Calculation of laser-induced temperature field on moving thin metal foils in consideration of Stefan problem

摘要

A temperature field on a moving thin sheet heated by a high-quality laser beam (TEM00) is calculated. Effects of melting and solidification of sheet material is taken into account. Convective and radiation cooling is included into a mathematical model. Nonlinear effects connected with temperature dependencies of material properties are considered. An explicit finite-difference numerical method was used to calculate the non-steady-state 2D and 3D Stefan problems. A surface, on which the melting occur, is replaced by a zone of finite thickness. All physical properties in this zone are smoothed and considered as continuous values. Evaporation of liquid metal begins when temperature reaches some critical value. This effect is also included in the developed model. As a result, the geometry of the melting zone can be derived and is compared with a cross section of real laser welding seem. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 18]