JPH0751416A - Shaft for golf club and its production - Google Patents

Abstract

PURPOSE:To improve properties, such as pliability and stiffness, and to reduce the weight of a shaft by subjecting a pipe-shaped body consisting of a steel blank to a soln. heat treatment and forming this body, then subjecting the pipe body to a precipitation hardening heat treatment, then coating the surface of the body with a hard ceramic by sputtering. CONSTITUTION:This shaft for golf club is formed by providing the surface of the pipe-shaped body made of the precipitation hardening type stainless steel with a hard ceramic layer of a titanium carbide, titanium nitride, or etc., formed by the sputter coating. The shaft is produced by a stage for forming the stainless steel blank into the pipe-shaped body, a stage for subjecting the pipe-shaped body to the soln. heat treatment, a stage for subjecting the body to forming, such as drawing and stepping, a stage for subjecting the stepped pipe-shaped body subjected to the forming to the precipitation hardening heat treatment and a stage for coating the pipe-shaped body with the hard ceramic such as the titanium carbide, titanium nitride, etc., by sputtering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf shaft having a unique color tone and a long flight distance, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Golf clubs have been variously improved in terms of shape, structure, material, etc. in order to stabilize the flight distance and directionality of the ball. For example, regarding the material of the club head, metal, carbon fiber composite material, etc. are used in addition to the conventional persimmon. Also, for the shaft, various materials such as steel, carbon, boron, and titanium have been developed. For the shaft, bending rigidity, torsional rigidity, weight, etc. are particularly important in order to increase the flight distance.
In addition, excellent material strength and toughness are also properties required of the shaft material. Steel, carbon,
Materials such as boron and titanium have advantages and disadvantages,
Elasticity, strength, toughness required for the characteristics of shaft materials,
It is inferior to either specific gravity or the like, or is extremely expensive.

Recently, shafts made of materials such as carbon, boron and titanium have been widely used. However, when materials having improved elasticity, strength, toughness, specific gravity and the like are provided, steel is used. The drawbacks of the shaft are improved and the steel shaft is reevaluated. From this point of view, one of the applicants of the present invention is to improve the elasticity, strength, toughness, etc. by performing quenching and tempering after forming a golf club shaft by welding pipe made of polished steel. Found and introduced in Japanese Examined Patent Publication No. 3-44126. This golf club shaft has a 0.03% proof stress of 130 kg.
It has an elasticity of f / mm ² or more and a tensile strength of 18
It has an excellent mechanical strength of 0 kgf / mm ² or more.

[0004]

When a material having high strength, toughness, etc. is used for a golf club shaft, the shaft is made thinner and the golf club becomes lighter. Therefore, from downswing to impact. Swing speed increases. As a result, the head speed at impact is increased, and the flight distance can be further increased. In this regard, in the conventional steel shaft, the required characteristics are improved by selecting the material and heat treatment. However, there is a limit to the improvement of characteristics that can be expected by selection of materials and heat treatment, and it is the current situation that the golfers' demand for a lightweight golf club with a long flight distance cannot be completely satisfied. The present invention has been devised in order to solve such a problem, and improves the properties such as bending and stiffness by sputter-coating a hard ceramic layer on a precipitation hardening stainless steel substrate. It is an object of the present invention to provide a shaft for a golf club which has a large whipping effect while achieving a lightweight shaft.

[0005]

In order to achieve the object, a golf club shaft of the present invention is formed by a precipitation hardening stainless steel pipe-shaped body and a surface of the pipe-shaped body by sputter coating. It is provided with a hard ceramic layer such as titanium carbide or titanium nitride. This golf club shaft is manufactured by forming a stainless steel material into a pipe-shaped body, solution-treating the pipe-shaped body, forming by drawing, stepping, etc., processed stepped pipe-shaped body Is subjected to a precipitation hardening heat treatment, and then a step of sputter coating a surface of the pipe-shaped body with a hard ceramic such as titanium carbide or titanium nitride.

Precipitation hardening type stainless steel used as a pipe-shaped main body is a martensitic steel represented by 17-4PH.
There is an austenite type represented by 17-7PH.
On the other hand, as the hard ceramics layer formed on the surface of the steel pipe-shaped body, TiN, TiAlN _x , TiAlC
_x N _y, TiC or the like is used. The effect of improving the elasticity, toughness, etc. of the steel pipe-shaped body by the hard ceramics layer becomes remarkable when the thickness of the hard ceramics layer is 3 μm or more. Further, even if the hard ceramics layer is formed with a thickness exceeding 20 μm, the property improvement commensurate with the increase in the thickness is not seen, and on the contrary, the sputtering requires a long time.

[0007]

Function: The mechanism by which the hard ceramic layer is formed to improve the elasticity, toughness, bending, and restoration speed of the steel shaft is unknown. However, it has been confirmed in Examples described later that these properties are improved, and a shaft having an excellent whipping effect can be obtained.
For example, in comparison with a shaft with a wall thickness of 0.5 mm, which is made by shaping a strip steel into a diameter of 19 mm, a shaft coated with TiN, TiAl or the like having a thickness of 2.4 μm has a wall thickness reduced by 10%. It shows the same level of elasticity, and the amount of bending increases accordingly. As a result, the flight distance is improved.

The ceramic coated shaft has a higher Young's modulus in the circumferential direction than in the axial direction. Therefore, the resistance against twisting is large, and the directionality of the hit ball is stable. Further, the ceramic coating layer exhibits various color tones depending on the type and composition. For example, in TiAlN _x ceramics, bronze becomes more bluish as the x value becomes smaller. Alternatively,
When a small amount of Au is included in the TiN system, the surface has a deep golden color. Therefore, a golf club with a good design can be obtained. In addition, the ceramic coating layer increases surface hardness to improve scratch resistance, and also has good impact resistance, abrasion resistance, stain resistance, etc., so that the initial characteristics can be maintained for a long period of time. It becomes an excellent club shaft.

[0009]

[Example] Production of steel pipe-shaped body C: 0.04% by weight, Si: 1.50% by weight, Mn:
0.29% by weight, P: 0.027% by weight, S: 0.00
1% by weight, Ni: 6.93% by weight, Cr: 13.93% by weight, Ti: 0.32% by weight, Mo: 0.81% by weight,
A steel having a composition of Cu: 0.69% by weight, the balance Fe and impurities was hot-rolled, pickled, and then repeatedly cold-rolled and annealed to manufacture a strip steel having a thickness of 0.5 mm. Diameter of steel strip is 16.7 mm
Was piped and subjected to solution treatment at 1050 ° C. Then, it was drawn and stepped, subjected to precipitation hardening heat treatment at 525 ° C., and surface-polished. The pipe after surface polishing was cut into a length of 1000 mm to prepare a pipe-shaped main body.

TiN coating by sputtering
Formation of Layer The degreased and washed pipe-shaped main body was placed as an anode in a vacuum container and faced a Ti-based target (cathode). 1 x
Flow rate 400 in a vacuum container maintained at a high vacuum of 10 ^-5 Torr.
Glow discharge was generated by applying a high voltage of −450 V between the anode and the cathode while supplying Ar gas at −600 cc / min to generate plasma. The atomic Ti knocked out from the target by Ar ionized in plasma collided with the pipe-shaped body and formed a uniform film on the surface. At this time, nitrogen gas was caused to flow near the surface at a flow rate of 100 cc / min, and a TiN film having a gold color tone was obtained by the reaction of Ti and N. Under these conditions, sputtering was continued for 10 minutes, then allowed to cool and the pipe-shaped body was taken out from the vacuum container.
A steel shaft with a uniform ceramic coating was obtained. The thickness of the ceramic coating layer was measured and found to be 0.8 μm. When sputtering was continued for 30 minutes under the same conditions, Ti
The N coating layer was as thick as 2.4 μm. Ti
Each of the N coating layers had a bright golden metallic luster.

TiAlN _x coating by sputtering
Formation of the wing layer After depressurizing the sealed vacuum container to a high vacuum of 1 × 10 ⁻⁵ Torr, Ar gas is introduced at a flow rate of 400 to 500 cc / min, and a bias voltage of −50 to 75 V is applied to the pipe-shaped body. Target (cathode) containing Ti and Al while applying
Was supplied with a current of 50 to 70A. As a result, glow discharge was generated inside the vacuum container and a plasma state was obtained. In this case, Ti and A knocked out from the target
The 1 atom reacted with N in the atmosphere to form a uniform TiAlN _x film on the surface of the pipe-shaped body. Under this condition,
After continuing the sputtering for 10 minutes, it was allowed to cool and the pipe-shaped body was taken out from the vacuum container.
m of TiAlN _x coating layer was formed on the surface of the pipe-shaped body. Further, when sputtering was continued for 30 minutes under the same conditions, the TiAlN _x coating layer was as thick as 2.4 μm. The TiAlN _x coating layers all had a vivid bluish bronze metallic luster.

Characteristic Test Table 1 shows the results of examining the mechanical and physical characteristics of a pipe-shaped body coated with a ceramic having a thickness of 2.4 μm. In Table 1, a solid pipe-shaped body is listed as a comparative example. The strength of the waist is determined by applying a load of 10.9 kg to a location 20 inches in length from the support point of the cantilever-supported pipe-shaped body, removing the load after holding for 1 minute, and reading the amount of deformation of the tip. , I.e., permanent set. The amount of bending is 2.7 at the tip of the pipe-shaped body.
It was represented by the amount of displacement of the tip portion with a weight of kg attached. The amount of twist is represented by the twist angle when the grip part is fixed and a predetermined torque is applied to the tip part.

[0013]

[Table 1]

As is clear from Table 1, TiN and Ti
The shaft coated with AlN _x has no substantial difference in tensile strength and toughness as compared with a shaft made of a solid pipe-shaped body, but has a waist strength and flexibility required for a golf club shaft. It turns out that the amount is excellent. This means that a golf shaft having a strong whipping effect can be obtained. In the above examples, the case where TiN and TiAlN _x are coated has been described. However, the present invention is not limited to this, and is similarly applied to sputter coating other hard ceramic layers. For example,
Even when TiAlC _x N _y , TiC, etc. were sputter coated, a shaft having a large whipping effect was obtained.

[0015]

As described above, according to the present invention, TiN, TiAlN _x , and TiAlC are added to the pipe-shaped body.
_x N _y, by sputter coating a hard ceramic TiC, etc., of the hips required for golf club shaft strength, have improved properties such as bending. Therefore, a golf club having a great whipping effect and an excellent flight distance and directionality can be obtained, which is useful for golfers. Further, the hard ceramics layer has various color tones depending on the type and composition, so that the golf club has high designability and distinctiveness.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shozo Tokui 2-3-1, Tsujiya Amagasaki City, Hyogo Prefecture Nisshin Steel Co., Ltd.Osaka Works (72) Inventor Yasuhiko Matsuno 2 Tsujiya Amagasaki City, Hyogo Prefecture 3-1 No. 3 Nisshin Steel Co., Ltd. Osaka Works (72) Inventor Politics Harada 2-3-1, Tsujiya, Amagasaki City, Hyogo Prefecture Nisshin Steel Co., Ltd. Osaka Works

Claims (2)

[Claims] 1. A pipe-shaped main body made of a steel material is subjected to solution treatment, forming, and then precipitation hardening heat treatment, and then hard ceramics such as titanium carbide and titanium nitride are applied to the surface of the pipe-shaped main body. A method for manufacturing a golf club shaft, which comprises sputter coating. 2. A pipe-shaped main body made of precipitation hardening stainless steel, and a hard ceramics layer such as titanium carbide or titanium nitride formed by sputtering coating on the surface of the pipe-shaped main body. Shafts for golf clubs.