TITANIUM ALLOY FOR MAKING A GOLF CLUB HEAD

Abstract

A titanium alloy for making a golf club head includes aluminum in an amount of greater than 8.0 wt % and not more than 10.0 wt %, molybdenum in an amount of greater than 0 wt % and not more than 2 wt %, vanadium in an amount of greater than 0 wt % and not more than 2 wt %, silicon in an amount of greater than 0 wt % and not more than 2 wt %, and a balance of titanium, based on a total weight of the alloy. A golf club head made by the titanium alloy is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of the U.S. patent application Ser. No. 11/759,861, filed on Jun. 7, 2007, and the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a titanium alloy, more particularly to a titanium alloy for making a golf club head.

2. Description of the Related Art

Ti-6A1-4V titanium alloy is a conventional alloy for making a golf club head that is popular in the market because the golf club head made thereby has satisfactory mechanical strength and abrasive resistance meeting the requirements of most golf players.

Ti-6A1-1Mo-1V-2Zr titanium alloy is another convention alloy for making a golf club head having superior mechanical strength and abrasive resistance. The alloy primarily includes 6 wt % aluminum (A1), 1.0 wt % molybdenum (Mo), 1.0 wt % vanadium (V), 2.0 wt % zirconium (Zr), and a balance of titanium (Ti).

Although the aforesaid conventional titanium alloys may be used for making a golf club head having high mechanical strength and abrasive resistance, it is still desirable in the art to provide a titanium alloy usable to make a golf club head having relatively light weight at relatively low production cost while having superior mechanical strength and abrasive resistance.

U.S. Pat. No. 2,918,367 discloses a titanium based alloy composed essentially of 2% to 8% of aluminum, 2% to 6% of a metal selected from the class consisting of vanadium, molybdenum and mixtures thereof, 0.1% to 1.5% of silicon, and balance of titanium. As indicated, the amount of aluminum in this patent may range from a minimum effective amount for appreciably increasing the strength, of about 2% of the alloy, to a maximum amount of aluminum, of about 8% of the alloy. A preferred range is about 4% to about 6% aluminum in the alloy. Even narrower ranges for the amount of aluminum are preferred in the case of certain specific uses.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a titanium alloy which may be used for making a golf club head having relatively low density, relatively low production cost, and superior mechanical strength and abrasive resistance.

Another object of the present invention is to provide a golf club head made of the titanium alloy.

Accordingly, in a first aspect of the present invention, a titanium alloy for making a golf club head includes:

aluminum in an amount of greater than 8.0 wt % and not more than 10.0 wt %;

molybdenum in an amount of greater than 0 wt % and not more than 2 wt %;

vanadium in an amount of greater than 0 wt % and not more than 2 wt %;

silicon in an amount of greater than 0 wt % and not more than 2 wt %; and

a balance of titanium, based on a total weight of the alloy.

In a second aspect of the present invention, a golf club head is made of the titanium alloy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As described above, the amount of aluminum in the titanium alloy of the present invention is greater than 8.0 wt % and not more than 10.0 wt %, which is higher than that of aluminum used in the conventional Ti-6Al-4V and Ti-6Al-1Mo-1V-2Zr titanium alloys and the alloy disclosed in U.S. Pat. No. 2,918,367. An increase in aluminum reduces the density of the titanium alloy of the present invention. Therefore, a golf club head made of the titanium alloy of the present invention may have a relatively light weight compared to the golf club heads made of the aforesaid conventional titanium alloys. Furthermore, an increase in aluminum raises extensibility of the titanium alloy of the present invention. Therefore, the titanium alloy of the present invention may be processed easier to make a golf club head. Noted that the amount of aluminum in the titanium alloy of the present invention should not be higher than 10.0 wt %. If the amount of aluminum is higher than 10.0 wt %, the flowability of the alloy may be further reduced so that more silicon must be used to improve the flowability. As such, the amount of titanium in the titanium alloy must be significantly reduced, and the mechanical strength of the golf club head may therefore decrease. Furthermore, since the over growth of crystals in the alloy may be inhibited by aluminum, the crystal grains of the alloy may be maintained at a relatively fine size, which may improve the mechanical strength and abrasive resistance of the golf club head made of the alloy of the present invention.

Molybdenum in an amount of greater than 0 wt % and not more than 2 wt % may further increase the high temperature strength, the creep strength, and the high temperature hardness of the alloy so as to improve the abrasive resistance and the mechanical strength of the golf club head made of the alloy of the present invention.

Vanadium in an amount of greater than 0 wt % and not more than 2 wt % may also avoid the over growth of crystal grains in the alloy so as to micronize the crystal grains of the alloy, thereby improving the mechanical strength and abrasive resistance of the golf club head made of the alloy of the present invention.

The increased amount of aluminum in the alloy of the present invention may reduce the flowability of the alloy during the fabrication of a golf club head from the alloy. Silicon is added to increase the flowability of the alloy and to improve the processability thereof. The processing of the alloy may therefore be made easier and the production cost may therefore be reduced.

The golf club head can be made of the alloy of the present invention using a conventional method for fabricating a golf club head that includes a former processing stage and a latter processing stage. The former processing stage involves precision casting technology, and generally includes the steps of mold-making, wax injection, hanging, dipping, dewaxing, casting, cutting, heat treating, etc. The latter processing stage includes the steps of surface grinding, washing, lacquering, punching, embedding, assembling, torque testing, polishing, etc.

EXAMPLES

Alloys having compositions listed in the following Table 1 was made. Golf club heads were fabricated from the alloys, and were compared to the golf club heads made of the Ti-6Al-4V titanium alloy and the Ti-6Al-1Mo-1V-2Zr titanium alloy in terms of tensile strength, yield strength, extensibility, density, and total weight. The results are shown in Table 2.

TABLE 1
	Al	Mo	V	Si	Ti
Examples	(wt %)	(wt %)	(wt %)	(wt %)	(wt %)
Ex. 1	8.1	1.0	1.0	1.0	88.9
Ex. 2	8.3	1.0	1.0	1.0	88.7
Ex. 3	8.5	1.0	1.0	1.0	88.5
Ex. 4	9.0	1.0	1.0	1.0	88.0
Ex. 5	10.0	1.0	1.0	1.0	87.0

	TABLE 2
	Tensile	Yield	Extensi-		Total
	strength	strength	bility	Density	weight
	(Mpa)	(Mpa)	(%)	(g/cm3)	(g)
Ex. 1	882	820	12	4.29	147.29
Ex. 2	885	822	12	4.29	147.29
Ex. 3	889	825	11	4.28	146.95
Ex. 4	805	770	10	4.28	146.95
Ex. 5	850	722	12	4.27	146.61
Ti—6Al—4V	820	738	6	4.51	150
titanium alloy
Ti—6Al—1Mo—1V—	816	799	7.5	4.45	148
2Zr titanium alloy
Ti—8Al—1Mo—1V—	880	818	8	4.2-4.3	148.25
1Si titanium alloy

As shown in the results of Table 2, in the golf club head made of the alloy of the present invention, the tensile strength and the yield strength are improved or comparable, the extendibility is significantly raised, and the density and total weight are reduced as compared to the golf club heads made of the Ti-6Al-4V titanium alloy, the Ti-6Al-1Mo-1V-2Zr titanium alloy, and the Ti-8Al-1Mo-1V-1Si titanium alloy. Therefore, the titanium alloy of the present invention may be used for making a golf club head having relatively light weight and superior mechanical strength and abrasive resistance.

While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

1. A titanium alloy for making a golf club head, comprising:

aluminum in an amount of greater than 8.0 wt % and not more than 10.0 wt %;

molybdenum in an amount of greater than 0 wt % and not more than 2 wt %;

vanadium in an amount of greater than 0 wt % and not more than 2 wt %;

silicon in an amount of greater than 0 wt % and not more than 2 wt %; and

a balance of titanium, based on a total weight of said alloy.

2. A golf club head made of the titanium alloy of claim 1.