Both welding and additive manufacturing are characterized by the use of moving heat sources, such that the workpiece experiences localized high temperature (typically melting), while the rest of the component is unaffected. The thermal features have a significant effect on the resulting phase transformations and metallurgical properties. Practical questions associated with moving heat sources include the cooling rate after the heat source passed, thickness of the heat affected zone, desired preheat to reach a target cooling rate, and solidification time. Thermal features can be estimated from a large variety of numerical, analytical and semi-analytical models. In all cases, the results are a temperature as a function of location and time, and the thermal features are calculated from these results. Even for the simplest of models, the process can be tedious, for example to determine the width of a weld, it is necessary to solve the implicit equation giving the isotherm, and then find its maximum. This work presents a methodology in which moving heat sources are generalized using dimensional analysis, and explicit expressions for the thermal features are obtained using asymptotic analysis and blending techniques. Expressions and examples will be presented for the features mentioned above and more.

Moderated by: Steve Cockcroft / Farzaneh Farhang Mehr