The development of high thermal conductivity die steel with excellent performance: Integrating alloy design, heat treatment, and ceramic particle reinforcement

Hot-forming processes including die casting, hot stamping, and injection molding impose high demands on die steels, where the choice of steels directly impacts the service life of molds, speed of production, costs and product quality. Currently, most research focuses on properties such as strength, toughness, wear resistance, and oxidation resistance of die steels, while neglecting the critical property of thermal conductivity. This review emphasizes the importance of high thermal conductivity for die steels and, for the first time, conducts a comprehensive review centered on the thermal conductivity of steel, thereby addressing the long-standing gap in systematic summaries in this field. This review comprehensively summarizes the mechanism of thermal conduction and key microstructural factors influencing thermal conductivity. Based on this, two main approaches for enhancing the thermal conductivity of steels are discussed, including alloy composition optimization (low alloying element content, particularly with low silicon and chromium levels) and heat treatment process optimization (heat treatment like quenching and tempering is superior to quenching and deep cryogenic treatment, and appropriately increasing the tempering temperature within a certain range). High-thermal conductivity steels often face challenges such as insufficient mechanical properties and poor oxidation resistance. Since conventional strengthening methods are of limited feasibility, this review provides a fresh perspective by highlighting an emerging approach—reinforcing die steels with trace nano-ceramic particles to overcome the traditional trade-off between thermal conductivity and mechanical/oxidation properties. This integrated angle and the proposed strategy constitute a notably novel contribution for a review paper in this field.