As the carbon content of steel rises the metal becomes harder and stronger but less ductile and more difficult to weld. Cast irons are hard and brittle; they cannot be easily machined.
|Type of steel||% Carbon|
|Mild Steel||up to 0.25|
|Medium Carbon Steel||0.25-0.45|
|High Carbon Steel||0.45-1.50|
Carbon is the most cost-effective alloying material for iron, but various other alloying elements such as manganese, chromium, vanadium, and tungsten are also used.