Golf club head having localized heat affected part

Abstract

To provide a golf club head having a localized heat treatment.SOLUTION: A golf club head, and in particular, a wood-type golf club head including a faceplate having one or plural heat affected parts (HAZ) to enable a consistent or a reasonable tolerance error variation in CT over the entire faceplate is disclosed. The heat affected part can be formed via weld beads that locally alter a specific part, a portion, or a region of the faceplate without entirely altering the characteristics and properties of the faceplate all at once. Locally altering the specific part or the region of the faceplate via weld beads (or spot welds) to form a heat affected part can alter a microstructure of that region or the part.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure generally relates to golf clubs. In particular, the present disclosure relates to a golf club head having one or more local heat affected zones (HAZs).

[0002] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 900,378, filed September 13, 2019, the entire contents of which are hereby incorporated by reference in their entirety.

Background Art

[0003] Characteristic time (CT) is a measure of the amount of time in microseconds that a golf ball is in contact with the face plate during impact. The characteristic time requirement is one of many rules that the United States Golf Association (USGA) and the Royal & Ancient Golf Club of St Andrews (R&A) impose on golf equipment manufacturers to determine club head compliance. In many cases, the characteristic time characteristics of a golf club head are not uniform and vary substantially across the face plate. This variation can lead to inconsistencies in club head performance and, more specifically, can produce different ball speeds depending on where on the face plate the ball impact occurs. These small variations in the location of the ball impact across the face plate can lead to significant variations in the ball speed and ball flight distance produced, thereby making the game unpredictable for the golfer.

[0004] Changes in the characteristics of the golf club head over time can be brought about by a face plate having an asymmetric outer peripheral shape and / or variable face plate features (i.e., thickness, material, texture, face-body transition, etc.). Reducing the thickness of the material used to form the golf club head, and more particularly the face plate, can be beneficial for a number of reasons. Among these reasons, a thinner face plate can reduce weight, increase flexibility, and reduce the amount of material used. By reducing the weight in a certain area of the golf club head, the weight can be redistributed (as needed) to improve club head performance.

[0005] Redistributing the weight from the face plate can result in an increase in flexibility and an increase in energy transfer to the golf ball. This increase in flexibility (resulting from the thinner face plate) can result in a more variable CT across the face plate. In the art, there is a need for a reproducible, efficient, and cost-effective manufacturing method that allows for locally changing the CT to reduce the CT variation across the face plate.

Brief Description of the Drawings

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[0007] Other aspects of the present disclosure will become apparent by considering the detailed description and the accompanying drawings.

[0008] For simplicity and clarity of the figures, the drawings show general types of structures, and well-known features and techniques of description and details may be omitted to avoid unnecessarily obscuring the present disclosure. Further, the elements in the drawings are not necessarily drawn to scale. For example, some dimensions of the elements in the figures may be exaggerated relative to other elements to assist in the understanding of the embodiments of the present disclosure. The same reference numerals in different drawings represent the same element.

DETAILED DESCRIPTION OF THE INVENTION

[0009] Presented herein is a golf club head comprising a face plate having one or more heat affected zones (HAZs) to allow for a constant or reasonable tolerance variation of CT across the entire face plate, particularly a wood-type golf club head. The heat affected zones may be formed via weld beads that locally modify specific parts, portions, or regions of the face plate without changing the characteristics and properties of the face plate as a whole all at once. The local modification of a specific part or region of the face plate via weld beads (or spot welds) for forming the heat affected zones may change the microstructure of that region or part. The change in the microstructure in the region or part of interest may change the characteristic time properties of that region or part when impacted by a golf ball.

[0010] Because the characteristics of the characteristic time vary across the faceplate in both the heel-toe direction and the crown-sole direction, the area of the faceplate that is subject to heat treatment and / or HAZ may be an area approximating a characteristic time threshold to avoid the golf club head having a hot spot (i.e., a portion of the faceplate that is at, approximates, or is near the CT limit of the USGA and R&A), an area of the club head that potentially has non-compliant CT due to manufacturing variations, and / or a specific area of the faceplate that deviates from compliance due to repeated club head use and wear. As a result of local heat affected zone treatment (via a weld bead or spot weld) of the faceplate, the treated portion may have different material properties (i.e., different microstructures for changing CT) from the non-heat affected portion of the same material. These parts, regions, or portions targeted for adjustment may generally be defined by a reference shape. Further, a method of manufacturing a golf club head described herein is outlined below.

[0011] Terms such as "first," "second," "third," "fourth," etc. in the specification and claims, when present, are used to distinguish between similar elements and do not necessarily describe a particular order or chronological sequence. It should be understood that such terms are mutually interchangeable in appropriate circumstances so that the embodiments described herein can operate in an order other than, for example, the order illustrated or otherwise described herein. Further, the terms "include" and "have," and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that includes a list of elements is not necessarily limited to those elements and may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0012] The terms "left", "right", "front", "back", "upper", "lower", "above", "below", etc. in the specification and claims are used for illustrative purposes, if present, and do not necessarily describe permanent relative positions. Such terms are to be understood as being interchangeable with each other under appropriate circumstances so that the embodiments of the devices, methods, and / or manufactured articles described herein can be operated in orientations other than, for example, the orientations illustrated or otherwise described herein.

[0013] The term "driver-type golf club head" described herein may be defined by one or more of loft angle, club head volume, club head weight, or club head material.

[0014] 1. Loft Angle In many embodiments, the loft angle of the driver-type club head may be less than about 16 degrees, less than about 15 degrees, less than about 14 degrees, less than about 13 degrees, less than about 12 degrees, less than about 11 degrees, less than about 10 degrees, less than about 9 degrees, less than about 8 degrees, or less than about 7 degrees.

[0015] 2. Volume Furthermore, in many embodiments, the volume of the driver-type club head may be greater than about 400 cc, greater than about 425 cc, greater than about 450 cc, greater than about 475 cc, greater than about 500 cc, greater than about 525 cc, greater than about 550 cc, greater than about 575 cc, greater than about 600 cc, greater than about 625 cc, greater than about 650 cc, greater than about 675 cc, or greater than about 700 cc. In some embodiments, the volume of the driver-type club head may be about 400 cc - 600 cc, about 425 cc - about 500 cc, about 500 cc - about 600 cc, about 500 cc - about 650 cc, about 550 cc - about 700 cc, about 600 cc - about 650 cc, about 600 cc - about 700 cc, or about 600 cc - about 800 cc.

[0016] 3. Weight In some embodiments, the driver-type club head may have a weight (or mass) of 170 grams to 250 grams. In other embodiments, the driver-type club head may be 170 grams to 175 grams, 175 grams to 180 grams, 180 grams to 185 grams, 185 grams to 190 grams, 190 grams to 195 grams, 195 grams to 200 grams, 200 grams to 205 grams, 205 grams to 210 grams, 210 grams to 215 grams, 215 grams to 220 grams, 220 grams to 225 grams, 225 grams to 230 grams, 230 grams to 235 grams, 235 grams to 240 grams, 240 grams to 245 grams, or 245 grams to 250 grams. In some embodiments, the weight of the driver-type club head may be 170 grams, 171 grams, 172 grams, 173 grams, 174 grams, 175 grams, 176 grams, 177 grams, 178 grams, 179 grams, 180 grams, 181 grams, 182 grams, 183 grams, 184 grams, 185 grams, 186 grams, 187 grams, 188 grams, 189 grams, 190 grams, 191 grams, 192 grams, 193 grams, 194 grams, 195 grams, 196 grams, 197 grams, 198 grams, 199 grams, 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, 215 grams, 216 grams, 217 grams, 218 grams, 219 grams, 220 grams, 221 grams, 222 grams, 223 grams, 224 grams, 225 grams, 226 grams, 227 grams, 228 grams, 229 grams, 230 grams, 231 grams, 232 grams, 233 grams, 234 grams, 235 grams, 236 grams, 237 grams, 238 grams, 239 grams, 240 grams, 241 grams, 242 grams, 243 grams, 244 grams, 245 grams, 246 grams, 247 grams, 248 grams, 249 grams, or 250 grams.

[0017] 4. Material The material of the driver-type golf club head may be constructed from any material used to construct conventional golf club heads. For example, the material of the driver-type golf club head may be any one or combination of the following, namely, 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 1380 stainless steel, 303 stainless steel, stainless steel alloy, steel alloy, tungsten, aluminum, aluminum alloy, ADC-12, titanium, titanium alloy, or any other known metal or composite material for making a driver-type golf club head. In many embodiments, the driver-type golf club head may be constructed from titanium and / or composite materials.

[0018] The term "fairway wood-type golf club head" as described herein may be defined by one or more of loft angle, club head volume, club head weight, or club head material.

[0019] 1. Loft Angle In many embodiments, the loft angle of the fairway wood-type club head may be less than about 35 degrees, less than about 34 degrees, less than about 33 degrees, less than about 32 degrees, less than about 31 degrees, or less than about 30 degrees. Further, in many embodiments, the loft angle of the club head may be greater than about 12 degrees, greater than about 13 degrees, greater than about 14 degrees, greater than about 15 degrees, greater than about 16 degrees, greater than about 17 degrees, greater than about 18 degrees, greater than about 19 degrees, or greater than about 20 degrees. For example, in some embodiments, the loft angle of the fairway wood-type club head may be 12 degrees to 35 degrees, 15 degrees to 35 degrees, 20 degrees to 35 degrees, or 12 degrees to 30 degrees.

[0020] 2. Volume In many embodiments, the volume of the fairway wood type club head may be less than about 400 cc, less than about 375 cc, less than about 350 cc, less than about 325 cc, less than about 300 cc, less than about 275 cc, less than about 250 cc, less than about 225 cc, or less than about 200 cc. In some embodiments, the volume of the club head may be about 150 cc - 200 cc, about 150 cc - 250 cc, about 150 cc - 300 cc, about 150 cc - 350 cc, about 150 cc - 400 cc, about 300 cc - 400 cc, about 325 cc - 400 cc, about 350 cc - 400 cc, about 250 cc - 400 cc, about 250 cc - 350 cc, or about 275 cc - 375 cc.

[0021] 3. Weight In many embodiments, the fairway wood type club head may have a weight of 170 grams to 215 grams. In other embodiments, the fairway wood type golf club head may be 170 grams - 175 grams, 175 grams - 180 grams, 180 grams - 185 grams, 185 grams - 190 grams, 190 grams - 195 grams, 195 grams - 200 grams, 200 grams - 205 grams, 205 grams - 210 grams, or 210 grams - 215 grams. In some embodiments, the weight of the fairway wood type club head may be 170 grams, 171 grams, 172 grams, 173 grams, 174 grams, 175 grams, 176 grams, 177 grams, 178 grams, 179 grams, 180 grams, 181 grams, 182 grams, 183 grams, 184 grams, 185 grams, 186 grams, 187 grams, 188 grams, 189 grams, 190 grams, 191 grams, 192 grams, 193 grams, 194 grams, 195 grams, 196 grams, 197 grams, 198 grams, 199 grams, 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, or 215 grams.

[0022] 4. Material The material of the fairway wood type golf club head may be constructed from any material used to construct conventional golf club heads. For example, the material of the fairway wood type golf club head may be any one or combination of the following, namely, 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 1380 stainless steel, 303 stainless steel, stainless steel alloy, steel alloy, tungsten, aluminum, aluminum alloy, ADC-12, titanium, titanium alloy, steel alloy, or any other known metal or composite material for making a fairway wood type golf club head. In many embodiments, the fairway wood type golf club head is constructed from titanium and / or composite materials.

[0023] The term "hybrid type golf club head" described herein may be defined by one or more of loft angle, club head volume, club head weight, or club head material.

[0024] 5. Loft Angle In many embodiments, the loft angle of the hybrid type golf club head may be less than about 40 degrees, less than about 39 degrees, less than about 38 degrees, less than about 37 degrees, less than about 36 degrees, less than about 35 degrees, less than about 34 degrees, less than about 33 degrees, less than about 32 degrees, less than about 31 degrees, or less than about 30 degrees. Further, in many embodiments, the loft angle of the hybrid type club head may be greater than about 16 degrees, greater than about 17 degrees, greater than about 18 degrees, greater than about 19 degrees, greater than about 20 degrees, greater than about 21 degrees, greater than about 22 degrees, greater than about 23 degrees, greater than about 24 degrees, or greater than about 25 degrees.

[0025] 6. Volume In many embodiments, the volume of the hybrid type club head may be less than about 200 cc, less than about 175 cc, less than about 150 cc, less than about 125 cc, less than about 100 cc, or less than about 75 cc. In some embodiments, the volume of the club head may be about 100 cc to 150 cc, about 75 cc to 150 cc, about 100 cc to 125 cc, or about 75 cc to 125 cc.

[0026] 7. Weight In many embodiments, the hybrid club head may have a weight of from 190 grams to 240 grams. In other embodiments, the hybrid golf club head may be from 190 grams to 195 grams, 195 grams to 200 grams, 200 grams to 205 grams, 205 grams to 210 grams, 210 grams to 215 grams, 215 grams to 220 grams, 220 grams to 225 grams, 225 grams to 230 grams, 230 grams to 235 grams, or 235 grams to 240 grams. In some embodiments, the weight of the hybrid club head may be 190 grams, 191 grams, 192 grams, 193 grams, 194 grams, 195 grams, 196 grams, 197 grams, 198 grams, 199 grams, 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, 215 grams, 216 grams, 217 grams, 218 grams, 219 grams, 220 grams, 221 grams, 222 grams, 223 grams, 224 grams, 225 grams, 226 grams, 227 grams, 228 grams, 229 grams, 230 grams, 231 grams, 232 grams, 233 grams, 234 grams, 235 grams, 236 grams, 237 grams, 238 grams, 239 grams, or 240 grams.

[0027] 8. Material The material of the hybrid golf club head may be constructed from any material used to construct conventional golf club heads. For example, the material of the hybrid golf club head may be, hereinafter, i.e., 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 1380 stainless steel, 303 stainless steel, stainless steel alloy, steel alloy, tungsten, aluminum, aluminum alloy, ADC-12, titanium, titanium alloy, steel alloy, or any other known metal or composite for making a hybrid golf club head, either singly or in combination. In many embodiments, the hybrid golf club head may be constructed from a titanium alloy and / or composite material.

[0028] As used herein, the term "spot welding" may be defined as applying a weld bead to a material at a specific location to create a heat affected zone that changes the physical particle structure from an equiaxed circular microstructure to a dendritic microstructure, where the material microstructure deforms to return to an equiaxed circular microstructure away from the spot weld.

[0029] Before explaining any embodiment of the present disclosure in detail, it is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0030] A golf club head is described below that includes a reference shape to assist in providing a consistent CT across the face plate. The reference shape includes a heat affected zone (HAZ) that provides the ability to reduce / limit the CT characteristics of a particular region, thereby producing a CT within a predetermined tolerance across the face. More specifically, a golf club head, particularly a golf club head (driver, fairway wood, or hybrid) that includes a face plate having at least one heat affected zone (HAZ) to enable a consistent (or within a predetermined tolerance) CT across the face plate of the golf club head is described herein. As described above, the heat affected zone may be formed via spot welding or a weld bead that modifies a particular portion, part, or region of the face plate without changing the features and characteristics of the face plate as a whole. The local modification of a particular portion or region of the face plate (via spot welding or a weld bead) to form the heat affected zone may change the microstructure of that region or part (to a dendritic microstructure), and thus may change the characteristic time features of the treated location.

[0031] For example, generally, the portion of the golf club head having the maximum characteristic time measurement is typically found (1) towards the geometric center of the face plate, (2) offset from the geometric center of the face plate towards the toe of the face plate, (3) offset from the geometric center towards the upper end of the face plate, or a combination thereof. These regions may potentially have a characteristic time measurement that is at, near, or approximates the CT threshold (i.e., the CT limit of the USGA and R&A).

[0032] To form a faceplate having a more uniform CT (i.e., no "CT hot spots"), the region of interest for the local heat-affected zone may be characterized by a reference shape. A local heat-affected zone may be formed via spot welding or a weld bead inside or on the outer periphery of the reference shape. The heat-affected zone within the reference shape may have different material properties (i.e., different or (dendritic) microstructures) from the non-heat-affected zone outside the reference shape for locally changing the CT.

[0033] (Golf club head) The golf club head described herein may be a driver-type club head, a fairway wood-type golf club, or a hybrid-type club head as defined above. In many embodiments, the golf club head may be a wood-type golf club head (i.e., a driver-type golf club head, a fairway wood-type golf club head, or a hybrid-type golf club head). Driver-type golf club heads, fairway wood-type golf club heads, and hybrid-type golf club heads may be characterized by loft angle, head volume, and / or head weight as described above.

[0034] In some embodiments, the golf club head may be formed of stainless steel, titanium, aluminum, or a steel alloy (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), an aluminum alloy, or a composite material. In some embodiments, the faceplate of the golf club head may be formed of stainless steel, titanium, aluminum, or a steel alloy (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), an aluminum alloy, or a composite material.

[0035] (Composition and setup of golf club head) In many embodiments, the golf club head 100 includes a club head body 124 (which may also be referred to as the "body"). The club head body 124 forms a face plate opening configured to receive a toe portion 106, a heel portion 105, an upper portion 108, a sole portion 109, a rear portion 125, and a face plate 102. The face plate 102 may provide a surface adapted for impact with a golf ball. The rear portion 125 is spaced rearwardly from the face plate 102. The sole portion 109 is between the face plate 102 and the rear portion 125 and is defined as being placed on the ground 118 (or playing surface) at the address position. The upper portion 108 may be formed on the opposite side of the sole portion 109. The face plate 102 is defined by the sole portion 109, the upper portion 108, the heel portion 105, and the toe portion 106 which is on the opposite side of the heel portion 105.

[0036] As described above, the golf club head 100 may be configured to be in the "address position". Unless otherwise stated or described, the golf club head 100 is in the address position for all reference measurements, ratios, and / or descriptive parameters. The address position may be defined as (1) the sole portion of the golf club head being placed on the ground 118 such that it is in contact with and parallel to the playing surface, and (2) the striking face being in a state where it may be substantially perpendicular to the ground.

[0037] The face plate 102 of the club head 100 defines a geometric center 104. In some embodiments, the geometric center 104 may be positioned at the geometric center point of the outer periphery of the face plate and the midpoint of the face height. In the same or other examples, the geometric center may also be centered with respect to a designed impact portion defined by a groove region on the face plate. As another approach, the geometric center of the face plate 102 may be positioned according to the definition of a golf governing body such as the United States Golf Association (USGA). For example, the geometric center of the face plate 102 may be determined according to Section 6.1 of the procedure for measuring the flexibility of a USGA golf club head (USGA-TPX3004, Revision 1.0.0, May 1, 2008) (available at http: / / www.usga.org / equipment / testing / protocols / Procedure-For-Measuring-The-Flexibility-Of-A-Golf-Club-Head / ) ("Flexibility Procedure").

[0038] The club head 100 further defines a loft plane that is tangent to the geometric center 104 of the face plate 102. The face height may be measured parallel to the loft plane between the upper end of the outer periphery of the face plate near the crown portion 108 and the lower end of the outer periphery of the face plate near the sole portion 109. In these embodiments, the outer periphery of the face plate 102 may be positioned along the outer edge of the face plate, where the curvature deviates from the bulge and / or roll of the face plate 102.

[0039] The geometric center 104 of the faceplate 102 further defines a coordinate system having an origin positioned at the geometric center of the faceplate 102, and the coordinate system has an X'-axis 103, a Y'-axis 107, and a Z'-axis. The X'-axis 103 extends through the geometric center 104 of the faceplate 102 in the direction from the heel 105 to the toe 106 of the club head 100. The Y'-axis 107 extends through the geometric center 104 of the faceplate 102 in a direction perpendicular to the X'-axis 103 from the crown 108 to the sole 109 of the club head 100, and the Z'-axis extends through the geometric center 104 of the faceplate 102 in a direction perpendicular to the X'-axis 103 and the Y'-axis 107 from the front end to the rear end of the club head 100.

[0040] The coordinate system defines an X'Y' plane 101 that extends through the X'-axis 103 and the Y'-axis 107. The X'Y' plane 101 extends parallel to a hosel axis (not shown) and is positioned at an angle corresponding to the loft angle of the club head 100 from the loft plane. Further, the X'-axis 103 may be positioned at an angle of 60 degrees with respect to the hosel axis when viewed from a direction perpendicular to the X'Y' plane. In these embodiments or other embodiments, the club head may be viewed from the front (FIG. 1) when viewing the faceplate 102 from a direction perpendicular to the X'Y' plane 101.

[0041] When the golf club head 100 is in the address position, the golf club head 100 may be divided into four quadrants (i.e., the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant) bounded by the outer periphery of the face plate 102, the X' axis 103, and the Y' axis 107. Within one or more quadrants, a reference shape 126 may be projected onto the face plate 102, and the reference shape 126 may generally include a HAZ portion for modifying an area having a characteristic time value greater than a characteristic time threshold or a target characteristic time. In many embodiments, the reference shape 126 may be bounded or positioned entirely within the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant. In alternative embodiments, the reference shape 126 may extend into one or more quadrants, two or more quadrants, or three or more quadrants. In other embodiments, the reference shape 126 may extend into one or more quadrants along the quadrant boundary (i.e., along the X' axis or the Y' axis).

[0042] In most embodiments, one or more HAZ portions may be positioned within the high toe quadrant. In some embodiments, one or more HAZ portions may be positioned in both the low toe quadrant and the high toe quadrant. In some embodiments, one or more HAZ portions may be positioned in both the high toe quadrant and the high heel quadrant. In some embodiments, one or more HAZ portions may be in both the high toe quadrant and the low heel quadrant. In alternative embodiments, one or more HAZ portions may be in all quadrants and / or may be grouped around the geometric center.

[0043] The reference shape 126 may take the form of any shape and preferably does not extend into the body portion of the club head 100 (i.e., is positioned only on the face plate 102). For example, in many embodiments, the reference shape 126 may be substantially triangular, square, rectangular, polygonal, semi-circular, curved, etc. Generally, the reference shape comprises an area having a characteristic time value greater than a characteristic time threshold or a target characteristic time value.

[0044] One or more characteristic time values on the faceplate 102 that are greater than the threshold value, the designed, or the measured characteristic time value of the object may be detected or positioned through (1) the standard USGA test method for measuring characteristic time through a thermal search process (attempting to identify the position and value of the maximum characteristic time value of the club head by taking measurements at strategically selected positions), or (2) by identifying related known areas through aggregation of CT data, depending on the manufacturer. For the detection or identification of areas, regions, and / or positions of the golf club head having characteristic time values approximating the CT threshold value, a given area, region, and / or position of the golf club head may be subject to, or may be configured with, local weld beads (or spot welds) to generate a heat affected zone (HAZ).

[0045] This generates a faceplate 102 having a non-uniform micro-structure (see FIGS. 6-9). The CT characteristics of the processing unit may be changed by subjecting a local weld bead or spot weld to a related given area on the faceplate 102 to generate a heat affected zone. In other words, a faceplate area (or position) that approximates or is greater than the CT threshold value may be subjected to a weld bead or spot weld to locally change the micro-structure of the processed area (to locally generate a higher strength area and / or a hardened area) to generate a heat affected zone to the extent that the CT characteristics of that area are reduced according to a value below the target CT threshold value. Thus, instead of changing the contour of the club head to accommodate a faceplate area having a high CT area (i.e., increasing the face thickness, modifying the varying face thickness contour of the faceplate, introducing club head reinforcement elements, etc.), the applied HAZ structure reduces the reliance on a global (or large-scale) design modification to the club head and instead focuses on local changes to the micro-structure (or small-scale) modification to the faceplate 102.

[0046] I. Embodiments In many embodiments of the golf club head 100 described below, the heat affected zone may be found in certain regions of the face plate 102, and further, the heat affected zone may border within or be positioned entirely within the reference shape 126. As described above and discussed in detail below, the deposition of weld beads or spot welds within the reference shape produces a HAZ region that forms a dendritic microstructure (different from the non-spot weld regions). By placing spot welds at relevant locations in regions where the CT properties are above a threshold value, a CT reduction due to the dendritic microstructure properties is brought about. The reference shape may more readily assist in identifying the locations of individual CT corrections, as it generates the outer profile around and / or across the region to be CT adjusted.

[0047] In many embodiments, the golf club head 100 may also be viewed in a direction generally perpendicular to the X'Y' plane 101 and the face plate 102 as shown by FIGS. 1 - 8. When viewing the golf club head in a direction generally perpendicular to the X'Y' plane 101 and the face plate 102, the golf club head 100 may be defined by a coordinate system having an X' axis 103 extending through the geometric center 104 of the face plate 102 in the heel 105 - toe 106 direction, and a Y' axis 107 extending through the geometric center 104 in the top - bottom (or crown 108 - sole 109) direction.

[0048] The X'-axis 103 horizontally divides the golf club head into an upper region 110 and a lower region 111. The upper region 110 of the golf club head is bounded by the X'-axis 103, the crown 108, and the maximum heel-toe width of the club head. The lower region 111 of the golf club head is bounded by the X'-axis 103, the sole 109, and the maximum heel-toe width of the golf club head. The Y'-axis 107 vertically separates the club head into a left region 112 and a right region 113. The left region 112 may be bounded by the Y'-axis and the toe end of the golf club head. The right region may be bounded by the Y'-axis 107 and the heel 105 of the golf club head 100. Further, the X'-axis 103 and the Y'-axis 107 are perpendicular to each other and form four face plate quadrant regions.

[0049] The four face plate quadrant regions may be defined as a center-high toe quadrant 114, a center-low toe quadrant 115, a center-high heel quadrant 116, and a center-low heel quadrant 117 when the golf club head is placed on the ground 118 at the address position. The center-high toe quadrant 114 extends from the geometric center 104 and reaches the upper left face plate region. The center-low toe quadrant 115 extends from the geometric center 104 and reaches the lower left face plate region. The center-high heel quadrant 116 extends from the geometric center 104 and reaches the upper right face plate region. The center-low heel quadrant 117 extends from the geometric center 104 and reaches the lower right face plate region.

[0050] One or more of the face plate quadrant regions 114, 115, 116, 117 may include characteristic time values that are the target characteristic time value, exceed it, or approximate it. In many embodiments, the quadrant of interest may be the center-high toe quadrant 114. This is because this region can be identified as an important region having one or more positions approximating important CT thresholds due to manufacturing tolerances and / or variations.

[0051] As shown by Figure 2, the setup (or address) positions of Figures 1 and 2 are the same. Figure 2 further maps points at a plurality of potential positions within the center - high toe quadrant 114 to identify whether the faceplate characteristic time value is at, approximates, or exceeds the target characteristic time limit. Generally, CT readings are typically emphasized at the center - high toe as this is the known quadrant to which it is relevant. Table 1, further provided in the exemplary section, provides the average of the approximate CT readings (in microseconds) at the corresponding mapped position points on the club head within the center - high toe quadrant 114 for each faceplate without HAZ. In other words, the faceplates 102 of Figure 2 and Table 1 have a uniform micro - structure.

[0052] As further shown by Figure 6, the first spot weld 119 and the second spot weld 120 formed on the faceplate 102 locally change the micro - structure of the faceplate 102 within the heat - affected zone described above. The micro - structure of the heat - affected zone brought about by spot welding forms a dendritic structure, which is a needle - like or finger - like structure that produces smaller grain boundaries in order to harden or increase the faceplate strength in the weld (or HAZ) region. This local hardening directly correlates with a decrease in the characteristic time of the region where the flexibility of the faceplate is restricted. Positions outside the weld pool and the heat - affected zone (i.e., positions not affected by spot welding) have a homogeneous micro - structure with larger grain boundaries relative to the grain boundaries of the heat - affected zone. In many embodiments, the HAZ structure defined by spot welding produces a faceplate with a 2% - 6% increase in dendritic micro - structure compared to the non - spot - welded faceplate.

[0053] As is apparent from the following examples, a golf club head having a face plate with a uniform microstructure or non-HAZ structure within the center / high toe quadrant can have characteristic time values that vary up to 20 μs in the crown / sole direction and the heel / toe direction. Further, points measured directly adjacent to another point can vary up to 16 μs. Having a golf club head with a face plate 102 having a wide range of characteristic time characteristics depending on the location of golf ball impact can have an adverse effect on the ball speed generated. In many golf club head embodiments, it is desirable for a given quadrant to have characteristic time characteristics that are more uniform (i.e., have less variation in the heel / toe and crown / sole directions).

[0054] For the identification of quadrants having a high degree of variation and / or meeting or exceeding the designed CT parameters, the quadrant, more particularly the location of interest, and thus the reference shape may be projected onto the HAZ portion. The reference shape may surround the location of interest or may partially enclose it. As described below, in many embodiments, the reference shape may enclose a large region of interest or a small region of interest depending on the CT characteristics of the face plate 102.

[0055] (Rectangular reference shape) In many embodiments, the heat affected zone may be found in a particular region of the face plate, and further, the heat affected zone may border within the reference shape or be positioned entirely within the reference shape. The deposition of weld beads or spot welds within the reference shape creates a HAZ region that forms a dendritic microstructure (different from the non-spot weld region). By placing spot welds at the relevant locations in regions where the CT characteristics are above a threshold value, it results in a CT reduction due to the dendritic microstructure characteristics. The reference shape may help to more easily identify the location of individual CT corrections in order to generate the outer shape around and / or across the region to be CT adjusted.

[0056] As shown by FIG. 3, in many embodiments, the reference shape 126 encompassing the region of interest (i.e., one or more faceplate CT measurements that meet or exceed the designed CT parameters) may be substantially rectangular. Alternatively, the reference shape 126 may be in the form of a square that extends from the geometric center 104 of the faceplate 102 to a point within the center - high toe quadrant 114.

[0057] The rectangular (or square) reference shape 126 may have a height measured in the loft plane that extends in the crown - sole direction by about 5% to about 50% of the overall height of the faceplate 102. In many embodiments, the height of the rectangular reference shape 126 may be about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, or about 45% to about 50% of the overall height of the faceplate 102.

[0058] In alternative embodiments, the rectangular reference shape 126 may have a maximum height measured in the loft plane in the crown - sole direction of about 0 inches to 1.05 inches. In many embodiments, the maximum height of the rectangular reference shape 126 may be about 0 inches to about 0.25 inches, about 0.25 inches to about 0.5 inches, about 0.5 inches to about 0.75 inches, about 0.75 inches to 1.00 inches, or about 1.00 inches to about 1.05 inches. In other embodiments, the maximum height of the rectangular reference shape may be greater than about 0 inches, greater than about 0.25 inches, greater than about 0.5 inches, greater than about 0.75 inches, or greater than about 1 inch. In alternative embodiments, the maximum height of the rectangular reference shape may be less than about 1.05 inches, less than about 1.0 inches, less than about 0.75 inches, less than about 0.5 inches, or less than about 0.25 inches.

[0059] The reference shape 126 of the rectangle (or square) may have a width measured in the loft plane that is about 5% to about 25% of the overall width of the face plate 102 in the heel-to-toe direction. In many embodiments, the width of the rectangular reference shape 126 may be about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, or about 20% to about 25% of the overall width of the face plate 102.

[0060] In an alternative embodiment, the reference shape of the rectangle may have a maximum width of about 0 inches to 1.05 inches measured in the loft plane in the heel-to-toe direction. In many embodiments, the maximum width of the rectangular reference shape 126 may be about 0 inches to about 0.25 inches, about 0.25 inches to about 0.5 inches, about 0.5 inches to about 0.75 inches, about 0.75 inches to 1.00 inches, or about 1.00 inches to about 1.05 inches. In other embodiments, the maximum width of the rectangular reference shape 126 may be greater than about 0 inches, may be greater than about 0.25 inches, may be greater than about 0.5 inches, may be greater than about 0.75 inches, or may be greater than about 1 inch. In an alternative embodiment, the maximum width of the rectangular reference shape 126 may be less than about 1.05 inches, may be less than about 1.0 inches, may be less than about 0.75 inches, may be less than about 0.5 inches, or may be less than about 0.25 inches.

[0061] (Oval reference shape) As described above, the heat-affected zone may be found in a particular region of the face plate 102, and further, the heat-affected zone may border within the reference shape 126 or may be positioned entirely within the reference shape 126. The deposition of the weld bead or spot weld within the reference shape generates a HAZ region that forms a dendritic microstructure (different from the non-spot-welded region). By placing spot welds at the relevant locations in regions where the CT characteristic is above the threshold value, it results in a CT reduction due to the dendritic microstructure characteristic. The reference shape 126 may help to more easily identify the location of individual CT corrections in order to generate the outer shape around and / or across the region subject to CT adjustment.

[0062] As shown by FIG. 4, in many embodiments, a reference shape 126 that encompasses an area of interest for applying the HAZ region (i.e., one or more faceplate CT measurement values that meet or exceed the designed CT parameters) may be substantially elliptical. The reference shape 126, more particularly the elliptical reference shape 126, may extend from the geometric center 104 of the faceplate 102 to a point within the central-height quadrant 114.

[0063] An exemplary elliptical reference shape may be about 5% to about 50% of the overall height of the faceplate 102, measured in the loft plane, and may have a minor axis 127 that passes through the center of the ellipse. In many embodiments, the minor axis of the elliptical reference shape 126 may be about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, or about 45% to about 50% of the overall height of the faceplate 102.

[0064] In an alternative embodiment, the elliptical reference shape 126 may have a minor axis 127 that is about 0 inches to 1.05 inches, measured in the loft plane. In many embodiments, the minor axis 127 measurement dimension of the elliptical reference shape 126 may be about 0 inches to about 0.25 inches, about 0.25 inches to about 0.5 inches, about 0.5 inches to about 0.75 inches, about 0.75 inches to 1.0 inches, or about ,0 inches to about 1.05 inches. In other embodiments, the minor axis 127 of the elliptical reference shape may be greater than about 0 inches, may be greater than about 0.25 inches, may be greater than about 0.5 inches, may be greater than about 0.75 inches, or may be greater than about 1 inch. In an alternative embodiment, the minor axis 127 of the elliptical reference shape may be less than about 1.05 inches, may be less than about 1.0 inches, may be less than about 0.75 inches, may be less than about 0.5 inches, or may be less than about 0.25 inches.

[0065] The elliptical reference shape 126 may have a major axis 128 measured in the loft plane that is about 5% to about 25% of the overall height of the faceplate 102. In many embodiments, the major axis 128 of the elliptical reference shape 126 may be about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, or about 20% to about 25% of the overall height of the faceplate 102.

[0066] In an alternative embodiment, the elliptical reference shape 126 may have a major axis 128 that is about 0 inches to 1.05 inches measured in the loft plane. In many embodiments, the major axis 128 of the elliptical reference shape 126 may be about 0 inches to about 0.25 inches, about 0.25 inches to about 0.5 inches, about 0.5 inches to about 0.75 inches, about 0.75 inches to 1.00 inches, or about 1.00 inches to about 1.05 inches. In other embodiments, the major axis 128 of the elliptical reference shape 126 may be greater than about 0 inches, may be greater than about 0.25 inches, may be greater than about 0.5 inches, may be greater than about 0.75 inches, or may be greater than about 1 inch. In an alternative embodiment, the major axis 128 of the elliptical reference shape 126 may be less than about 1.05 inches, may be less than about 1.0 inches, may be less than about 0.75 inches, may be less than about 0.5 inches, or may be less than about 0.25 inches.

[0067] In many embodiments, the major axis 128 of the elliptical reference shape 126 may be angled with respect to the x-axis 103. The angle between the major axis 128 of the elliptical reference shape and the x-axis 103 may be 20 degrees to 80 degrees. In many embodiments, the angle formed between the elliptical reference shape 126 and the x-axis 103 may vary based on the location of interest. In some embodiments, the angle of the major axis and the x-axis may be about 20 degrees to about 25 degrees, about 30 degrees to about 35 degrees, about 35 degrees to about 40 degrees, about 40 degrees to about 45 degrees, about 45 degrees to about 50 degrees, about 50 degrees to about 55 degrees, about 55 degrees to about 60 degrees, about 60 degrees to about 65 degrees, about 65 degrees to about 70 degrees, about 70 degrees to about 75 degrees, or about 75 degrees to about 80 degrees. In many embodiments, the angle formed may be about 45 degrees.

[0068] (Reference shape of the straight line) As described above, the heat affected zone may be found in a specific region of the face plate. Further, the heat affected zone may form a boundary within the reference shape 126 or may be entirely positioned within the reference shape 126. The deposition of the weld bead or spot weld within the reference shape 126 generates a HAZ region that forms a dendritic microstructure (different from the non-spot weld region). By placing spot welds at relevant positions in regions where the CT characteristic is above the threshold value, a CT reduction due to the dendritic microstructure characteristic is brought about. The reference shape may more easily assist in identifying the positions of individual CT corrections in order to generate the outer shape around and / or across the region targeted for CT adjustment.

[0069] As shown by FIG. 5, in many embodiments, the reference shape encompassing the region of interest (i.e., one or more face plate CT measurements that meet or exceed the designed CT parameters) may be substantially straight. The reference shape, more particularly the straight reference shape 126, may extend from the geometric center 104 of the face plate 102 to a point within the center-high toe quadrant 114. In many embodiments, one or more HAZ portions (or weld beads) are applied along the straight reference shape 126.

[0070] In many embodiments, the straight reference shape 126 may be angled with respect to the x-axis 103. The angle between the straight reference shape 126 and the x-axis 103 may be between 20 degrees and 80 degrees. In many embodiments, the angle formed between the straight reference shape 126 and the x-axis may vary based on the position of interest. In some embodiments, the angle formed between the straight reference shape 126 and the x-axis 103 may be from about 20 degrees to about 25 degrees, from about 30 degrees to about 35 degrees, from about 35 degrees to about 40 degrees, from about 40 degrees to about 45 degrees, from about 45 degrees to about 50 degrees, from about 50 degrees to about 55 degrees, from about 55 degrees to about 60 degrees, from about 60 degrees to about 65 degrees, from about 65 degrees to about 70 degrees, from about 70 degrees to about 75 degrees, or from about 75 degrees to about 80 degrees. In many embodiments, the formed angle may be about 45 degrees.

[0071] The straight reference shape 126 may have a maximum height of about 5% to about 50% of the overall height of the faceplate 102 in the crown - sole direction and may have a height measured in the loft plane. In many embodiments, the height of the straight reference shape is about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, or about 45% to about 50% of the overall height of the faceplate 102.

[0072] In an alternative embodiment, the straight reference shape 126 may have a maximum height of about 0 inches to 1.05 inches measured in the loft plane in the crown - sole direction. In many embodiments, the maximum height of the straight reference shape 126 is about 0 inches to about 0.25 inches, about 0.25 inches to about 0.5 inches, about 0.5 inches to about 0.75 inches, about 0.75 inches to 1.00 inches, or about 1.00 inches to about 1.05 inches. In other embodiments, the maximum height of the straight reference shape 126 may be greater than about 0 inches, greater than about 0.25 inches, greater than about 0.5 inches, greater than about 0.75 inches, or greater than about 1.0 inches. In an alternative embodiment, the maximum height of the straight reference shape 126 may be less than about 1.05 inches, less than about 1.0 inches, less than about 0.75 inches, less than about 0.5 inches, or less than about 0.25 inches.

[0073] The straight reference shape 126 may have a maximum width measured in the loft plane that is about 5% to about 25% of the overall width of the faceplate 102 in the heel - toe direction. In many embodiments, the width of the straight reference shape 126 is about 5% to about 10%, about 10% to about 15%, about 15% to about 20%, or about 20% to about 25% of the overall width of the faceplate 102.

[0074] In an alternative embodiment, the straight reference shape 126 may have a maximum width, measured within the loft plane, of from about 0 inches to 1.05 inches in the heel-to-toe direction. In many embodiments, the maximum width of the straight reference shape 126 may be from about 0 inches to about 0.25 inches, from about 0.25 inches to about 0.5 inches, from about 0.5 inches to about 0.75 inches, from about 0.75 inches to about 1.00 inches, or from about 1.00 inches to about 1.05 inches. In other embodiments, the maximum width of the straight reference shape 126 may be greater than about 0 inches, greater than about 0.25 inches, greater than about 0.5 inches, greater than about 0.75 inches, or greater than about 1 inch. In an alternative embodiment, the maximum width of the straight reference shape 126 may be less than about 1.05 inches, less than about 1.0 inches, less than about 0.75 inches, less than about 0.5 inches, or less than about 0.25 inches.

[0075] As described above, the reference shape 126 described above is projected onto the face plate 102 to create a boundary around the relevant area. These relevant areas are typically areas that have a high CT value and can generally be found in the central-high toe quadrant 114. Within the central-high toe quadrant 114, specifically referring to FIGS. 2 and Table 1, it is seen that at the point of a given measurement location (i.e., the CT measurement area), the CT can vary by up to about 15 μs within a 1 inch × 1 inch area. Further, at the points of adjacent face plate positions, the CT can vary by up to 11 μs. This variation can further increase over time due to repeated impacts (i.e., wear). To reduce the variation, within a local area and without affecting adjacent measurement positions, the HAZ portion may be formed within the reference shape 126 or at the boundary of the reference shape 126 via spot welding and / or weld beads.

[0076] (Reference shape having one or more HAZ portions) As described above, the heat-affected zone may be found in one or more regions of the faceplate, and further, the heat-affected zone may form a boundary within the reference shape or may be positioned entirely within the reference shape. The deposition of a weld bead or spot weld within the reference shape generates a HAZ region that forms a dendritic microstructure (different from the non-spot-welded regions). By placing spot welds at relevant positions in regions where the CT characteristic is above a threshold value, a CT reduction due to the dendritic microstructure characteristic is brought about. The reference shape may more easily assist in identifying the positions of individual CT corrections, as it generates an outer profile around and / or across the region to be CT-adjusted.

[0077] As described above, the HAZ region is the region brought about by a weld bead that changes the microstructure of the faceplate. As shown in FIG. 6, two spot welds (i.e., the first spot weld may also be referred to as the "first weld bead" and the second spot weld may also be referred to as the "second weld bead") are formed on the outer surface of the faceplate 102. In other words, the first spot weld 119 and the second spot weld 120 may be applied to the (outer) surface of the faceplate 102 that directly contacts the golf ball during impact. In other embodiments, the first and second spot welds 119, 120 need not be formed / applied on the outer surface of the faceplate 102; conversely, the first and second spot welds 119, 120 may be applied to the rear surface of the faceplate 102 in an open crown or open sole design (i.e., where the body of the golf club head provides access to the interior of the club head). In many embodiments, the first spot weld 119 may be positioned at the geometric center of the faceplate, and the second spot weld 120 is spaced from the geometric center and is positioned alone in the center-high toe quadrant.

[0078] As described above, one or more spot welds locally affect the microstructure of a specific region on the faceplate 102 without globally changing the microstructure across the faceplate 102. One or more spot welds in FIG. 6 may generally be defined by diameter. The diameter of one or more spot welds in contact with the faceplate 102 may be from about 0.125 inches to about 0.75 inches. In many embodiments, the diameter of one or more spot welds may be from about 0.125 inches to about 0.225 inches, from about 0.225 inches to about 0.325 inches, from about 0.325 inches to about 0.425 inches, from about 0.425 inches to about 0.525 inches, from about 0.525 inches to about 0.625 inches, or from about 0.625 inches to about 0.75 inches. In other embodiments, the diameter of one or more spot welds may be about 0.1 inches, 0.150 inches, 0.2 inches, 0.250 inches, 0.3 inches, 0.350 inches, 0.4 inches, 0.450 inches, 0.5 inches, 0.550 inches, 0.6 inches, 0.650 inches, 0.7 inches, or 0.750 inches. In alternative embodiments, the diameter of one or more spot welds may be less than about 0.750 inches, less than about 0.7 inches, less than about 0.65 inches, less than 0.6 inches, less than about 0.55 inches, less than about 0.50 inches, less than about 0.45 inches, less than about 0.40 inches, less than about 0.35 inches, less than about 0.30 inches, less than about 0.20 inches, or less than about 0.15 inches. <0000XX8><0000XX9><0000XXX> It should be noted that the tags ,

[0079] , in the original text seem to be some kind of specific identifiers in a particular context. Since their nature is not clear from the given text, they are simply preserved as is in the translation. If there is more information about these tags, a more accurate translation might be possible. Also, the "XX" and "XXX" in the translated tags are placeholders for the original tag values which are maintained exactly as they are.The heat affected zone formed by spot welding may be about 20% to about 50% of the diameter of the spot welding. In many embodiments, the spot welding may form a heat affected zone (i.e., the location where the microstructure changes) of about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, about 45% to about 50% of the diameter of the spot welding. In other embodiments, the spot welding may form a heat affected zone of less than about 50%, less than about 45%, less than about 40%, less than about 35%, less than about 30%, or less than about 25% of the diameter of the spot welding. The heat affected zone is the non-molten region of the face plate 102 where the microstructure has changed as a result of the metal matrix portion being exposed to a high welding temperature. The remaining region of the spot welding may be defined as the weld pool region (i.e., the region where the face plate 102 reaches its melting point and filler material can be injected), as an example shown in FIG. 9. FIG. 9 merely illustrates the reference between the weld bead (or spot welding) and the HAZ portion. The weld bead may be disposed outside the face plate surface via heating. The bead portion is removed via finishing techniques (grinding, machining, polishing, etc.), but the formed HAZ portion still easily exists within the structure.

[0080] As described above, FIG. 6 shows a first spot weld 119 and a second spot weld 120 applied to the faceplate 102 to locally vary the microstructure of the faceplate 102 within the heat affected zone described above. The microstructure of the heat affected zone caused by the spot weld forms a dendritic structure, which is a needle-like or finger-like structure that produces smaller grain boundaries in order to harden or increase the faceplate strength in the weld (or HAZ) region. This local hardening directly correlates with a decrease in the characteristic time of the region where the flexibility of the faceplate is limited. The positions outside the weld pool and the heat affected zone (i.e., positions not affected by the spot weld) have a homogeneous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zone. In many embodiments, the HAZ structure defined by the spot weld produces a faceplate with a 2% to 6% increase in dendritic microstructure compared to the non-spot welded faceplate.

[0081] In this particular embodiment, the first spot weld 119 and the second spot weld are positioned on and / or within the reference shape 126 described above, are spaced apart, and do not touch each other. In many embodiments, the center of the first spot weld 119 and the center of the second spot weld 120 are spaced about 0.1 inch to 1 inch apart. For example, in many embodiments, the center of the first spot weld 119 and the center of the second spot weld 120 may be 0.1 inch, 0.15 inch, 0.2 inch, 0.25 inch, 0.3 inch, 0.35 inch, 0.4 inch, 0.45 inch, 0.5 inch, 0.55 inch, 0.60 inch, 0.65 inch, 0.70 inch, 0.75 inch, 0.80 inch, 0.85 inch, 0.90 inch, 0.95 inch, or 1.0 inch apart from each other. In other embodiments, the separation distance between the center of the first spot weld and the center of the second spot weld 120 may be less than 1.0 inch, may be less than 0.95 inch, may be less than 0.90 inch, may be less than 0.85 inch, may be less than 0.80 inch, may be less than 0.75 inch, may be less than 0.70 inch, may be less than 0.65 inch, may be less than 0.60 inch, may be less than 0.55 inch, may be less than 0.50 inch, may be less than 0.45 inch, may be less than 0.40 inch, may be less than 0.35 inch, may be less than 0.30 inch, may be less than 0.20 inch, or may be less than 0.150 inch.

[0082] In many embodiments, the second spot weld 120 may be offset from the geometric center by up to about 0.84 inches along the X-axis and / or toward the toe. In alternative embodiments, the second spot weld 120 may be offset from the geometric center by about 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, 0.21 inches, 0.22 inches, 0.23 inches, 0.24 inches, 0.25 inches, 0.26 inches, 0.27 inches, 0.28 inches, 0.29 inches, 0.30 inches, 0.31 inches, 0.32 inches, 0.33 inches, 0.34 inches, 0.35 inches, 0.36 inches, 0.37 inches, 0.38 inches, 0.39 inches, 0.40 inches, 0.41 inches, 0.42 inches, 0.43 inches, 0.44 inches, 0.45 inches, 0.46 inches, 0.47 inches, 0.48 inches, 0.49 inches, 0.50 inches, 0.51 inches, 0.52 inches, 0.53 inches, 0.54 inches, 0.55 inches, 0.56 inches, 0.57 inches, 0.58 inches, 0.59 inches, 0.60 inches, 0.61 inches, 0.62 inches, 0.63 inches, 0.64 inches, 0.65 inches, 0.66 inches, 0.67 inches, 0.68 inches, 0.69 inches, 0.70 inches, 0.71 inches, 0.72 inches, 0.73 inches, 0.74 inches, 0.75 inches, 0.76 inches, 0.77 inches, 0.78 inches, 0.79 inches, 0.80 inches, 0.81 inches, 0.82 inches, 0.83 inches, or 0.84 inches along the X-axis and / or toward the toe.

[0083] In the same or other embodiments, the second spot weld 120 may be offset from the geometric center by up to about 0.42 inches toward the upper end of the crown or face plate. The second spot weld 120 may be offset from the geometric center by about 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, 0.21 inches, 0.22 inches, 0.23 inches, 0.24 inches, 0.25 inches, 0.26 inches, 0.27 inches, 0.28 inches, 0.29 inches, 0.30 inches, 0.31 inches, 0.32 inches, 0.33 inches, 0.34 inches, 0.35 inches, 0.36 inches, 0.37 inches, 0.38 inches, 0.39 inches, 0.40 inches, 0.41 inches, or 0.42 inches along the Y-axis direction and / or toward the crown. In many embodiments, the first and second spot welds are spaced apart and do not contact or abut the face-body transition region.

[0084] In many embodiments, as shown in FIG. 6, the first spot weld 119 and the second spot weld 120 are collinear with each other. In alternative embodiments, the first spot weld 119 and the second spot weld need not be collinear. Based on the face plate surface area of the club head shown, about 0.5% to 1.0% of the face plate surface area may contact a single weld bead. No more than 16.5% of the external face plate surface area may contact any weld.

[0085] (Straight reference shape with one or more HAZ regions) The heat affected zone may be found in a specific region of the faceplate. Further, the heat affected zone may form a boundary within the reference shape or be positioned entirely within the reference shape. The deposition of weld beads or spot welds within the reference shape creates a HAZ region that forms a dendritic microstructure (different from the non-spot weld regions). By placing spot welds at relevant locations in regions where the CT characteristic is above a threshold value, a CT reduction due to the dendritic microstructure characteristic is brought about. The reference shape may more easily assist in identifying the location of individual CT corrections, as it generates the outer shape around and / or across the region subject to CT adjustment.

[0086] As described above, the HAZ portion may also be arranged linearly along the reference shape. As described above, the reference shape 126 may be projected onto the faceplate 102. More specifically, the linear reference shape 126 may be projected onto a plurality of relevant points on the faceplate 102. These relevant points are typically regions where the CT value is high and can generally be found in the central and high toe quadrant 114. Within the central and high toe quadrant 114, with specific reference to the following example, at the points of the faceplate measurement positions (i.e., the CT measurement regions), it is seen that the CT can vary by up to approximately 15 μs within a 1-inch by 1-inch region. Further, at the points of adjacent faceplate positions, the CT can vary by up to 11 μs. This variation can further increase over time due to repeated impact (i.e., wear). To reduce the variation, within a local region and without affecting adjacent measurement positions, the HAZ portion may be formed via spot welds and / or weld beads.

[0087] As shown in FIG. 7, a plurality of spot welds 121 (i.e., the plurality of spot welds may also be referred to as "a plurality of weld beads") are formed on the outer surface of the face plate 102. In other words, the plurality of spot welds 121 may be applied to the (outer) surface of the face plate 102 that directly contacts the golf ball during impact. In other embodiments, the plurality of spot welds 121 need not be formed / applied on the outer surface of the face plate 102. Instead, the plurality of spot welds 121 may be applied to the rear surface of the face plate 102 in an open crown or open sole design (i.e., the body of the golf club head provides access to the interior of the club head).

[0088] In many embodiments, the plurality of spot welds may be referred to as two or more spot welds, three or more spot welds, four or more spot welds, five or more spot welds, six or more spot welds, seven or more spot welds, eight or more spot welds, nine or more spot welds, ten or more spot welds, eleven or more spot welds, or twelve or more spot welds. The plurality of spot welds may generally be formed along a linear reference shape. In some embodiments, due to accuracy errors, the plurality of spot welds may be slightly offset from the linear reference shape 126.

[0089] As described above, the plurality of spot welds 121 locally affect the microstructure of a specific region on the faceplate 102 without globally changing the microstructure across the faceplate 102. The plurality of spot welds shown by FIG. 7 may generally be defined by diameter. The diameter of the plurality of spot welds 121 in contact with the faceplate 102 may be from about 0.125 inches to about 0.75 inches. In many embodiments, the diameter of the plurality of spot welds may be from about 0.125 inches to about 0.225 inches, from about 0.225 inches to about 0.325 inches, from about 0.325 inches to about 0.425 inches, from about 0.425 inches to about 0.525 inches, from about 0.525 inches to about 0.625 inches, or from about 0.625 inches to about 0.75 inches. In other embodiments, the diameter of the plurality of spot welds 121 may be about 0.1 inches, 0.150 inches, 0.2 inches, 0.250 inches, 0.3 inches, 0.350 inches, 0.4 inches, 0.450 inches, 0.5 inches, 0.550 inches, 0.6 inches, 0.650 inches, 0.7 inches, or 0.750 inches. In alternative embodiments, the diameter of the plurality of spot welds 121 may be less than about 0.750 inches, less than about 0.7 inches, less than about 0.65 inches, less than 0.6 inches, less than about 0.55 inches, less than about 0.50 inches, less than about 0.45 inches, less than about 0.40 inches, less than about 0.35 inches, less than about 0.30 inches, less than about 0.20 inches, or less than about 0.15 inches.

[0090] The heat affected zone formed by a plurality of spot welds 121 may be about 20% to about 50% of the diameter of each of the plurality of spot welds. In many embodiments, the spot welds may form a heat affected zone (i.e., a location where the microstructure changes) of about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, about 45% to about 50% of the diameter of the spot weld. In other embodiments, the plurality of spot welds 121 may form a heat affected zone of less than about 50%, less than about 45%, less than about 40%, less than about 35%, less than about 30%, or less than about 25% of the diameter of the spot weld. The heat affected zone is a non-molten region of the face plate 102 whose microstructure has changed as a result of being exposed to a high welding temperature. The remaining region of the spot weld may be defined as a weld pool region (i.e., a region where the face plate 102 can reach its melting point and filler material can be injected), as an example shown in FIG. 9.

[0091] Further shown by FIG. 7, as described above, the plurality of spot welds formed on the face plate 102 locally change the microstructure of the face plate 102 within the heat affected zone described above. The microstructure of the heat affected zone caused by the spot weld forms a dendritic structure, which is a needle-like or finger-like structure that produces a smaller grain boundary size in order to harden or increase the strength of the face plate 102 in the weld (or HAZ) region. This local hardening is directly correlated with a reduction in the characteristic time of the region such that the flexibility of the face plate is reduced. Positions outside the weld pool and the heat affected zone (i.e., positions not affected by the spot weld) have a homogeneous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zone.

[0092] In this particular embodiment, the plurality of spot welds 121 are positioned along a straight reference shape 126, extending from the geometric center 104 of the face plate 102 to a point within the center - high toe quadrant and not extending into the body portion of the club head. In this exemplary embodiment, each of the plurality of spot welds 121 is in contact with or touches another spot weld of the plurality of spot welds. In other embodiments, the plurality of spot welds need not touch or be in contact with another spot weld. In these embodiments, the plurality of spot welds may be spaced from each other by about 0.1 inch to 1 inch. For example, in many embodiments, the plurality of spot welds may be spaced 0.1 inch, 0.15 inch, 0.2 inch, 0.25 inch, 0.3 inch, 0.35 inch, 0.4 inch, 0.45 inch, 0.5 inch, 0.55 inch, 0.60 inch, 0.65 inch, 0.70 inch, 0.75 inch, 0.80 inch, 0.85 inch, 0.90 inch, 0.95 inch, or 1.0 inch from each other.

[0093] Of the plurality of spot welds 121, the spot weld that is farthest from the geometric center (along the X-axis and / or toward the toe) may be separated by up to approximately 0.84 inches. In an alternative embodiment, the farthest spot weld of the plurality of spot welds 121 may be separated from the geometric center by about 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, 0.21 inches, 0.22 inches, 0.23 inches, 0.24 inches, 0.25 inches, 0.26 inches, 0.27 inches, 0.28 inches, 0.29 inches, 0.30 inches, 0.31 inches, 0.32 inches, 0.33 inches, 0.34 inches, 0.35 inches, 0.36 inches, 0.37 inches, 0.38 inches, 0.39 inches, 0.40 inches, 0.41 inches, 0.42 inches, 0.43 inches, 0.44 inches, 0.45 inches, 0.46 inches, 0.47 inches, 0.48 inches, 0.49 inches, 0.50 inches, 0.51 inches, 0.52 inches, 0.53 inches, 0.54 inches, 0.55 inches, 0.56 inches, 0.57 inches, 0.58 inches, 0.59 inches, 0.60 inches, 0.61 inches, 0.62 inches, 0.63 inches, 0.64 inches, 0.65 inches, 0.66 inches, 0.67 inches, 0.68 inches, 0.69 inches, 0.70 inches, 0.71 inches, 0.72 inches, 0.73 inches, 0.74 inches, 0.75 inches, 0.76 inches, 0.77 inches, 0.78 inches, 0.79 inches, 0.80 inches, 0.81 inches, 0.82 inches, 0.83 inches, or 0.84 inches along the X-axis 103 direction and / or toward the toe.

[0094] In the same or other embodiments, the spot weld among the plurality of spot welds 121 that is farthest from the geometric center along the Y-axis 107 may be spaced from the geometric center by up to about 0.42 inches towards the upper end of the crown or face plate. The farthest spot weld may be spaced from the geometric center by about 0.01 inches, 0.02 inches, 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, 0.21 inches, 0.22 inches, 0.23 inches, 0.24 inches, 0.25 inches, 0.26 inches, 0.27 inches, 0.28 inches, 0.29 inches, 0.30 inches, 0.31 inches, 0.32 inches, 0.33 inches, 0.34 inches, 0.35 inches, 0.36 inches, 0.37 inches, 0.38 inches, 0.39 inches, 0.40 inches, 0.41 inches, or 0.42 inches along the Y-axis direction and / or towards the crown. In many embodiments, the plurality of spot welds 121 are spaced apart and do not contact or abut the face-body transition region.

[0095] In many embodiments, as shown in FIG. 7, the plurality of spot welds are collinear with each other. In alternative embodiments, the plurality of spot welds need not be collinear and are slightly offset from a straight reference line (i.e., non-collinear). Based on the face plate surface area of the club head shown in the exemplary embodiment of FIG. 7, about 0.5% to 1.0% of the face plate surface area may be in contact with a single weld bead. Up to 16.5% of the external face plate surface area may be in contact with any weld.

[0096] (Rectangular reference shape having one or more HAZ regions) The heat affected zone may be found in a specific region of the faceplate, and further, the heat affected zone may form a boundary within the reference shape 126 or may be positioned entirely within the reference shape 126. The deposition of weld beads or spot welds within the reference shape 126 generates a HAZ region that forms a dendritic microstructure (different from the non-spot weld region). By placing spot welds at relevant locations in regions where the CT characteristic is above a threshold value, a CT reduction due to the dendritic microstructure characteristic is brought about. The reference shape 126 may more easily assist in identifying the location of individual CT corrections in order to generate an outer shape around and / or across the region to be CT adjusted.

[0097] As described above, the reference shape 126 is projected onto the faceplate 102 to generate a boundary around the relevant region. These relevant areas are typically regions where the CT value is high and can generally be found in the central and high-toe quadrant 114. Within the central and high-toe quadrant 114, specifically referring to FIG. 2, it can be seen that at the points of the faceplate position (i.e., the CT measurement region), the CT can vary by up to approximately 15 μs within a 1-inch by 1-inch region. Further, at the points of adjacent faceplate positions, the CT can vary by up to 11 μs. This variation can further increase over time due to repeated impact (i.e., wear). To reduce the variation, within a local region, the HAZ portion may be formed via spot welds and / or weld beads without affecting adjacent measurement positions.

[0098] As shown in FIG. 8, at least four spot welds (i.e., the first spot weld 119, the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 may also be referred to as the first weld bead, the second weld bead, the third weld bead, and the fourth weld bead, respectively) are formed on the outer surface of the face plate 102. In other words, the first spot weld 119, the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 may be applied to the (outer) surface of the face plate 102 that directly contacts the golf ball during impact. In other embodiments, the first, second, third, and fourth spot welds 119, 120, 122, 123 need not be formed / applied on the outer surface of the face plate 102. Instead, the first, second, third, and fourth spot welds 119, 120, 122, and 123 may be applied to the rear surface of the face plate 102 in an open crown or open sole design (i.e., where the golf club head provides access to the interior of the club head).

[0099] As described above, spot welds 119, 120, 122, and 123 can locally affect the microstructure of specific regions on the faceplate 102 without globally changing the microstructure across the faceplate 102. Four or more spot welds, as illustrated in FIG. 8, may generally be defined by diameter. The diameters of four or more spot welds 119, 120, 122, and 123 in contact with the faceplate 102 may be from about 0.125 inches to about 0.75 inches. In many embodiments, the diameter of one or more spot welds may be from about 0.125 inches to about 0.225 inches, from about 0.225 inches to about 0.325 inches, from about 0.325 inches to about 0.425 inches, from about 0.425 inches to about 0.525 inches, from about 0.525 inches to about 0.625 inches, or from about 0.625 inches to about 0.75 inches. In other embodiments, the diameters of four or more spot welds may be about 0.1 inches, 0.150 inches, 0.2 inches, 0.250 inches, 0.3 inches, 0.350 inches, 0.4 inches, 0.450 inches, 0.5 inches, 0.550 inches, 0.6 inches, 0.650 inches, 0.7 inches, or 0.750 inches. In alternative embodiments, the diameters of four or more spot welds may be less than about 0.750 inches, less than about 0.7 inches, less than about 0.65 inches, less than 0.6 inches, less than about 0.55 inches, less than about 0.50 inches, less than about 0.45 inches, less than about 0.40 inches, less than about 0.35 inches, less than about 0.30 inches, less than about 0.20 inches, or less than about 0.15 inches.

[0100] The heat-affected zone formed by a single spot weld may be about 20% to about 50% of the diameter of the spot weld. In many embodiments, the spot weld may form a heat-affected zone (i.e., the location where the microstructure changes) of about 20% to about 25%, about 25% to about 30%, about 30% to about 35%, about 35% to about 40%, about 40% to about 45%, about 45% to about 50% of the diameter of the spot weld. In other embodiments, the spot weld may form a heat-affected zone of less than about 50%, less than about 45%, less than about 40%, less than about 35%, less than about 30%, or less than about 25% of the diameter of the spot weld. The heat-affected zone is the non-molten region of the face plate 102 where the microstructure has changed as a result of being exposed to a high welding temperature. The remaining region of the spot weld may be defined as a weld pool region (i.e., the region where the face plate 102 reaches its melting point and is ready to receive the filler material), as shown in the example of FIG. 9.

[0101] As further shown by FIG. 8, the first spot weld 119, the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 formed on the face plate 102 locally change the microstructure of the face plate 102 within the heat-affected zone described above. The microstructure of the heat-affected zone caused by the spot weld forms a dendritic structure, which is a needle-like or finger-like structure that generates smaller grain boundaries in order to harden or increase the strength in the weld (or HAZ) region of the face plate 102. This local hardening is directly correlated with a decrease in the characteristic time of the region where the flexibility of the face plate is reduced. The positions outside the weld pool and the heat-affected zone (i.e., the positions not affected by the spot weld) have a homogeneous microstructure with larger grain boundaries compared to the grain boundaries of the heat-affected zone (i.e., the region with low rigidity and higher flexibility).

[0102] In this particular embodiment, the first spot weld 119, the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 are positioned at related positions on and / or within a rectangular reference shape 126, may be spaced apart from each other, and do not touch each other. In many embodiments, the separation distances between the centers of the first spot weld 119, the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 may vary. In many embodiments, the separation distance may be from about 0.1 inch to 1 inch. For example, in many embodiments, from the center of the first spot weld 119 to at least one of the centers of the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 may be spaced 0.1 inch, 0.15 inch, 0.2 inch, 0.25 inch, 0.3 inch, 0.35 inch, 0.4 inch, 0.45 inch, 0.5 inch, 0.55 inch, 0.60 inch, 0.65 inch, 0.70 inch, 0.75 inch, 0.80 inch, 0.85 inch, 0.90 inch, 0.95 inch, or 1.0 inch from each other. In other embodiments, the separation distance between the center of the first spot weld 119 and at least one of the centers of the second spot weld 120, the third spot weld 122, and the fourth spot weld 123 may be less than 1.0 inch, may be less than 0.95 inch, may be less than 0.90 inch, may be less than 0.85 inch, may be less than 0.80 inch, may be less than 0.75 inch, may be less than 0.70 inch, may be less than 0.65 inch, may be less than 0.60 inch, may be less than 0.55 inch, may be less than 0.50 inch, may be less than 0.45 inch, may be less than 0.40 inch, may be less than 0.35 inch, may be less than 0.30 inch, may be less than 0.20 inch, or may be less than 0.150 inch. In many embodiments, the first, second, third, and fourth spot welds are spaced apart and do not contact or abut the face-body transition region.

[0103] In many embodiments, as shown in FIG. 8, at least two spot welds are collinear with each other. In the same or alternative embodiments, at least two spot welds are not collinear with each other. Based on the face plate surface area of the club head shown in the example of FIG. 8, about 0.5% to 1.0% of the surface area of the face plate may be in contact with a single weld bead. Up to 16.5% of the external face plate surface area may be in contact with any weld.

[0104] (Manufacturing method) FIG. 10 shows a process for forming and / or assembling a golf club head 100. In a first step 200, a face plate 102 may be aligned with the body of the golf club head 100. A second step 300 involves welding the face plate 102 to the body of the club head 100. In a third step 400, the club head and face plate may be heated through a series of solution and / or aging steps to a solvus temperature of the face plate material, a temperature higher than the solvus temperature, or a temperature lower than the solvus temperature. In a fourth step 500, the club head and face plate are air cooled.

[0105] Once the club head is cooled, a fifth step 600 involves identifying at least one relevant region on the face plate. This relevant region may typically be identified or found by determining the location where a golf ball remains on the face plate during impact for a period longer than the intentionally designed period. That location may be identified or found by (1) a standard USGA test method for measuring characteristic time via a thermal search process (attempting to identify the location and value of the maximum characteristic time value of the club head by taking measurements at strategically selected locations), or (2) by identifying relevant known regions through club head aggregation of CT data.

[0106] Once at least one associated region on the faceplate is identified, spot welding via plasma welding or laser welding is applied to the at least one associated region at a predetermined temperature of 500°C to 650°C for a time range of 1 second to 5 seconds, thereby possibly forming a HAZ region. This step 700 may be completed prior to any faceplate finishing step. For example, the local heat treatment may be completed prior to a smoothing or texturing process, a coating / aesthetic process, and a thermal polishing process of the entire faceplate and / or club head.

[0107] Finally, in a seventh step 800, the filler material formed by the spot welding may be polished, smoothed, and / or removed from the faceplate to produce a smooth faceplate surface. In other words, the excess material on the faceplate as a result of the spot welding may be removed prior to polishing so that there is no additional mass added to the faceplate. After the removal of the spot welding as described above, macroscopically, the faceplate appears unchanged, but microscopically, the portion of the faceplate microstructure is changed to have a dendritic structure.

[0108] (Example 1) To analyze the effectiveness of the golf club head embodiments described herein and obtain quantifiable information regarding the club head's characteristic time, ball speed, launch angle, and spin characteristics, three club robot test experiments were conducted. Specifically, the embodiment of FIG. 7 was benchmarked against a control club without a HAZ portion and a control club with one degree of loft without a HAZ portion.

[0109] The tested golf club head of FIG. 7 was a driver type golf club head having a loft angle of about 8.95 degrees, a swing weight of D4.2, a total club head weight (grip + shaft + head) of 317.9 grams, and a finished head weight of 204.5 grams. The control club was a driver type golf club head having a loft angle of about 9.1 degrees, a swing weight of D4.1, a total club head weight (grip + shaft + head) of 317.6 grams, and a finished head weight of 204.6 grams.

[0110] The control club with 1 degree more loft was lofted (via an adjustable hosel) to have a club head having a loft angle of about 8.1 degrees, a swing weight of D4.1, a total club head weight (grip + shaft + head) of 317.6 grams, and a finished head weight of 204.6 grams.

[0111] Furthermore, various characteristic time measurement values in the center - high toe quadrant were recorded at various positions on the control club. The following table (Table 1) summarizes the recorded values. The measurement position at the point (0 inches, 0 inches) is defined as the geometric center (or origin) of the golf club head. Moving from right to left in the table, the horizontal reference position is adjusted, and thus it moves closer to the toe of the club head. Moving from bottom to top in the table, the vertical reference position is adjusted, and thus it moves towards the crown of the club head.

[0112]

Table 1

[0113] For comparison purposes, in the tested embodiment of FIG. 7, the center - high toe characteristic time values were also measured and are shown in Table 2. Comparing Table 1 and Table 2, it can be seen that at important positions (i.e., the center - high toe quadrant) on the face plate, the characteristic time measurement values before spot welding (Table 1) and after spot welding (Table 2) decreased by an average of about 4% or 12 μs.

[0114]

Table 2

[0115] Typically, the decrease in the characteristic time result also results in a decrease in the ball speed. However, this was not the case in that instance. Specifically, referring to FIG. 11, it can be seen that the ball speed of the tested club increased for all of the center, toe, and heel impacts compared to the control club and the lofted control club. Further, in FIGS. 12 and 13, it can be seen that the tested clubhead was launched about 8% lower with about 9% less spin.

[0116] It was concluded that this phenomenon was due to both the impact speed and the local faceplate hardening. The characteristic time test is a low (or slow) impact test that measures the time the golf ball remains in contact with the faceplate at impact. Alternatively, the ball speed data is typically taken at high speed impacts with the golf ball. For this reason, the clubhead described herein with the HAZ region (more particularly, the faceplate response) varies according to the low impact setting and the high impact setting.

[0117] For example, at the characteristic time measurement location where the heat affected zone is present, the heat affected zone is harder due to smaller grain boundaries adjacent to the (non-HAZ location). The heat affected zone results in a decrease in the CT (at a particular location) due to the harder region since it does not allow the faceplate to bend significantly. For this reason, the golf ball does not remain in contact with the faceplate for long at impact. However, at high impacts (such as a full swing) when the overall system is harder, the heat affected zone generates an increased ball speed and thus, due to the decreased face bending and / or curvature in a particular region, the energy transfer to the golf ball at impact is not lost during face curvature.

[0118] The replacement of one or more claimed elements constitutes reconstruction, not repair. Further, benefits, other advantages, and solutions to problems have been described with respect to specific embodiments. However, no benefit, advantage, solution to a problem, and any element that may give rise to or make more apparent any benefit, advantage, or solution should be construed as a critical, essential, or fundamental feature or element of any or all of the claims.

[0119] The rules for golf can often be changed (e.g., new rules can be applied or old rules can be deleted or modified by golf standard organizations and / or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St Andrews (R&A), etc.), so the golf equipment related to the devices, methods, and articles of manufacture described herein may or may not conform to the rules of golf at any particular time. Accordingly, the golf equipment related to the devices, methods, and articles of manufacture described herein may be advertised, sold, and / or sold as conforming or non-conforming golf equipment. The devices, methods, and articles of manufacture described herein are not limited in this regard.

[0120] Furthermore, the embodiments and limitations disclosed herein are not dedicated to the public under the doctrine of dedication where the embodiments and / or limitations (1) are not expressly claimed in the claims and (2) are equivalent or potentially equivalent to the elements and / or limitations recited in the claims under the doctrine of equivalents.

[0121] The various features and advantages of the present disclosure are set forth in the following claims.

[0122] Item 1. A face plate and a body, the body comprising a sole, a crown, a heel end, and a toe end, the sole being on the ground at address, the crown being on the opposite side of the sole, the heel end being on the opposite side of the toe end, being perpendicular to the sole and the crown, the face plate having a geometric center that is equidistant from the crown and the sole and equidistant from the heel end and the toe end, the face plate defining a loft surface, the loft surface intersecting the ground and being tangent to the geometric center, the face plate and the body, a reference shape having a height and a width, the reference shape extending from the geometric center toward the crown and the toe end, the height of the reference shape being about 25% of the overall height of the face plate measured within the loft surface in the crown-sole direction, the width of the reference shape being about 25% of the overall width of the face plate measured perpendicular to the loft surface in the heel end-toe end direction, the reference shape further comprising a characteristic time threshold, within the reference shape, one or more positions including characteristic time values higher than the characteristic time threshold, a first heat-affected zone being formed at or near the one or more positions, the position of each heat-affected zone after formation including a characteristic time value below the characteristic time threshold, the reference shape, a golf club head.

[0123] Item 2. The geometric center of the face plate further defines an origin with respect to a coordinate system having an X' axis and a Y' axis, the X' axis extending through the geometric center of the face plate in the direction from the heel to the toe of the club head, the Y' axis extending through the geometric center of the face plate in a direction from the crown to the sole of the club head, perpendicular to the X' axis, forming four face plate quadrant regions including a center-high toe quadrant, the reference shape being a linear reference shape extending from the geometric center of the face plate and bounded only in the center-high toe quadrant, the golf club head according to Item 1.

[0124] Item 3. The reference shape of the straight line of the golf club head according to Item 2, wherein an angle of about 20 degrees to about 80 degrees is provided with respect to the X' axis.

[0125] Item 4. The reference shape of the straight line of the golf club head according to Item 3, wherein an angle of about 45 degrees to about 50 degrees is provided with respect to the X' axis.

[0126] Item 5. Along the reference shape of the straight line, at least the first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part are present, and the first, second, third, and fourth heat-affected parts have a microstructure different from the microstructure of the non-heat-affected face plate region of the golf club head according to Item 2.

[0127] Item 6. The microstructures of the first, second, third, and fourth heat-affected parts are needle-like or finger-like structures having grain boundaries smaller than those of the microstructure of the non-heat-affected face plate region of the golf club head according to Item 5.

[0128] Item 7. The first heat-affected part of the golf club head according to Item 1 extends to 16.5% or less of the external face plate surface area.

[0129] Item 8. The first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part of the golf club head according to Item 5 are substantially collinear with each other.

[0130] Item 9. The first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part of the golf club head according to Item 8 do not exist at any position along the face plate - body transition region.

[0131] Item 10. A face plate and a body, the body comprising a sole, a crown, a heel end, and a toe end, the sole being on the ground at address, the crown being on the opposite side of the sole, the heel end being on the opposite side of the toe end, and being perpendicular to the sole and the crown, the face plate having a geometric center that is equidistant from the crown and the sole and equidistant from the heel end and the toe end, the face plate defining a loft surface, the loft surface intersecting the ground and being tangent to the geometric center, the face plate and the body having a reference shape with a height and a width, the reference shape extending from the geometric center towards the crown and the toe end, the height of the reference shape being about 5% to about 25% of the overall height of the face plate measured within the loft surface in the crown-sole direction, the width of the reference shape being about 5% to about 25% of the overall width of the face plate measured perpendicular to the loft surface in the heel end-toe end direction, the reference shape further comprising a characteristic time threshold, within the reference shape, one or more positions comprising characteristic time values higher than the characteristic time threshold, a first heat affected zone being formed at or near the one or more positions, and the position of each heat affected zone after formation comprising a characteristic time value below the characteristic time threshold, the golf club head comprising the reference shape.

[0132] Item 11. The geometric center of the face plate further defines an origin with respect to a coordinate system having an X' axis and a Y' axis, the X' axis extending through the geometric center of the face plate in the direction from the heel to the toe of the club head, the Y' axis extending through the geometric center of the face plate in a direction from the crown to the sole of the club head, perpendicular to the X' axis, forming four face plate quadrant regions including a center-high toe quadrant, the reference shape being a reference shape of a straight line extending from the geometric center of the face plate and bounded only in the center-high toe quadrant, the golf club head according to Item 10.

[0133] Item 12. The golf club head according to Item 11, wherein the reference shape of the straight line is at an angle of about 20 degrees to about 80 degrees with respect to the X' axis.

[0134] Item 13. The golf club head according to Item 12, wherein the reference shape of the straight line is at an angle of about 45 degrees to about 50 degrees with respect to the X' axis.

[0135] Item 14. Along the reference shape of the straight line, at least the first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part are present, and the first, second, third, and fourth heat-affected parts have a microstructure different from the microstructure of the non-heat-affected face plate region. The golf club head according to Item 11.

[0136] Item 15. The golf club head according to Item 14, wherein the microstructure of the heat-affected part is a needle-like or finger-like structure, forming a grain boundary smaller than the microstructure of the non-heat-affected face plate region.

[0137] Item 16. The golf club head according to Item 10, wherein the first heat-affected part extends to 16.5% or less of the external face plate surface area.

[0138] Item 17. The golf club head according to Item 14, wherein the first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part are collinear with each other.

[0139] Item 18. The golf club head according to Item 17, wherein the first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part do not exist at any position along the face plate - body transition region.

[0140] Item 19. The golf club head according to Item 11, wherein the golf club head is a driver-type club head.

[0141] The golf club head according to item 11, wherein the golf club head is a driver-type club head having a loft angle of less than 10 degrees.

Claims

1. A face plate and a body, the body comprising a sole, a crown, a heel end, and a toe end, wherein the sole is on the ground at address, the crown is on the opposite side of the sole, the heel end is on the opposite side of the toe end and is perpendicular to the sole and the crown, the face plate has a geometric center that is equidistant from the crown and the sole and equidistant from the heel end and the toe end, the face plate defines a loft surface, and the loft surface intersects the ground and is tangent to the geometric center of the face plate and the body, a reference shape having a height and a width, the reference shape extends from the geometric center toward the crown and the toe end, the height of the reference shape is about 25% of the overall height of the face plate measured within the loft surface in the crown-sole direction, the width of the reference shape is about 25% of the overall width of the face plate measured perpendicular to the loft surface in the heel end-toe end direction, the reference shape further comprises a characteristic time threshold, and within the reference shape, one or more positions include characteristic time values higher than the characteristic time threshold, a first heat-affected portion is formed at or near the one or more positions, and the position of each heat-affected portion after formation includes a characteristic time value below the characteristic time threshold, the golf club head comprising the reference shape.

2. the geometric center of the face plate further defines an origin with respect to a coordinate system having an X' axis and a Y' axis, the X' axis extends through the geometric center of the face plate in the direction from the heel to the toe of the club head, and the Y' axis extends through the geometric center of the face plate in a direction perpendicular to the X' axis from the crown to the sole of the club head, forming four face plate quadrant regions including a center-high toe quadrant, the reference shape is a linear reference shape that extends from the geometric center of the face plate and is bounded only in the center-high toe quadrant, the golf club head according to claim 1.

3. The reference shape of the straight line has an angle of about 20 degrees to about 80 degrees with respect to the X' axis. The golf club head according to claim 2.

4. The reference shape of the straight line has an angle of about 45 degrees to about 50 degrees with respect to the X' axis. The golf club head according to claim 3.

5. Along the reference shape of the straight line, at least the first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part are present. The first, second, third, and fourth heat-affected parts have a microstructure different from that of the non-heat-affected face plate region. The golf club head according to claim 2.

6. The microstructure of the first, second, third, and fourth heat-affected parts is a needle-like or finger-like structure with grain boundaries smaller than those of the non-heat-affected face plate region. The golf club head according to claim 5.

7. The first heat-affected part extends to 16.5% or less of the external face plate surface area. The golf club head according to claim 1.

8. The first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part are substantially collinear with each other. The golf club head according to claim 5.

9. The first heat-affected part, the second heat-affected part, the third heat-affected part, and the fourth heat-affected part do not exist at any position along the face plate - body transition region. The golf club head according to claim 8.

10. A face plate and a body, the body comprising a sole, a crown, a heel end, and a toe end, The sole is on the ground at address, The crown is on the opposite side of the sole, The heel end is on the opposite side of the toe end and is perpendicular to the sole and the crown, The face plate has a geometric center that is equidistant from the crown and the sole and equidistant from the heel end and the toe end, The face plate defines a loft surface, and the loft surface intersects the ground and is tangent to the geometric center. The face plate and the body, A reference shape having a height and a width, The reference shape extends from the geometric center toward the crown and the toe end, The height of the reference shape is about 5% to about 25% of the overall height of the face plate measured within the loft plane in the crown - sole direction, the width of the reference shape is about 5% to about 25% of the overall width of the face plate measured perpendicular to the loft plane in the heel - toe direction, the reference shape further comprises a characteristic time threshold, and within the reference shape, one or more positions include characteristic time values higher than the characteristic time threshold, a first heat - affected portion is formed at or near the one or more positions, and the position of each heat - affected portion after formation includes a characteristic time value below the characteristic time threshold, and the golf club head comprises the reference shape.

11. The geometric center of the face plate further defines an origin for a coordinate system having an X' axis and a Y' axis, the X' axis extends through the geometric center of the face plate in the direction from the heel to the toe of the club head, and the Y' axis extends through the geometric center of the face plate in a direction from the crown to the sole of the club head perpendicular to the X' axis, forming four face - plate quadrant regions including a center - high - toe quadrant. The golf club head according to claim 10, wherein the reference shape is a linear reference shape extending from the geometric center of the face plate and bounded only in the center - high - toe quadrant.

12. The golf club head according to claim 11, wherein the linear reference shape is angled about 20 degrees to about 80 degrees with respect to the X' axis.

13. The golf club head according to claim 12, wherein the linear reference shape is angled about 45 degrees to about 50 degrees with respect to the X' axis.

14. Along the linear reference shape, at least the first heat - affected portion, the second heat - affected portion, the third heat - affected portion, and the fourth heat - affected portion are present, and the first, second, third, and fourth heat - affected portions have a microstructure different from the microstructure of the non - heat - affected face - plate region. The golf club head according to claim 11.

15. The golf club head according to claim 14, wherein the microstructure of the heat - affected portion is a needle - like or finger - like structure, forming a grain boundary smaller than the microstructure of the non - heat - affected face - plate region. Claim 16 The golf club head according to claim 10, wherein the first heat-affected portion extends over 16.5% or less of the surface area of the external face plate. Claim 17 The golf club head according to claim 14, wherein the first heat-affected portion, the second heat-affected portion, the third heat-affected portion, and the fourth heat-affected portion are collinear with each other. Claim 18 The golf club head according to claim 17, wherein the first heat-affected portion, the second heat-affected portion, the third heat-affected portion, and the fourth heat-affected portion do not exist at any position along the face plate - body transition region. Claim 19 The golf club head according to claim 11, wherein the golf club head is a driver-type club head. Claim 20 The golf club head according to claim 11, wherein the golf club head is a driver-type club head having a loft angle of less than 10 degrees.

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