Addressing Stress Mitigation in Electron Beam Processing

The productivity and commercial attractiveness of high deposition rate additive processes are clear but may be tainted by concerns over management of in-process distortion bought about by repeated thermal cycles and resultant stress build-up, where mitigation costs may be high. TWI has extensive knowledge and expertise in distortion control and mitigation in the fabrication of weld structures; this takes the form of practical and finite element methods and may be applied to benefit those engaging in additive manufacture.

To date, from work reported globally, control of resultant stresses and distortion in practical electron beam wire-fed additive processing has been largely rudimentary and has often taken the form of inter-pass furnace heat treatments. TWI’s experiences and know-how in power beam-material interaction, melt pool and structural modelling are now being applied to overcome these technical challenges and will form the basis of this paper. Initial testing and validation of residual stress mitigation methodologies through practical changes to the process parameters and procedures will also be discussed.