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Licensed Unlicensed Requires Authentication Published by De Gruyter March 26, 2019

Influence of variation of energy per unit length on mechanical-technological properties of ultra-high-strength steel 22MnB5 in the laser beam welding process

Uwe Reisgen, Simon Olschok, Benjamin Gerhards and Fatma Akyel
From the journal Materials Testing

Abstract

Ultra-high strength steel 22MnB5 with 1.5 mm thickness was laser beam butt welded under varied welding parameters such as focal diameter, welding speed and beam power. The ultra-high strength material is softened by the laser beam welding process due to tempering in the heat-affected zone, which causes a loss in tensile strength and hardness compared to the base material. The influence of softening on the mechanical-technological properties was investigated. Hardness profiles of welded specimens were examined and tensile tests with digital image correlation were carried out. The digital image correlation showed the area in which the strain was concentrated as well as the location of fraction initiation. The microstructure was examined using micrographs and scanning electron microscopy images; the composition of the structure was subjected to X-ray diffraction. Dilatometry was used to map the individual areas of the heat-affected zone with respect to temperature and hardness. An increase in the energy per unit length influenced the width of the heat-affected zone and thus, the width of the softened zone. It was not possible to exert influence on the depth of hardness drop. The tensile strength, however, increased due to the narrower width of the softened zone.


*Correspondence Address, Fatma Akyel, M.Sc., RWTH Aachen, Pontstr. 49, 52062 Aachen, Germany, E-mail:

Prof. Dr.-Ing. Uwe Reisgen, born in 1962, studied Mechanical Engineering at the RWTH Aachen University and received a doctorate at the 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 has been Head of the Welding and Joining Institute at the RWTH Aachen University, Germany.

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

Benjamin Gerhards, M.Eng. (IWE), born in 1985, studied Mechanical Engineering and graduated with a Masters Degree as well as International Welding Engineer Diploma. From 2012 – 2018 he was a research engineer at the RWTH Aachen University ISF Welding and Joining Institute in the field of laser beam welding. Currently he is Head of welding applications at the Company Lava-X GmbH in Herzogenrath, Germany.

Fatma Akyel, M.Sc., born in 1988, studied Mechanical Engineering at RWTH Aachen University. Since January 2018 she has been working as a research assistant and PhD student at the Welding and Joining Institute in the Department of Power Beam Welding of RWTH Aachen University, Germany, with a focus on laser beam welding. She is currently working on several projects in industry and publicly funded research.


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Published Online: 2019-03-26
Published in Print: 2019-04-04

© 2019, Carl Hanser Verlag, München