Spheroidal graphite cast iron, spheroidizing and inoculation treatment to obtain spheroidal graphite, which effectively improves the mechanical properties of cast iron, especially plasticity and toughness, thereby obtaining higher strength than carbon steel. It is said that nodular cast iron is a high-strength cast iron material developed in the 1950s. Its comprehensive performance is almost close to that of steel. It is based on its excellent performance that it has been successfully used for casting some complex forces, strength, toughness, Parts requiring high wear resistance. Nodular cast iron has rapidly developed into a cast iron material second only to gray cast iron and widely used. The so-called "substituting iron for steel" mainly refers to ductile iron.