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TY  - THES
AU  - Gach, Stefan
TI  - Verzugsminderung durch Volumenexpansion einer kontrollierten martensitischen Phasenumwandlung in Strahlschweißprozessen
VL  - 2024,4
PB  - RWTH Aachen University
VL  - Dissertation
CY  - Düren
M1  - RWTH-2024-08591
T2  - Aachener Berichte Fügetechnik
SP  - 1 Online-Ressource : Illustrationen
PY  - 2024
N1  - Druckausgabe: 2024. - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University
N1  - Dissertation, RWTH Aachen University, 2024
AB  - Low transformation temperature (LTT) materials have been designed as additive materials to reduce tensile residual stresses in high-strength fine-grained structural steels. These materials utilize the volume expansion effect during a martensitic transformation that be-gins at reduced temperature. This volume expansion counteracts the volume shrinkage, which is the cause of component distortion, during cooling. The positive effects of these LTT alloys on tensile residual stress loading have been demonstrated in various investigations, primarily in the area of arc welding. Due to the reduction in tensile stress, these materials also offer the potential to have a positive effect on component distortion. In contrast to the arc processes described in the literature, where LTT material is added in wire form in large volumes, the filler material in beam welds takes up a much smaller pro-portion. An in-situ alloying of the LTT structure, consisting of filler material and base material, takes place, since, depending on the filler ratio, the phase transformation takes place at a reduced martensite start temperature. In the present work, a concept is developed and tested for using these materials in beam welding processes with the aim of minimizing distortion. The approach follows a modular design principle. Individual methods, metallurgical, analytical process engineering or simulative in nature, are examined regarding their contribution to mastering the LTT concept. In combination, the methods provide the possibility to apply the LTT concept in beam welding and to test it on more complex geometries in the future. The outlook provides an example of a possible application of the LTT concept to minimise distortion in an example application in rail vehicle construction. The individual methods of the modular principle are extrapolated and applied on a theoretical basis.
LB  - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3
DO  - DOI:10.18154/RWTH-2024-08591
UR  - https://publications.rwth-aachen.de/record/993080
ER  -