Influence of residual oxygen during laser beam welding under vacuum

Thorsten Twiehaus; Simon Olschok; Uwe Reisgen

doi:10.1515/mt-2021-2183

Article

Influence of residual oxygen during laser beam welding under vacuum

Thorsten Twiehaus
Thorsten Twiehaus – M.Sc., M.Sc., born 1991. Thorsten Twiehaus studied Mechanical Engineering at the RWTH Aachen University and Management Science and Engineering at the Tsinghua University in Beijing. He is currently working as a research engineer at the beam welding department of ISF Welding and Joining Institute of the RWTH Aachen University.
, Simon Olschok
Simon Olschok – Dr.-Ing., born 1972. Simon Olschok studied Mechanical Engineering at the RWTH Aachen University. From 2002 till 2007, he worked as a research engineer at the ISF Welding and Joining Institute of the RWTH Aachen University and received a doctorate in 2008 with the thesis “Hybrid Welding of Thick Plates”. Since 2007 he is head of the beam welding department at the ISF Welding and Joining Institute of the RWTH Aachen University.
and Uwe Reisgen
Uwe Reisgen – Univ.-Prof. Dr.-Ing., born 1962. Uwe Reisgen studied Mechanical Engineering at the RWTH Aachen University and received a doctorate at the ISF Welding and Joining Institute of the RWTH Aachen University in 1995 with a thesis on the research of wire feeding systems and their components for GMA Welding. Since 2007 he is head of the ISF Welding and Joining Institute at the RWTH Aachen University.

Published/Copyright: July 7, 2022

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From the journal Materials Testing Volume 64 Issue 7

Abstract

Laser beam welding under vacuum (LaVa) offers advantages regarding the achievable weld penetration depths compared to conventional laser beam welding. Thus, it is increasingly used in industry. Despite the high weld penetration depths that can be achieved and the good inner seam qualities, undesirable reworking is often necessary due to surface deposits on the welded sample. The causes of these surface deposits have not yet been investigated in depth. In this context, the influence of the residual oxygen present inside the vacuum chamber is investigated in this study. For this purpose, the oxygen content within the chamber is recorded for LaVa welds at different working pressures and different evacuation times. The welded specimens are evaluated metallographically and investigated with regard to an influence of the oxygen content within the working chamber. This study shows that the residual oxygen content considerably influences the weld formation and the surface weld appearance for all working pressures investigated. For lower oxygen contents, the weld penetration depth decreases, and the weld width, on the other hand, increases. These observations can be explained in good agreement with findings for the influence of oxygen on the weld appearance for other material joining processes, such as TIG welding.

Keywords: evacuation times; laser beam welding under vacuum; residual oxygen; stainless steel; weld seam quality and topology

Corresponding author: Thorsten Twiehaus, Welding and Joining Institute, RWTH Aachen University, Pontstrasse 49, 52062 Aachen, Germany, E-mail: twiehaus@isf.rwth-aachen.de

Funding source: Allianz Industrie Forschung

Award Identifier / Grant number: IGF 20.069N

About the authors

Thorsten Twiehaus

Thorsten Twiehaus – M.Sc., M.Sc., born 1991. Thorsten Twiehaus studied Mechanical Engineering at the RWTH Aachen University and Management Science and Engineering at the Tsinghua University in Beijing. He is currently working as a research engineer at the beam welding department of ISF Welding and Joining Institute of the RWTH Aachen University.

Simon Olschok

Simon Olschok – Dr.-Ing., born 1972. Simon Olschok studied Mechanical Engineering at the RWTH Aachen University. From 2002 till 2007, he worked as a research engineer at the ISF Welding and Joining Institute of the RWTH Aachen University and received a doctorate in 2008 with the thesis “Hybrid Welding of Thick Plates”. Since 2007 he is head of the beam welding department at the ISF Welding and Joining Institute of the RWTH Aachen University.

Uwe Reisgen

Uwe Reisgen – Univ.-Prof. Dr.-Ing., born 1962. Uwe Reisgen studied Mechanical Engineering at the RWTH Aachen University and received a doctorate at the ISF Welding and Joining Institute of the RWTH Aachen University in 1995 with a thesis on the research of wire feeding systems and their components for GMA Welding. Since 2007 he is head of the ISF Welding and Joining Institute at the RWTH Aachen University.

Acknowledgment

The Welding and Joining Institute of the RWTH Aachen University would like to thank all participating partners from the industry for their support. The results shown are part of the IGF project 20069 N of the Research Association Forschungsvereinigung Schweißen und verwandte Verfahren e.V. des DVS, Aachener Str. 172, D-40223 Düsseldorf. The project was supported via the AIF e.V. and financed within the budget of the Federal Ministry of Economic Affairs and Climate Action to promote joint industrial research and development (IGF). (By decision of the German Bundestag).

Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The presented work was supported by German Federation of Industrial Research Associations (AiF) in the context of the IGF project: 20069 N.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Published Online: 2022-07-07

Published in Print: 2022-07-26

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https://doi.org/10.1515/mt-2021-2183

Keywords for this article

evacuation times; laser beam welding under vacuum; residual oxygen; stainless steel; weld seam quality and topology