Push-pull fatigue test on ductile and vermicular cast irons

This article aims at measuring and comparing the fatigue strength by fully reversed push-pull tests in the case of two different cast irons: ductile and vermicular. Spheroidal Graphite Iron (SGI), also known as ductile cast iron, is nowadays used in a very large variety of applications. It represents a valid option when strength and stiffness are required: high values of tensile strength and Young’s modulus are coupled with appreciable deformation before failure. On the contrary, a different cast iron, known as Compacted Graphite Iron (CGI) or vermicular cast iron, is presenting its benefits in replacing SGI respect to specific applications. In particular, with a better castability, machinability and thermal resistance, SGI is ideal when components suffer simultaneous mechanical and thermal loadings, such as cylinder blocks and heads. While SGI benefits of a wide scientific literature, CGI is a relatively unknown material, especially referring to its response under fatigue loads.