Golf club head

Abstract

A hollow golf club head made of a metallic material. The golf club head has a three piece structure, a main head body, face, and crown. The main head body and the crown are formed by casting or press-forming, the face is formed by press-forming, and these are joined together by welding. The metallic material used is selected from a steel material group of martensite deposition hardening-type stainless steel, maraging steel, and maraging stainless steel. Only a material having a specific gravity of 7.7 or higher is used, and the head body has a volume of 280-320 cc and a weight of 180-205 g. The golf club head enables increasing the meet rate, has design freedom, exhibits excellent processability, and can be manufactured at a low cost.

What is claimed is:  
     
         1 . A golf club head comprising: 
 a hollow structure made of a martensite deposition hardening-type stainless steel having a specific gravity of 7.70 or more, and the head having a volume of 280-320 cc and a weight of 180-205 g.    
     
     
         2 . The golf club head according to  claim 1 , comprising a main head body formed by press-forming from a casting material or sheet material, a face part formed by press-forming or forging, and a sole or crown part formed by press-forming from a casting material or sheet material, all of which are joined by welding or brazing.  
     
     
         3 . The golf club head according to  claim 1 , wherein the martensite deposition hardening-type stainless steel further comprises 0.1-0.5% by weight of V.  
     
     
         4 . The golf club head according to  claim 1 , wherein the martensite deposition hardening-type stainless steel has a tensile strength of more than 1700 MPa.  
     
     
         5 . The golf club head according to  claim 4 , wherein the martensite deposition hardening-type stainless steel has a tensile strength of more than 1700 MPa.  
     
     
         6 . The golf club head according to  claim 1 , wherein the martensite deposition hardening-type stainless steel is an alloy having Ms point of 130° C. or higher and usable for welding.  
     
     
         7 . The golf club head according to  claim 4 , wherein the martensite deposition hardening-type stainless steel is an alloy having Ms point of 130° C. or higher and usable for welding.  
     
     
         8 . The golf club head according to  claim 1 , wherein the head has a moment of inertia in the range from 3,000-4,400 g·cm 2 .  
     
     
         9 . The golf club head according to  claim 1 , comprising a main head body formed by vacuum casting or atmospheric casting, and a sole or crown part formed by atmospheric casting.  
     
     
         10 . The golf club head according to  claim 1 , comprising at least a face part formed by press-forming from a sheet material or by forging from a bar, and the face part is joined to other parts of the head by welding or brazing.  
     
     
         11 . The golf club head according to  claim 1 , comprising a main head body, sole, crown, and neck formed by press-forming from a casting material or sheet material and joined by welding or brazing.  
     
     
         12 . A golf club head comprising a hollow surface including a face part, at least the face part being made of a martensite deposition hardening-type stainless steel having a specific gravity of 7.70 or more, and the head having a volume of 280-320 cc and a weight of 180-205 g.  
     
     
         13 . The golf club head according to  claim 12 , wherein the martensite deposition hardening-type stainless steel is an alloy having the composition by weight of C=0.01% or less, N=0.01% or less, Si=0.1% or less, Mn=0.1% or less, Cr=10.0-12.5%, Ni=8.5-10.5%, Mo=1.5-2.5%, Ti=1.2-1.6%, B=0.001-0.005%, provided that C+N=0.015, with the balance being Fe and inevitable impurities, the composition satisfying 
       957-4930×(C(%)+N(%))−23.5×Cr(%)−44.8×Ni(%)−28.7×Mo(%)−22.2×Ti(%)≧120 
     
     
         14 . The golf club head according to  claim 13 , wherein the martensite deposition hardening-type stainless steel further comprises 0.1-0.5% by weight of V.  
     
     
         15 . The golf club head according to  claim 12 , wherein the martensite deposition hardening-type stainless steel has a tensile strength of more than 1700 MPa.  
     
     
         16 . The golf club head according to  claim 14 , wherein the martensite deposition hardening-type stainless steel has a tensile strength of more than 1700 MPa.  
     
     
         17 . The golf club head according to  claim 12 , wherein the martensite deposition hardening-type stainless steel is an alloy having Ms point of 130° C. or higher and usable for welding.  
     
     
         18 . The golf club head according to  claim 14 , wherein the head has a moment of inertia in the range from 3,000-4,400 g·cm 2 .  
     
     
         19 . The golf club head according to  claim 12 , comprising a main head body formed by vacuum casting or atmospheric casting, and a sole or crown part formed by atmospheric casting.  
     
     
         20 . A golf club head comprising: 
 a hollow structure made of a metal having a specific gravity of 7.70 or more, and the head having a volume of 280-320 cc and a weight of 180-205 g.