Patent ID: 8075421

Claim:
A golf club head comprising a face portion of which front face defines a club face, a crown portion, a sole portion, a side portion between the crown portion and sole portion, and a hosel portion, wherein said golf club head has a hollow shell structure with a thin wall and is composed of a main shell body provided with a front opening and a face plate covering the front opening, wherein the face plate is provided around its main portion with a turnback, and the main portion of the face plate forms the entirety of the face portion, whereby the main shell body includes a major part of the golf club head excluding the face portion and a portion corresponding to the turnback, wherein the face plate is made of a unidirectionally rolled plate of a titanium alloy, the titanium alloy is an alpha+beta titanium alloy selected from a group consisting of Ti-4.5Al-3V-2Fe-2Mo, Ti-4.5Al-2Mo-1.6V-0.5Fe-0.3Si-0.03C, Ti-1Fe-0.35O-0.01N, Ti-8Al-1Mo, Ti-5.5Al-1Fe, Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo, Ti-6Al-2Sn-4Zr-2Mo, and Ti-8Al-1Mo-1V, and the unidirectionally rolled plate is unidirectionally rolled in a unidirectional rolled direction, the unidirectional rolled direction of the plate is oriented in a toe-heel direction of the head so that an angle between the unidirectional rolled direction and the toe-heel direction becomes at most 15 degrees, wherein a tensile strength Spd of the unidirectionally rolled plate in a direction perpendicular to the unidirectional rolled direction is not less than 1.20 times, but not more than 1.60 times a tensile strength Srd of the unidirectionally rolled plate in the unidirectional rolled direction, and said club face has an aspect ratio of not less than 1.65 but not more than 2.10, wherein the aspect ratio is a ratio (FW/FH) of a width FW of the club face measured in the toe-heel direction along the club face passing through a sweet spot to a height FH of the club face measured in a crown-sole direction along the club face passing through the sweet spot.