Percentage of carbon in carbon steel hand instruments is
1-1.2%
10-12%
0.6 to 0.8%
6 to 8%
MATERIALS USED FOR MANUFACTURING CUTTING INSTRUMENTS 
Carbon Steel

Carbon steel alloy contains 0.5 to 1.5 percent carbon in iron.
Instruments made from carbon steel are known for their hardness and sharpness.
Disadvantages with these instruments are their susceptibility to corrosion and fracture. They are of two types:

1. Soft steel: It contains <0.5% carbon
2. Hard steel: It contains 0.5 to 1.5% carbon
Nisha Garg, Amit Garg. Textbook of Operative Dentistry.  Edition 3. Page: 80