Experimental Investigations of Thermal Contact Conductance for Tool–Sample Interface

Abstract

There are many practical applications where two metals are kept in contact, such as metal forming, metal cutting, fin-tube heat exchangers, electronic packaging, metal casting, I C engines, nuclear reactors, and bolted joints. The study of thermal contact conductance (TCC) is essential for the thermal and mechanical analysis required for the suitable design of a system. In this work, the thermal contact conductance has been studied for metal cutting applications. In metal cutting operations, a tool comes in contact with a metal to be cut, and the heat is generated at the contact interface. Hence, axial heat flow experiments have been carried out to evaluate the thermal contact conductance at the interface of tool and metal, placed in line contact. The upper specimen is essentially a metal cutting tool made of high-speed steel while the lower specimen is of mild steel, a common metal to be machined. Steady state approach has been employed to estimate the thermal contact conductance at the interface of tool and metal, under atmospheric conditions. The experiments have been carried out with different surface finishes for each specimen pairs, under varying loads and varying interface temperatures to study the effect of surface properties, contact pressure, temperature and surface deformations on thermal contact conductance. Further, the normalized results of TCC at the interface of tool and metal have been compared with theoretical models. Moreover, the results have been presented in the form of a suitable correlation which would be beneficial for the design of these systems for the present range of working parameters.