Nodulizers are certain metals or alloys added to molten iron in order to obtain spherical graphite cast iron during the casting process. Moreover, there are many types of nodulizers, and the needs of foundries in many countries are also different. In China, ferrosilicon rare earth magnesium nodulizers are commonly used.
In short, nodulizers are additives that make graphite in cast iron crystallize into spherical shapes, so-called “nodulizers”. Let’s take a look at the main component elements of “spheroidizing agent” are nodularizing elements, such as Mg, Ce, Ca, etc. Spheroidal graphite in ductile cast iron is formed by spheroidizing molten cast iron, making it much stronger than gray cast iron and tougher than malleable cast iron, while maintaining a series of advantages of gray cast iron. However, the “spheroidizer” used in the casting of ductile iron can increase the tendency of the weld to produce “white mouth” and hardened structure, and induce cracks in the weld and heat-affected zone (especially the fusion zone). Therefore, the weldability of ductile iron is worse than that of gray cast iron.
The nodulizers commonly used in China are iron-silicon rare earth magnesium alloys, and most foreign countries use magnesium-based nodulizers (pure magnesium and magnesium alloys), and a few countries use calcium-based nodulizers.
The development of nodulizer plays an important role in promoting the production of nodular iron. Cerium was recognized as a nodularizer very early. At that time, the source of cerium was scarce, and the requirements for the composition of molten iron were harsh, so that cerium nodular iron could not be used in industrial production. Magnesium nodulizers enable nodular iron to be applied on an industrial scale. The development of nodulizers from pure magnesium to magnesium-nickel, magnesium-copper, and magnesium-silicon-iron alloys has promoted the expansion of nodular iron production.
The development of rare earth magnesium ferrosilicon nodularizers makes the production of ductile iron in China basically based on domestic resources, establishes the series of rare earth magnesium ductile iron in China, expands the use range of pig iron, improves the performance and quality of ductile iron castings, and makes ductile iron Production flourished even more. The application of yttrium heavy rare earth has created conditions for the development of new composite nodulizers. The comprehensive utilization of various nodular elements will create good conditions for the further development and improvement of nodular iron production.