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;

wherein said striking face portion is comprised of a material having a martensitic crystalline structure;

wherein said golf club head 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 divided by a hardness of said rear portion.

2. The golf club head of claim 1 , wherein said striking face portion is harder than said rear portion.

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

4. The golf club head of claim 1 , wherein said hardness of said striking face portion is greater than about 400 VH1.

5. The golf club head of claim 1 , wherein said martensitic crystalline structure is created by a method comprising:

heating said striking face portion to a target temperature for a target duration; and

rapidly quenching said striking face portion in a coolant.

6. The golf club head of claim 5 , wherein said target temperature is greater than about 700 degrees Celsius.

7. The golf club head of claim 6 , wherein said striking face portion is quenched at a cooling rate of greater than about 1,000 degrees Celsius per second.

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

9. The golf club head of claim 1 , wherein an impact point of said striking face portion is the hardest, and wherein said striking face portion has a variable hardness inversely decreasing away from said impact point of said striking face portion.

10. 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 about 2.0 mm deep inside said golf club head and said hardness of said rear portion remains substantially constant thereafter.

11. The golf club head of claim 10 , wherein said gradually decreasing scope is about 150 VH1/mm within said striking face portion of said golf club head.

12. A method of hardening a striking face portion of a golf club head comprising:

heating said striking face portion of said golf club head to a target temperature for a target duration; and

rapidly quenching said striking face portion in a coolant;

wherein said golf club head has a loft angle greater than about 45 degrees;

wherein said striking face portion transforms into a material having a martensitic crystalline structures;

wherein said golf club head an improved striking surface hardness ratio of greater than about 1.3; and

wherein said improved striking face hardness ratio is defined by a hardness of said striking face portion divided by a hardness of the remainder of said golf club head.

13. The method of claim 12 , wherein said striking face portion has a thickness of less than about 2.0 mm.

14. The method of claim 12 , wherein said hardness of said striking face portion is greater than about 300 VH1.

15. The method of claim 14 , wherein said target temperature is greater than about 700 degrees Celsius.

16. The golf club head of claim 15 , wherein said hitting surface is quenched at a cooling rate of greater than about 1,000 degrees Celsius per second.

17. The method of claim 12 , wherein the step of heating said striking face portion to said target temperature for said target duration is further comprising:

concentrating the heating source at an impact point of said striking face portion;

wherein said impact point of said striking face portion is the hardest; and

wherein said striking face portion has a variable hardness decreasing radially from said impact point of said striking face portion moving outward.

18. 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 golf club head has an 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 divided by a hardness of said rear portion.

19. The golf club head of claim 18 , wherein said hardness of said striking face portion decreases at a gradual slope from said impact point to a point about 2.0 mm deep inside said golf club head and said hardness of said rear portion remains substantially constant thereafter.

20. The golf club head of claim 19 , wherein said gradually decreasing scope is about 150 VH1/mm within said striking face portion of said golf club head.

21. The golf club head of claim 20 , wherein said hardness of said striking face portion is greater than about 300 VH1.

22. The golf club head of claim 21 , wherein said martensitic crystalline structure is created by a method comprising:

heating said striking face portion to a target temperature for a target duration; and

rapidly quenching said striking face portion in a coolant.

23. The golf club head of claim 22 , wherein said target temperature is greater than about 700 degrees Celsius.

24. The golf club head of claim 23 , wherein said striking face portion is quenched at a cooling rate of greater than about 1,000 degrees Celsius per second.