Ductile iron casting process sometimes can replace expensive cast steel and forging steel. Ductile iron casting process is widely used in mechanical manufacturing industry with excellent performance. Choosing right chemical composition and reasonable spheroidization and inoculation process is the key to the production of ductile iron casting process with high quality. Especially, inoculation is an important part in the process.
The method of inoculation has the following purposes: first one is to eliminate the tendencyof crystallization supercooling. Although content of Ce in ductile iron casting process is higher than ingeneral grey iron casting, there are still a larger chilling tendency. After spheroidization, itmust be effective inoculated to eliminate the spheroidizing elements caused by chilling tendency. Then the ductile iron casting process can obtain casting without free cementite.The second purpose is to promote the graphite spheroidization. Inoculation treatment can increase the graphite core, refine spheroidal graphite, and improve the relative stability of the spheroidal graphite growth and the roundness of the graphite ball.
The third purpose is to reduce the intergranular segregation. Inoculation method can refine the eutectic group, so as to reduce the degree of segregation between the eutectic groupand improve its mechanical properties. As a result, it can increase the elongation and impact toughness of ductile iron casting process.