Thermal shock resistance of electroslag cast steel for hot-working tools

Thermal shock resistance of electroslag cast steel for hot-working tools has been studied. High resistance to thermal shock is an important requirement for hot-working tool steels, which are exposed, to both severe thermal and mechanical stresses. Electroslag casting is a method of producing shaped ingots in a water cooled metal mould by the heat generated in the current-conductive slag when electric current passes through a consumable steel electrode. The method provides the possibility of producing material for high quality hot-working tools cast into a variety shapes. Good ductility and toughness as well as high tensile strength at elevated temperatures are important properties for high thermal shock resistance. Direct measurements of quantitative values for the thermal shock resistance of hot-working tool steels is needed. Hence, a new testing procedure is proposed in the present study to measure the relative thermal shock resistance of electroslag cast steel. The reliability and reproducibility of the results from the new test are confirmed by measurements of the thermal shock resistance for several commercially available hot-working tool steels, which are consistent with high temperature mechanical properties.