Railway wheel steel behaviour upon thermo-mechanical loadings
Licentiatavhandling, 2022
The material behaviour of the ferritic-pearlitic railway wheel steel ER7T was studied during severe block braking (i.e., slow heating and cooling) at peak temperatures varying between 300 °C and 650 °C. The thermal dilatation was restricted to different degrees between free expansion and full restriction. This study thus explores the combined effect of thermal and mechanical cycling on the mechanical properties and material structure. The experimental results from the thermo-mechanical testing were also used to validate a new constitutive material model for use in FE models to predict severe block braking.
The second part of the thesis explored the effect of rapid heating and cooling events on the microstructure and residual stress state of railway wheel steel. Localised heating using laser scanning with additive manufacturing equipment was compared to the heating done by scanning with laser welding equipment. This study thus investigated the similarities of different rapid heating (high temperature) processes and the effect of process parameter variations.
The results can be used to provide insight into the material behaviour of railway steels during local heating events. Furthermore, it can support the development of more accurate simulations for both operation and maintenance processes.
residual stress
thermo-mechanical fatigue
railway wheel steel
pearlitic microstructure
severe block braking
repair welding
Författare
Erika Steyn
Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial
E. Steyn, J. Ahlström. Thermo-mechanical response of near-pearlitic steel heated under restriction of thermal expansion.
E. Voortman Landström, E. Steyn, J. Ahlström, T. Vernersson. Thermomechanical testing and modelling of railway wheel steel.
E. Steyn, J. Ahlström. Simulation of repair welding on pearlitic railway steel using additive manufacturing equipment.
Materialkarakteristik vid svetsning och annan lokal upphettning (CHARMEC MU36)
Europeiska kommissionen (EU), 2019-06-10 -- 2024-06-09.
Chalmers järnvägsmekanik (CHARMEC) (MU36), 2019-06-10 -- 2024-06-09.
Ämneskategorier
Annan maskinteknik
Bearbetnings-, yt- och fogningsteknik
Annan materialteknik
Farkostteknik
Metallurgi och metalliska material
Styrkeområden
Materialvetenskap
Utgivare
Chalmers
Virtual Development Lab (VDL), Chalmers Tvärgata 4C, Chalmers University of Technology in Gothenburg
Opponent: Prof. Johan Moverare, Department of Management and Engineering - Engineering Materials, Linköping University