Relation between tensile strength and hardness of spheroidal graphite cast iron at elevated-temperatures

Static tension tests at room temperature to 500°C and Vickers hardness tests at room temperature to 700°C were performed on as-cast and heat-treated materials. A regression equation that could estimate the tensile strength from Vickers hardness at elevated temperatures was calculated. The tensile strength at an elevated-temperature decreased with increasing temperature decreased more rapidly when the temperature was above 600°C. A straight line relationship was established between tensile strength and hardness in the temperature range from room to 500°C.