Hardened golf club head

1. A golf club head comprising:

a body portion; and

a hosel extending from said body wherein a relationship between said body portion and said hosel defines a loft angle;

wherein said loft angle is greater than about 45 degrees;

wherein said body portion comprises a striking face portion and a rear portion;

wherein said striking face portion has a thickness of less than about 2.0 mm at an impact point, said impact point defined as a point that bisection the scoreline in a lengthwise direction at a point 15 mm above a ground plane,

wherein at least said impact point of said striking face portion has a martensitic crystalline structure;

wherein said impact point of said striking face portion has a striking face hardness ratio of greater than about 1.3, and

wherein said striking face hardness ratio is defined by a hardness of said striking face portion at said impact point divided by a hardness of said rear portion.

2. The golf club head of claim 1 , wherein said hardness of said striking face portion is greater than about 300 VH1.

3. The golf club head of claim 2 , wherein said hardness of said striking face portion is greater than about 400 VH1.

4. The golf club head of claim 1 , wherein said body portion is comprised at most about 2 wt. % of C, at most about 5 wt. % of non-carbon additions, and the remainder being substantially Fe.

5. The golf club head of claim 1 , wherein said golf club head is comprised of a carbon steel material.

6. The golf club head of claim 1 , wherein said impact point is the hardest point on said striking face, and wherein said striking face portion has a variable hardness decreasing inversely as the distance away from the impact point increases radially.

7. The golf club head of claim 1 , wherein said hardness of said striking face portion decreases at a gradual slope from said impact point to a point of about 2.0 mm deep inside the striking face portion of said golf club head.

8. The golf club head of claim 7 , wherein said gradually decreasing slope is about 150 VH1/mm.

9. A golf club head comprising

a body portion, and

a hosel;

wherein said body portion comprises a striking face portion and a rear portion;

wherein said striking face portion comprises a material having a martensitic crystalline structure,

wherein said hardness of said striking face is greater than about 400 VH;

wherein said golf club head is comprised of a carbon steel material; and

wherein said golf club head has a striking face hardness ratio of greater than 1.3; said striking face hardness ratio defined by a hardness of said striking face portion divided by a hardness of said rear portion.

10. The golf club head of claim 9 , wherein said impact point is the hardest point on said striking face, and wherein said striking face portion has a variable hardness decreasing inversely as the distance away from the impact point increases radially.

11. The golf club head of claim 9 , wherein said hardness of said striking face portion decreases at a gradual slope from said impact point to a point of about 2.0 mm deep inside the striking face portion of said golf club head.

12. The golf club head of claim 11 , wherein said gradually decreasing slope is about 150 VH1/mm.

13. A golf club head comprising:

a body portion; and

a hosel;

wherein said body portion comprises a striking face portion and a rear portion;

wherein said striking face portion comprises a material having a martensitic crystalline structure,

wherein said hardness of said striking face portion is greater than a hardness of said body portion, and

wherein said golf club head has a striking face hardness ratio of greater than about 1.3; said striking face hardness ratio defined by a hardness of said striking face portion divided by a hardness of said rear portion.

14. The golf club head of claim 13 , wherein said golf club head is comprised of a carbon steel material.