A Process Model for Electron Beam Welding with Variable Thickness

Abstract

A process model for electron beam (EB) welding with a variable thickness weld joint has been developed. Based on theoretical aspects and experimental calibration of electron beam focusing, welding parameters including beam power, focus current, working distance and welding speed were formulated in the heat source model. The model has been applied for the simulation of assembly of components in a gas turbine engine compressor. A series of metallographic weld sections with different welding thickness were investigated to validate the predicted thermal results. The workpieces were scanned both prior to-and after welding, using automated optical metrology (GOM scanning) in order to measure the distortion induced in the welding process. The measured result was compared with predicted displacement. This work demonstrates the attempts to improve the EB welding process modelling by connecting the heat input directly from the actual welding parameters, which could potentially reduce (or even remove) the need for weld bead calibrations from experimental observation.