Ductile cast irons (DCIs) offer an interesting combination of good castability (typical of gray irons) and good mechanical properties, first of all the toughness (peculiar of many steels). Recently discovered and developed, DCIs family is nowadays characterized by different chemical compositions and heat treatments, optimized with the aim to control the matrix microstructure and obtain different combinations of mechanical properties. DCIs are widely used to produce pipes (for transportation of raw and tap water, sewage, slurries, and process chemicals) and safety-related components for automotive applications (gears, bushings, suspension, brakes, steering, crankshafts), and they are also used for more critical applications as containers for storage and transportation of nuclear wastes.