The production of thin-wall ductile iron can be challenging due to the formation of carbides during the solidification process. One way to reduce carbides in thin sections is by the addition of silicon, but this is detrimental for the impact strength and fracture toughness of ductile iron. It is known that cobalt as an alloying element in ductile iron increases the nodule count resulting in a larger fraction of ferrite. Therefore, the ability of cobalt to inhibit carbide formation was studied. The goal was to inhibit carbide formation without increasing silicon content. Five heats were produced: Co-free ductile iron, 1 wt%, 2 wt%, 3 wt%, and 4 wt% Co. These were cast into plates with thicknesses of 2, 2.5, 3, 3.5, 4, and 6 mm. Metallography was performed to evaluate the percent nodularity, nodule count (N/mm²), and ferrite/pearlite/carbide percentages. Tensile testing was performed using flat sub-size dogbone samples. Also, the fracture surfaces of the 2 and 6 mm sections were analyzed using SEM. Finally, Brinell hardness was performed on each section thickness. There was no increase in the percent nodularity with the addition of cobalt, but with 4 wt% Co an increase in nodule count was observed. With the addition of 3 wt% and 4 wt% Co, there was a reduction in carbide percentage due to an increase in ferrite content. With the addition of 4 wt% Co, there is a reduction in yield strength and an increase in elongation due to a higher ferrite percentage. It was discovered that with the addition of 4 wt% Co the production of carbide-free sections is possible without increasing the silicon percentage above 2.41 wt% Si.

由于凝固过程中会形成碳化物，因此薄壁球墨铸铁的生产可能具有挑战性。减少薄片中碳化物的一种方法是添加硅，但这对球墨铸铁的冲击强度和断裂韧性有害。众所周知，作为球墨铸铁中的合金元素，钴会增加球根数，从而导致铁素体含量更高。因此，研究了钴抑制碳化物形成的能力。目的是在不增加硅含量的情况下抑制碳化物的形成。产生了五次加热：无钴球墨铸铁，1 wt％，2 wt％，3 wt％和4 wt％Co。将它们铸成厚度为2、2.5、3、3.5、4和6 mm的板。进行金相分析以评估结节百分数，结节数（N / mm ²），以及铁素体/珠光体/碳化物的百分比。使用扁平亚尺寸的犬骨样品进行拉伸测试。另外，使用SEM分析了2mm和6mm截面的断裂表面。最后，在每个截面厚度上进行布氏硬度。钴的添加，球化百分数没有增加，但是，钴含量为4％（重量）时，结节数却增加了。通过添加3wt％和4wt％的Co，由于铁素体含量的增加，碳化物百分比降低。加入4wt％的Co，由于较高的铁素体百分比，导致屈服强度降低和伸长率增大。已经发现，通过添加4wt％的Co，可以在不将硅百分比增加到高于2.41wt％的Si的情况下生产无碳化物的段。