JP2865127B2 - Golf club head manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a golf club head in which at least a striking surface portion and a sole portion are formed from a magnesium-based alloy.

[0002]

2. Description of the Related Art In a wood-based golf club head formed of a magnesium-based alloy, the head volume can be increased without increasing the head weight. The crown, the ball striking surface, and the side wall are integrally cast with a magnesium-based alloy by a method such as a lost wax method, and this is used as a head base material.
Is applied to improve the tensile strength and hardness. Next, the sole portion is formed of the same or different material, and is integrated with the head base material by means such as welding. Further, the magnesium-based alloy is painted after being subjected to a corrosion protection treatment.

[0003]

The golf club head always collides with a ball or tee or soil or sand on the ground,
Because they rub each other, they are easily damaged. There is a problem in the corrosion resistance in the corrosion prevention treatment for general metal materials.

Accordingly, an object of the present invention is to provide a method of manufacturing a golf club head having excellent corrosion resistance.

[0005]

In order to achieve the above object, the present invention provides a method for manufacturing a golf club head in which at least a ball striking surface portion and a sole portion of a golf club head are formed from a magnesium-based alloy. The surface is cleaned by blasting or the like, and then this magnesium-based alloy is treated with 0.2 to 0.4 mol / mol of dichromate.
1, nitric acid (60%) 7-15 ml / l, primary phosphate 0.
A protective film is formed on the surface by dipping in a treatment solution having a composition of 5 to 0.7 mol / l and selenous acid of 10 to 20 g / l. As a dichromate, sodium dichromate is used. As the first phosphate, sodium first phosphate can be suitably used.

[0006]

[Function] When the protective film is damaged and the magnesium-based alloy is exposed, a local battery is formed between magnesium and selenium, and the selenium oxide precipitates to form a protective film again on the alloy surface. Was.

[0007]

FIG. 1 shows a wood type golf club head in which a hollow head body 1 is formed from a metal material. A hosel portion 2 for connecting a shaft connected to the head body 1 is herein a head body. Not included in 1. In some golf club heads, the hosel portion 2 does not exist, and a shaft is directly inserted into the head main body 1 and attached. The head body 1 has a striking surface portion 11, a sole portion 12, a crown portion 13, and a peripheral wall portion 14. In this embodiment, portions other than the crown portion 13 are manufactured by casting or forging, and the crown portion 13 is attached by means of post-processing such as welding. In this embodiment, the entire head body 1 is formed of a magnesium-based alloy. The thickness of the magnesium-based alloy forming the ball striking surface portion 11 was 5 to 7 mm or more, the thickness of the sole portion 12 was 1.5 mm or more, and the crown portion 13 was formed to be the thinnest. In this embodiment, the hosel portion 2 is formed of a magnesium-based alloy, similarly to the head body 1.

[0008] The head body 1 and the hosel portion 2 excluding the crown portion 13 are cast by, for example, a lost wax method, and the crown portion 13 is manufactured separately. Heat treatment is performed after manufacturing each part constituting the head. By performing the heat treatment represented by JIS standard symbols T5 and T6, tensile strength and hardness are increased. Here, “T5” is for stabilizing by removing artificial aging and casting strain, and “T6” is for artificial aging after solution treatment. The solution treatment temperature differs depending on the type of alloy. Minimum 380 ℃, Maximum 5
00 ° C. The artificial aging temperature also varies depending on the type of alloy, but is 170 ° C. at the minimum and 260 ° C. at the maximum.

In a golf club head called a driver in a wood system, when the thickness of the magnesium-based alloy of the ball striking surface portion 11 is 6 mm, the heat treatment is "T5" for a golf club having a club length of 42.5 inches or more. When a person with a head speed of 45 m / s was used for a long period of time, a concave portion was formed in the striking surface portion 11. In the case of "T6", no recess was formed even when a person with a head speed of 50 m / s was used for a long time. As a magnesium-based alloy, "AZ9
2 "alloy," T5 "
In the case of “6”, the tensile strength (Kg / mm ² ) is “275” for “180”, and the Purinel hardness is “8” for “80”.
4 ”, and the 0.2% proof stress was“ 14 ”compared to“ 117 ”.
5 ".

In the above-described embodiment, after the crown portion 13 is welded, the golf club head is blasted to clean the surface, and then the dichromate is 0.2 to 0.4.
Mol / l, nitric acid (60%) 7-15 ml / l, primary phosphate 0.5-0.7 mol / l, selenous acid 10-20 g / l
1 to form a protective film on the surface. A more preferred composition of the treatment liquid is as follows. Sodium dichromate 65-80 g / l Nitric acid (60%) 7-15 ml / l Sodium monophosphate 65-80 g / l Selenous acid 10-20 g / l After immersion, wash with water, dry and protect the surface of the alloy A film was formed. As a more preferred treatment condition, it is immersed in a treatment solution heated to 80 to 90 ° C. for 2 to 8 minutes.

As a comparative example, "AZ92" alloy was immersed in 248 ml / l of hydrofluoric acid (46%) at a liquid temperature of 20 to 30 ° C. for 30 seconds to 5 minutes after pretreatment such as blasting, and washed with water. Sodium acid fluoride (or potassium acid fluoride or ammonium acid fluoride) at a liquid temperature of 20-30 ° C
Dipped in 50 g / l for 5 minutes, washed with water, and immersed in a boiling solution of 120-130 g / l sodium bichromate and 50 g / l calcium fluoride (or magnesium fluoride) for 30 minutes in a boiling state. It was washed with water, and finally immersed in warm water and then dried to be subjected to anticorrosion treatment. The corrosion resistance of the golf club head provided with the protective film of the above-described example and the golf club head of the comparative example were compared. As a result of reproducing and observing the scratches created by the actual contact of the golf club head with the ground, the comparative example remains exposed when the magnesium-based alloy is exposed, but in the example, when the magnesium-based alloy is exposed, the magnesium and selenium are exposed. A local battery was formed in between, and selenium oxide was deposited, whereby a protective film was formed again on the surface of the magnesium-based alloy.

Further, only the sole portion 12 was cut out from the comparative example and the above-mentioned example to obtain a test piece, which was obtained according to JIS Z 2371.
The corrosion resistance was determined by the salt spray test method described above. The test duration was 120 hours. In the comparative example, white corrosion products were scattered, but hardly observed in the examples.
Further, the weight after the test was reduced in the comparative example, and no change was observed in the examples. The weight loss is due to material loss due to corrosion.

In the case of coating after applying a protective film as a corrosion-resistant treatment on the surface, the electrodeposition coating has a durable coating film and is hardly damaged. It goes without saying that painting may be performed by other painting methods used for golf club heads. Further, as the paint, an epoxy-based or urethane-based paint is suitable.

In the above-described embodiment, the crown portion 13 is retrofitted, but the sole portion 12 may be retrofitted. That is, the portion excluding the sole portion 12 is integrally formed, and the sole portion 1 is formed.
2 can be attached by welding or the like. In the embodiment, the entire head body 1 is formed of a magnesium-based alloy. However, at least the striking surface portion 11 and the sole portion 12 may be formed of a magnesium-based alloy, and the other portions may be formed of a different metal material. In particular, the crown portion 13 may be made of a plastic material, or may be a golf club head having no crown portion 13.

The head body 1 made of a magnesium-based alloy has an axis perpendicular to the center of gravity G of the head body 1 as Y.
Axis, and an axis orthogonal to the Y axis is a Z axis.
When the axis parallel to 1 and extending in the direction of the paper of the drawing is the X axis, the moment of inertia around the X axis is 17 g · mm · S ² or more, and the moment of inertia around the Y axis is 28 g · mm · S.
It is preferably at least ² . The reason for setting the moment of inertia in this way is to make the flight direction stable and reduce the flight distance when the ball is hit with the center removed. If the moment of inertia around the X axis is less than the above value or the moment of inertia around the Y axis is less than the above value, the direction of flight becomes unstable when the ball is hit off the center, and the flight distance does not appear. . By reducing the thickness of the crown portion 13 and reducing the weight, the center of gravity of the head main body 1 can be reduced. Further, the sole portion 12 and the sole portion 12
It is also desirable that the thickness of the side wall portion 14 following the crown portion 13 be the same as that of the crown portion 13, preferably 1.2 to 2.5 mm, or set to be thicker than the crown portion 13. In the embodiment shown in FIG. 1, since the hosel portion 2 and the head main body 1 are formed of a magnesium-based alloy by a lost wax method or the like, the specific gravity is small and the head volume is 2
It can be formed in a size of 00 to 350 cc, and the sweet area can be expanded. Even when the head volume is 200 to 350 cc, the head weight is in the range of 130 to 210 g.

In the head body 1 shown in FIG. 2, a rib 3 is formed inside the hollow head body 1 and a weight 4 is provided. The rib 3 is connected to the sole 1 from the back side of the striking surface 11.
A plurality is formed over two. The presence of the ribs 3 increases the strength of the striking surface portion 11. A hole 5 is formed in the upper surface of the head main body 1, and this hole 5
3 and integrated by means such as welding. FIG. 3 is a view as seen from above before the crown portion 13 is fitted. A plurality of claws 6 for mounting the crown portion 13 are formed at the holes 5. The weight 4 is provided for adjusting the moment of inertia around the X axis and the position of the center of gravity of the head. The weight 4 may be formed of a magnesium-based alloy material or the same material. Here, a magnesium-based alloy refers to an alloy in which the amount of magnesium exceeds 50%. Besides magnesium, Al, Zn, Mn, Zr, Si, Cu,
Other metal components such as Ni may be included. Magnesium-based alloys that can be suitably used include JIS symbol M
C2 and MC3 can be suitably used.

Since the magnesium-based alloy has a lower specific gravity than many other metals, if it is used to form the whole or most of the head, it is possible to increase the head volume without causing excess weight. Further, since the head itself made of a magnesium-based alloy is relatively light, the weight member can be arranged at a desired position inside the head, for example, as in the embodiment shown in FIG. Therefore, it is possible to easily set the position of the center of gravity of the head (the height of the center of gravity, the depth of the center of gravity, etc.) (the degree of freedom in head design is increased).

[0018]

As described above, since the hitting surface portion and the sole portion, which are easily damaged, are made of at least a magnesium-based alloy and form the above-mentioned protective film after pre-treatment such as blasting, it is manufactured by this manufacturing method. The resulting golf club head has improved corrosion resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a head body.

FIG. 2 is a cross-sectional view of a head main body having a different internal structure.

FIG. 3 is a plan view of FIG. 2 excluding a crown portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head main body 11 Striking surface part 12 Sole part

Claims (2)

(57) [Claims] 1. A method of manufacturing a golf club head in which at least a ball striking surface portion and a sole portion of a golf club head are formed from a magnesium-based alloy, wherein the surface of the magnesium-based alloy is cleaned by blasting or the like, and then the magnesium-based alloy is heavy-chromium Acid salt 0.2 ~
0.4 mol / l, nitric acid (60%) 7-15 ml / l, first
Phosphate 0.5-0.7 mol / l, selenous acid 10-2
A method for manufacturing a golf club head, wherein a protective film is formed on a surface by immersion in a processing solution having a composition of 0 g / l. 2. The method of manufacturing a golf club head according to claim 1, wherein a portion of the wood-based golf club head other than a crown portion is formed from a magnesium-based alloy.