Influence of Inoculant Type on the Microstructure Characteristics and Mechanical Properties of Ductile Iron

摘要

The inoculation process of molten cast iron defines the final microstructure of the produced castings. The current study is concerned with the microstructure and mechanical properties of ductile iron castings as influenced by the type of inoculant. Inoculation treatment was done through one step and double step processes with different types of inoculants. The most efficient inoculant was that containing (1.0% Sr, 0.1% Ca, 0.5% Al) when used in single step or double step with (1.0% Sr, 0.5% Al) containing inoculant. As-cast tensile strength of 580 and 550 MPa at 20 mm thickness was achieved when this inoculant was used in single and double inoculation treatments, respectively. On the other hand, inoculation using the inoculant containing up to 2.0% Ce showed the lowest tensile strength of about 340 MPa. Though the nodule count (at 20 mm) was 100/mm(2) for (1.0% Sr, 0.1% Ca, 0.5% Al) inoculant compared to 280/mm(2) for the Ce containing inoculants, the pearlite content was higher in case of treatment by the former inoculant which resulted in higher tensile strength.