Golf club head

Abstract

A golf club head includes a unitary component. The unitary component is formed of a stainless steel material. The unitary component has variable hardness. A first portion of the component exhibits a first hardness H1 no less than 50HRC. A second portion of the component exhibits a second hardness H2 no greater than 85HRB.

1 - 29 . (canceled) 
     
     
         30 . A golf club head comprising a material having a material composition such that:
 (a) an Iron content by weight is highest of all constituents;   (b) a Chromium content is no less than 10.5% by weight; and   (c) a Nickel content is no greater than 0.5% by weight.   
     
     
         31 . The golf club head of  claim 30 , wherein the material comprises stainless steel. 
     
     
         32 . The golf club head of  claim 30 , wherein the material composition comprises a Carbon content no less than 0.25% by weight. 
     
     
         33 . The golf club head of  claim 30 , wherein the Nickel content is no greater than 0.35% by weight. 
     
     
         34 . The golf club head of  claim 30 , wherein the Chromium content is no less than 16% by weight. 
     
     
         35 . The golf club head of  claim 30 , further comprising:
 a striking face;   a rear portion;   a hosel portion; and   a unitary component comprising the material, the unitary component including a first portion forming at least a portion of the striking face.   
     
     
         36 . The golf club head of  claim 35 , wherein the unitary component comprises a second portion located at the hosel portion or the rear portion. 
     
     
         37 . The golf club head of  claim 35 , further comprising a head mass Mh, wherein the unitary component further comprises a component mass Mc such that Mc/Mh is greater than 0.5. 
     
     
         38 . The golf club head of  claim 37 , wherein substantially the entire club head is formed of the unitary component. 
     
     
         39 . The golf club head of  claim 35 , wherein the striking face comprises a nitrided surface. 
     
     
         40 . A golf club head comprising a material having a material composition such that:
 (a) an Iron content by weight is highest of all constituents;   (b) a Chromium content is no less than 10.5% by weight;   (c) the material is capable of being quenched to achieve a material hardness of at least 50 HRC; and   (d) the material is capable of being quenched and tempered to achieve a hardness of no more than 90 HRB.   
     
     
         41 . The golf club head of  claim 40 , wherein the material is capable of being quenched and tempered to achieve a hardness of no more than 85 HRB. 
     
     
         42 . The golf club head of  claim 40 , wherein the material comprises stainless steel. 
     
     
         43 . The golf club head of  claim 40 , wherein the material composition comprises a Carbon content no less than 0.25% by weight. 
     
     
         44 . The golf club head of  claim 40 , wherein the material composition comprises a Nickel content no greater than 0.35% by weight. 
     
     
         45 . The golf club head of  claim 40 , wherein the Chromium content is no less than 16% by weight. 
     
     
         46 . The golf club head of  claim 40 , wherein the striking face comprises a nitrided surface. 
     
     
         47 . A golf club head comprising a material having a material composition such that:
 (a) an Iron content by weight is highest of all constituents;   (b) a Chromium content is no less than 10.5% by weight; and   (c) a ratio of a maximum quenched hardness, in HRC, and a minimum quenched and tempered hardness, in HRB, is at least 0.5 HRC/HRB.   
     
     
         48 . The golf club head of  claim 47 , wherein the material is capable of being quenched and tempered to achieve a hardness of no more than 85 HRB. 
     
     
         49 . The golf club head of  claim 47 , wherein the material comprises stainless steel. 
     
     
         50 . The golf club head of  claim 47 , wherein the material composition comprises a Carbon content no less than 0.25% by weight. 
     
     
         51 . The golf club head of  claim 47 , wherein the material composition comprises a Nickel content no greater than 0.35% by weight. 
     
     
         52 . The golf club head of  claim 47 , wherein the Chromium content is no less than 16% by weight. 
     
     
         53 . The golf club head of  claim 47 , wherein the striking face comprises a nitrided surface.