Process for making a plate for a golf club head face, and golf club head

Abstract

A process for making a plate composed of a β-type titanium alloy material for a golf club head face includes subjecting the β-type titanium alloy material to cold working with controlling the reduction rate thereof to vary the reduction rate depending on a position across a plain direction of the β-type titanium alloy material, and then subjecting the β-type titanium alloy material to an aging treatment so as to build up a hardness distribution across the plain direction of the β-type titanium alloy material.

1 . A process for making a plate composed of a β-type titanium alloy material for a golf club head face, comprising subjecting said β-type titanium alloy material to cold working with controlling the reduction rate thereof to vary the reduction rate depending on a position across a plain direction of said β-type titanium alloy material, and then subjecting said β-type titanium alloy material to an aging treatment so as to build up a hardness distribution across said plain direction of said β-type titanium alloy material.  
   
   
       2 . The process for making a plate according to  claim 1 , wherein said β-type titanium alloy material is subjected to a solution annealing prior to said cold working.  
   
   
       3 . The process for making a plate according to  claim 1 , wherein said cold working is controlled so as to allow said β-type titanium alloy material to have a reduction rate varied across the plain direction thereof with a minimum value of less than 10% and a maximum value of 35% or higher, and said aging treatment is carried out at a temperature in the range of 300° C. to the β-transus temperature for 1-60 minutes.  
   
   
       4 . A golf club head comprising said plate manufactured according to  claim 1 , wherein said hardness distribution is built up so as to have a Vickers hardness varied in the range of 200-500 across the plain direction of said β-type titanium alloy while having a difference of 30 or greater between a maximum value and a minimum value in said Vickers hardness.