Alloying treatment of cast iron can be traced back to the 1930s and 1940s. Alloying treatment has made a qualitative leap in the properties of cast iron. At the same time, some special uses of cast iron such as wear resistance, corrosion resistance and heat resistance have been born. The production of cast iron by inoculation was also produced during this period. In the late 1940s, the cast iron with spherical graphite after inoculation replaced the usual flake graphite cast iron. We call this kind of cast iron spherical graphite cast iron.

Classification of Spheroidizing Elements and Antispheroidizing Elements

Spheroidizing elements are generally divided into three groups according to their spheroidizing effect.

The first group: Mg, Y, Ce, La, Pr, Sm, Dy, Ho, Er.

The second group: Ba, Li, Cs, Rb, Sr, Th, K, Na.

The third group: Al, Zn, Cd, Sn.

The first group has the strongest spheroidizing ability, the second group has the weakest spheroidizing ability and the third group has the weakest spheroidizing ability.

When magnesium is used as spheroidizing element, the third group of elements often produce anti-spheroidizing effect.

Anti-spheroidizing elements: sulfur and oxygen are common anti-spheroidizing elements in cast iron. In addition, Ti, Al, B, As, Pb, Sn, Sb, Bi, Te and Se are common anti-spheroidizing elements in molten iron. The schedules are classified according to their mechanism of action.