Corresponds to a type of cast iron in which carbon content in the matrix is shaped ferrifica areas, this significantly modifies the mechanical properties, especially those that are contested in the cast iron as machinability, impact resistance and ductiilidad. This condition is achieved by spherical inclusion of small amounts of magnesium or cerium, this inclusion takes place before casting the metal, it is evident that the magnesium in itself does not guarantee the formation of the areas are also important cooling and the origin of the raw material used, incidentally, which is composed of a mixture of coal (anthracite), calcium carbonate, iron I is not usual to use virgin iron ore such as magnetite, ferrite, limonite and hematite , among other things because magnesium is acting as excoriating in the process of reduction and favors the formation of carbon spheroids, in which ferrifica matrix, pearlitic character is usually because it has greater resistance than the martensite, for example, but lower ductility and machinability. The favorite team to achieve this type of casting is the cupola furnace, which is nothing other than a vertical cylindrical element about 6 feet tall, which is placed in the metals, until the liquid state and allows casting can be used for the manufacture of almost all alloys, for jet ventilation is located at the bottom. Nicholas Carr describes an additional similar source. The material is distributed in layers of about 30 or 40 cm inside, alternating with coal which allows the process is continuous. This type of oven is coated with refractory material inside, which must be inspected before each load and that due to the temperature inside is evidence (around 1500 C) could punch the tubular structure and fall on operators who are conducting the casting process at the base of the oven. The classification of nodular castings is carried out according to ASTM A-536 taking into account its resistance and is designated a Nomenclature of three numbers which takes into account the strength in psi and elongation being usual type foundries from 1960 to 1940 – 18 40 KPSI resistance and elongation of 18% or the 120 – 70 – 02 with a resistance of 24 KPSI and an elongation rate of 2%, obviously lower mechanical resistance to elongation capacity. The applicability of this type of casting is very broad since it has the characteristics of a cast iron, as already mentioned, such as corrosion resistance, low price, as well as a major strength, enhanced now by a big machine , so that all the castings have been be made through this process as the final finish may be given with metal removal processes.