The research project is the ﬁrst step aimed at identifying moving heat source features of interest to practitioners and presenting practical and accurate engineering expressions useful to them. With the understanding that many critical aspects of complex problems, for example, welding can be treated using a minimal representation that captures only the dominant physics: heat transfer, with the secondary physics included as correction factors.
The model considered consists of a point heat source moving in steady state along a straight line with constant velocity on the ﬂat surface of the base material of constant thermophysical properties. The methodology employed involves normalization, dimensional analysis, asymptotic analysis and blending techniques. Engineering expressions for characteristic values of interest to practitioners dominated by heat transfer include size of the isotherm, thermal history, the size of the heat affected zone and so on have been obtained. The engineering expressions are in the form of simple case solutions multiplied by its corresponding correction factors. Besides predictive estimations, those engineering expressions can also reﬂect quantitative effects of different process parameters and their variation on resulting thermal conditions. The methodology and engineering expressions obtained can be applied into a number of processes and materials in different disciplines since they capture the inherent essence of complex physical phenomena. The error between experimental data and results calculated by those engineering expressions is around 18% which approaches the limit of the ability to measure parameters in welding processes. Examples of engineering expressions for isotherm characteristics under a moving point heat source will be given at the presentation.