Study of the effect of commercial inoculants in high silicon cast iron components

High-silicon alloys have experienced significant growth in recent years due to their highly homogeneous structure, excellent mechanical properties, and excellent performance in aggressive environments. However, they have a significant drawback: a tendency to form micro-sinks, which can lead to internal sanitation problems in the parts.

To determine the influence of the inoculation process on reducing microporosity, ensuring healthy parts with improved metallurgical quality, the AZTERLAN Metallurgical Research Center conducted a comparative study of several inoculants on the market. This research was conducted both in the laboratory and in an industrial process, with very similar results in both environments.

In both cases, the same standard part was used: a thermal mug (also called a quick-cup), which was inoculated with different commercial inoculants. The main difference between them all lies in the trace elements that comprise their chemical composition, including lanthanum, cerium, zirconium, calcium, aluminum, and manganese.

The study of the effect of inoculation on part quality was conducted from four different perspectives, which will complement each other to provide a comprehensive view of the situation. These different perspectives include a study of the internal defect using computerized axial tomography, thermal analysis of the cooling curves using the Thermolan® system to define the metallurgical quality, as well as a complete characterization of the material’s microstructure and an in-depth understanding of the main graphite nucleation points using the most advanced scanning electron microscopy techniques.