Width of thermal features induced by a 2-D moving heat source

Abstract

Novel expressions in explicit form are presented for the estimation of the width of the bead, location of heat affected zone, and the width of any chosen isotherm in materials processes such as welding, additive manufacturing, laser heat treatment, and cutting. These expressions are applicable when the substrate is relatively thin (as in most cases of welding and additive manufacturing of walls), or when the heat source penetrates deeply into the substrate (as in keyhole mode in laser or electron beam welding). The explicit expressions are based on the widely used Rosenthal 2-D solution, which yields results of the correct order of magnitude compared to experiments for a broad range of materials, processes, and parameters. Asymptotic analysis was applied and a new blending technique was developed to arrive to explicit expressions within 7% of the exact solution. The key dimensionless group in this case is the Rosenthal number Ro, which enables the blending of solutions corresponding to fast and slow heat sources. A comprehensive survey of experimental results indicates a good agreement with the predictions resulting from the proposed expression.