JP3715363B2 - Golf club head and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a golf club head having sufficient strength and good hitting feel, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, various metal materials have been used for golf club heads. For the wood club head, martensitic stainless steel (for example, SUS630 stainless steel), titanium alloy (for example, 6Al-4V titanium alloy) or the like is used. For the iron club head, mild steel, martensitic stainless steel, austenite Stainless steel (for example, SUS304 stainless steel) or the like is used.
[0003]
[Problems to be solved by the invention]
Martensitic stainless steel has excellent mechanical strength and is used for both wood club heads and iron club heads. Titanium alloys are used in wood club heads that are light and have a relatively large head because of their high strength and specific gravity smaller than stainless steel. However, since all materials have high hardness, there is a problem that a golf club head using martensitic stainless steel or titanium alloy feels hard to hit. Furthermore, a titanium alloy golf club head has the disadvantage that it is extremely difficult to manufacture because the titanium alloy is a very active material.
[0004]
Mild steel, on the other hand, has a low hardness, so it can provide a soft feel, but its mechanical strength is low, so it is only used for iron club heads, and it is used for thin wood club heads. Is inappropriate. In addition, since a mild steel golf club head is a material in which mild steel is easily rusted, it has a disadvantage that it must be subjected to rust prevention treatment such as plating.
[0005]
Furthermore, austenitic stainless steel is soft, like soft steel, but lacks strength and is not suitable for thin wood club heads.
[0006]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a golf club head having a sufficient strength and good hitting feel, and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a manufacturing method of the golf club head of the present invention, after forming at least the face portion from the martensitic stainless steel or maraging steel, at least the face portion is formed by ammonia gas In a nitriding atmosphere, the temperature is set to 540 to 590 ° C. and held for 7 to 9 hours, followed by gas nitriding treatment, and then held at a temperature of 1000 to 1200 ° C. for 0.5 to 3 hours to perform heat treatment. A thin layer containing an austenitic metal structure having a hardness lower than that of the core portion side of the face portion is formed on the surface of the hitting portion of the face portion .
[0009]
In the present invention, the golf club head has a thin layer rich in an austenitic metal structure having a lower hardness than the core portion side of the golf club head at least on the surface of the hitting portion of the face portion. This thin layer is formed by forming at least the face part from martensitic stainless steel or maraging steel having excellent mechanical strength, nitriding at least the formed face part, and then heat-treating. It is.
[0010]
As martensitic stainless steel which is at least the material of the face portion, for example, there is SUS630 stainless steel which has been most commonly used for golf club heads, and maraging steel contains a lot of nickel (12 ~ 25% Ni) Martensitic metal alloy steel and the like. In golf club heads that are integrally formed without dividing the entire head, such a material is used for the entire head, but the face member or the member including the face portion and one or more other members are separately formed. In the golf club head in which these are joined and integrated, a material different from such a material can be used other than the face member or the member including the face portion.
[0011]
In the present invention, a thin layer rich in an austenitic metal structure having a lower hardness than the core side of the golf club head is formed at least on the surface of the hitting portion of the face portion. At least the core side has a martensitic metal structure, and at least the hitting portion surface side of the face part is softer than the core side. Since the face portion is configured in this way, the golf club head of the present invention does not decrease in strength and improves the hit feeling.
[0012]
In the present invention, a method of forming a thin layer rich in austenite metal structure at least on the surface of the hit ball portion of the face portion is to nitride at least the face portion formed from martensitic stainless steel or maraging steel, and then heat-treat. Is due to.
[0013]
First, at least the face portion is formed from martensitic stainless steel or maraging steel by precision casting, forging, or the like. Then, the molded product is nitrided in a nitriding atmosphere. The nitriding treatment includes gas nitriding treatment, ion nitriding treatment, salt bath nitriding treatment, etc., but at least the face portion needs to be nitrided by an appropriate method. It should be noted that nitriding treatment is performed on the portions that do not require nitriding treatment. In addition, heat treatment and welding treatment can be performed on the necessary portions before nitriding treatment. In this nitriding treatment, since nitrogen atoms generate nitrides, the outermost surface of the nitrided portion is cured, and the curing depth is about 0.1 mm from the surface.
[0014]
Next, the nitrided material is held at a temperature of 1000 to 1200 ° C. for 0.5 to 3 hours. By this heat treatment, nitrogen atoms that have formed nitrides penetrate and diffuse from the surface to a depth exceeding about 0.1 mm, and a layer rich in austenite metal structure is formed, so that a hardened layer after nitriding treatment remains. There is nothing. Since the formed layer rich in austenite metal structure is thin, even a thin wood club head does not have insufficient strength.
[0015]
Thereafter, the heat-treated material is polished to adjust its shape, but is polished so that a layer rich in austenite metal structure remains at least on the surface of the hit ball portion of the face portion. Thus, the golf club head of the present invention can be easily manufactured.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described. The iron club head 10 shown in FIGS. 1 and 2 is integrally molded by a precision casting method using martensitic stainless steel such as SUS630 stainless steel as a material. As shown in FIG. 2, the iron club head 10 is formed with a thin layer 14 rich in an austenitic metal structure having a hardness lower than that of the core 12 on the outer peripheral portion. As shown in FIG. 3, the thickness of the thin layer 14 is about 0.4 mm, and the Vickers hardness of the core portion 12 is about 350. The thin layer 14 may be formed only on the surface side of the hit ball portion 18 of the face portion 16. The iron club head 10 can also be formed using maraging steel as a material.
[0017]
Next, the manufacturing method of the iron club head 10 of this embodiment is demonstrated according to the flowchart shown in FIG. First, the iron club head 10 is integrally formed from SUS630 stainless steel or the like by precision casting (step S1). Next, the molded iron club head 10 is nitrided in a nitriding atmosphere (step S2). In this embodiment, the treatment was performed at a temperature of 570 ° C. for 8 hours by a gas nitriding treatment that mainly creates a nitriding atmosphere using ammonia gas. For example, in the case of gas nitriding, the processing temperature is about 540 to 590 ° C., and the processing time is about 7 to 9 hours. Next, the nitrided iron club head 10 is held at a temperature of 1000 to 1200 ° C. for 0.5 to 3 hours (step S3). In this embodiment, the treatment was performed at a temperature of 1150 ° C. for 1.5 hours. FIG. 3 shows the Vickers hardness of the iron club head 10 after heat treatment, which is softened to a depth of about 0.6 mm from the surface. Thereafter, the head is polished to adjust the shape (step S4). In this embodiment, the face portion 16 is polished by about 0.2 mm. Since SUS630 stainless steel having corrosion resistance is used as a material, rust prevention treatment was not performed.
[0018]
The flowchart shown in FIG. 5 shows the procedure of the manufacturing method of the wood club head. First, the hollow main body member and the sole member constituting the wood club head are separately molded by precision casting (step S10). Of the main body member and the sole member, at least the main body member is made of martensitic stainless steel or maraging steel. Next, the molded body member and sole member are heat-treated under the same conditions as in step S3 of the iron club head 10 (step S11), and then integrated by welding to form an unshaped wood club head ( Step S12). In this case, the heat treatment is performed before welding in order to make the metal structure of each member immediately after forming fine by heat treatment to improve resistance and prevent cracking. Then, by nitriding the unshaped wood club head under the same conditions as in step S2 of the iron club head 10, a thin layer rich in an austenite metal structure is formed at least on the surface of the hit ball portion of the face portion. Form (step S13). Thereafter, after further heat treatment under the same conditions as in step S11 (step S14), the shape of the wood club head is adjusted by polishing (step S15).
[0019]
【The invention's effect】
According to the present invention, the golf club head has a martensitic metal structure with excellent mechanical strength on the core side of the face part, and a thin layer rich in a soft austenitic metal structure on the surface of the hit ball part of the face part. The advantage of having sufficient strength and soft feeling upon impact is obtained.
[Brief description of the drawings]
FIG. 1 is a front view of a golf club head according to an embodiment.
2 is a cross-sectional view of the golf club head taken along the line II-II shown in FIG.
FIG. 3 is an explanatory diagram of the relationship between the depth from the surface of the face portion of the golf club head according to the present embodiment and the hardness.
FIG. 4 is a flowchart of a method of manufacturing an iron club head according to the present embodiment.
FIG. 5 is a flowchart of a method for manufacturing a wood club head according to the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Iron club head 12 ... Core part 14 ... Thin layer 16 ... Face part 18 ... Hitting ball part

Claims (1)

After forming at least the face portion from martensitic stainless steel or maraging steel, gas nitriding is performed by holding at least the formed face portion in a nitriding atmosphere with ammonia gas at a temperature of 540 to 590 ° C. for 7 to 9 hours. Processed, and then heat-treated at a temperature of 1000 to 1200 ° C. for 0.5 to 3 hours, so that at least the ball hitting surface side of the face part has a lower hardness than the core part side of the face part. A method of manufacturing a golf club head, comprising forming a thin layer containing an austenitic metal structure .

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