JP2022045056A - Iron club head and manufacturing method thereof - Google Patents

Abstract

To prevent change in durability and mechanical characteristics by employing in a face part a material that hardly softens even under thermal effect of welding.SOLUTION: An iron club head has a club head body 12, and a face part 11 fixed thereto by laser welding and comprising a different material. The face part 11 is of a tabular alloy tool steel material made by hot rolling, and is fixed to the body by welding. The alloy tool steel material comprises 0.35-0.42 wt.% of C, 0.80-1.20 wt.% of Si, 0.25-0.50 wt.% of Mn, 4.50-5.50 wt.% of Cr, 1.00-1.50 wt.% of Mo, 0.80-1.15 wt.% of V, and the balance of Fe with inevitable impurities.SELECTED DRAWING: Figure 3

Description

The present invention relates to an iron club head and a method for manufacturing the same. More specifically, the present invention relates to an iron club head and a method for manufacturing the iron club head, which uses a material having excellent thermal resistance, which is less affected by welding heat, as a material of a face portion assembled by welding to the iron club head.

As for the performance required for golf clubs, woods represented by drivers generally pursue the flight distance, while irons often pursue the accuracy of the flight distance. However, in recent years, irons have also appeared in the pursuit of distance, and are preferred by players. When pursuing a flight distance with an iron, from the technical aspect of the tool, there is a method of increasing the coefficient of restitution (COR) as in the case of wood. As a means for increasing the coefficient of restitution, it is easy to bend the face portion due to the impact with the ball. As elements for that purpose, methods such as reducing the plate thickness of the face portion, lowering the Young's modulus of the face portion, and increasing the face portion are known. Of these, Young's modulus is unique to the material, and considering that iron is the mainstream for the iron face, it is difficult to significantly change the Young's modulus determined by the material, so it is not possible to reduce Young's modulus. .. On the other hand, enlarging the face portion is meaningless as it only raises the center of gravity for an iron that directly hits a ball on the ground.

From the above situation, the easiest way to increase the coefficient of restitution of the iron is to reduce the thickness of the face portion. However, if the plate thickness of the face portion is reduced, there is a problem that the durability is lowered. Therefore, in many cases, irons generally use a high-strength material different from the head body for the face portion. The present applicant prepares a plate member blanked in a face shape from a rolled steel plate made of a high-strength material different from that of the head body by performing heat treatment such as quenching / tempering and tempering to prepare the head body. We have proposed a golf club for laser welding and a method for manufacturing the same (Patent Document 1). Further, in order to make the face portion thinner, the applicant has added molybdenum (Mo) and vanadium (V) to the base material of nickel-chromium-molybdenum alloy steel (SAE8655) as the material of the face portion. We proposed the special steel (Patent Document 2). Special steel does not lose its toughness even when tempered at a low temperature in order to maintain its toughness, and mechanical elasticity, repulsive force, and strength can be obtained.

JP-A-2006-223686 Japanese Unexamined Patent Publication No. 2005-7049

However, the face part, which is a different material from the head body, is fixed (assembled) by laser welding, but the bond part "the boundary between the molten part (welded metal) and the base metal" and its vicinity are laser welded. Due to the heat of melting of the welded portion due to the above, there is a problem that a part of the face portion whose hardness and the like are optimally tempered before welding is tempered and softened. This softening of the bond portion and its vicinity lowers the springiness of the face portion, halves the effect of thinning the face portion, and also reduces the mechanical strength, leading to impact fatigue fracture.
An object of the present invention is to provide an iron head and a method for manufacturing the same, in which durability and mechanical properties do not change by using a material that is hard to soften even under the influence of welding heat for the face portion.
Another object of the present invention is to provide an iron head and a method for manufacturing the same, which employs an alloy tool steel material widely used in other product fields as the material of the face portion.

The iron club head of the present invention 1 is
In an iron club head having a main body of an iron club head and a face portion having a material different from that of the main body,
The face portion is a plate-shaped alloy tool steel material made by rolling, which is fixed to the main body by welding, and the tempered hardness before welding is 470 Hv or more on average. It is characterized by that.
The iron club head of the present invention 2 is the iron club head of the present invention 1, wherein the welding is laser welding using a laser beam as a heat source.

The iron club head of the present invention 3 is the iron club head of the present invention 1 or 2, and the alloy tool steel material is C: 0.35 to 0.42% by weight and Si: 0.80 to 1.20% by weight. , Mn: 0.25 to 0.50% by weight, Cr: 4.50 to 5.50% by weight, Mo: 1.00 to 1.50% by weight, V: 0.80 to 1.15% by weight, inevitable Target impurities and Fe: The balance.

The method for manufacturing an iron club head according to the present invention 4 is the method for manufacturing an iron club head according to the present invention 2, wherein a through hole is formed in the main body and the joint surface of the face member tempered in the main body is used. The face member is welded to a certain mounting surface from the outer peripheral side of the mounting surface by the laser welding.

In the iron club head of the present invention and the manufacturing method thereof, alloy tool steel is used as the material of the face portion to improve the temper softening resistance due to welding heat, so that the face surface is uniform even after welding. It is possible to maintain the hardness of. Further, since this alloy tool steel is resistant to thermal shock and thermal fatigue due to welding heat, it can withstand fatigue failure due to the impact of a ball.

FIG. 1 is a front view showing an iron club head according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the iron club head shown in FIG. FIG. 3 is a cross-sectional view of the iron club head according to the embodiment of the present invention when the iron club head is cut at the center of the score line. FIG. 4 is an enlarged cross-sectional view of a welded portion of the iron club head according to the embodiment of the present invention. FIG. 5 is a cross-sectional view of a welded portion on the sole side of the iron club head according to the embodiment of the present invention, and is a Vickers hardness measured in the vicinity of the welded portion. FIG. 6 is a cross-sectional view obtained by cutting the vicinity of the welded portion on the sole side of the conventional iron club head, and is the Vickers hardness measured in the vicinity of the welded portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show structural examples of an iron club head according to an embodiment to which the present invention is applied. The iron club head 1 is substantially composed of a head body 12 and a shaft 2. The club head 1 has a face surface 3 formed on the front surface for hitting a golf ball (not shown), an upper surface 4 called a top on the upper portion of the face 3, a sole 5 on the lower portion, a toe 6 on one side, and the like. A heel 7 is formed on the side. A hosel 8 for attaching the shaft 2 is provided above the heel 7. The lower end of the shaft 2 is connected and fixed to the hosel 8. A back recess 9 called a cavity is formed in the center of the back of the head body 12 of the iron club head 1. The lower portion of the back recess 9 is formed with a bottom recess 10 that looks like it has been scraped (see FIG. 3).

Next, a method of manufacturing the club head 1 will be described. As shown in FIG. 2, the club head 1 of this example integrates two members, a face member 11 of a plate material having a face 3 and a head main body 12 arranged on the back surface side of the face member 11. .. The face member 11 and the head body 12 are made of different materials. The material of the head body 12 is carbon steel for machine structure (S20C or the like) in this example. The material of the face member 11 is a plate-shaped alloy tool steel material (Japanese Industrial Standards (JIS) SKD61, etc.) manufactured by rolling. The head body 12 has a sole 5 formed in the lower portion, an upper surface 4 formed in the upper portion, a toe 6 formed on one side, and a hosel 8 formed on the other side. Further, in order to attach the face member 11 to the front surface of the head body 12 except on the heel 7 side, a step portion 13 forming a depth equivalent to the thickness of the face member 11 is formed, and the step portion 13 is formed. The mounting surface 14 of the face member 11 is formed including the above. Further, the head body 12 is formed with a bottom recess 10 in addition to the back recess 9 (see FIG. 3).

The one side edge 15, the upper edge 17, and the lower edge 18 of the face member 11 are formed to have the same size as the leading edge 6A on the toe 7 side of the head body 12, the leading edge 4A of the upper surface 4, and the leading edge 5A of the sole 5. Further, the other side edge 16 is formed to have the same size as the step portion 13. Then, the back surface of the face member 11 is brought into contact with the mounting surface 14, and the face member 11 is attached to each of the leading edge 6A on the toe 6 side of the head body 12, the leading edge 4A of the upper surface 4, and the leading edge 5A of the sole 5. The back sides of the one side edge 15, the upper edge 17, and the lower edge 18 are aligned and abutted. The butt portion 19A is welded (FIG. 3), and the face portion 11 is fixed to the head main body 12 by the welded portion 19. The other side edge 16 of the face portion 11 is abutted against the stepped portion 13 of the head main body 12, and the abutted portion is also fixed by the welded portion 19B (see FIG. 1).

The welding method is performed by laser welding, and as shown in FIG. 4, the nozzle 20 of the laser welding device is opposed to the outer edge of the butt portion 19A, and the laser beam 20A is directed to the outer edge of the butt portion 19A. The welded portion 19 is formed by irradiating the welded portion 19. In such welding, the nozzle 20 moves along the longitudinal direction Z of the butt portion 19A (see FIG. 1), that is, along the top surface 4, toe 6 and sole 5 of the head 1, or along the sole 5, toe and top surface 4. To form a continuous welded portion 19. The back recess 9 in the center of the back of the head body 12 is a through hole before the face member 11 is welded, but the corner portion of the inner peripheral surface on the face member 11 side of the through hole on the face member 11 side is formed. It is chamfered 19A. Since the laser beam 20A has excellent directivity in laser welding, the weld bead flows along the central portion of the face 3, that is, the surface direction of the face 3 at the penetration portion of the welded portion 19.

In this way, after or before the face member 11 is fixed to the head body 12, lateral small grooves 21 which are score lines are formed in multiple stages in the upper and lower stages on the front surface of the face member 11, and the club head 1 is formed. After being polished, plated, or the like, the shaft 2 is connected to and fixed to the hosel 3 by an adhesive or the like.

The club head 1 obtained by the above structure and manufacturing method was subjected to a striking test using a standardized standard golf ball to determine the durability of the face member 11 and the tempering and softening of the face member 11 due to the welding heat of the face member 11 by laser welding. The hardness was measured. Hereinafter, the test results are shown as experimental examples instead of the examples. Table 1 shows an outline of the experimental method.

[Experimental Example 1]
The experimental conditions and results are as shown below.
-Face material: SKD61 (JIS alloy tool steel), plate thickness 1.8 mm, heat treatment conditions (after quenching at 1050 ° C for air cooling, tempering twice at 600 ° C), target hardness by heat treatment (500Hv ± 30Hv)
The components of the material constituting this face portion are as shown in Table 2 below.

-Material of head body: Carbon steel for machine structure (S20C)
-Summary of manufacturing method: The face material heat-treated under the above conditions was laser-welded to the machined head body, and the surface was plated.
-Laser welding: Welding was performed at an output of 1600 W and a feed rate of 700 to 850 mm / min.
-Strike test method: After the plating treatment, the ball was hit with the hitting robot at a hitting speed of 40 m / s until the face portion was destroyed. After the above fracture, the hardness of the cross section in the vicinity of the weld was measured.
-Strike tester: A "striking durability tester" (manufactured by Endo Manufacturing Co., Ltd. (applicant)) that accelerates the ball with compressed air was used.
・ Ball used for hitting: USGA / R & A Calibration

(Test results)
With the 3022 ball by the above-mentioned impact test device, a crack (crack along the small groove 21) of the face portion 11 occurred along the score line at the lowermost stage on the sole 5 side. FIG. 5 is a cross section on the sole 5 side showing a cross section perpendicular to the direction of the small groove 21 which is the score line. Shows Vickers hardness near the weld (0.2 mm pitch). The measured hardness of each part is as follows.
-Hardness in the quadrangle in Fig. 5 (part not affected by welding): Average 513.5Hv
Hardness region of 462 Hv or less (hardness region of 10% or less reduction of the above average 513.5 Hv): within the dotted line in FIG. 5 (maximum about 0.25 mm in vertical width)

From the results of Experimental Example 1 above, the hardness of the face portion 11 using this alloy tool steel material is generally in the range of 500 to 600 Hv including the outer bond portion of the welded portion 19 by laser welding, and the laser. It is hardly affected by the welding heat due to welding, and the hardness tempered by heat treatment before laser welding is not significantly reduced. However, although it was a small region, there was a hardness region (inside the dotted line) of 462 Hv or less. The hardness (356Hv, 372Hv) of the chamfered portion 9A (see FIG. 4) of the back recess 9 is reduced, but this portion is the portion where the bead of the welded portion 19 has flowed, and the body portion of the face portion 11 is formed. This is a part that does not affect the mounting strength to 12.

・ヘッド本体の素材：機械構造用炭素鋼（Ｓ２０Ｃ）
レーザ溶接した後、表面にメッキ処理した後、実験例１と同様に、溶接部の近傍の断面の硬度を測定した。
・レーザ溶接：出力１６００Ｗ、送り速度７００～８５０ｍｍ／min.で溶接した。 [Experimental Example 2] (Comparative Example)
Except for the following experimental conditions, it is the same as Experimental Example 1.
-Face material: SAE8655 (nickel, chrome, molybdenum steel) -MOD-AY, plate thickness 1.9 mm, heat treatment conditions (after oil quenching at 850 ° C, tempering at 300 ° C), target hardness by heat treatment (500Hv ± 30Hv) )
The components of the material constituting this face portion are as shown in Table 3 below.

-Material of head body: Carbon steel for machine structure (S20C)
After laser welding, the surface was plated, and then the hardness of the cross section in the vicinity of the welded portion was measured in the same manner as in Experimental Example 1.
-Laser welding: Welding was performed at an output of 1600 W and a feed rate of 700 to 850 mm / min.

(Test results)
With about 4,000 balls by the impact test device, cracks in the face portion 11 (cracks along the small groove 21) occurred along the score line at the bottom of the sole 5 side. As shown in FIG. 6, the measured hardness (0.2 mm pitch) of each part is generally as follows.
-Hardness in the quadrangle in Fig. 6 (part not affected by welding): Average 497.6Hv
-Hardness region of 448 Hv or less (hardness of 10% or less reduction of an average of 497.6 Hv): within the dotted line in FIG. 6 (approximately 1.4 mm in vertical width)

In Experimental Example 2 (Comparative Example), as can be understood from the hardness shown in FIG. 6, the hardness of the face portion 11 due to the heat effect of welding is higher than the hardness of the face portion 11 tempered by the welding heat (500 Hv or more). Also low and wide area confirmed. In particular, the hardness of the "connecting portion" in the vicinity of the welded portion 19 is 337 to 453 Hv (the region within the dotted line), which is considerably lower than that before tempering.

1 ... Iron club head 2 ... Shaft 3 ... Face 4 ... Top surface 4A ... Leading edge 5 ... Sole 6 ... Toe 7 ... Heel 8 ... Hosel 9 ... Back recess 10 ... Bottom recess 11 ... Face member 12 ... Head body 13 ... Step 14 ... Mounting surface 15 ... One side edge 16 ... Other side edge 17 ... Upper edge 18 ... Lower edge 19, 19B ... Welded portion 19A ... Butting portion 20 ... Nozzle 20A ... Laser beam 21 ... Small groove

Claims (4)

In an iron club head having a main body of an iron club head and a face portion having a material different from that of the main body,
The face portion is a plate-shaped alloy tool steel material made by rolling, which is fixed to the main body by welding, and the tempered hardness before welding is 470 Hv or more on average. An iron club head that features that. In the iron club head according to claim 1.
The iron club head is characterized in that the welding is laser welding using a laser beam as a heat source. In the iron club head according to claim 1 or 2.
The alloy tool steel material has C: 0.35 to 0.42% by weight, Si: 0.80 to 1.20% by weight, Mn: 0.25 to 0.50% by weight, Cr: 4.50 to 5 by weight. An iron club head characterized by .50% by weight, Mo: 1.00 to 1.50% by weight, V: 0.80 to 1.15% by weight, unavoidable impurities, and Fe: balance. The method for manufacturing an iron club head according to claim 2.
A through hole is formed in the main body, and the face member is welded to the mounting surface, which is the joint surface of the face member tempered in the main body, by laser welding from the outer peripheral side of the mounting surface. How to manufacture an iron club head.

Images