Golf club head

Abstract

A hollow golf club head has a head body having a face aperture part and a face member held to the face aperture part by welding, the face member formed by forging a rolled material of a titanium alloy having an α phase, and the face member comprising a thick-material part positioned in the center of the face member, an outer peripheral part positioned at the periphery of the thick-material part, and a thin-material part partially positioned between the thick-material part and the outer peripheral part. The thick-material part is formed in an area having a shape obtained by depressing a substantially elliptical or substantially circular shape in a substantially arcuate shape toward the center of the ellipse at two opposite sides thereof. The thick-material part, the thin-material part, and the peripheral part are formed by the forging so as to destroy an orientation of the α-phase.

1 . A golf club head having a hollow part, comprising:
 a head body having a face aperture part; and   a face member held to the face aperture part by welding, the face member being formed by forging of a rolled material of a titanium alloy having an α phase, and the face member comprising a thick-material part positioned in the center of the face member, an outer peripheral part positioned at the periphery of the thick-material part, and a thin-material part partially positioned between the thick-material part and the outer peripheral part,   wherein the thick-material part is formed in an area having a shape obtained by depressing a substantially elliptical or substantially circular shape in a substantially arcuate shape toward the center of the ellipse at two opposite sides thereof,   wherein the thick-material part has a material thickness that is thickest at the center part of the face part and also gradually becomes thin from the center part toward the outer peripheral part,   wherein the thick-material part has a material thickness that is thicker than the outer peripheral part and the thin-material part has a material thickness that is thinner than the outer peripheral part, and   wherein the thick-material part, the thin-material part, and the peripheral part are formed by the forging so as to destroy an orientation of the α-phase.   
     
     
         2 . The golf club head according to  claim 1 , wherein the forging is hot forging. 
     
     
         3 . The golf club head according to  claim 1 , wherein the thin-material part is disposed so as to be inclined in the sole direction at the toe side of the thick-material part, and to be inclined in the crown direction at the heel side of the thick-material part, and has a score line groove on the surface of the face. 
     
     
         4 . The golf club head according to  claim 1 , wherein the face member further has a rib that passes through the center part of the thick-material part and extends from the outer edge of both the heel side and the crown side of the face toward the outer edge of both the toe side and sole side, wherein the rib has a material thickness that is thicker than the outer peripheral part. 
     
     
         5 . The golf club head according to  claim 1 , wherein the rolling direction of the rolled material is a direction at an angle within ±5° with respect to the score line. 
     
     
         6 . The golf club head according to  claim 1 , wherein the face member is either an α titanium alloy or an α-β titanium alloy.