JP2017086766A - Iron golf club head manufacturing method and iron golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iron golf club head manufacturing method and the iron golf club head in which a quench-hardened layer is deep, the appearance is also good, the change of the hardness and a metallographic structure is fluent, and a hitting sound and a feeling of hitting are improved.SOLUTION: A metal mold 3B and a metal mold 4B are pressed on a golf club head 1A in warm forging of 650-780 degrees. Flat pressing surfaces 32, 42 are formed on the metal mold 3B and the metal mold 4B, respectively. The whole golf club head 1A is plastically deformed by the warm forging, and a semi-circular shape protrusion 51 and a semi-circular shape protrusion 52 are crushed flatly. The crushed semi-circular shape protrusion 51 and the semi-circular shape protrusion 52 form grain flow, and the crystal grain of the metallographic structure is miniaturized.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing an iron golf club head and the iron golf club head. More specifically, a method of manufacturing an iron golf club head with improved hit feeling by compressing crystal grains on the surface of the face portion and making crystal grains on the striking surface finer than crystal grains of the base material, and its method The present invention relates to an iron golf club head.

  One of the important factors in the performance of a golf club is the hitting sound and feel. In the case of an iron head, what is produced by forging a so-called soft iron produced by hot forging low carbon steel is said to have good hitting sound and feel. As the shape of the iron head, a muscle back type and a cavity back type are known. The cavity back type is inferior in the sound and feel compared to the muscle back type. On the other hand, in order to improve the hitting sound and feel, there is also a method of quenching or heat treatment with a laser to increase the strength of the face part, but even if the surface becomes hard due to this heat treatment, The forging effect may fade. The present applicant has proposed a cavity back type iron head that is excellent in sound and feel by pulverizing a partial convex portion of the face portion by cold forging and increasing hardness (Patent Document 1). .

  The score line (groove) formed in the face portion has a great influence on the spin of the ball. The score line is a groove formed in the face part to release grass and water droplets sandwiched between the face part and the ball at the moment of impact, thereby increasing the adhesion of the ball and obtaining an appropriate spin. . However, in the method of crushing convex portions by cold forging in Patent Document 1, the hardened layer is shallow, and changes in hardness and structure become abrupt. In addition, even if the convex portion is crushed flat, a minute convex portion having a height of 0.02 to 0.03 mm remains on the face portion due to the springback phenomenon, so the fine convex portion is scraped off by machining. Need to be flattened. Therefore, the hardened layer becomes further shallow, the R shape of the groove edge of the score line does not appear well, and it is difficult to obtain a desired groove shape. Further, even if the minute protrusions are scraped off by machining, a very minute protrusion may remain on the face part due to the springback phenomenon, which may cause a defect in appearance. Even in the conventional cold forging, if the volume of the convex portion to be crushed is reduced, the above-described problems can be avoided, but it is difficult to obtain sufficient hardness.

JP 2013-128765 A

The present invention has been made based on the technical background described above, and achieves the following objects.
An object of the present invention is to provide a method of manufacturing an iron golf club head having a deep hardened layer and good appearance, a smooth change in hardness and metal structure, and improved sound and feel, and the iron golf club head. There is.

The said subject is solved by the following means.
That is, the method for manufacturing an iron golf club head according to the first aspect of the present invention is a method for manufacturing an iron golf club head manufactured by forging low carbon steel, and hot forging the low carbon steel to form a face portion. A striking surface including a partial convex portion is formed, and after the hot forging, the convex portion is flattened by warm forging at 650 to 780 degrees to finely refine the crystal grains of the convex portion and its peripheral region. The strength and hardness of the striking surface are increased, and the score line formed on the striking surface is arranged so as to intersect with the traces of the crushed convex portions.

The method for manufacturing an iron golf club head according to the second aspect of the present invention is the method according to the first aspect, wherein the convex portion has a plurality of concentric circular shapes or a plurality of concentric linear shapes when the striking surface is viewed from the front. A circle (51), a linear turtle shell pattern (53) in which hexagons are connected, and a plurality of straight lines (55A, 55B, 55C) that are parallel to each other and formed at equal intervals in the toe heel direction. A plurality of planar circular shapes (55D) or polygons, a plurality of linear waveforms (55E, 55F) formed at equal intervals in the toe heel direction or in a direction orthogonal to the toe heel direction and arranged at equal intervals Selected from a plurality of linear V shapes (55G), a plurality of planar star shapes (55H) arranged at equal intervals, and a plurality of planar cloud shapes (55J) arranged at equal intervals. One or more combinations, and
The cross-sectional shape of one convex portion in the convex portion is one selected from a triangular mountain shape, a semicircular shape, and a trapezoidal shape.

The method for manufacturing an iron golf club head according to the third aspect of the present invention is the method of manufacturing the iron golf club head according to the second aspect, wherein after the convex portion is flattened by warm forging, a machining step is performed to process the striking surface and scrape the surface. After the processing step, a score line forming step for forming a score line by coining is performed on the striking surface.
The iron golf club head of the present invention 4 is manufactured by the method for manufacturing an iron golf club head according to any one of the present inventions 1 to 3.

  The method for manufacturing an iron golf club head according to the present invention and the iron golf club head have a hardened layer having a good appearance, a smooth change in hardness and metal structure, since the convex portions are flattened by warm forging. Improves sound and feel.

FIG. 1 shows a golf club head according to a first embodiment of the present invention in the process of manufacturing, and a convex portion forming step for forming a striking surface having a concentric semicircular convex portion in FIG. 6A on a face portion. FIG. 1A is an overall front view, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. FIG. 2 is a P arrow view of FIG. FIG. 3 shows the golf club head according to the first embodiment of the present invention in the process of manufacturing, which is a golf club head subjected to the flattening process of FIG. 6B, and FIG. FIG. 3B is an overall front view, and FIG. 3B is a cross-sectional view taken along the line BB in FIG. FIG. 4 is a view taken in the direction of the arrow Q in FIG. FIG. 5 shows the golf club head according to the first embodiment of the present invention in the process of manufacturing, which is a golf club head subjected to the score line forming step of FIG. 7B, and FIG. A front view and FIG.5 (b) are CC sectional drawing of Fig.5 (a). FIG. 6 is an explanatory view showing the manufacturing process of the first embodiment of the present invention. FIG. 6 (a) is a hot forging of low carbon steel and has a concentric semicircular convex part on the face part. FIG. 6B is a process for forming a striking surface, and FIG. 6B is a subsequent process of FIG. 6A, which is a flattening process that flatly crushes the protrusion by warm forging. FIG. 7 is an explanatory view showing a post-process of FIG. 6B. FIG. 7A is a machining process in which the face portion is ground by a grindstone, and FIG. 7B is FIG. a) A score line forming process for forming a score line in the subsequent process with the toe heel direction as the longitudinal direction on the face part. FIG. 8 shows a golf club head according to a second embodiment of the present invention that is in the process of being manufactured, and is provided with a projecting portion forming step for forming a striking surface having a tortoiseshell-shaped projecting portion connected with hexagons on the face portion. FIG. 8A is an overall front view, and FIG. 8B is a sectional view taken along the line DD of FIG. 8A. FIG. 9 is a view taken in the direction of arrow R in FIG. FIG. 10 is an overall front view showing a golf club head in which convex portions having shapes different from those of the above embodiment are formed. FIG. 11 is an overall front view showing a golf club head in which convex portions having shapes different from those in FIG. 10 are formed. FIG. 12 is an overall front view showing a golf club head in which convex portions having shapes different from those in FIGS. 10 and 11 are formed.

[First Embodiment of Iron Golf Club Head]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 6A is an explanatory view showing the manufacturing process of the first embodiment of the present invention, in which a low carbon steel is hot forged to form a striking surface having a concentric semicircular convex portion on the face portion. It is a convex part formation process. As shown to Fig.6 (a), the metal mold | die 3A and the metal mold | die 4A are pressed against the raw material 100 of low carbon steel of S10C-S30C by hot forging of 950-1050 degree | times. In the mold 3A, 26 concentric semicircular recesses 31 are formed at equal intervals. Further, ten concentric semicircular recesses 41 are formed at equal intervals in the mold 4A. The cross-sectional shapes of the semicircular recess 31 and the semicircular recess 41 (the cross-sectional shape in the direction parallel to the paper surface) are semicircular.

  1A and 1B show a golf club head 1A subjected to the hot forging projection forming step shown in FIG. 6A. FIG. 1A is an overall front view, and FIG. 1B is FIG. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. The golf club head 1A shown in FIGS. 1 to 2 is an iron golf club head, which is a cavity back type iron golf club head having a recess 11 formed on the back surface. The golf club head 1A has a face portion 12 having a striking surface for striking a ball, a hosel portion 13 as a shaft connecting portion on the shaft side, a top portion 14 at an upper portion, a toe portion 15 at a front portion, and a ground surface. A sole portion 16 is formed in the lower portion, and a heel portion 17 is formed in the rear portion. A shaft (not shown) is inserted and connected to the hosel portion 13 of the golf club head 1A. When the face portion 12 is viewed from the front, the face portion 12 is formed with 26 semicircular convex portions 51 that are concentric at equal intervals. Strictly speaking, it is a linear semicircular convex portion 51. Moreover, the concentric ten semicircular convex parts 52 are also formed in the recessed part 11 at equal intervals. As shown in FIG. 1B, one cross-sectional shape of the semicircular convex portion 51 and the semicircular convex portion 52 is a semicircular (arc) shape.

  FIG. 6B shows a flattening process step in which the semicircular convex portion 51 and the semicircular convex portion 52 are flattened by warm forging in the subsequent step of FIG. 6A. That is, as shown in FIG. 6B, the mold 3B and the mold 4B are pressed against the golf club head 1A shown in FIGS. 1 to 2 by warm forging at 650 to 780 degrees. Flat pressing surfaces 32 and 42 are formed on the mold 3B and the mold 4B, respectively. The warm forging temperature is more preferably 750 to 780 degrees. 6B, the entire golf club head 1A is plastically deformed, and the semicircular protrusion 51 and the semicircular protrusion 52 are flattened. 3A and 3B show the golf club head 1B subjected to the flattening process by warm forging shown in FIG. 6B. FIG. 3A is an overall front view, and FIG. BB sectional view of FIG. 4 is a cross-sectional view taken along the line Q in FIG. As shown by broken lines in FIGS. 3 and 4, the crushed semicircular convex portions 51 and the semicircular convex portions 52 form forged lines, and the crystal grains of the metal structure are refined.

  FIG. 7A is an explanatory diagram showing a post-process of FIG. 6B, and is a machining process in which the face portion 12 is ground by the grindstone 6 to be flattened. Even if the thin belt-like (linear) semicircular convex portion 51 is flattened in the flattening process shown in FIG. 6B, the minute convex portion remains on the face portion 12 due to the springback phenomenon. As shown in FIG. 7A, the face portion 12 of the golf club head 1B shown in FIGS. 3 to 4 is ground with a grindstone 6, and the minute convex portions are scraped off to make the face portion 12 flat.

  FIG. 7B is an explanatory diagram showing a post-process of FIG. 7A, and is a score line forming process for forming a score line on the face portion 12. That is, as shown in FIG. 7B, the die 7 is pressed by coining to the flat face portion 12 of the golf club head 1 </ b> C that has been ground. In the mold 7, 12 cross-sectional trapezoidal convex portions 71 are formed at equal intervals in a parallel and straight belt shape. When the score line forming step of FIG. 7B is completed, as shown in FIG. 5, the face portion 12 of the golf club head 1D after the coining process has twelve score lines (with the toe heel direction as the longitudinal direction) Groove) 2 is formed. The twelve score lines 2 are parallel to each other and formed at equal intervals in a direction orthogonal to the toe heel direction. The depth of the score line 2 is 0.3 mm and is formed in a trapezoidal shape. The score line 2 intersects with the traces of the crushed semicircular convex portion 51 at a number of locations.

  In the first embodiment of the present invention, because of the warm forging, the hardened layer is formed deeper than the conventional cold forging, and the strength and hardness of the face portion 12 are increased, so that the hitting sound and feel are improved. To do. In addition, due to warm forging, changes in hardness and metal structure become smooth. Therefore, the R shape of the groove edge of the score line 2 can be successfully obtained and a desired groove shape can be easily obtained. Further, since the springback phenomenon becomes very small, the trace of the crushed semicircular convex portion 51 does not remain and the appearance is improved. When the warm forging temperature is lower than 650 to 780 ° C., the hardness of the face portion 12 increases, but this is not preferable because the above-mentioned problem of cold forging occurs. On the other hand, when the warm forging temperature is higher than 650 to 780 degrees, the hardness of the face portion 12 is insufficient, and a lot of oxide scale is generated, which causes rough skin, which is not preferable. The golf club head 1D performs finishing such as polishing and plating after the score line forming process of FIG. 7B, and the manufacturing process of the golf club head 1D is completed.

[Second Embodiment of Iron Golf Club Head]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. The second embodiment is an example in which the shape of the convex portion is formed in a shape different from that of the first embodiment. FIG. 8 shows a golf club head 1E formed with a convex portion according to the second embodiment of the present invention. FIG. 8 (a) is an overall front view, and FIG. 8 (b) is D in FIG. 8 (a). -D sectional drawing and FIG. 9 are R arrow line views of FIG.8 (b). As shown in FIGS. 8 and 9, a tortoiseshell-shaped convex portion 53 connected with hexagons when the face portion 12 is viewed from the front is formed on the face portion 12 by hot forging. Strictly speaking, the convex portion 53 having a turtle shell pattern has a linear shape with a sharp tip (see FIG. 8B). Further, the concave portion 11 is also formed with a turtle shell-shaped convex portion 54 in which hexagons are connected.

  As shown in FIG. 8B, the cross-sectional shapes of the turtle shell pattern convex portion 53 and the turtle shell pattern convex portion 54 that are linear are triangular mountain shapes. The turtle shell pattern convex portion 53 and the turtle shell pattern convex portion 54 are flattened by warm forging, and then the face portion 12 is ground by the grindstone 6. Thereafter, although not shown, a plurality of score lines are formed on the face portion 12 in the same manner as in the first embodiment. Then, the score line intersects with the traces of the crushed turtle shell pattern convex portion 53 at a number of locations.

[Embodiments showing other convex shapes]
FIG. 10 is an overall front view showing a golf club head in which convex portions having shapes different from those of the above embodiment are formed by hot forging. In the golf club head 10A shown in FIG. 10A, a plurality of linear convex portions 55A are formed on the face portion 12 with the direction perpendicular to the toe heel direction (from the leading edge to the top line direction) as the longitudinal direction. ing. The plurality of linear convex portions 55A are parallel to each other and are formed at equal intervals in the toe heel direction. In the golf club head 10B of FIG. 10B, the face portion 12 has an acute angle from the direction orthogonal to the toe heel direction (from the leading edge to the top line direction), that is, the direction inclined upward from the leading edge is the longitudinal direction. As shown, a plurality of linear convex portions 55B that are linear are formed at equal intervals in the toe heel direction.

  A golf club head 10C shown in FIG. 10C has a plurality of linear convex portions 55B that are linearly spaced at equal intervals in the toe heel direction, with the face portion 12 having a longitudinal direction that is inclined upward from the leading edge. In the toe heel direction, a plurality of linear convex portions 55C which are linearly inclined to the lower right are crossed. In the golf club head 10D of FIG. 10D, a plurality of planar circular convex portions 55D are formed on the face portion 12 at equal intervals. Instead of the circular convex portion 55D, a triangular convex portion, a quadrangular convex portion, or a pentagonal convex portion may be used.

  FIG. 11 is an overall front view showing a golf club head in which convex portions having shapes different from those in FIG. 10 are formed by hot forging. A golf club head 10E shown in FIG. 11A has a plurality of linear shapes on the face portion 12 with the direction perpendicular to the sole direction (from the leading edge to the top line direction) as the longitudinal direction and at equal intervals in the toe heel direction. A corrugated convex portion 55E is formed. A golf club head 10F shown in FIG. 11B has a plurality of corrugated convex portions 55F that are linear at equal intervals in a direction perpendicular to the toe heel direction, with the toe heel direction being the longitudinal direction. . A golf club head 10 </ b> G in FIG. 11C has a plurality of V-shaped convex portions 55 </ b> G formed at equal intervals on the face portion 12. In the golf club head 10 </ b> H of FIG. 11D, a plurality of cross-shaped convex portions 55 </ b> H are formed at equal intervals on the face portion 12.

  FIG. 12 is an overall front view showing a golf club head in which convex portions having shapes different from those in FIGS. 10 and 11 are formed by hot forging. A golf club head 10J of FIG. 12 has a plurality of cloud-shaped convex portions 55J formed at equal intervals on the face portion 12. The convex portions 55A to 55J shown in FIGS. 10 to 12 are flattened by warm forging, and then the face portion 12 is ground with a grindstone 6 or the like. Thereafter, although not shown, a plurality of score lines are formed on the face portion 12 in the same manner as in the first embodiment. Then, the score line intersects with the traces of the crushed convex portions 55A to 55J at a number of locations.

  As mentioned above, although the Example of this invention was described, this invention is not limited to this Example. For example, in the above-described embodiment, convex portions are formed on both the face portion 12 and the concave portion 11, but only the face portion 12 may be used. Further, although the concentric semicircular convex portions 51 and 52 are formed, a plurality of concentric circular convex portions may be formed. Furthermore, the cross-sectional shapes of the semicircular convex portions 51 and 52 are semicircular, and the cross-sectional shapes of the turtle shell pattern convex portion 53 and the turtle shell pattern convex portion 54 are triangular mountain shapes, but may be trapezoidal. Further, although the grinding process is performed with a grindstone and the fine convex portions of the face portion are scraped off and flattened, the fine convex portions of the face portion may be scraped off with a cutting tool such as a milling tool.

DESCRIPTION OF SYMBOLS 100 ... Material 1A ... Golf club head 1B ... Golf club head 1C ... Golf club head 1D ... Golf club head 1E ... Golf club head 10A ... Golf club head 10B ... Golf club head 10C ... Golf club head 10D ... Golf club head 10E ... Golf club head 10F ... Golf club head 10G ... Golf club head 10H ... Golf club head 10J ... Golf club head 11 ... Recess 12 ... Face 13 ... Hosel 14 ... Top 15 ... Toe 16 ... Sole 17 ... Heel 2 ... Score line 3A ... Mold 3B ... Mold 31 ... Semicircular recess 32 ... Pressing surface 4A ... Mold 4B ... Mold 41 ... Semicircular recess 42 ... Pressing surface 51 ... Semicircular convex portion 52 ... Semicircular convex portion 53 ... Turtle-shaped convex portion 54 ... Turtle-shaped convex portion 55A ... Linear convex portion 5 B ... Linear convex portion 55C ... Linear convex portion 55D ... Circular convex portion 55E ... Wave convex portion 55F ... Wave convex portion 55G ... V-shaped convex portion 55H ... Cross-shaped convex portion 55J ... Cloud-shaped convex portion 6 ... Grinding stone 7 ... Gold Mold 71 ... Trapezoidal convex section

Claims (4)

A method for manufacturing an iron golf club head manufactured by forging low carbon steel,
Hot forging the low carbon steel to form a striking surface including a partial convex portion on the face portion,
After the hot forging, by crushing the convex portion flat by warm forging at 650 to 780 degrees, to refine the crystal grains of the convex portion and its peripheral region, increase the strength and hardness of the striking surface,
The method of manufacturing an iron golf club head, wherein the score line formed on the hitting surface is arranged so as to intersect with the trace of the crushed convex portion. In the manufacturing method of the iron golf club head according to claim 1,
When the striking surface is viewed from the front, the shape of the convex portion is a plurality of concentric linear circles or a plurality of concentric linear circles, a linear turtle shell pattern in which hexagons are connected, and parallel to each other. A plurality of straight lines formed at equal intervals in the toe heel direction, a plurality of planar circles or polygons arranged at equal intervals, formed at equal intervals in the toe heel direction or in a direction perpendicular to the toe heel direction. Select from a plurality of linear waveforms, a plurality of linear V shapes arranged at equal intervals, a plurality of planar stars arranged at equal intervals, and a plurality of planar clouds arranged at equal intervals One or more combinations, and
A method for manufacturing an iron golf club head, wherein a cross-sectional shape of one of the convex portions is one selected from a triangular mountain shape, a semicircular shape, and a trapezoidal shape. In the manufacturing method of the iron golf club head according to claim 2,
After crushing the convex part flat by warm forging, a machining process is performed to cut the surface by processing the striking surface,
A method of manufacturing an iron golf club head, wherein a score line forming step of forming a score line by coining is performed on the striking surface after the machining step.   The iron golf club head manufactured with the manufacturing method of the iron golf club head of any one of Claim 1 to 3.

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