Golf Club Head and Method of Making Same

Abstract

A golf club head is described which has a body that is formed at least in part from a stainless steel alloy having the following composition in weight percent: Carbon 0.25 max. Manganese 14-20 Silicon up to 2.0 Phosphorus 0.05 max. Sulfur  0.5 max. Chromium 12-22 Nickel  3.5 max. Molybdenum 0.5-4   Copper  2.0 max. Nitrogen 0.2-0.8 Boron 0.06 max. The balance of the alloy is iron and the usual impurities. The stainless steel alloy provides a hardness of about 80 HRB up to about 25 HRC. The golf club head provides a unique combination of high strength and hardness, good ductility, excellent “feel”, and good durability. A method of making the disclosed golf club head is also described.

1 . A golf club comprising a head that is formed at least in part from a stainless steel alloy having the following composition in weight percent: 
     
       
         
               
               
               
             
                   
                   
               
                   
                 Carbon 
                 0.25 max. 
               
                   
                 Manganese 
                 14-20 
               
                   
                 Silicon 
                 up to 2.0 
               
                   
                 Phosphorus 
                 0.05 max. 
               
                   
                 Sulfur 
                  0.5 max. 
               
                   
                 Chromium 
                 12-22 
               
                   
                 Nickel 
                  3.5 max. 
               
                   
                 Molybdenum 
                 0.5-4   
               
                   
                 Copper 
                  2.0 max. 
               
                   
                 Nitrogen 
                 0.2-0.8 
               
                   
                 Boron 
                 0.06 max. 
               
                   
                   
               
           
              
             
             
              
              
              
              
              
              
              
              
              
              
              
              
             
          
         
       
       and the balance is iron and the usual impurities; 
       wherein said stainless steel alloy provides a hardness of about 80 HRB to about 25 HRC. 
     
   
   
       2 . The golf club set forth in  claim 1  wherein said head comprises a body and a face plate assembled together and the body is formed of said stainless steel alloy. 
   
   
       3 . The golf club set forth in  claim 2  wherein the face plate is formed of a material selected from the group consisting of a precipitation hardenable stainless steel, titanium, and a titanium alloy. 
   
   
       4 . The golf club set forth in  claim 1  wherein said head is formed entirely of said stainless steel alloy. 
   
   
       5 . A method of making a golf club head comprising the steps of:
 melting charge materials selected to provide a stainless steel alloy having the following composition in weight percent:   
     
       
         
               
               
               
             
                   
                   
               
                   
                 Carbon 
                 0.25 max. 
               
                   
                 Manganese 
                 14-20 
               
                   
                 Silicon 
                 up to 2.0 
               
                   
                 Phosphorus 
                 0.05 max. 
               
                   
                 Sulfur 
                  0.5 max. 
               
                   
                 Chromium 
                 12-22 
               
                   
                 Nickel 
                  3.5 max. 
               
                   
                 Molybdenum 
                 0.5-4   
               
                   
                 Copper 
                  2.0 max. 
               
                   
                 Nitrogen 
                 0.2-0.8 
               
                   
                 Boron 
                 0.06 max. 
               
                   
                   
               
           
              
             
             
              
              
              
              
              
              
              
              
              
              
              
              
             
          
         
       
     
     and the balance is iron and the usual impurities;
 casting said stainless steel alloy into a mold; 
 solidifying said stainless steel alloy in said mold to form a body of a golf club head or a preform thereof; and then 
 processing said body to provide a finished golf club head. 
 
   
   
       6 . The method as set forth in  claim 5  wherein the step of processing said body comprises the step of heat treating said golf club head to provide a hardness of about 80 HRB to about 25 HRC. 
   
   
       7 . The method as set forth in  claim 5  wherein the step of casting the stainless steel alloy comprises the step of investment casting the stainless steel alloy. 
   
   
       8 . The method as set forth in  claim 6  wherein the step of processing the body of said golf club head comprises the step of machining the body to finished dimensions. 
   
   
       9 . The method as set forth in  claim 5  wherein the step of processing said body comprises the steps of cold working said body and then heat treating the cold-worked body to provide a hardness of about 30 HRC. 
   
   
       10 . The method as set forth in  claim 5  wherein the step of casting the stainless steel alloy comprises the step of casting the alloy into an ingot mold, the step of solidifying the stainless steel alloy comprises the step of forming bar from said alloy, and the step of processing the golf club head body comprises the steps of:
 forging the bar to provide a semi-finished golf club head; and then   machining the semi-finished golf club head to finished dimensions.   
   
   
       11 . The method as set forth in  claim 5  comprising the step of bonding a face plate to said golf club head body after said processing step. 
   
   
       12 . The method as set forth in  claim 11  comprising the step of forming the face plate from a material selected from the group consisting of a precipitation hardenable stainless steel, titanium, and a titanium alloy.