Metallographic properties evaluation of the specimens obtained by the vibratory method (cast iron ISO 400-12)

Abstract

The objective of this research is to evaluate the metallographic properties to obtain cast iron with nodular spherical graphite ISO 400-12 by “In mold” modification using the vibratory method. To carry out the experiments, a model was prepared to reproduce the specimens used, according to the ASTM A0536-84R04 standard for the certification of the quality of cast iron with spherical nodular graphite. The pouring temperature levels were adapted to the wall thickness of the specimens. Vibration frequency (65 Hz, 70 Hz, 75 Hz), pouring temperature (1450°C and 1425°C) and mass of nodulizing alloy FeSiMg (NODULAN II) (189.98 g; 170.99 g; 151.99 g), calculated by the traditional method, were set as independent variables. The applied vibratory method caused changes in the morphology of the metal, as high spheroidization was obtained for all levels of modified alloy mass and smaller nodules (from 40 μm to 60 μm in diameter) were achieved. The tensile strength and relative elongation of the specimens obtained by the vibratory method were similar to the international standards for this type of casting and higher than the castings with nodular spherical graphite obtained under static conditions. Finally, the standard specimens (static method) and the specimens obtained by the vibratory method were obtained, and the metallographic and mechanical properties tests established by the international standards were carried out.