Experimental investigation of thermal properties of tool steel and mild steel with heat treatment

Abstract The determination of the thermal properties of materials like H13 tool steel and mild steel has received great attention due to their wide applications in industrial as well as in manufacturing sectors. Due to the excellent resistance to softening, AISI H13 tool steel is widely used for higher temperature applications like cutting, forming and shaping the materials. The parameters that relate the interfacial heat transfer and interface temperature are thermal conductivity and thermal contact conductance (TCC) of the materials in contact. Thermal properties are affected by the heat treatment processes which are mainly employed for the formation of tools and dies. Hence in his work, different heat treatment processes have been performed on the selected materials, viz. Tool steel (H13) and Mild steel. These materials have been chosen for their extensive use in making tools, dies and other instruments. Microhardness of the materials has been compared with and without heat treatments. Further, heat transfer studies have been performed in order to evaluate the thermal properties mainly thermal conductivity and thermal contact conductance. Standard ASTM test methods have been employed for the estimation of thermal conductivity and TCC of the specimens. Experiments have been conducted for varying degree of loading and heat flux in order to observe the effect of contact pressure and mean interface temperatures. Effect of heat treatment has been observed on thermal conductivity of mild steel and tool steel and thermal contact conductance of the tool steel-mild steel contacts. Moreover, the results have been presented in normalized form and suitably compared with the existing literatures.