Patent Description:
Characteristic Time (CT) is a measurement of the amount of time, in microseconds, that a golf ball is in contact with the faceplate during impact. Characteristic time requirements are one of the many rules that the United States Golf Association (USGA) and the Royal and Ancient Golf Club of St. Andrews (R&A) impose on golf equipment manufactures to determine club head conformance. Oftentimes, the characteristic time properties of golf club heads are not uniform and substantially varies across the faceplate. This variation can cause inconsistencies in club head performance, and more particularly produce different ball speeds depending on where the ball impact occurs on the faceplate. These minor variations in ball impact locations across the faceplate can lead to notable variations in produced ball speed and ball travel distance thereby making the game unpredictable to the golfer.

Variations in the characteristic time properties of the golf club head can be caused by faceplates with an asymmetrical perimeter geometry and/or variable faceplate features (i.e. thickness, material, texture, face-to-body transition, etc.). Reducing the thickness of materials used to form a golf club head, and more particularly a faceplate can be beneficial for many reasons. Among those reasons, a thinner faceplate can reduce weight, increase flexibility, and reduce the amount of materials used. A weight reduction in one area of the golf club head can allow for that weight to be redistributed (as desired) to increase clubhead performance.

Redistributing weight from the faceplate can lead to an increase in flexibility and an increase in energy transfer to the golf ball. This increase in flexibility (resulting from a thin faceplate) can lead to a more variable CT across the faceplate. There is a need in the art for a repeatable, efficient, and affordable manufacturing method that allows the CT to be locally altered to reduce CT variation across the faceplate.

<CIT> describes a striking face for golf clubs, including zones of the same or different material arranged to create a desired "feel" to the golfer and/or produce a desired effect on the golf ball. The zones can be created by using "pixels" such as round or hexagonal rods arranged with their central axes perpendicular to the striking face. Pixels of a first material such as a shape memory alloy such as superelastic NiTi can be arranged in one or more concentric patterns and the remainder of the striking face can be made up of pixels of a second material such as beta-titanium, martensitic NiTi or stainless steel.

<CIT> describes a cast-type golf iron head alloy, which consists of <NUM>-<NUM>. 5wt% of chrome, <NUM>-<NUM>. 0wt% of nickel, <NUM>-<NUM>. 6wt% of molybdenum, <NUM>-<NUM>. 0wt% of silicon, <NUM>-<NUM>. 0wt% of manganese, <NUM>-<NUM>. 50wt% of carbon and the balance of iron as well as inevitable trace alloy elements. Based upon solution treatment at <NUM>-<NUM> and oil cooling at <NUM>-<NUM> as well as tempering treatment at <NUM>-<NUM>, the obtained cast-type golf iron head alloy is <NUM>-1960MPa in tensile strength, <NUM>-1700MPa in yield strength, <NUM>-<NUM>% in ductility and HRC40-<NUM> in hardness.

For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present disclosure. The same reference numerals in different figures denotes the same elements.

Presented herein are golf club heads, and in particular, wood-type golf club heads comprising a faceplate having one or more heat affected zone(s) (HAZ) to enable a consistent or reasonable tolerance variation in CT over the entire faceplate. Heat affected zone(s) can be formed via weld beads that locally alters a certain zone, portion, or region of the faceplate without globally altering the characteristics and properties of the faceplate in its entirety. Locally altering a certain zone or region of the faceplate via weld bead(s) (or spot welds) to form a heat affected zone can alter the microstructure of that region or zone. Altering the microstructure, at targeted regions or zones can alter that the characteristic time properties of that region or zone when impacted by a golf ball.

As the characteristic time properties varies across the faceplate in both a heel-to-toe direction and in a crown-to-sole direction, the region(s) of the faceplate targeted by the heat treatment and/or HAZ can be those approaching a characteristic time threshold to avoid the golf club head having hot spots (i.e. portions of the faceplate at, approaching, or near the USGA and R&A CT limits), regions of the club head potentially having a non-compliant CT due to manufacturing variability; and/or a particular region of the faceplate falling out of compliance due to repeated clubhead use and wear. Following a faceplate having a localized heat affected zone treatment (via a weld bead or spot weld), the treated zone can have a different material characteristic than non-heat-affected zones of the same material (i.e. a different microstructure to modify CT). These zones, regions, or portions targeted for adjustment can generally be defined by a reference shape. Further, a method of manufacturing the golf club heads described herein is outlined below.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the apparatus, methods, and/or articles of manufacture described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

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

In many embodiments, the loft angle of the driver-type club head can be less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, or less than approximately <NUM> degrees.

Further, in many embodiments, the volume of the driver-type club head can be greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, greater than approximately <NUM> cc, or greater than approximately <NUM> cc. In some embodiments, the volume of the driver-type club head can be approximately 400cc - 600cc, 425cc - 500cc, approximately 500cc - 600cc, approximately 500cc - 650cc, approximately 550cc - 700cc, approximately 600cc - 650cc, approximately 600cc - 700cc, or approximately 600cc - 800cc.

In many embodiments, the driver-type golf club head can have a weight (or mass) that ranges between <NUM> grams and <NUM> grams. In other embodiments, the driver-type golf club head can range between <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, or <NUM> grams - <NUM> grams. In some embodiments, the weight of the driver-type golf club head can be <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, or <NUM> grams.

The material of the driver-type golf club head can be constructed from any material used to construct a conventional golf club head. For example, the material of the driver-type golf club head can be constructed from any one or combination of the following: <NUM> alloy steel, S25C steel, carbon steel, maraging steel, <NUM>-<NUM> stainless steel, <NUM> stainless steel, <NUM> stainless steel, stainless steel alloys, steel alloys, tungsten, aluminum, aluminum alloys, ADC-<NUM>, titanium, titanium alloys, or any other known metal or composite materials for creating a driver-type golf club head. In many embodiments, the driver-type golf club head can be constructed from a titanium and/or composite material.

The term "fairway wood-type golf club head" described herein can be defined by one or more of a loft angle, a club head volume, a club head weight, or a club head material.

In many embodiments, the loft angle of the fairway wood-type club head can be less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, or less than approximately <NUM> degrees. Further, in many embodiments, the loft angle of the club head is greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, or greater than approximately <NUM> degrees. For example, in some embodiments, the loft angle of the fairway wood-type club head can be between <NUM> degrees and <NUM> degrees, between <NUM> degrees and <NUM> degrees, between <NUM> degrees and <NUM> degrees, or between <NUM> degrees and <NUM> degrees.

In many embodiments, the volume of the fairway wood-type club head is less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, or less than approximately <NUM> cc. In some embodiments, the volume of the club head can be approximately 150cc - 200cc, approximately 150cc - 250cc, approximately 150cc - 300cc, approximately 150cc - 350cc, approximately 150cc - 400cc, approximately 300cc - 400cc, approximately 325cc - 400cc, approximately 350cc - 400cc, approximately 250cc - 400cc, approximately <NUM> - <NUM> cc, or approximately <NUM>-<NUM> cc.

In many embodiments, the fairway wood-type golf club head can have a weight that ranges between <NUM> grams and <NUM> grams. In other embodiments, the fairway wood-type golf club head can range between <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, or <NUM> grams - <NUM> grams. In some embodiments, the weight of the fairway wood-type golf club head can be <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, or <NUM> grams.

The material of the fairway wood-type golf club head can be constructed from any material used to construct a conventional golf club head. For example, the material of the fairway wood-type golf club head can be constructed from any one or combination of the following: <NUM> alloy steel, S25C steel, carbon steel, maraging steel, <NUM>-<NUM> stainless steel, <NUM> stainless steel, <NUM> stainless steel, stainless steel alloys, steel alloys, tungsten, aluminum, aluminum alloys, ADC-<NUM>, titanium, titanium alloys, steel alloys or any other known metal or composite material for creating a fairway wood-type golf club head. In many embodiments, the fairway wood-type golf club head is constructed from a titanium alloy and/or composite material.

The term "hybrid-type golf club head" described herein can be defined by one or more of a loft angle, a club head volume, a club head weight, or a club head material.

In many embodiments, the loft angle of the hybrid-type club head can be less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, or less than approximately <NUM> degrees. Further, in many embodiments, the loft angle of the hybrid-type club head is greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, or greater than approximately <NUM> degrees.

In many embodiments, the volume of the hybrid-type club head is less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, less than approximately <NUM> cc, or less than approximately <NUM> cc. In some embodiments, the volume of the club head can be approximately 100cc - 150cc, approximately 75cc - 150cc, approximately 100cc - 125cc, or approximately 75cc - 125cc.

In many embodiments, the hybrid-type golf club head can have a weight that ranges between <NUM> grams and <NUM> grams. In other embodiments, the fairway wood-type golf club head can range between <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, <NUM> grams - <NUM> grams, or <NUM> grams - <NUM> grams. In some embodiments, the weight of the hybrid-type golf club head can be <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams or <NUM> grams.

The material of the hybrid-type golf club head can be constructed from any material used to construct a conventional golf club head. For example, the material of the hybrid-type golf club head can be constructed from any one or combination of the following: <NUM> alloy steel, S25C steel, carbon steel, maraging steel, <NUM>-<NUM> stainless steel, <NUM> stainless steel, <NUM> stainless steel, stainless steel alloys, steel alloys, tungsten, aluminum, aluminum alloys, ADC-<NUM>, titanium, titanium alloys, steel alloys or any other known metal or composite for creating a hybrid-type golf club head. In many embodiments, the hybrid-type golf club head can be constructed from a titanium alloy and/or composite material.

The term "spot weld" described herein can be defined as applying a weld bead, at a specified location, to a material, to create a heat affected zone that changes the physical grain structure from an equiaxed, circular microstructure to a dendrite microstructure, and wherein the material microstructure transforms back to the equiaxed, circular microstructure away from the spot weld.

Described below are golf club heads comprising reference shapes to help provide consistent CT across the faceplate. The reference shape comprise heat affected zone(s) (HAZ) that provides the ability to reduce/limit certain regions CT characteristics thereby creating a CT that is within a predetermined tolerance across the face. More specifically described herein are golf club heads, and in particular, are golf club heads (drivers, fairway woods, or hybrids) comprising a faceplate having at least one heat affected zone (HAZ) to enable a consistent CT (or within a predetermined tolerance) over the entire faceplate of the golf club head. As discussed above, heat affected zone(s) can be formed via spot welds or weld beads that alters a certain zone, portion, or region of the face plate without globally altering the characteristics and properties of the faceplate in its entirety. Locally altering a certain zone or region of the face plate (via a spot weld or weld bead) to form a heat affected zone(s) can alter the microstructure (to a dendritic microstructure) of that region or zone, and thus, can alter the characteristic time properties of the treated location.

For example, and in general, portions of a golf club head having the greatest characteristic time measurements can typically be found (<NUM>) towards the geometric center of the faceplate, (<NUM>) offset from the geometric center of the faceplate towards the toe of the faceplate, (<NUM>) offset from the geometric center towards the top end of the faceplate, or combinations thereof. These areas can potentially have a characteristic time measurement that is at, near, or approaching a threshold CT value (i.e. a USGA and R&A CT limit).

To form a faceplate with a more uniform CT (i.e. devoid of "CT hotspots"), the region of target for a local heat affected zone can be characterized by a reference shape. Inside or on a perimeter of the reference shape, a localized heat affected zone can be formed via a spot weld or weld bead. The heat affected zone within the reference shape can have a different material characteristic (i.e. a different or (dendritic) microstructure) than non-heat-affected zones outside of the reference shape to locally modify CT.

The golf club head described herein can 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 can 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 can be characterized by a loft angle, a head volume, and/or by a head weight as mentioned above.

In some embodiments, the golf club head can be formed from a stainless steel, titanium, aluminum, or steel alloy (e.g. <NUM> steel, <NUM> steel, <NUM> steel, <NUM>-<NUM> stainless steel, maraging steel), a titanium alloy (e.g. Ti <NUM>-<NUM>, Ti <NUM>-<NUM>, T-<NUM>), an aluminum alloy, or a composite material. In some embodiments, the faceplate of the golf club head can be formed from a stainless steel, titanium, aluminum, or a steel alloy (e.g. <NUM> steel, <NUM> steel, <NUM> steel, <NUM>-<NUM> stainless steel, maraging steel), a titanium alloy (e.g. Ti <NUM>-<NUM>, Ti <NUM>-<NUM>, T-<NUM>), an aluminum alloy, or a composite material.

In many embodiments, the golf club head <NUM> comprises a club head body <NUM> (may also be referred to as "body"). The club head body <NUM> forms a toe portion <NUM>, a heel portion <NUM>, a top portion <NUM>, a sole portion <NUM>, a rear portion <NUM> and a faceplate opening configured to receive a faceplate <NUM>. The faceplate <NUM> can provide a surface adapted for impact with a golf ball. The rear portion <NUM> is rearwardly spaced from the faceplate <NUM>. The sole portion <NUM> is defined as being between the faceplate <NUM> and the rear portion <NUM>, and resting on a ground plane <NUM> (or playing surface) at an address position. The top portion <NUM> can be formed opposite the sole portion <NUM>. The faceplate <NUM> is defined by the sole portion <NUM>, the top portion <NUM>, the heel portion <NUM>, and the toe portion <NUM> which is opposite the heel portion <NUM>.

As previously mentioned, the golf club head <NUM> can be configured to reside in the "address position". Unless otherwise described or stated, the golf club head <NUM> is in an address position for all reference measurements, ratios, and/or descriptive parameters. The address position can be referred to as being in a state where (<NUM>) the sole portion of the golf club head rests on the ground plane <NUM>, which contacts and is parallel to a playing surface and (<NUM>) the striking surface can be substantially perpendicular to the ground plane.

The faceplate <NUM> of the clubhead <NUM> defines a geometric center <NUM>. In some embodiments, the geometric center <NUM> can be located at the geometric centerpoint of a faceplate perimeter, and at a midpoint of face height. In the same or other examples, the geometric center also can be centered with respect to engineered impact zone, which can be defined by a region of grooves on the faceplate. As another approach, the geometric center of the faceplate <NUM> can be located in accordance with the definition of a golf governing body such as the United States Golf Association (USGA). For example, the geometric center of the faceplate <NUM> can be determined in accordance with <NPL>) (the "Flexibility Procedure").

The club head <NUM> further defines a loft plane tangent to the geometric center <NUM> of the faceplate <NUM>. The face height can be measured parallel to the loft plane between a top end of the faceplate perimeter near the crown portion <NUM> and a bottom end of the faceplate perimeter near the sole portion <NUM>. In these embodiments, the perimeter of the faceplate <NUM> can be located along the outer edge of the faceplate where the curvature deviates from the bulge and/or roll of the faceplate <NUM>.

The geometric center <NUM> of the faceplate <NUM> further defines a coordinate system having an origin located at the geometric center of the faceplate <NUM>, the coordinate system having an X' axis <NUM>, a Y' axis <NUM>, and a Z' axis. The X' axis <NUM> extends through the geometric center <NUM> of the faceplate <NUM> in a direction from the heel <NUM> to the toe <NUM> of the club head <NUM>. The Y' axis <NUM> extends through the geometric center <NUM> of the faceplate <NUM> in a direction from the crown <NUM> to the sole <NUM> of the club head <NUM> and perpendicular to the X' axis <NUM>, and the Z' axis extends through the geometric center <NUM> of the faceplate <NUM> in a direction from the front end to the back end of the club head <NUM> and perpendicular to the X' axis <NUM> and the Y' axis <NUM>.

The coordinate system defines an X'Y' plane <NUM> extending through the X' axis <NUM> and the Y' axis <NUM>. The X'Y' plane <NUM> extends parallel to a hosel axis (not shown) and is positioned at an angle corresponding to the loft angle of the club head <NUM> from the loft plane. Further the X' axis <NUM> can be positioned at a <NUM> degree angle to the hosel axis when viewed from a direction perpendicular to the X'Y' plane. In these or other embodiments, the club head can be viewed from a front view (<FIG>) when the faceplate <NUM> is viewed from a direction perpendicular to the X'Y' plane <NUM>.

When the golf club head <NUM> is at an address position, the golf club head <NUM> can be divided into four quadrants (i.e. a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant) bounded by the perimeter of the faceplate <NUM>, the X' axis <NUM>, and the Y' axis <NUM>. Within one or more quadrants, a reference shape <NUM> can be projected onto the faceplate <NUM> and can harbor a HAZ zone to alter an area having a characteristic time value that is generally greater than a threshold or targeted characteristic time. In many embodiments, the reference shape <NUM> in its entirety can be bounded or located within the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant. In alternative embodiments, the reference shape <NUM> can extend into one or more quadrants, two or more quadrants, or three or more quadrants. In other embodiments, the reference shape <NUM> can extend along a quadrant border (i.e. along the X' axis or Y' axis) and into one or more quadrants.

In most embodiments, one or more HAZ zone(s) can be located within a high toe quadrant. In some embodiments, one or more HAZ zone(s) can be located in both a low toe and high toe quadrant. In some embodiments, one or more HAZ zone(s) can be located in both a high toe and high heel quadrant. In a few embodiments, one or more HAZ zone(s) can be in a high toe and low heel quadrant. In alternatives embodiments, one or more HAZ zone(s) can be in all quadrants and/or clustered around the geometric center.

The reference shape <NUM> can take the form of any shape and preferably does not extend into a body portion of the club head <NUM> (i.e. only located on the faceplate <NUM>). For example, in many embodiments, the reference shape <NUM> can be substantially triangular, square, rectangular, polygonal, semi-circular, curvilinear, or the like. The reference shape generally comprises of an area having a characteristic time value that is generally greater than a threshold or targeted characteristic time value.

The one or more characteristic time value(s) on a faceplate <NUM> that is greater than a threshold, designed, or targeted characteristic time measurement due to manufacturer variability can be detected or located via (<NUM>) the standard USGA test method for measuring characteristic time via a heat seeking process (which looks to identify the location and value of the greatest characteristic time value(s) of a club head by taking measurements at strategically chosen locations) or (<NUM>) by identifying a known area of concern through an aggregation of CT data. Upon detection or identification of a region, area, and/or location of the golf club head having a characteristic time value approaching a threshold CT value, the given region, area, and/or location of the golf club head can be imposed or configured to a localized weld bead (or spot weld) to create a heat affected zone (HAZ).

This creates a faceplate <NUM> having a non-uniform microstructure (see <FIG>). Imposing a localized weld bead or spot weld to create a heat affected zone to a given area of interest on the faceplate <NUM> can alter the CT properties of the treated zone. In other words, a faceplate region (or location) approaching or greater than a threshold CT value can be subjected to a weld bead or spot weld to create a heat affected zone that locally alters the microstructure (to locally create a higher strength and/or stiffened region) of the treated region to the point, in which the CT properties of that area decreases in accordance with a value at or below the targeted CT threshold. Therefore, instead of altering the profile of the club head to accommodate for a faceplate region having high CT region, (i.e. increasing the thickness of the face, modifying the variable face thickness profile of the faceplate, introducing club head reinforcing elements, etc.) the applied HAZ structure reduces the dependency on global (or large-scale) design modifications to the club head, and alternatively focuses on locally altering the microstructure (or small-scale) modifications to the faceplate <NUM>.

In many of the golf club head <NUM> embodiments described below, a heat affected zone can be found in a certain area of the faceplate <NUM>, and further the heat affected zone can border or be entirely located within a reference shape <NUM>. As mentioned above, and discussed in detail below, depositing a weld bead or spot weld within a reference shape creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In area(s), where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

In many embodiments, the golf club head <NUM> can also be viewed in a perpendicular direction to an XY' plane <NUM> and faceplate <NUM> as shown by <FIG>. When viewing the golf club head in a generally perpendicular direction to the XY' plane <NUM> and the faceplate <NUM>, the golf club head <NUM> can be defined by a coordinate system having an X' axis <NUM> that extends through the geometric center <NUM> of the faceplate <NUM> in a heel <NUM>-to-toe <NUM> direction and a Y' axis <NUM> that extends through the geometric center <NUM> in a top-to-bottom (or crown <NUM>-to-sole <NUM>) direction.

The X' axis <NUM> horizontally divides the golf club head into an upper region <NUM> and a lower region <NUM>. The upper region <NUM> of the golf club head is bounded by the X' axis <NUM>, the crown <NUM>, and the maximum heel-to-toe width of the club head. The lower region <NUM> of the golf club head is bounded by the X' axis <NUM>, the sole <NUM>, and the maximum heel to toe width of the golf club head. The Y' axis <NUM> vertically separates the club head into a left region <NUM> and a right region <NUM>. The left region <NUM> can be bounded by the Y' axis and the toe end of the golf club head. The right region can be bounded by the Y' axis <NUM> and the heel <NUM> of the golf club head <NUM>. Further, the X' axis <NUM> and the Y' axis <NUM> are perpendicular to each other and form four faceplate quadrant regions.

The four face plate quadrant regions can be defined as a center-to-high toe quadrant <NUM>, center-to-low toe quadrant <NUM>, a center-to-high heel quadrant <NUM>, and a center-to-low heel quadrant <NUM> when the golf club head is resting on the ground plane <NUM> at an address position. The center-to-high toe quadrant <NUM> extends from the geometric center <NUM> and spans the upper, left face plate region. The center-to low toe quadrant <NUM> extends from the geometric center <NUM> and spans the lower, left face plate region. The center-to-high heel quadrant <NUM> extends from the geometric center <NUM> and spans the upper, right face plate region. The center-to-low heel quadrant <NUM> extends from the geometric center <NUM> and spans the lower, right faceplate region.

The one or more faceplate quadrant regions <NUM>, <NUM>, <NUM>, <NUM> can comprise of a characteristic time value that is either at, exceeding, or approaching a targeted characteristic time value. In many embodiments, the quadrant of focus can be the center-to-high toe quadrant <NUM>, as this region can be identified as the critical region that comprises one or more locations approaching a critical CT threshold value due to manufacturing tolerances and/or variability.

As shown by <FIG>, the setup (or address) position of <FIG> and <FIG> are similar. <FIG> further maps a plurality of potential location points within the center-to-high toe quadrant <NUM> to identify whether the faceplate characteristic time values are either at, approaching, or exceeding a targeted characteristic time limit. In general, typically, CT readings are emphasized in the center-to-high toe as this is a known quadrant for concern. Further provided in the example section, Table <NUM> provides an average of approximate CT readings (in microseconds) at corresponding mapped location points on the club head within the center-toe high toe quadrant <NUM> for respective faceplates devoid of a HAZ. In other words, the faceplate <NUM> of <FIG> and Table <NUM> have a uniform microstructure.

As further illustrated by <FIG>, the first spot weld <NUM> and the second spot weld <NUM> formed on the faceplate <NUM> locally changes the microstructure of the faceplate <NUM> within the heat effected zone mentioned above. The microstructure of the heat effected zone caused by the spot weld forms a dendrite structure that are needle-like or finger-like structures that produce smaller grain boundaries to stiffen or increase the faceplate strength in the welded (or HAZ) region. This localized stiffening directly correlates to a decrease in characteristic time of that region as faceplate flexibility is limited. The locations outside of the weld pool and heat effected zones (i.e. locations unaffected by the spot weld) have a homogenous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zone(s). In many embodiments, the HAZ structure defined by the spot weld creates a faceplate having a <NUM>% to <NUM>% increase in dendrite microstructures compared to non-spot-welded faceplates.

As can be seen, by the below example, golf club heads having a faceplate with a uniform microstructure or a non-HAZ structure within the center-to-high toe quadrant can have characteristic time values that vary by as much as <NUM> in the crown-to-sole direction and the heel-to-toe direction. Furthermore, a point measured immediately adjacent another point can vary by as much as <NUM>. Depending upon the location of golf ball impact, having a golf club head with a faceplate <NUM> having a widespan of characteristic time properties can negatively affect produced ball speeds. In many golf clubs head embodiments, it is desired to have characteristic time properties with a given quadrant to be more uniform (i.e. less variation in a heel-to-toe and crown-to-sole direction).

Upon identification of a quadrant having a high degree of variation and/or that meets or exceeds a designed CT parameter, a reference shape can be projected onto the quadrant, and more particularly, the location of focus, and thereby the HAZ zone. The reference shape can either surround or partially encompass the location of focus. As will be described below, in many embodiments, the reference shape can encompass a large area of focus or a small area of focus depending upon the faceplate <NUM> CT properties.

In many embodiments, a heat affected zone can be found in a certain area of the faceplate, and further the heat affected zone can border or be entirely located within a reference shape. Depositing a weld bead or spot weld within the reference shape creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As illustrated by <FIG>, in many embodiments, the reference shape <NUM> that encompasses an area of focus (i.e. one or more faceplate CT measurements that meets or exceeds a designed CT parameter) can be substantially rectangular. Alternatively, the reference shape <NUM>, can be in the form of a square that can extend from the geometric center <NUM> of the faceplate <NUM> to a point within the center-to-high toe quadrant <NUM>.

The rectangular (or square) reference shape <NUM> can have a height measured within the loft plane, in a crown to sole direction that extends between approximately <NUM>% and approximately <NUM>% of a total height of the faceplate <NUM>. In many embodiments, the height of the rectangular reference shape <NUM> can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% to approximately <NUM>% of the total height of the faceplate <NUM>.

In the following description, to convert inches to millimetres , the length in inches must be multiplied by <NUM>.

In alternative embodiments, the rectangular reference shape <NUM> can have a maximum height measured within the loft plane, in a crown-to-sole direction between approximately <NUM> inch and <NUM> inches. In many embodiments, the maximum height of the rectangular reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the maximum height of the rectangular reference shape can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the maximum height of the rectangular reference shape can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The rectangular (or square) reference shape <NUM> can have a width measured within the loft plane, in a heel to toe direction between approximately <NUM>% and approximately <NUM>% of a total width of the faceplate <NUM>. In many embodiments, the width of the rectangular reference shape <NUM> can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% - approximately <NUM>% of the total width of the faceplate <NUM>.

In alternative embodiments, the rectangular reference shape can have a maximum width measured within the loft plane, in a heel-to-toe direction between approximately <NUM> inch and <NUM> inches. In many embodiments, the maximum width of the rectangular reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the maximum width of the rectangular reference shape <NUM> can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the maximum width of the rectangular reference shape <NUM> can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

As discussed above, a heat affected zone can be found in a certain area of the faceplate <NUM>, and further the heat affected zone can either border or be entirely located within a reference shape <NUM>. Depositing a weld bead or spot weld within the reference shape creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape <NUM> can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As illustrated by <FIG>, in many embodiments, the reference shape <NUM> that encompasses an area of focus (i.e. one or more faceplate CT measurements that meets or exceeds a designed CT parameter) for applying a HAZ region can be substantially ellipsoidal. The reference shape <NUM>, and more particularly, the ellipsoidal reference shape <NUM> can extend from the geometric center <NUM> of the faceplate <NUM> to a point within the center-to-high toe quadrant <NUM>.

An exemplary ellipsoidal reference shape can have a minor axis <NUM> measured within the loft plane and through the center of the ellipse, that can be between approximately <NUM>% and approximately <NUM>% of a total height of the faceplate <NUM>. In many embodiments, the minor axis of the ellipsoidal reference shape <NUM> can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% to approximately <NUM>% of the total height of the faceplate <NUM>.

In alternative embodiments, the ellipsoidal reference shape <NUM> can have a minor axis <NUM> measured within the loft plane, between approximately <NUM> inch and <NUM> inches. In many embodiments, the minor axis <NUM> measurement dimension of the ellipsoidal reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the minor axis <NUM> of the ellipsoidal reference shape can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the minor axis <NUM> of the ellipsoidal reference shape can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The ellipsoidal reference shape <NUM> can have a major axis <NUM> measured within the loft plane, that can be between approximately <NUM>% and approximately <NUM>% of a total height of the faceplate <NUM>. In many embodiments, the major axis <NUM> of the ellipsoidal reference shape <NUM> can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% - approximately <NUM>% of the total height of the faceplate <NUM>.

In alternative embodiments, the ellipsoidal reference shape <NUM> can have a major axis <NUM> measured within the loft plane, between approximately <NUM> inch and <NUM> inches. In many embodiments, the major axis <NUM> of the ellipsoidal reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the major axis <NUM> of the ellipsoidal reference shape <NUM> can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the major axis <NUM> of the ellipsoidal reference shape <NUM> can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

In many embodiments, the major axis <NUM> of the ellipsoidal reference shape <NUM> can be at an angle relative to the x-axis <NUM>. The angle between the major axis <NUM> of the ellipsoidal reference shape and the x-axis <NUM> can be between <NUM> degrees and <NUM> degrees. In many embodiments, the angle formed between the ellipsoidal reference shape <NUM> and the x-axis <NUM> can vary based upon the location of focus. In some embodiments, the angle of the major axis and the x-axis can be between approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, or approximately <NUM> degrees to approximately <NUM> degrees. In many embodiments, the formed angle can be approximately <NUM> degrees.

As discussed above, a heat affected zone can be found in a certain area of the faceplate, and further the heat affected zone can either border or be entirely located within a reference shape <NUM>. Depositing a weld bead or spot weld within the reference shape <NUM> creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As illustrated by <FIG>, in many embodiments, the reference shape that includes an area of focus (i.e. one or more faceplate CT measurements that meets or exceeds a designed CT parameter) can be substantially linear. The reference shape, and more particularly, the linear shape <NUM> can extend from the geometric center <NUM> of the faceplate <NUM> to a point within the center-to-high toe quadrant <NUM>. In many embodiments, one or more HAZ zones (or weld beads) are applied along the linear reference shape <NUM>.

In many embodiments, the linear reference shape <NUM> can be at an angle relative to the x-axis <NUM>. The angle between the linear reference shape <NUM> and the x-axis <NUM> can be between <NUM> degrees and <NUM> degrees. In many embodiments, the angle formed between the linear reference shape <NUM> and the x-axis can vary based upon the location of focus. In some embodiments, the angle formed between the linear reference shape <NUM> and the x-axis <NUM> can be between approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees - approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, approximately <NUM> degrees to approximately <NUM> degrees, or approximately <NUM> degrees to approximately <NUM> degrees. In many embodiments, the formed angle can be approximately <NUM> degrees.

The linear reference shape <NUM> can have a height measured within the loft plane, in a crown to sole direction that can have a maximum height between approximately <NUM>% and approximately <NUM>% of a total height of the faceplate <NUM>. In many embodiments, the height of the linear reference shape can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% - approximately <NUM>% of the total height of the faceplate <NUM>.

In alternative embodiments, the linear reference shape <NUM> can have a maximum height measured within the loft plane, in a crown-to-sole direction between approximately <NUM> inch and <NUM> inches. In many embodiments, the maximum height of the linear reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the maximum height of the linear reference shape <NUM> can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the maximum height of the linear reference shape <NUM> can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The linear reference shape <NUM> can have a maximum width measured within the loft plane, in a heel to toe direction that can be between approximately <NUM>% and approximately <NUM>% of a total width of the faceplate <NUM>. In many embodiments, the width of the linear reference shape <NUM> can be between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, or approximately <NUM>% - approximately <NUM> of the total width of the faceplate <NUM>.

In alternative embodiments, the linear reference shape <NUM> can have a maximum width measured within the loft plane, in a heel-to-toe direction between approximately <NUM> inch and <NUM> inches. In many embodiments, the maximum width of the linear reference shape <NUM> can be between approximately <NUM> inch - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - <NUM> inches, or approximately <NUM> inches to approximately <NUM> inches. In other embodiments, the maximum width of the linear reference shape <NUM> can be greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, greater than approximately <NUM> inches, or greater than approximately <NUM> inch. In alternative embodiments, the maximum width of the linear reference shape <NUM> can be less than approximately <NUM> inches, less than approximately <NUM> inch, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

As previously mentioned, the above described reference shapes <NUM> are projected onto the faceplate <NUM> to create a border around an area of interest. These areas of interest are typically areas where CT values are high, which generally can be found in the center-to-high toe quadrant <NUM>. Within the center-to-high toe quadrant <NUM> and with specific reference to <FIG> and Table <NUM>, it can be seen that at predetermined measurement location points (i.e. CT measurement regions), the CT can vary as much as approximately <NUM> within a one inch by one inch region. Further, at adjacent faceplate location points, the CT can vary by as much as <NUM>. This variability can further increase overtime with repeated impacts (i.e. wear). To reduce variability, within a localized region without effecting adjacent measurement locations HAZ zones can be formed via spot welding and/or a weld bead within or bordering a reference shape <NUM>.

As discussed above, a heat affected zone can be found in one or more areas of the faceplate, and further the heat affected zone can border or be entirely located within a reference shape. Depositing a weld bead or spot weld within the reference shape creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As discussed above, a HAZ zone is an area caused by a weld bead that alters the microstructure of the faceplate. As illustrated in <FIG>, two spots welds (i.e. a first spot weld can also be referred to as a "first weld bead" and a second spot weld can also be referred to as a "second weld bead" are formed on the exterior surface of the faceplate <NUM>. In other words, the first spot weld <NUM> and the second spot weld <NUM> can be applied to the (exterior) surface of the faceplate <NUM> that directly contacts a golf ball during impact. In other embodiments, the first and second spot welds <NUM>, <NUM> not need to be formed/applied to the exterior surface of the faceplate <NUM>, rather the first and second spot welds <NUM>, <NUM> can be applied to the rear surface of the faceplate <NUM> 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). In many embodiments, the first spot weld <NUM> can be located at the geometric center of the faceplate and the second spot weld <NUM> is spaced from the geometric center and solely located in the center-to-high toe quadrant.

As previously mentioned, the one or more spot welds locally effect the microstructure of a certain region on the faceplate <NUM> without globally altering the microstructure of the entire faceplate <NUM>. The one or more spot welds of <FIG> can be generally defined by a diameter. The diameter of one or more spot welds in contact with the faceplate <NUM> can be between approximately <NUM> inches and approximately <NUM> inches. In many embodiments, the diameter of the one or more spot welds can be between approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, or approximately <NUM> inches - approximately <NUM> inches. In other embodiments, the diameter of the one or more spot welds can be approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches. In alternative embodiments, the diameter of the one or more spot welds can be less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The heat affected zone formed by the spot weld can be between approximately <NUM>% and approximately <NUM>% of the diameter of the spot weld. In many embodiments, the spot weld can form a heat affected zone (i.e. where the microstructure changes) between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>% of the diameter of the spot weld. In other embodiments, the spot weld can form a heat affected zone less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, or less than approximately <NUM>% of the diameter of the spot weld. The heat affected zone is a non-melted area of the faceplate <NUM> that has undergone microstructure changes as a result of portions of the metal matrix being exposed to high welding temperatures. The remaining area of the spot weld can be defined as the weld pool area (i.e. the area where the faceplate <NUM> has reached its melting point and may be ready to be infused with a filler material), and by way of example shown in <FIG> is merely to exemplify a reference between the weld bead (or spot weld) and the HAZ zone. The weld bead can be placed on the exterior of the faceplate surface via heating. The bead portion is removed via a finishing technique (sanding, grinding, polishing, or the like) but the formed HAZ zones are still readily present in the structure.

As previously mentioned, <FIG> illustrates the first spot weld <NUM> and the second spot weld <NUM> applied to the faceplate <NUM> to locally change the microstructure of the faceplate <NUM> within the heat effected zone mentioned above. The microstructure of the heat effected zone caused by the spot weld forms a dendrite structure that are needle-like or finger-like structures that produce smaller grain boundaries to stiffen or increase the faceplate strength in the welded (or HAZ) region. This localized stiffening directly correlates to a decrease in characteristic time of that region as faceplate flexibility is limited. The locations outside of the weld pool and heat effected zones (i.e. locations unaffected by the spot weld) have a homogenous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zone(s). In many embodiments, the HAZ structure defined by the spot weld creates a faceplate having a <NUM>% to <NUM>% increase in dendrite microstructures compared to non-spot-welded faceplates.

In this specific the embodiment, the first spot weld <NUM> and the second spot weld are located on and/or within a reference shape <NUM> discussed above, spaced, and do not touch each other. In many embodiments, the center of the first spot weld <NUM> and the center of the second spot weld <NUM> are spaced between approximately <NUM> inches and <NUM> inch. For example, in many embodiments, the center of the first spot weld <NUM> and the center of the second spot weld <NUM> can be spaced from each other by <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inch. In other embodiments, the spacing distance between the center of the first spot weld and the center of the second spot weld <NUM> can be less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, or less than <NUM> inch.

In many embodiments, the second spot weld <NUM> can be offset from the geometric center along the X-axis and/or towards the toe by up to approximately <NUM> inches. In alternative embodiments, the second spot weld <NUM> can be offset from the geometric center along the X-axis direction, and/or towards the toe by approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches.

In the same or other embodiments, the second spot weld <NUM> can be offset from the geometric center towards the crown or top end of the face plate by up to approximately <NUM> inches. The second spot weld <NUM> can be offset from the geometric center along the Y-axis direction, and/or towards the crown by approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches. In many embodiments, the first and second spot welds are spaced from and do not contact or engage the face-to-body transition region.

In many embodiments, as illustrated in <FIG>, the first spot weld <NUM> and the second spot weld <NUM> are colinear to each other. In alternative embodiments, the first spot weld <NUM> and the second spot weld need not to be colinear. Based on the faceplate surface area of the club head illustrated, approximately <NUM>% to <NUM>% of the surface area of the faceplate can be contacted by a single weld bead. No more than <NUM>% of the external faceplate surface area can be in contact with any weld.

A heat affected zone can be found in a certain area of the faceplate, and further the heat affected zone can either border or be entirely located within a reference shape. Depositing a weld bead or spot weld within the reference shape creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As mentioned above, HAZ zone(s) can also be linearly placed along a reference shape. As described above, reference shapes <NUM> can be projected onto the faceplate <NUM>, and more particularly a linear reference shape <NUM> can be projected over a plurality of interest points on the faceplate <NUM>. These points of interest are typically areas where CT values are high, which generally can be found in the center-to-high toe quadrant <NUM>. Within the center-to-high toe quadrant <NUM> and with specific reference to the below example, it can be seen that at faceplate measurement location points (i. e CT measurement regions), the CT can vary as much as approximately <NUM> with in a one inch by one inch region. Further, at adjacent faceplate location points, the CT can vary by as much as <NUM>. This variability can further increase overtime with repeated impacts (i.e. wear). To reduce variability, within a localized region without effecting adjacent measurement locations HAZ zones can be formed via spot welding and/or a weld bead.

As illustrated in <FIG>, a plurality of spots welds <NUM> (i.e. a plurality of spot welds can also be referred to as a "a plurality of weld beads" are formed on the exterior surface of the faceplate <NUM>. In other words, the plurality of spot welds <NUM> can be applied to the (exterior) surface of the faceplate <NUM> that directly contacts a golf ball during impact. In other embodiments, the plurality of spot welds <NUM> not need to be formed/applied to the exterior surface of the faceplate <NUM>, rather the plurality of spot welds <NUM> can be applied to the rear surface of the faceplate <NUM> 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).

In many embodiments, the plurality of spot welds can 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 can generally be formed along the linear reference shape. In some embodiments, due to precision error the plurality of spot welds can be slightly offset from the linear reference shape <NUM>.

As previously mentioned, the plurality of spot welds <NUM> locally effect the microstructure of a certain region on the faceplate <NUM> without globally altering the microstructure of the entire faceplate <NUM>. The plurality of spot welds illustrated by <FIG> can be generally defined by a diameter. The diameter of the plurality of spot welds <NUM> in contact with the faceplate <NUM> can be between approximately <NUM> inches and approximately <NUM> inches. In many embodiments, the diameter of the plurality of spot welds can be between approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, or approximately <NUM> inches - approximately <NUM> inches. In other embodiments, the diameter of the plurality of spot welds <NUM> can be approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches. In alternative embodiments, the diameter of the plurality of spot welds <NUM> can be less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The heat affected zone formed by the plurality of spot welds <NUM> can be between approximately <NUM>% and approximately <NUM>% of each diameter of the plurality of spot welds. In many embodiments, the spot weld can form a heat affected zone (i.e. where the microstructure changes) between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>% of the diameter of the spot weld. In other embodiments, the plurality of spot welds <NUM> can form a heat affected zone less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, or less than approximately <NUM>% of the diameter of the spot weld. The heat affected zone is a non-melted area of the faceplate <NUM> that has undergone microstructure changes as a result of being exposed to high welding temperatures. The remaining area of the spot weld can be defined as the weld pool area (i.e. the area where the faceplate <NUM> has reached its melting point and may be ready to be infused with a filler material), and by way of example shown in <FIG>.

As further illustrated by <FIG> and discussed above, the plurality of spot welds formed on the faceplate <NUM> locally changes the microstructure of the faceplate <NUM> within the heat effected zone mentioned above. The microstructure of the heat effected zone caused by the spot weld forms a dendrite structure that are needle-like or finger-like structures that produce smaller grain boundaries sizes to stiffen or increase the strength of the faceplate <NUM> in the welded (or HAZ) region. This localized stiffening directly correlates to a decrease in characteristic time of that region as faceplate flexibility is reduced. The locations outside of the weld pool and heat effected zones (i.e. locations unaffected by the spot weld) have a homogenous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zones.

In this specific the embodiment, the plurality of spot welds <NUM> are located along the linear reference shape <NUM> and extend from the geometric center <NUM> of the faceplate <NUM> to a point within the center-to-high toe quadrant and does not extend into a body portion of the club head. In this exemplary embodiment, each of the plurality of spot welds <NUM> contact or touch another spot weld of the plurality of spot welds. In other embodiments, the plurality of spot welds need not to touch or contact another spot weld. In these embodiments, the plurality of spot welds can be spaced from each spot weld between approximately <NUM> inches and <NUM> inch. For example, in many embodiments, the plurality of spot welds can be spaced from one another by <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inch.

The furthest spot weld of the plurality of spot welds <NUM> from the geometric center (along the X-axis and/or towards the toe) can be spaced up to approximately <NUM> inches. In alternative embodiments, the furthest spot weld of the plurality of spot welds <NUM> can be spaced from the geometric center along the X-axis <NUM> direction, and/or towards the toe by approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches.

In the same or other embodiments, the furthest spot weld of the plurality of spot welds <NUM> from the geometric center, along the Y-axis <NUM> can be spaced from the geometric center towards the crown or top end of the face plate by up to approximately <NUM> inches. The furthest spot weld can be spaced from the geometric center along the Y-axis direction, and/or towards the crown by approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches. In many embodiments, the plurality of spot welds <NUM> are spaced from and do not contact or engage the face-to-body transition region.

In many embodiments, as illustrated in <FIG>, the plurality of spot welds are colinear to each other. In alternative embodiments, the plurality of spot welds need not to be colinear and slightly offset from the linear reference line (i.e. noncolinear) Based on the faceplate surface area of the club head illustrated in the exemplary embodiment of <FIG>, approximately <NUM>% to <NUM>% of the surface area of the faceplate can be contacted by a single weld bead. No more than <NUM>% of the external faceplate surface area can be in contact with any weld.

Heat affected zone(s) can be found in certain area(s) of the faceplate, and further the heat affected zone can border or be entirely located within a reference shape <NUM>. Depositing a weld bead or spot weld within the reference shape <NUM> creates a HAZ region forming a dendritic microstructure (different from non-spot-welded areas). In areas, where CT properties are at or above a threshold value, placing a spot weld at location(s) of concern, results in a CT reduction due to the dendritic microstructure properties. The reference shape <NUM> can more easily assist an individual with identifying a location of CT correction, as it creates an outline around and/or over the area targeted for CT adjustment.

As previously mentioned, reference shapes <NUM> are projected onto the faceplate <NUM> to create a border around an area of interest. These areas of interest are typically areas where CT values are high, which generally can be found in the center-to-high toe quadrant <NUM>. Within the center-to-high toe quadrant <NUM> and with specific reference to <FIG>, it can be seen that at faceplate location points (i.e. CT measurement regions), the CT can vary as much as approximately <NUM> within a one inch by one inch region. Further, at adjacent faceplate location points, the CT can vary by as much as <NUM>. This variability can further increase overtime with repeated impacts (i.e. wear). To reduce variability, within a localized region without effecting adjacent measurement locations HAZ zones can be formed via spot welding and/or a weld bead.

As illustrated in <FIG>, at least four spots welds (i.e. a first spot weld <NUM>, second spot weld <NUM>, third spot weld <NUM>, and fourth spot weld <NUM> can also be referred to as a first weld bead, a second weld bead, a third weld bead, and a fourth weld bead, respectively) are formed on the exterior surface of the faceplate <NUM>. In other words, the first spot weld <NUM>, the second spot weld <NUM>, the third spot weld <NUM>, and the fourth spot weld <NUM> can be applied to the (exterior) surface of the faceplate <NUM> that directly contacts a golf ball during impact. In other embodiments, the first, second, third and fourth spot welds <NUM>, <NUM>, <NUM>, <NUM> not need to be formed/applied to the exterior surface of the faceplate <NUM>, rather the first, second, third, and fourth spot welds <NUM>, <NUM>, <NUM>, and <NUM> can be applied to the rear surface of the faceplate <NUM> in an open crown or open sole design (i.e. the golf club head provides access to the interior of the club head).

As previously discussed, the spot welds <NUM>, <NUM>, <NUM>, and <NUM> can locally affect the microstructure of a certain region on the faceplate <NUM> without globally altering the microstructure of the entire faceplate <NUM>. The four or more spot welds exemplified in <FIG> can be generally defined by a diameter. The diameter of four or more spot welds <NUM>, <NUM>, <NUM>, and <NUM> in contact with the faceplate <NUM> can be between approximately <NUM> inches and approximately <NUM> inches. In many embodiments, the diameter of the one or more spot welds can be between approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, approximately <NUM> inches - approximately <NUM> inches, or approximately <NUM> inches - approximately <NUM> inches. In other embodiments, the diameter of the four or more spot welds can be approximately <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inches. In alternative embodiments, the diameter of the four or more spot welds can be less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, less than approximately <NUM> inches, or less than approximately <NUM> inches.

The heat affected zone formed by a single spot weld can be between approximately <NUM>% and approximately <NUM>% of the diameter of the spot weld. In many embodiments, the spot weld can form a heat affected zone (i.e. where the microstructure changes) between approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>%, approximately <NUM>% - approximately <NUM>% of the diameter of the spot weld. In other embodiments, the spot weld can form a heat affected zone less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, less than approximately <NUM>%, or less than approximately <NUM>% of the diameter of the spot weld. The heat affected zone is a non-melted area of the faceplate <NUM> that has undergone microstructure changes as a result of being exposed to high welding temperatures. The remaining area of the spot weld can be defined as the weld pool area (i.e. the area where the faceplate <NUM> has reached its melting point and may be ready to be infused with a filler material), and by way of example shown in <FIG>.

As further illustrated by <FIG>, the first spot weld <NUM>, the second spot weld <NUM>, the third spot weld <NUM>, and the fourth spot weld <NUM> formed on the faceplate <NUM> locally changes the microstructure of the faceplate <NUM> within the heat effected zone mentioned above. The microstructure of the heat effected zone caused by the spot weld forms a dendrite structure that are needle-like or finger-like structures that produce smaller grain boundaries to stiffen or increase the strength in the welded (or HAZ) region of the faceplate <NUM>. This localized stiffening directly correlates to a decrease in characteristic time of that region as faceplate flexibility is reduced. The locations outside of the weld pool and heat effected zones (i.e. locations unaffected by the spot weld) have a homogenous microstructure with larger grain boundaries relative to the grain boundaries of the heat affected zones (i.e. less stiffer regions, more flexibility).

In this specific the embodiment, the first spot weld <NUM>, the second spot weld <NUM>, the third spot weld <NUM>, and the fourth spot weld <NUM> are located on and/or within a rectangular reference shape <NUM>, at locations of interest, and can be spaced from one another and do not touch each other. In many embodiments, the spacing distance between the center of the first spot weld <NUM>, the center of the second spot weld <NUM>, the center of the third spot weld <NUM>, and the center of the fourth spot weld <NUM> can vary. In many embodiments, the spacing distance can be between approximately <NUM> inches and <NUM> inch. For example, in many embodiments, the center of the first spot weld <NUM> to at least one of the center of the second spot weld <NUM>, the center of the third spot weld <NUM>, and the center of the fourth spot weld <NUM> can be spaced from each other by <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, or <NUM> inch. In other embodiments, the spacing distance between the center of the first spot weld <NUM> and at least one of the center second spot weld <NUM>, the center of the third spot weld <NUM>, and the center of the fourth spot weld <NUM> can be less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, less than <NUM> inch, or less than <NUM> inch. In many embodiments, the first, second, third, and fourth spot welds are spaced from and do not contact or engage the face-to-body transition region.

In many embodiments, as illustrated in <FIG>, at least two spot welds are colinear with each other. In the same or alternative embodiments, at least two spots welds are not colinear with each other. Based on the faceplate surface area of the club head illustrated in the examples of <FIG>, approximately <NUM>% to <NUM>% of the surface area of the faceplate can be contacted by a single weld bead. No more than <NUM>% of the external faceplate surface area can be in contact with any weld.

<FIG> shows the process for forming and/or assembling the golf club head <NUM>. In the first step <NUM>, the faceplate <NUM> can be aligned with respect to the body of the golf club head <NUM>. The second step <NUM> involves welding the faceplate <NUM> to the body of the club head <NUM>. In the third step <NUM>, the club head and the faceplate can be heated to a temperature at, above, or below the solvus temperature of the faceplate material through a series of solution and/or aging steps. In the fourth step <NUM>, the club head and the faceplate are air cooled.

Once the club head is cooled, the fifth step <NUM> involves identifying at least one area of interest on the face plate. This area(s) of interest can typically be identified or found by determining locations where the golf ball stays on the faceplate at impact for a period of time longer than intentionally designed. The locations can be identified or found by (<NUM>) the standard USGA test method for measuring characteristic time via a heat seeking process (which looks to identify the location and value of the greatest characteristic time value(s) of a club head by taking measurements at strategically chosen locations) or (<NUM>) by identifying a known area of concern through a club head aggregation of CT data.

Upon at least one area of interest on the faceplate being identified, a spot weld via plasma welding or laser welding can be applied to the at least one area of interest at a predetermined temperature between <NUM> degrees Celsius and <NUM> degrees Celsius for a time span between one second and five seconds, thereby forming a HAZ region. This step <NUM> can be completed prior to any faceplate finishing steps. For example, the localized heat treatment can be completed prior to a smoothing or texturing processes, coating/aesthetic processes, and entire faceplate and/or club head heat polishing processes.

Finally, in the seventh step <NUM>, the filler material formed by the spot weld can be grinded, smoothed and/or removed from the faceplate to create a smooth faceplate surface. In other words, the excess material on the faceplate as a result of the spot weld can be removed prior to polishing so that no mass is added to the faceplate. After removal of the spot weld as discussed above, from a macroscopic view the faceplate appears to unaltered, however, from a microscopic view portions of the faceplate microstructure are altered to have a dendrite structure.

A three-club robotic test experiment was conducted to analyze the effectiveness of the golf club head embodiments described herein to obtain quantifiable information with regards to club head characteristic time, ball speed, launch angle, and spin properties. Specifically, the embodiment of <FIG> was benchmarked against a control club without a HAZ zone and a control club without a HAZ zone being delofted one degree.

The tested golf club head of <FIG> was a driver-type golf club head with a loft angle of approximately <NUM> degrees, a swing weight of D4. <NUM>, a total club head weight (grip+shaft+head) of <NUM> grams, and a finished head weight of <NUM> grams. The control club was a driver-type golf club head with a loft angle of approximately <NUM> degrees, a swing weight of D4. <NUM>, a total club head weight (grip+shaft+head) of <NUM> grams, and a finished head weight of <NUM> grams.

The one-degree delofted control club was delofted (via an adjustable hosel) to have a club head with a loft angle of approximately <NUM> degrees, a swing weight of D4. <NUM>, a total club head weight (grip+shaft+head) of <NUM> grams, and a finished head weight of <NUM> grams.

Further, at various locations on the control club, the center-to-high toe quadrant various characteristic time measurements were recorded. The below table (Table <NUM>) summarizes the recorded values. The measurement location with the point location at (<NUM> inch, <NUM> inch) is defined at the geometric center (or origin) of the golf club head. Moving right-to-left on the table, adjusts the horizontal reference position, therefore moving closer to the toe of the club head. Moving from bottom-to-top on the table adjusts the vertical reference position, therefore moving towards the crown of the club head.

For comparison purposes, in the tested embodiment of <FIG>, the center-to-high toe characteristics time values were also measured and shown in Table <NUM>. When comparing Table <NUM> and Table <NUM>, it can be seen that at critical locations on the faceplate (i.e. the center to high-toe quadrant) the characteristic time measurements before spot welding (Table <NUM>) and after spot welding (Table <NUM>) decreased on average approximately <NUM>% or <NUM>.

Typically, a decrease in characteristic time results also results in decreased ball speeds. However, this was not the case. Specifically, referring to <FIG>, it can be seen that across all center, toe, and heel impacts the ball speeds in the tested club increased over the control club, and the delofted control club. Further, in <FIG> and <FIG>, it can also be seen that the tested club head launched approximately <NUM>% lower with approximately <NUM>% lower spin.

It was concluded that this phenomenon was due both to impact speed and localized faceplate stiffening. Characteristic Time tests are low (or slow) impact tests that measures how long the golf ball stays in contact with the faceplate upon impact. Alternatively, ball speed data is typically captured at a high rate of impact with a golf ball. So, the club heads described herein with HAZ zones (and more particularly the faceplate response) varies according to low and high impact settings.

For example, at a characteristic time measurement location, where the heat affected zone is present, the heat affected zone is stiffer due to smaller grain boundaries than adjacent (non-HAZ locations). A stiffer region results in a decrease in CT (at the specified location) because the heat affected zone does not allow the faceplate to flex as much, so the golf ball will not stay in contact with faceplate as long upon impact. However, at high impacts (such as full swings), the heat affected zone produces increased ball speeds, as the system as a whole is stiffer, and thus energy transfer upon impact to the golf ball is not lost upon face flexure due to decreased face bending and/or flexure in the specified region.

Replacement of one or more claimed elements constitutes reconstruction and not repair. Additionally, benefits, other advantages, and solutions to problems have been described with regard to specific embodiments. The benefits, advantages, solutions to problems, and any element or elements that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as critical, required, or essential features or elements of any or all of the claims.

As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated 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.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and/or sold as conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.

Claim 1:
A golf club head (<NUM>) comprising:
a faceplate (<NUM>) and a body (<NUM>), the body comprising a sole (<NUM>), a crown (<NUM>), a heel end (<NUM>), and a toe end (<NUM>); wherein:
the sole is in a ground plane at address;
the crown is opposite the sole;
the heel end is opposite the toe end and perpendicular to the sole and the crown;
the faceplate comprises a geometric center (<NUM>) that is equidistant from the crown and the sole, and equidistant from the heel end and the toe end; and
the faceplate defines a loft plane, wherein the loft plane intersects the ground plane and is tangent to the geometric center;
the faceplate further comprises a region defined by a reference shape (<NUM>) having a height and a width; wherein:
the reference shape extends toward the crown and the toe end from the geometric center;
the reference shape height is between approximately <NUM>% and approximately <NUM>% of a total height of the faceplate, measured within the loft plane, in a crown to sole direction;
the reference shape width is between approximately <NUM>% and approximately <NUM>% of a total width of the faceplate, measured perpendicularly to the loft plane, in a heel end to toe end direction;
the reference shape further comprises a threshold characteristic time value, and within the reference shape, one or more locations comprise a characteristic time value higher than the threshold characteristic time value; and
the faceplate further comprises a first heat affected zone formed at or near the one or more locations, the first heat affected zone location comprising a characteristic time value lower than or equal to the threshold characteristic time value, wherein:
the first heat affected zone comprises a spot weld (<NUM>) comprising a diameter between approximately <NUM> (<NUM> inch) and <NUM> (<NUM> inch), and the first heat affected zone comprises a diameter between approximately <NUM>% to <NUM>% of the diameter of the spot weld; and
a physical grain structure of the first heat affected zone is a dendrite microstructure.