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Simulated and experimental analysis of laser beam energy profiles to improve efficiency in wire-fed laser deposition

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AbstractLaser cladding is a well-established technique, with the majority of prior numerical modelling work focused on delivery and melt pool behaviour of powder-based processes. This research presents new investigations into optimised laser beam shaping for the unique characteristics of wire-based processes, where direct substrate heating, as well as heat transfer between the wire and substrate, is important. The value of this subject is the improved deposition rates and dense metallic structures that can be achieved by wire-based deposition processes compared to powder-based material delivery. The within-wire temperature distribution (AISI 316 stainless steel), the heat transfer and direct heating of the substrate (mild steel) are modelled via heat transfer simulations, with three laser beam irradiance distributions. This analysis identified the removal of localised high-temperature regions typically associated to standard Gaussian distributions, and the improved substrate heating that a uniform square beam profile can provide. Experiments using pre-placed wire and a 1.2 kW CO2 laser were analysed using cross-sectional optical microscopy to provide model validation and evidence of improved wire-substrate wetting, while maintaining favourable austenitic metallurgy in the clad material. A key finding of this work is a reduction, from 480 to 190 W/mm2, in the required irradiance for effective melt pool formation when changing from a Gaussian distribution to a uniform square distribution. This also provided a 50% reduction in total energy. The potential improvements to energy efficiency, cost reductions and sustainability improvements are recognised and discussed.

Funding

The Engineering and Physical Sciences Research Council (EPSRC) has funded this research via a research studentship grant

History

School

  • Mechanical, Electrical and Manufacturing Engineering
  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Published in

The International Journal of Advanced Manufacturing Technology

Volume

114

Issue

9-10

Pages

3021-3036

Publisher

Springer Science and Business Media LLC

Version

VoR (Version of Record)

Rights holder

© The authors

Publisher statement

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

29/03/2021

Publication date

2021-04-20

Copyright date

2021

ISSN

0268-3768

eISSN

1433-3015

Language

en

Depositor

Dr Nick Goffin. Deposit date: 21 April 2021