JP2008018115A - Golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club head having an excellent corrosion resistance and high strength even if a surface treatment is not applied. <P>SOLUTION: The golf club head is made using a high strength and high corrosion resistance nitrogen-containing austenitic stainless steel at least at a part of the golf club head, wherein the stainless steel has a composition consisting of 0.10 wt.% or less of C, 1.0 wt.% or less of Si, 5-10 wt.% of Mn, 0.01 wt.% or less of S, 8-15 wt.% of Ni, 15-25 wt.% of Cr, 0.5-4 wt.% of Mo, 0.3-1.0 wt.% of N, and the balance of substantially Fe. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a golf club head, and more particularly to a golf club head using a high-strength, high-corrosion-resistant nitrogen-containing austenitic stainless steel that does not require surface treatment.

Various materials such as wood, metal, carbon, and titanium are used for golf club heads such as wood, iron, and putter. For example, with regard to irons, low carbon steel, so-called soft iron, is preferred in recent years because of its good shot feeling, but soft iron has low strength and corrosion resistance. Therefore, when a golf club head is manufactured using soft iron, surface treatment such as plating is applied to increase strength and corrosion resistance.
However, the surface treatment needs to be performed after the waste material is disposed. Therefore, it has been pointed out that the regulations are becoming stricter due to the impact on the environment due to the disposal of waste materials, making it difficult to carry out surface treatment.

Therefore, Patent Document 1 and Patent Document 2 disclose materials for golf clubs and golf club heads having high strength and high corrosion resistance in a direction that does not require surface treatment. For example, Patent Document 1 discloses a martensitic stainless steel for a golf club head containing 0.1 to 0.3% by weight of N. And according to patent document 1, when N is added more than a solid solution limit, the problem that a bubble generate | occur | produces at the time of casting and a casting defect arises is pointed out. Patent Document 2 discloses a golf club made of stainless steel containing 0.1 to 0.3% by weight of N. And according to Patent Document 2, even if the nitrogen content exceeds 0.3% by weight, the strength does not increase so much. It has been pointed out that it gets worse.
JP 2001-89832 A JP 2002-143351 A

  However, in the case of the golf clubs disclosed in Patent Documents 1 and 2, since the upper limit of the N content was 0.3%, the strength was improved, and the stability and corrosion resistance of the austenite phase was improved. There was a problem in terms of strength improvement. Therefore, in the case of the golf clubs disclosed in Patent Documents 1 and 2, since the N content is small, it is insufficient in terms of suppressing rusting. For golf club heads used outdoors and exposed to rain and wind, it is particularly important to suppress rusting. To suppress rusting, it is effective to increase the N content. If rusting can be suppressed, there is no need for surface treatment.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a golf club head having excellent corrosion resistance and high strength without performing surface treatment.

In order to solve the above-described problems, a golf club head according to the present invention has at least a portion of the golf club head in weight percent: C: 0.10% or less, Si: 1.0% or less, Mn: 5 -10%, S: 0.01% or less, Ni: 8-15%, Cr: 15-25%, Mo: 0.5-4%, N: 0.3-1.0%, the balance being substantially The main point is that a high-strength and high corrosion-resistant nitrogen-containing austenitic stainless steel having a composition composed of Fe is used.
In this case, further, any one or more of Cu, Nb, B, V, and W, in terms of weight percent, Cu: 3% or less, B: 0.01% or less, Nb: 1.0% In the following, it is desirable that V: 1.0% or less and W: 1.0% or less.

  At least a part of the golf club according to the present invention is, by weight percent, C: 0.10% or less, Si: 1.0% or less, Mn: 5-10%, S: 0.01% or less, Ni : 8 to 15%, Cr: 15 to 25%, Mo: 0.5 to 4%, N: 0.3 to 1.0%, high strength and high corrosion resistance including the balance substantially consisting of Fe Since nitrogen austenitic stainless steel is used, there is an effect that excellent corrosion resistance and high strength can be obtained without performing surface treatment.

Hereinafter, an embodiment of the present invention will be described. In the following description, “%” means% by weight unless otherwise specified.
First, at least a part of a golf club head (for wood, iron, wedge, putter) according to an embodiment of the present invention, such as a face surface, an upper surface of a face surface, a toe side surface, a heel side surface, a sole surface, The reason for limiting the component range of the high-strength, high-corrosion-resistant nitrogen-containing austenitic stainless steel as the back face surface material will be described.

C: 0.10% or less C is an interstitial element and contributes to the improvement of strength. However, the addition of a large amount reduces the solid solution amount of N and combines with Cr to form a carbide, thereby reducing the solid solution Cr amount of the parent phase and deteriorating the corrosion resistance. There is a need to.

Si: 1.0% or less Si is an element mainly acting as a deoxidizer during melting and refining. However, if it is contained in a large amount, the manufacturability deteriorates, so the upper limit was made 1.0%.

Mn: 5 to 10%
Mn is an austenite-forming element and significantly increases the amount of nitrogen dissolved. In order to obtain an austenite single phase with a phase balance, addition of 5% or more is necessary. Moreover, since hot workability will deteriorate when it exceeds 10%, the range was made into 5 to 10%.

S: 0.01% or less
Since S becomes MnS and becomes a starting point of cracking during cold working, cold workability is remarkably deteriorated. Therefore, the upper limit was made 0.01%.

Ni: 8-15%
Ni is an austenite generating element and contributes to austenite phase stability. Moreover, although a deformation resistance is reduced and cold workability is improved, since a large amount of addition causes a decrease in strength, the range is made 8 to 15%.

Cr: 15-25%
Cr is effective as an element for increasing the solid solution amount of nitrogen in stainless steel and improving corrosion resistance, and is a ferrite-forming element. If it is 15% or less, the corrosion resistance is not sufficient, but the nitrogen solid solution amount and the corrosion resistance increase with the increase. However, since it becomes a ferrite-austenite two-phase structure when it becomes 25% or more, the range was made 15% to 25%.

Mo: 0.5-4%
Mo is effective as an element for increasing the solid solution amount of nitrogen in stainless steel and improving corrosion resistance, and is a ferrite-forming element. If it is 0.5% or less, the effect of improving the characteristics is thin and increases with the increase. However, if it becomes 4% or more, the hot workability deteriorates and the cost increases, so the range was made 0.5% to 4%.

N: 0.3-1.0%
N is an interstitial element that contributes to strength improvement, stability of the austenite phase and corrosion resistance, and strength improvement by aging treatment after processing. The effect is low at 0.3% or less, and when it is 1% or more, the nitride does not completely dissolve, and the ST (solution treatment) temperature increases and cold workability and toughness deteriorate. The range was from 0.3% to 1.0%. In addition, if the N content is 0.3 to 1.0%, N can be dissolved in a solid solution without applying pressure up to 0.6%. Thus, N can be dissolved.
If the N content is 0.4% or more, a steel having higher strength and good corrosion resistance can be obtained. When the N content is 0.4% or more, cold workability or tough ductility is lowered due to incomplete solid solution of N or the like.

Cu: 0.3% or less Cu has an effect of improving the solubility of N and suppressing N ₂ blow (a phenomenon in which N becomes a gas during solidification in the casting process and escapes from the steel). However, if the content exceeds 3%, the strength decreases, so the upper limit was made 3%.

B: 0.01 or less Since B contributes to the improvement of hot workability, it may be added if necessary. However, if added in an amount of 0.01% or more, it combines with nitrogen, and conversely reduces hot workability, so it is necessary to make it 0.01% or less.

Nb: 1.0% or less, V: 1.0% or less, W: 1.0% or less Nb, V, and W contribute to refinement of crystal grains and improvement in strength. More than seeds may be added. However, when added in a large amount, it combines with nitrogen to reduce the amount of dissolved N, so the upper limit was made 1.0% or less.

(Production of test materials and their property evaluation tests)
The chemical components shown in Table 1 were melted in a 50 kg high frequency induction furnace, then cast into a 50 kg steel ingot, then turned into a 20 mm round bar by forging, heated at 1100 ° C x 1 hr, and then subjected to water cooling solution heat treatment. did. Thus, test materials of high strength and high corrosion resistance nitrogen-containing austenitic stainless steels (invention steels 1 to 9), which are at least part of the material of the golf club head according to one embodiment of the present invention, were obtained. Thereafter, a test piece was cut out from each round bar and subjected to a tensile test and a CPT test. The comparative steels are JIS SUS304N, SUSXM7, SUS316L, and SUS836L.

  Here, the room temperature tensile test used a JIS No. 4 test piece and measured 0.2% proof stress and tensile strength. The CPT test was conducted according to JIS G 0578. The results are shown in Table 2. Moreover, according to the structure confirmation (x100) with a microscope, it was also found that almost no undissolved nitride was confirmed in the solution heat treatment state.

  As shown in Table 2, the inventive steels 1 to 9 are excellent in 0.2% proof stress and tensile strength at room temperature, and pitting corrosion resistance is much better than SUS316L even when compared with SUS304N and SUS836L. It has characteristics close to seawater resistant stainless steel.

  According to this embodiment, nitrogen can be completely dissolved by a solution heat treatment at 1100 ° C. or lower. Accordingly, an austenitic stainless steel for a golf club head having improved strength and corrosion resistance while suppressing an increase in cost and a decrease in workability is provided.

(Production of golf club head and cannon test)
Next, a golf club is produced by the lost wax method using high strength and high corrosion resistance nitrogen-containing austenitic stainless steel (invention steels 1 to 9) which is at least a part of the material of the golf club head according to one embodiment of the present invention. A head was fabricated and a Canon test was performed, which will be described. FIG. 1 schematically shows an outline of the Canon test. In the cannon test, an in-house measuring instrument (cannon gun) was used. The target was the face surface of a golf club head (# 5 iron) (produced using invention steels 1 to 9). A golf ball was launched from a cannon to a target 1 m away at an initial speed of 50 m / s and collided with 3000 shots. Thereafter, the face surface was visually checked for cracks and cracks (color check).

  As a result, no cracks or cracks occurred on the face surfaces produced using the inventive steels 1 to 9. From this, it was found that when a golf club head was produced using the inventive steels 1 to 9, a golf club head having excellent strength and durability was obtained.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In the above embodiment, an example in which high strength and high corrosion resistance nitrogen-containing austenitic stainless steel is applied to at least a part of the golf club head has been shown, but this may be applied to at least a part of the shaft of the golf club. .

  Since the golf club head according to the present invention does not require surface treatment, it can be used by manufacturers of golf-related products. In addition, since it has high strength and corrosion resistance, it can be applied to self-tapping, drill screws, bolts, stern shafts, etc. used outdoors, industrial, coastal areas and the like.

It is the figure which showed the outline | summary of the cannon test.

Claims (2)

At least part of the golf club head
% By weight
C: 0.10% or less,
Si: 1.0% or less,
Mn: 5 to 10%,
S: 0.01% or less,
Ni: 8-15%,
Cr: 15-25%,
Mo: 0.5-4%,
N: 0.3-1.0%
A golf club head characterized by using a high-strength, high-corrosion-resistant nitrogen-containing austenitic stainless steel having a composition substantially consisting of Fe. Furthermore, any one or two or more of Cu, Nb, B, V, and W
% By weight
Cu: 3% or less,
B: 0.01% or less,
Nb: 1.0% or less,
V: 1.0% or less,
2. The golf club head according to claim 1, wherein high strength and high corrosion resistance nitrogen-containing austenitic stainless steel contained in an amount of W: 1.0% or less is used.

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