Integrated modeling of cracking during deep penetration laser welding of nickel alloys

Abstract

During deep penetration laser welding of nickel alloys, interactions between composition and processing conditions can lead to the formation of defects. Inconel 740H, for example, has demonstrated a susceptibility to horizontal fusion zone cracking at locations between 70% and 80% of the weld depth during laser welding at powers above 5 kW. Coupling three-dimensional heat transfer, fluid flow, and stress modeling tools allowed that both the strain rate and stress normal to the solidification direction to be calculated. In the Inconel 740H welds, cracks formed at locations where the strain rate and stress simultaneously reached critical levels. No cracking was observed in the Inconel 690 welds, since the strain rate and stress did not simultaneously reach these critical levels.

KEYWORDS:

• Solidification cracking; deep penetration; keyhole mode laser welding; nickel alloys; heat transfer and fluid flow; finite element model
• strain rate
• tensile stress

Acknowledgements

The Inconel 740H plate material was provided by Dr. T.M. Lillo at the Idaho National laboratory. Dr. Lillo also provided many helpful discussions that contributed to the analysis. We also thank Dr. J.S. Zuback for his help with the Scheil calculations. Computations for this research were performed on the Roar supercomputer managed by the Institute for Computational and Data Sciences at Pennsylvania State University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

** IPG Photonics Corporation, Oxford, MA, USA

† Carl Zeiss Microscopy GmbH, Jena, Germany

‡ National Institute of Health, Bethesda, MD, USA

§ Thermo-Calc Software AB, Solna, Sweden

** Sente Software, Surrey Research Park, UK

†† Abaqus Inc, Palo Alto, CA, USA

Additional information

Funding

This work was supported by Battelle Energy Alliance, LLC under Contract No. DE-AC07-05ID14517 with the U.S. Department of Energy under Award Number FWP-B100-19010. The publisher, by accepting the paper for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.