Influence of pulsed laser beam welding in vacuum on the mechanical properties of non-grain oriented electrical steel sheets

Uwe Reisgen; Simon Olschok; Erik Rasbach; Thomas Krichel

doi:10.1515/mt-2022-0364

Article

Influence of pulsed laser beam welding in vacuum on the mechanical properties of non-grain oriented electrical steel sheets

Uwe Reisgen , Simon Olschok , Erik Rasbach
Erik Rasbach has been studying mechanical engineering with a focus on production engineering at RWTH Aachen University, Germany, since 2017. Since 2021, he has been working at the Institute of Joining and Welding Technology (ISF) at RWTH University as a student research assistant in the field of laser beam welding. In 2022, he completed a Six Sigma quality management course and is currently writing his bachelor thesis at ISF.
and Thomas Krichel

Published/Copyright: January 9, 2023

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From the journal Materials Testing Volume 65 Issue 1

Abstract

Major components of electrical machines are iron cores made of stacked electrical steel sheets. In this paper, pulsed laser beam welding in vacuum is used to join the individual electrical steel sheets. Three different non-grain-oriented electrical steel alloys are investigated and joined by individual spot welds. The influence of pulsed laser beam welding in atmosphere as well as in vacuum on the welding result and the tensile strength of the welded joint is discussed. The results show that the insulation coating of the electrical sheets has significant effects on the grain structure as well as the hardness of the weld spots. These effects can be reduced with decreased working pressure, which reduces the power loss of iron cores. The reduction of the working pressure and the associated reduction of the vapor plume, which appears to reduce the energy input into the component depending on the material and coating, results in an increase of the melt volume and the joint cross sectional area. The tensile strength of the performed welds was tested and interpreted with respect to the influencing process parameters.

Keywords: electrical steel sheet; insulation coating; laser beam welding in vacuum; pulsed laser welding; spot welding

Corresponding author: Thomas Krichel, Welding and Joining Institute, RWTH Aachen University, Pontstraße 49, 52457 Aachen, Germany, E-mail: krichel@isf.rwth-aachen.de

Funding source: Deutsche Forschungsgemeinschaft

Award Identifier / Grant number: 432930813

About the author

Erik Rasbach

Erik Rasbach has been studying mechanical engineering with a focus on production engineering at RWTH Aachen University, Germany, since 2017. Since 2021, he has been working at the Institute of Joining and Welding Technology (ISF) at RWTH University as a student research assistant in the field of laser beam welding. In 2022, he completed a Six Sigma quality management course and is currently writing his bachelor thesis at ISF.

Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The Welding and Joining Institute of RWTH Aachen University would like to express gratitude towards Deutsche Forschungsgemeinschaft e.V. (DFG, German Research Foundation) for their support.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Published Online: 2023-01-09

Published in Print: 2023-01-27

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Articles in the same Issue

https://doi.org/10.1515/mt-2022-0364

Keywords for this article

electrical steel sheet; insulation coating; laser beam welding in vacuum; pulsed laser welding; spot welding