A grey cast iron may have within a ferrous matrix: an amount of carbon between 3.60 and 3.90% by weight; an amount of silicon between 1.40 and 1.90% by weight; an amount of titanium not higher than 0.10% by weight; an amount of boron between 0.04 and 0.07% by weight; an amount of vanadium between 0.07 and 0.14% by weight; an amount of manganese between 0.60% and 0.90% by weight; an amount of nickel not higher than 0.20% by weight; an amount of chromium not higher than 0.35% by weight; an amount of copper not higher than 0.35% by weight; an amount of phosphorus not higher than 0.10% by weight; an amount of sulphur not higher than 0.12% by weight; an amount of tin not higher than 0.10% by weight; an amount of molybdenum not higher than 0.10% by weight.

A grey cast iron may have within a ferrous matrix an amount of carbon between 3.60 and 3.90% by weight; an amount of silicon between 1.40 and 1.90% by weight; an amount of titanium not higher than 0.10% by weight; an amount of manganese between 1.0% and 1.5% by weight; an amount of nickel not higher than 0.20% by weight; an amount of chromium between 0.40% and 1.0% by weight; an amount of copper not higher than 0.35% by weight; an amount of phosphorus not higher than 0.10% by weight; an amount of sulphur not higher than 0.12% by weight; an amount of tin not higher than 0.10% by weight; an amount of molybdenum not higher than 0.10% by weight.

[Task] To provide a method that makes it possible to easily, inexpensively and accurately manufacture a machined part with a simple configuration and an excellent strength. [Means for Solution] In a method for manufacturing a machined part according to the invention, a dislocation is partially introduced (S3), through shot peening, only into a surface layer of a raw material 1 in a region 1a to be machined, graphite is partially deposited (S4), through heating, only in the surface layer of the region 1a to be machined, and then, the surface layer of the region 1a where graphite is deposited is removed, through machining (S5), only by an amount corresponding to a working margin 1c, thereby manufacturing a machined part 1.

A method of casting a camshaft including iron includes determining a cooling rate profile based on a chemical composition of the camshaft and a target bearing life of the camshaft. The method includes casting the camshaft including cooling the camshaft in a chiller based on the cooling rate profile. The method includes imparting the camshaft with a microstructure comprising carbide, ledeburite, pearlite, ausferrite, or combinations thereof.