The development and validation of a model for the electron beam welding of aero-engine components

Abstract

Electron beam welding is used to manufacture high-integrity structures, for example compressor assemblies, for the latest generation of Rolls-Royce aero-engines. For such applications, the welding variables (for example welding current, voltage, beam focusing parameters) must be optimized, such that any distortion induced by the process is insignificant when compared to the dimensional tolerances allowed by the designers. Furthermore, the residual stresses induced by the process must be described and characterized, since these are required for estimates of component life. A model for such electron beam welding processes is described, along with the strategy adopted during its development. The basis of the model is a coupled thermal-mechanical finite element analysis. Particular attention is paid to (a) modelling of the heat source, (b) the frame of reference for the analysis, and (c) choice of finite element mesh. For the purposes of calibration and verification, a number of validatory experiments have been carried out. Typical results are presented and practical benefits are discussed.