Improvement of tensile strength and corrosion resistance of high-silicon cast irons by optimizing casting process parameters

In this study, the relationship between casting process parameters and mechanical properties in a 14.5%Si containing corrosion resistant cast iron was statistically investigated using Taguchi method, one of the design tools of experiments. Three casting process parameters, which might be thought to be closely related to the determination of mechanical properties of high-silicon cast irons, such as melting temperature, mischmetal addition, and pouring temperature were chosen. Using signal-to-noise (SN) ratio calculated from the ultimate tensile strength (UTS) of each experimental casting run, the relationship between the casting process parameters and mechanical properties was statistically evaluated. The casting condition of high melting temperature of 1,650 C, 0.2% mischmetal addition, and pouring temperature of 1,350 C, led to an excellent UTS of 110–150 MPa, which is beyond the industrial criterion. The effects of casting process parameters on mechanical properties and corrosion resistance were further confirmed by combined analysis of fractography, hydrogen content determination, microscopic test, and acid resistance test