Influence of Alloying Elements, Heat Treatment, and Temperature on the Thermal Conductivity of Heat Treatable Steels

The thermal conductivity of heat treatable martensitic steels plays an important role for many industrial applications. In case of hot stamping, the thermal conductivity of forging tools determines not only the product quality but also the productivity. Hence, the aim of ongoing developments is to increase the thermal conductivity of tool steels for several industrial applications. Therefore, it is highly beneficial to know how thermal conductivity is influenced by alloying elements, heat treatment, and temperature. This work deals with the thermal conductivity of non-alloyed heat treatable steel C45 and high-alloyed corrosion resistant steel X42Cr13 in the as-quenched and in the tempered condition. Additionally, the influence of dislocations on thermal conductivity is analyzed using commercially pure iron (Armco-Iron) in the annealed and in the cold-rolled condition. The results reveal that tempering affects both the electronic and the phononic contribution to thermal conductivity. Furthermore, due to the high chromium content, the thermal conductivity of steel X42Cr13 increases with temperature, which can be traced back to the electronic contribution. These results are useful for the development and improvement of tool steels, when the thermal conductivity of tools is not only a property but also a process parameter.