4a of the sole portion 4 and a fusel portion 3, and 8 Is a back side member and is composed of another part 2b of the crown part 2 and another part 4b of the sole part 4. 9b is a portion where the fosel portion 3 and the crown portion 2 are butted.

In the above publication, after a metal plate having a predetermined shape is roughly formed, it is forged to form a "face side member 7", while another metal plate having a predetermined shape is formed on the "back side member". An 8 "metal golf club head is disclosed which is manufactured by assembling these two members and welding the abutments together.

According to the prior art 2, the welding portion of the component member of the golf club head is the abutting portion between the face side member 7 and the back side member 8 as is clear from FIG. The line is long, and the abutting portion 9b between the fosel portion 3 and the crown portion 2 which is an important portion for the durability of the golf club is joined by welding.

Further, Japanese Utility Model Publication No. 61-33971 discloses a golf club head of a two-part type in which the constituent members of the head body are a front shell part and a rear shell part (hereinafter referred to as prior art 3). ing. However, in the prior art 3, the fossel portion which is most impacted at the time of hitting the golf ball is formed by butt-welding the "rear neck half-split portion" and the "front neck half-split portion", and the welding line is Two
Since it becomes a book, the shaft mounting pipe is used as a constituent member, and the head main body and the shaft mounting pipe are joined by welding. Furthermore, actual public Sho 61-339
70 and Japanese Utility Model Publication 60-30453,
A three-part golf club head is disclosed. However, since the inside of the head main body includes a reinforcing member for connecting and reinforcing the face portion, the crown portion and the sole portion to each other and a pipe for mounting the shaft, the structure and the manufacturing process Is complicated. Also,
Japanese Unexamined Patent Publication (Kokai) No. 63-154186 discloses a golf club head which mainly has a plurality of Ti-6Al-4V titanium alloy shells integrally joined together to form a hollow head body. However, in the invention of the same publication, the following points are required, that is, since water cooling is required after forging of a titanium alloy, dimensional deviation and deformation may occur due to thermal strain, and oxidation occurs because the forging temperature is 900 ° C. or higher. Are easily affected, the hot workability is poor, and cracks easily occur, so that a problem easily occurs in the shape of the molded product. Therefore, there is a problem that the optimum forging condition range becomes narrow and the degree of freedom in design cannot be increased.

[0015]

The above-mentioned prior art has the following problems. The prior art 1 is a method of manufacturing an integrated golf club head by forming a plurality of constituent members made of β-type titanium alloy by cold working, combining them, and welding the abutting portions. The component parts include a face portion, a crown portion,
Since it covers the four parts of the sole part and the fossel part, it is necessary to weld a large number of parts, as described above, at five parts. Further, the β-type titanium alloy is inferior in weldability to the α + β-type titanium alloy, and the metal characteristics (ductility and crystal grain state) in the welded portion of the above-mentioned constituent members are homogenized by plastic working. Since it is inferior to that of No. 1, the durability at the welded portion is inferior when the golf club head is used.

In particular, the durability of the golf club is problematic because it has a welded joint structure of the fosel portion, the crown portion, and the face portion, which are required to have high toughness. In addition, since there are many welding points and the length of the welding line is long, it causes the defective shape of the golf club head due to welding distortion. Further, there is a problem that the cost increases due to an increase in the number of welding steps. In Prior Art 1, since the titanium alloy material, which is a constituent member of the golf club head, is molded by cold working, it is difficult to perform molding with a high degree of working, and a constituent member having a complicated shape is obtained. Is difficult.

In prior art 2, the number of constituent members of the golf club head is as small as two, and therefore the problems associated with the execution of welding work are improved as compared with prior art 1. However, the method of forming the fosel portion in Prior Art 2 is to form the plate-shaped material into a cylindrical shape and then weld the abutting portion in a seam shape. Therefore, there is a problem that one seam-shaped weld line still remains in the fosel part. Further, since the length of the welding line is long, the problem of defective shape due to welding distortion remains, and
Golf clubs that require particularly high toughness in terms of durability
There is a problem in durability because the joint portion and the crown portion are joined by welding. Further, as a metal plate used for manufacturing a golf club head, there is no disclosure regarding a titanium alloy, and there is only disclosure regarding a low alloy steel. Therefore, Prior Art 2 cannot solve the problem that occurs when the titanium alloy is inferior in hot workability.

As described above, the plastic workability of the titanium alloy is improved at high temperatures, so the force required for plastic working is small, and the ductility is improved, so that the workability can be increased. It can be molded into more complex parts. Therefore, if it is possible to prevent oxidation and nitridation of the titanium alloy material at high temperatures, it is possible to manufacture a golf club head that is close to an integrated body. However, it is industrially difficult to suppress the oxidation and nitridation to a substantially harmless degree by controlling the atmosphere of the heating and forging process of the titanium alloy material. When the heating and forging temperature exceeds 900 ° C., the titanium alloy is significantly oxidized and nitrided.

Although β-type titanium alloy is excellent in cold workability among titanium alloys, it is extremely difficult to form a complicated shape such as a golf club head by cold working. In the case of β-type alloy, the head is divided into multiple parts and formed by hot forging. In recent golf club heads, large golf club heads having a capacity of 220 cc or more with a wide sweep spot are manufactured in order to improve the flight distance and the accuracy of the flying ball. As a result, the head weight of conventional materials increases with the increase in size of golf club heads, and it is important to increase the specific strength of the materials. In the case of β-type alloy, as hot forging, only strength of about 80 to 90 kg / mm ² can be obtained, and rigidity is low. Therefore, high specific strength and high specific rigidity expected for titanium alloy can be achieved with β-type titanium alloy golf In order to apply it to the club head, it must be solution-treated and aged after forging. In addition, there is a problem that a high strength requires a long aging of about 8 to 15 hours after solutionizing and air cooling, which requires a long time for heat treatment. Further, in strengthening a typical Ti + Al type Ti-6Al-4V alloy, water cooling is indispensable in the solution treatment before the aging treatment, and there is a problem of influence on dimensional accuracy and deformation due to thermal strain.

Therefore, an object of the present invention is to solve the above-mentioned problems and to use a titanium alloy material which can be formed into a part having a complicated shape by plastic working, so that the number of welded parts can be reduced. By obtaining the components of the golf club head, the manufacturability, durability, shape and dimensional accuracy are excellent, and the surface of the molded body after hot working can be easily maintained, resulting in high specific strength and high specific rigidity. It is an object of the present invention to provide a titanium alloy golf club head that can be easily applied and a method for manufacturing the same.

[0021]

SUMMARY OF THE INVENTION The present invention optimizes the chemical composition of a titanium alloy used as a material for a golf club head, and optimizes the shapes of the components of the golf club head molded from the material. It has been achieved by

A feature of the titanium alloy golf club head according to the present invention is a golf club head comprising a face portion, a fosel portion, a crown portion and a sole portion, wherein the face portion and the fore portion are formed. -A head main member (T1) in which a zel part is integrally formed, and one or two members including a crown part and a sole part that are formed independently of the head main member head (T1). And the other assembly adjacent parts except the part where the face part and the fosel part are adjacent to each other are joined by welding, and at least the head main member (T1) is , Α + β type titanium alloy, the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) +0 .28 × Nb (wt.%) + 0.22 × T (Wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) + 0.77 × Cu (Wt.%) -Al (wt.%) -------------------- Molybdenum equivalent calculated by (1): Mo _eq (wt.%) It is characterized by having a chemical component composition with a value within the range of 2 to 10 (hereinafter referred to as the first invention).

The features of the titanium alloy golf club head according to the present invention are the face portion, the crown portion and the fore portion.
A head main member (T2) in which a zel part is integrally formed,
A head member (T2) and an assembled butting portion of the head member (T2) are joined together by welding, and the crown portion is formed. Is a golf club head formed continuously from at least the upper portion of the face portion toward the rear thereof, and at least the head main member (T2) is an α + β type titanium alloy, and 1) Formula: Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) +0. 22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) +0. 77 × Cu (wt.%) -Al (wt.%) -------------------- (1) Molybdenum equivalent: Mo _eq (wt. % )of But those characterized by having a chemical composition within the range of 2 to 10 (hereinafter, second that the invention) is.

Another feature of the titanium alloy golf club head according to the present invention is a head main member (T3) in which a face portion, a sole portion and a fusel portion are integrally formed.
And a crown member formed of a crown portion, the assembled butting portion of the head main member (T3) and the crown member are joined by welding, and the sole portion is at least The fa
A golf club head that is formed continuously from the lower part of the sleeve portion toward the rear thereof, wherein at least the head main member (T3) is an α + β type titanium alloy, and the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta (wt .%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) + 0.77 × Cu (wt .%) -Al (wt.%) -------------------- The molybdenum equivalent calculated by (1): Mo _eq (wt.%) Is It is characterized by having a chemical composition within the range of 2 to 10 (hereinafter referred to as the third invention).

A more desirable titanium alloy golf club head according to the present invention (hereinafter referred to as the fourth invention) is characterized in that the chemical composition of the head main members (T1, T2 and T3) is aluminum (Al): 3. ~ 5 wt.
%, Vanadium (V): 2.1 to 3.7 wt.%, Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (Fe): 0.85 to 3.15 wt.%, And oxygen (O): 0.06 to 0.2 wt.%, And the contents of V, Fe and Mo are expressed by the following formula (2): 7 wt.% ≦ 0.67 × V (wt .%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, and the balance consists of titanium and unavoidable impurities.
The invention comprises the invention described in the first, second or third invention.

In the method for manufacturing a golf club head of the present invention, a head main member (T1) having a face portion and a fusel portion integrally formed is formed by hot working using a rod material, and Using a plate material or a bar material, one or two other members including a crown portion and a solder portion formed independently from the main member (T1) are formed by hot working, and then, The head main member (T
1) A method for manufacturing a golf club head, in which an assembled butt portion of the other member is joined by welding, wherein at least a material of the head main member (T1) is an α + β type titanium alloy, and the following ( 1) Formula: Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) +0. 22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) +0. 77 × Cu (wt.%) -Al (wt.%) -------------------- (1) Molybdenum equivalent: Mo _eq (wt. %) Is characterized by being manufactured by using a bar material having a chemical composition in the range of 2 to 10 (hereinafter referred to as the fifth invention).

According to the method of manufacturing a golf club head of the present invention, a head main member (T2) in which a face portion, a crown portion and a fusel portion are integrally formed is formed by hot working using a rod material. , And using plate or bar material,
A golf club head in which a sole member formed of a sole portion is formed by hot working, and then the abutting portion between the head main member (T2) and the sole member is joined by welding. In the manufacturing method, at least the material of the head main member (T2) is an α + β type titanium alloy, and the following formula (1): Mo _eq (wt.%) = Mo (wt.%) +0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) +1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) + 0.77 × Cu (wt.%) -Al (wt.%) ------ -------------- Molybdenum equivalent calculated in (1): Mo _eq (wt.%) Value is a bar with chemical composition that falls within the range of 2-10. Manufactured by using Doo to those having features (hereinafter, a sixth of the invention) is.

Another method of manufacturing the golf club head according to the present invention uses a bar member and hot-workes the face part and the source part.
A head main member (T3) integrally formed with a ruled part and a fosel part, and a plate member or a bar member to mold a crown member formed by a crown part by hot working, and Next, the head main member (T
3) A method for manufacturing a golf club head, in which a butted portion between the crown member and the crown member is joined by welding, in which at least the material of the head main member (T3) is α +
A β-type titanium alloy having the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) +0. 28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) +1. 4 x Co (wt.%) +0.77 x Cu (wt.%) -Al (wt.%) --------------------- (1) Characterized by being manufactured by using a bar material having a chemical composition that has a calculated molybdenum equivalent: Mo _eq (wt.%) Value within the range of 2 to 10 (hereinafter, referred to as the seventh invention. That is).

A more desirable characteristic of the golf club head manufacturing method according to the present invention (hereinafter referred to as the eighth invention) is as follows.
The chemical composition of the head main members (T1, T2 and T3) is aluminum (Al): 3 to 5 wt.%,
Vanadium (V): 2.1 to 3.7 wt.%, Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (F
e): 0.85 to 3.15 wt.%, and
Oxygen (O): 0.06 to 0.2 wt.% Is contained, and the contents of V, Fe and Mo are as follows (2).
Formula: 7 wt.% ≦ 0.67 × V (wt.%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, The balance consists of titanium and unavoidable impurities,
It comprises the method according to the fifth, sixth or seventh invention.

Another more desirable method for producing a golf club head according to the present invention (hereinafter referred to as the ninth invention) is characterized in that in the method for producing the golf club head according to the fifth, sixth or seventh invention, Component composition is aluminum (Al): 3-5 wt.%, Vanadium (V)
: 2.1 to 3.7 wt.%, Molybdenum (Mo):
0.85 to 3.15 wt.%, Iron (Fe):
0.85 to 3.15 wt.% And oxygen (O)
: 0.06 to 0.2 wt.%, And V, F
The content of e and Mo is expressed by the following formula (2): 7 wt.% ≤0.67 x V (wt.%) +2.9 x Fe (wt.%) + Mo (wt.%) ≤13 wt.%- ----- (2) is satisfied, the balance consists of titanium and inevitable impurities,
Moreover, in addition to the above, the head main members (T1, T
The heating temperature in the hot working of 2 or T3) is 120 ° C. lower than the β transformation point determined according to the chemical composition of the head main member (T1, T2 or T3), and is lower than the β transformation point. It is in the range up to 30 ° C. higher.

Another more desirable method for manufacturing a golf club head according to the present invention (hereinafter referred to as the tenth invention).
In the method for manufacturing a golf club head according to the fifth, sixth or seventh invention, the chemical composition is
Aluminum (Al): 3 to 5 wt.%, Vanadium (V): 2.1 to 3.7 wt.%, Molybdenum (M
o): 0.85 to 3.15 wt.%, iron (Fe)
: 0.85 to 3.15 wt.% And oxygen (O)
: 0.06 to 0.2 wt.%, And
The contents of V, Fe and Mo are expressed by the following formula (2): 7 wt.% ≤ 0.67 x V (wt.%) + 2.9 x Fe (wt.%) + Mo (wt.%) ≤ 13 wt. % ------ (2) is satisfied, and the balance is titanium and inevitable impurities,
Moreover, in addition to the above, the head main members (T1, T
The heating temperature in the hot working of 2 or T3) is 100 ° C. lower than the β transformation point which is determined according to the chemical composition of the head main member (T1, T2 or T3) and is lower than the β transformation point. It is in the range of up to 20 ° C. lower.

In the present invention, the constituent members of the golf club head formed by hot working using the titanium alloy material having the limited chemical composition are in the state of solution treatment at the end of hot working. Is substantially obtained. Therefore, solution treatment is not performed. In addition, since a so-called natural aging effect is obtained, the aging treatment is not performed unless it is desired to improve mechanical properties.

[0033]

In the present invention, the main head member including the fosel portion is formed as an integral body. In this case, since the rod material is used as the material shape, there is no welding line for forming the fosel part in a cylindrical shape, for example, a seam welding line as in the prior art 2. Therefore, the accuracy of the size and shape of the golf club head is improved, and the durability is also improved. As described above, the titanium alloy having the following chemical composition is used so that the main head member can be formed as one body. Among the constituent members of the golf club head of the present invention, since it is necessary to use a titanium alloy material excellent in hot workability in at least the main part of the head, it is necessary to use a titanium alloy having the above-described chemical composition. Use material. The reason is as follows.

[Α + β type titanium alloy, Mo _eq (wt.%
)]: The α + β type titanium alloy has excellent room temperature strength. In the present invention, if the value of molybdenum equivalent: Mo _eq (wt.%) _Represented by the formula (1) is 2 or more,
The volume fraction of β phase in the metal structure increases, and β phase-ric
Since it becomes an α + β type titanium alloy having a h, the β transformation point is lowered and the hot workability is improved. However, if the value is less than 2, the effect is not sufficiently exhibited. On the other hand, when the value exceeds 10, the volume ratio of β phase becomes too large,
The β grains become coarse and the hot workability deteriorates. For example, Ti-6A, which is a typical alloy of conventional α + β type titanium alloys.
In the 1-4V alloy, the β transformation point is approximately 1000 ° C., whereas in the α + β titanium alloy, the β transformation point is 900 ° C.
It becomes about ℃. The material of the titanium alloy having the above-mentioned chemical composition is not only excellent in mechanical properties such as strength and toughness at room temperature, but also cracks do not occur during processing, and heat at a lower temperature It becomes possible to perform hot working (so-called low temperature working). As a result, the head main member, which is a constituent member of the golf club head according to the present invention, can be integrally molded.

On the other hand, the β-type alloy is known to undergo hot working, but the forging heating temperature is 1000.
Since it is above ℃, there is no choice but to divide into many members and carry out hot forging. Therefore, oxidation also progresses.

Next, the chemical composition of at least the main components of the head is Al: 3-5 wt.%, V: 2.1-3.7 w.
t.%, Mo: 0.85 to 3.15 wt.%, Fe: 0.8
5 to 3.15 wt.% And O: 0.06 to 0.2 w
t.% and the contents of V, Fe and Mo are the following formula (2): 7 wt.% ≤ 0.67 x V (wt.%) + 2.9 x Fe (wt.%) + Mo The reason why it is desirable to satisfy (wt.%) ≦ 13 wt.% ------ (2) and the balance is made of titanium and unavoidable impurities is as follows.

[Al]: Titanium alloy material is usually hot forged,
It is formed by hot working by hot rolling or both of them. However, when the hot working temperature falls outside the proper range, the deformation resistance rapidly increases and the material cracks, resulting in a marked decrease in manufacturability. Such manufacturability is closely related to the content of Al. That is, Al is α +
It is added as a so-called α-phase stabilizing element for obtaining a β structure and contributes to an increase in strength. However, if the Al content is less than 3 wt.%, The desired strength cannot be obtained. On the other hand, when the Al content exceeds 5 wt.%, The hot deformation resistance increases and the manufacturability deteriorates. Therefore, the Al content is 3
It is desirable to limit the content within the range of ~ 5 wt.%.

[V]: V is for obtaining α + β texture,
It is added as a so-called β-phase stabilizing element and has an action of increasing strength without forming an intermetallic compound which is an embrittlement phase with Ti. That is, V mainly forms a solid solution in the β phase and strengthens it. However, the V content is 2.1 w
If it is less than t.%, the above-mentioned effects cannot be sufficiently exhibited. On the other hand, when the V content exceeds 3.7 wt.%, The β transformation point becomes too low. Therefore, the V content is 2.1 to
It is desirable to limit it to the range of 3.7 wt.%.

[Mo]: Mo is added as a β-phase stabilizing element and contributes to lowering the hot working temperature by lowering the β transformation point. Further, Mo has a function of forming a solid solution in the β phase to increase the strength. However, if the Mo content is less than 0.85 wt.%, The above-mentioned actions and effects cannot be sufficiently obtained. On the other hand, when the Mo content exceeds 3.15 wt.%, The density of the alloy material is increased, and the so-called high specific strength of the titanium alloy is impaired. Further, since Mo has a slow diffusion rate in the titanium alloy, the deformation stress during hot working increases. Therefore, the Mo content is 0.85 to 3.
It is desirable to limit it within the range of 15 wt.%.

[Fe]: Fe, like Mo, is added as a β-phase stabilizing element and contributes to the reduction of hot deformation resistance by lowering the β transformation point. Further, Fe has a function of forming a solid solution in the β phase to increase the strength. Also, Fe
Has an effect of reducing the hot deformation resistance and suppressing the occurrence of cracks, since it increases the volume fraction of the β phase having good workability during hot working. However, if the Fe content is less than 0.85 wt.%, The above effect is not sufficiently exhibited. On the other hand, when the Fe content exceeds 3.15 wt.%, T
An intermetallic compound, which is an embrittlement phase, is easily formed between i and i, and thus ductility deteriorates. Therefore, the Fe content is
It is desirable to limit the content within the range of 0.85 to 3.15 wt.%.

[O]: O has the function of forming a solid solution in the α phase to increase the strength. However, the O content is 0.0
If it is less than 6 wt.%, Its effect is not fully exhibited. on the other hand,
When the O content exceeds 0.2 wt.%, The hot deformation resistance increases, which is not desirable. Therefore, the O content is 0.1.
It is desirable to limit the content within the range of 06 to 0.2 wt.%.

[0.67 × V (wt.%) + 2.9 × Fe
(Wt.%) + Mo (wt.%)]: This value shows the stability of the β phase of the titanium alloy. When this value becomes small, the volume fraction of the β phase in the metal structure decreases and the β transformation point becomes On the contrary, when this value increases, the volume fraction of the β phase increases and the β transformation point decreases. And Al, V, Mo, F
When the contents of e and O are within the above-mentioned range and the value indicating the stability of the β phase is less than 7 wt.%,
The volume ratio of the α phase increases and the deformation resistance becomes too large. Therefore, the decrease of the β transformation point is slightly insufficient, and the hot workability is not sufficiently improved. On the other hand, this value is 13 w
When it exceeds t.%, the volume fraction of β phase becomes too large,
β-grains are slightly coarsened and the hot workability is slightly reduced. Therefore, in order to enable the integral molding of the constituent members of the golf club head by using the titanium alloy having excellent hot workability, 0.67 × V (wt.%) + 2.9 × Fe
The value of (wt.%) + Mo (wt.%) Should be limited to the range of 7 to 13 wt.%.

The above-mentioned member having the above-mentioned chemical composition becomes a so-called β phase-rich α + β type titanium alloy in which the volume fraction of the β phase is increased within a more appropriate range.
The β transformation point is as low as 900 ° C, which does not require a great amount of force for hot working, and cracks do not occur during working, which enables further low temperature working and improves hot workability. . As a result, it becomes easy to integrally form a main head member as described below.

That is, in the present invention, since the material of the titanium alloy having excellent hot workability as described above is used for at least the main member of the head, the face portion and the fusel portion are integrally formed. The main components of the head (hereinafter,
"1 type head main member"), a head main member (hereinafter referred to as "2 type head main member") in which a face part, a crown part and a fosel part are integrally formed, and a face part. , A head main member (hereinafter, referred to as “3 type head main member”) having a sole part and a fusel part integrally formed, which has a complicated and high workability, is formed into a bar member having a predetermined shape (for example, , Round bar and square bar) can be formed by hot working. On the other hand, other members other than the head main member, such as a solder member and a crown member, do not have a complicated shape like the head main member, so that they may be formed within a range in which they can be formed by hot working. It is not necessary to use a material having the above chemical composition, and it is desirable to use a plate material as the material shape.

Further, the golf club head of the present invention is
A main head member including a fosel portion is integrally formed. Therefore, since the boundary area between the fosel portion and the face portion, which receives the most impact force when the golf club is used, is an integrally molded product and not a joint structure such as welding, the durability is remarkably excellent. There is.

Then, a predetermined golf club head can be manufactured by joining by welding the abutting portions where the head main member and the sole member or the crown member are assembled. Therefore, since the welding line is short and there are few welding points, distortion due to welding is unlikely to occur,
Good shape and dimensional accuracy. Further, since the welded position is only the abutting portion of the sole portion with the face portion and the crown portion, the impact force is less likely to be applied when the golf club is used, and this portion is smooth. Since it has a curved shape, its durability is not impaired. Furthermore, since the welding lines are short and the number of welding lines is small, the solidification structure region associated with welding is narrow. Therefore, a region where mechanical properties such as strength and toughness are deteriorated is narrowly suppressed, and occurrence of defective size and shape of the golf club head due to welding distortion is also suppressed.

Next, the chemical composition of the head main member is
As described above, since the value of molybdenum equivalent: Mo _eq (wt.%) Is within the range of 2 to 10, Ti-6Al-4
Β compared to conventional α + β type titanium alloys such as V alloy
It is a phase-rich α + β type titanium alloy. Therefore, a phenomenon that has not been recognized in the past, that is, in this alloy material, at the end of hot working, a solution-treated state is substantially obtained, and the state is stabilized, After the hot working is completed, the solution treatment state can be stably obtained by air cooling at about 1 ° C./sec without rapid cooling. Therefore, it is not necessary to perform solution treatment after hot working. Therefore, after the above-mentioned members are welded, it is not necessary to perform an aging treatment for stabilizing the solution state of the members. However,
In order to obtain more excellent mechanical properties at room temperature, 0.5 to 10 at 450 to 650 ° C. after hot working.
It is desirable to apply aging treatment for about an hour. The reason for this is that the temperature is less than 450 ° C. or the time is 0.
If it is less than 5 hours, the increase in strength is insufficient, and
This is because if it exceeds 600 ° C. or exceeds 10 hours, it softens due to overaging. By applying the aging treatment, the strength of the natural aging material (about 110 to 130 kg / mm ² ) is 15 to 20%.
It can be improved to some extent, and the strength desired for increasing the size of the golf club head can be easily obtained.

The chemical composition of at least the main components of the head is Al: 3-5 wt.%, V: 2.1-3.7 w.
t.%, Mo: 0.85 to 3.15 wt.%, Fe: 0.8
5 to 3.15 wt.% And O: 0.06 to 0.2 w
When t.% is contained and the balance is made of titanium and unavoidable impurities, the above member becomes a so-called β phase-rich α + β titanium alloy in which the volume% of β phase is increased within a more appropriate range. Therefore, the β transformation point is further lowered to about 900 ° C., the hot workable temperature is further lowered, which is advantageous in terms of equipment and operation. Also in this case, it is not necessary to perform the solution treatment after the hot working for the same reason as described above. Further, after welding the above-mentioned members, it is not necessary to perform an aging treatment for stabilizing the solution state of the members. However, in order to obtain more desired desired mechanical properties at room temperature, it is desirable to perform the aging treatment after hot working.

Generally, the lower the heating temperature and the hot working temperature of the titanium alloy material, the more the oxidation and nitridation of the surface of the titanium alloy material are suppressed. In the production of the golf club head of the present invention, since the material of the titanium alloy having the chemical composition as described above is used, it is possible to perform good low temperature working within the range of hot working,
The effect of suppressing the above-mentioned oxidation and nitriding is exhibited.

[0050]

EXAMPLES The present invention will be further described below with reference to Examples, in comparison with Comparative Examples. First, the following ingots of various titanium alloys were prepared in a vacuum arc remelting furnace.

Table 1 shows the chemical composition of titanium alloys Nos. A1 and A2 having the chemical composition which should be satisfied by at least the main member of the present invention (hereinafter referred to as "the present invention type alloy"). The present invention type alloy No. A1 is an α + β type titanium alloy, and the molybdenum equivalent of the above formula (1): Mo _eq is 5.4 within the range of 2 to 10, and the present invention type alloy. No. A2 has a content of Al, V, Mo, Fe and O within a desirable range, and shows the stability of the β phase of 0.67 × V (wt.%) + 2.9 × Fe (w
The value calculated by t.% Mo (wt.%) is 10.1 within the range of 7 to 13.

[0052]

[Table 1]

Table 2 shows typical so-called 6Al of conventional titanium alloys suitable for golf club heads, which are β type titanium alloys and conventional α + β type titanium alloys.
-4V-Ti alloy (hereinafter referred to as "conventional alloy") No.
The chemical composition of B1 and No. B2 is shown.

[0054]

[Table 2]

The above ingot was hot-forged and hot-rolled under predetermined conditions to prepare a round bar material and a square bar material having a predetermined shape and size, and a plate material from each ingot. In addition,
The amount of reduction in hot rolling (represented by the rate of increase in the length of the material in the hot rolling direction) was within the range of 50 to 80%. The titanium alloy round bar and plate thus prepared were used as materials for golf club heads in Examples of the present invention and Comparative Examples.

Example A golf club head within the scope of the present invention was manufactured as follows. FIG. 1 is a schematic perspective view showing an example of an assembled state of constituent members of a titanium alloy golf club head according to the first invention. As shown in the figure, this golf club head is a sole comprising a type 1 head main member T1 in which a face portion 1 and a fosel portion 3 are integrally formed, and a sole portion 4. The member 6 and the crown member composed of the crown portion are assembled, and the abutting portions are joined by welding to be integrated.

FIG. 2 is a schematic perspective view showing an example of the assembled state of the constituent members of the titanium alloy golf club head according to the second invention. As shown in the figure, this golf club head has a type 2 head main member T in which a face portion 1, a crown portion 2 and a fosel portion 3 are integrally formed.
1 and the sole member 6 including the sole portion 4 are assembled,
The abutting parts are joined by welding and integrated.

FIG. 3 is a schematic perspective view showing an example of the assembled state of the constituent members of the titanium alloy golf club head according to the third invention. As shown in the figure, this golf club head has a face portion 1, a sole portion 4 and a fore portion.
3 type head main member T2 in which the gel part 3 is integrally formed
And the crown member 5 including the crown portion 2 are assembled, and the abutted portions are joined by welding to be integrated.

Using the titanium alloy materials shown in Tables 1 and 2, the golf club head of the present invention was manufactured under predetermined manufacturing conditions. Table 3 shows the types of alloy materials used for manufacturing the golf club head of the present invention and manufacturing conditions such as hot forging and aging treatment conditions.

[0060]

[Table 3]

That is, at least the head main members (the 1st type head main member, the 2nd type head main member and the 3rd type head main member) are made of the round bar or the square bar of the alloy of the present invention, and the other members. A plate material of the present invention type alloy or a conventional type alloy (No. B2: Ti-6Al-4V alloy) was used as the material, and each was heated to a predetermined temperature, and then hot die forging was performed. In the die forging of the head main member, after the face portion and the crown portion, or the face portion and the solder portion are roughly formed, the face portion and the crown portion, or the face portion and the saw portion are formed. -The finishing die forging of the reel portion and the drilling of the fosel portion 3 were performed.

In the die forging step, a round bar material or a plate material is heated to a predetermined temperature in a heating furnace, and after extraction, forging is quickly performed using a predetermined die. Therefore, since the time required for forging is short, the temperature of the object to be molded (forging temperature) during forging is a temperature close to the above heating temperature. Therefore, in the present invention, the heating temperature is used as the forging condition instead of the forging temperature.

In the hot die forging of the main member of the head described above, since the raw material had the chemical composition of the alloy of the present invention and the round bar was used, the samples of the present invention No. P1 to P1.
With respect to all of Nos. 6 and 6, it was possible to satisfactorily form a member having a complicated shape as an integral body. Next, predetermined members were assembled and joined by TIG welding to prepare an integrated golf club head. The golf club heads thus prepared were not subjected to the solution treatment after forging because the solution treatment state was obtained at the end of the forging.

As for the aging treatment after welding, since the effect of natural aging is obtained in the member using the alloy of the present invention as described above, it is not necessary to perform the aging treatment. However, in order to obtain better mechanical properties, only some of them were aged. The surface of the golf club head was then polished and painted to finish. In this way, six golf club heads having a volume of 230 cc and within the scope of the present invention (hereinafter, referred to as “specimens of the present invention”) were manufactured.

Comparative Example Next, a golf club head for comparison (hereinafter referred to as “comparative test piece”) was manufactured using the titanium alloy materials shown in Table 2.

Table 4 shows the type of alloy used as the material for manufacturing the golf club head for comparison, as well as hot forging conditions, solution treatment conditions and aging treatment conditions.

[0067]

[Table 4]

Regarding the comparative sample No. Q1, in order to manufacture a golf club head having the same form as the golf club head shown in FIG. 1, the conventional alloy No. B1 (β (Type alloy) round bar material, and for the crown member and the sole member, the plate material of the conventional alloy No. B1 was used as the raw material. Although the golf club head shown in FIG. 1 has a crown portion and a sole portion divided into respective members, it may be a member in which the crown portion and the sole portion are integrally formed.

For the test specimens No. Q2 and Q3 for comparison, in order to manufacture golf club heads having the same forms as those of the golf club heads shown in FIGS. 2 and 3, respectively.
For the head main members (type 2 head main member and type 3 head main member), round bar materials of conventional alloys No. B1 (β type alloy) and B2 (Ti-6Al-4V alloy), on the other hand,
Thin plates of conventional alloys No. B1 and B2 were used as the materials for the solder member and the crown member, respectively, and after heating to a predetermined temperature, hot die forging was carried out to form them.

As a result, the forging of the sole member and the crown member could be favorably carried out, but the head main member having a complicated shape was normally forged in any of Nos. Q1, Q2 and Q3. Could not be done. Therefore, the desired golf club head could not be manufactured.

For each of the comparative samples No. Q4 to Q7, a golf club head having the same form as the golf club head shown in FIG. 4 was manufactured as follows. That is,
4 constituent members (face portion, crown portion, fosel portion, and sole portion) were replaced with conventional alloy Nos. B1 and B.
Using the plate material of No. 2, after heating to a predetermined temperature, hot die forging was performed to form. Then, after forging, it was air cooled.

Next, the above-mentioned four constituent members were assembled, and the butted portions were joined and integrated by TIG welding. The golf club heads thus formed were subjected to solution treatment under the conditions shown in Table 4 with respect to the comparative samples No. Q4 to Q6. However, the comparative specimen N
Regarding o.Q6, heat distortion occurred due to water cooling quenching in the solution treatment, so the subsequent test was stopped.

Next, comparative specimens No. Q4 and Q5
No. Q7 was not subjected to the aging treatment for the golf club head of Comparative Example No. Q7 while the golf club head was subjected to the aging treatment under the conditions shown in Table 4. Then, the surface of the golf club head was then polished and painted to finish. In this way, three golf club heads (comparative test pieces) having a volume of 230 cc and outside the scope of the present invention were manufactured.

Durability tests were conducted on each of the six test pieces of the present invention and the three test pieces for comparison. The durability test method was carried out by preparing a golf club in which the shaft of the golf club was attached to each test piece,
The number of times until the golf ball actually hits at 0 m / sec and an abnormality occurs in any part of the golf club head,
The durability was evaluated. As a result, in the comparative test piece, all of the fractured or cracked welds occurred in less than 6000 actual hits. On the other hand, all the test pieces of the present invention showed durability of 6000 times or more.

[0075]

As described above, according to the present invention,
By using a β phase-rich α + β type titanium alloy, which has a lower β transformation point than the conventional α + β type titanium alloy,
That is, by using a titanium alloy that exhibits good hot workability at a relatively low temperature, a solution treatment state can be obtained at the end of hot forging, and further, an aging treatment need not be performed. Since the components of a large-sized golf club head having a complicated shape can be integrally formed, the number of welding points and welding lines can be significantly reduced, and the heat treatment process can be simplified. The manufacturability is improved, the manufacturing period is shortened, the cost is drastically reduced, and it is possible to provide a golf club head made of titanium alloy which is excellent in durability and a manufacturing method thereof, which is an extremely useful effect in industry. Is brought about.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of an assembled state of constituent members of a titanium alloy golf club head according to the present invention (first invention).

FIG. 2 is a schematic perspective view showing an example of an assembled state of constituent members of a titanium alloy golf club head according to the present invention (second invention).

FIG. 3 is a schematic perspective view showing an example of an assembled state of constituent members of a titanium alloy golf club head according to the present invention (third invention).

FIG. 4 is a schematic perspective view showing an example of an assembly view of a conventional titanium alloy golf club head.

FIG. 5 is an assembly drawing 1 of a conventional metal golf club head.
It is a schematic perspective view which shows an example.

[Explanation of symbols]

T1 type 1 head main member T2 type 2 head main member T3 type 3 head main member 1 face part 2 crown part 2a a part of the crown part and adjacent to the face part 2b another part of the crown part Portion which is not adjacent to the face portion 3 Fauxel portion 4 Sole portion 4a A portion which is a part of the solder portion and is adjacent to the face portion 4b Another portion of the solder portion 5 Crown member 6 Sol member 7 Face side member 8 Back side member 9a Butt portion between the fusel portion and the crown portion and face portion 9b Fo -Abutting part between the bell and the crown

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuninori Minagawa Marunouchi 1-2-2, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Makoto Yamada 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Inside the Steel Pipe Co., Ltd. (72) Inventor Atsushi Ogawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside Steel Pipe Co., Ltd. (72) Inventor Hiroshi Hashimoto 1-2-24 Higashiueno, Taito-ku, Tokyo G3 Co., Ltd. (72) Inventor Wei ▲ Long Tai Taiwan Chai Su Lin Lin Thong Lu 269 Shan 1 Non 55 Howe

Claims (10)

[Claims] 1. A head main member (T1) integrally formed with a face part and a fosel part, and a crown part and a sole part independently formed from the head main member (T1). It is composed of one or two members including, and other assembly adjacent parts except the part where the face part and the fosel part are adjacent to each other are joined by welding, and further, At least the head main member (T1) is an α + β type titanium alloy and has the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) +0. 44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) +1. 1 x Ni (wt.%) +1.4 x Co (wt.%) +0.77 x Cu (wt.%) -Al (wt.%) --------------- --- (1 In molybdenum equivalent is calculated: Mo _eq value of (. Wt%) is characterized by having a chemical composition within the range of 2-10, titanium alloy golf club head. 2. A head main member (T2) integrally formed with a face portion, a crown portion and a fusel portion, and a sole member formed of a sole portion.
An assembled butted portion of the head main member (T2) and the sole member is joined by welding, and the crown portion is continuous from at least the upper portion of the face portion toward the rear thereof. A formed golf club head, wherein at least the head main member (T1) is an α + β type titanium alloy, and the following formula (1): Mo _eq (wt.%) = Mo (wt.%) +0 .67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) +1 .6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) + 0.77 × Cu (wt.%) -Al (wt.%) ---- --------------- (1) molybdenum equivalent is calculated by: the value of Mo _eq (. wt%) is that it has a chemical composition within the range from 2 to 10 And wherein, titanium alloy golf club head. 3. A head main member (T3) in which a face portion, a sole portion and a fusel portion are integrally formed, and a crown member formed in a crown portion. An assembled butted portion of the main member (T3) and the crown member is joined by welding, and the solder portion is formed continuously from at least the lower portion of the face portion toward the rear thereof. At least the head main member (T3) is an α + β type titanium alloy, and the following formula (1): Mo _eq (wt.%) = Mo (wt.%) +0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) +1.6 X Cr (wt.%) +1.1 x Ni (wt.%) +1.4 x Co (wt.%) +0 77 × Cu (. Wt%) -Al (. Wt%) -------------------- (1) molybdenum equivalent is calculated by: Mo _eq (wt. %) Value has a chemical composition in the range of 2 to 10. A golf club head made of titanium alloy. 4. The chemical composition of the head main members (T1, T2 and T3) is aluminum (Al): 3 to 5 wt.%, Vanadium (V): 2.1 to 3.7 wt.%. , Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (Fe): 0.85 to 3.15 wt.%, And oxygen (O): 0.06 to 0.2 wt.% And containing V, Fe and Mo in the following (2)
Formula: 7 wt.% ≦ 0.67 × V (wt.%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, The balance consists of titanium and unavoidable impurities,
A titanium alloy golf club head according to claim 1, 2, or 3. 5. A head main member (T1) in which a face portion and a fosel portion are integrally formed by hot working is formed by using a bar material, and a hot work is performed by using a plate material or a bar material. By processing, one or two other members including a crown portion and a sole portion formed independently of the main member (T1) are molded, and then the head main member (T1) and the A method for manufacturing a golf club head, wherein an assembled butted portion with another member is joined by welding, wherein at least the head main member (T1) is made of an α + β type titanium alloy, and the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) + 0.22 × Ta ( wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) +1. × Ni (wt.%) + 1.4 × Co (wt.%) + 0.77 × Cu (wt.%) -Al (wt.%) ---------------- ---- (1) Molybdenum equivalent: Mo _eq (wt.%) Value is characterized by being manufactured by using a bar material having a chemical composition in the range of 2 to 10. A method of manufacturing a titanium alloy golf club head. 6. A face portion is formed by hot working using a bar material,
A head main member (T2) in which a crown portion and a fusel portion are integrally formed is molded, and a plate member or a bar member is used to mold a solder member formed in the solder portion by hot working. Then, the head main member (T
2) A method for manufacturing a golf club head, in which an assembled butted portion of the sole member is joined by welding, wherein at least a material of the head main member (T2) is an α + β type titanium alloy, Formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) + 0.28 × Nb (wt.%) +0 .22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) + 1.4 × Co (wt.%) +0 .77 × Cu (wt.%) -Al (wt.%) --------- (1) Molybdenum equivalent: Mo _eq (wt .%) Value is in the range of 2 to 10 and is manufactured by using a bar material having a chemical composition. 7. A face member is formed by hot working using a bar material,
Seo - le unit and follower - diesel portion is molded head main member formed integrally (T3), and, was sheet or using the bar, forming a crown member formed by the crown portion by hot working Then, a method of manufacturing a golf club head, in which an assembled butted portion of the head main member (T3) and the crown member is joined by welding, wherein at least the material of the head main member (T3) is An α + β type titanium alloy having the following formula (1): Mo _eq (wt.%) = Mo (wt.%) + 0.67 × V (wt.%) + 0.44 × W (wt.%) +0. 28 × Nb (wt.%) + 0.22 × Ta (wt.%) + 2.9 × Fe (wt.%) + 1.6 × Cr (wt.%) + 1.1 × Ni (wt.%) +1. 4 x Co (wt.%) +0.77 x Cu (wt.%) -Al (wt.%) -------------------- (1) Of a titanium alloy golf club head, characterized by being manufactured by using a bar material having a chemical composition in which the value of molybdenum equivalent: Mo _eq (wt.%) Is in the range of 2 to 10. Production method. 8. The chemical composition of the main head members (T1, T2 and T3) is aluminum (Al): 3 to 5 wt.%, Vanadium (V): 2.1 to 3.7 wt.%. , Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (Fe): 0.85 to 3.15 wt.%, And oxygen (O): 0.06 to 0.2 wt.% And containing V, Fe and Mo in the following (2)
Formula: 7 wt.% ≦ 0.67 × V (wt.%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, The balance consists of titanium and unavoidable impurities,
A method for manufacturing a titanium alloy golf club head according to claim 5, 6, or 7. 9. The method for manufacturing a golf club head according to claim 5, 6 or 7, wherein the chemical composition is aluminum (Al): 3-5 wt.%, Vanadium (V): 2 1 to 3.7 wt.%, Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (Fe): 0.85 to 3.15 wt.%, And oxygen (O): 0 0.06 to 0.2 wt.% And the contents of V, Fe and Mo are the following (2).
Formula: 7 wt.% ≦ 0.67 × V (wt.%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, The balance consists of titanium and unavoidable impurities,
Moreover, in addition to the above, the head main members (T1, T
The heating temperature in the hot working of 2 or T3) is 120 ° C. lower than the β transformation point determined according to the chemical composition of the head main member (T1, T2 or T3), and is lower than the β transformation point. A method for manufacturing a golf club head made of a titanium alloy, characterized in that the temperature is within a range of 30 ° C. higher. 10. The method of manufacturing a golf club head according to claim 5, 6 or 7, wherein the chemical composition is aluminum (Al): 3-5 wt.%, Vanadium (V): 2 1 to 3.7 wt.%, Molybdenum (Mo): 0.85 to 3.15 wt.%, Iron (Fe): 0.85 to 3.15 wt.%, And oxygen (O): 0 0.06 to 0.2 wt.% And the contents of V, Fe and Mo are the following (2).
Formula: 7 wt.% ≦ 0.67 × V (wt.%) + 2.9 × Fe (wt.%) + Mo (wt.%) ≦ 13 wt.% ------ (2) is satisfied, The balance consists of titanium and unavoidable impurities,
Moreover, in addition to the above, the head main members (T1, T
The heating temperature in the hot working of 2 or T3) is 100 ° C. lower than the β transformation point which is determined according to the chemical composition of the head main member (T1, T2 or T3) and is lower than the β transformation point. A method for producing a titanium alloy golf club head, characterized in that the temperature is within a range of 20 ° C. lower.