Thermal pulses on pearlitic steels: Influence of laser heat scanning parameters on surface layers transforming to martensite
Year: 2025
Type: article
Abstract: Industrial processes like grinding and welding impose cyclic heating and rapid cooling on steel surfaces, affecting material properties and residual stresses. This study examines how intense localised surface heating influences pearlitic railway steels using powder bed fusion laser beam additive manufacturing (PBF-LB) and laser welding (LW) as controlled heat sources, without powder or filler materials. Two steels were studied: high-carbon rail steel (R260) and medium-carbon wheel steel (ER7T).The findings reveal that applied power is the key factor affecting thermal gradients and material transformations, with scanning speed being secondary. Under identical thermal loads, R260 fully transformed to martensite at lower temperatures, creating pronounced shear stresses, while ER7T experienced partial transformation and more hydrostatic tensile stresses. Numerical simulations validated by experiments showed that residual tensile stresses in melted regions likely cause micro-cracks, unlike compressive stresses in unmelted martensitic zones.These results demonstrate the potential of PBF-LB and LW for studying high-energy heating effects on railway steels. Insights highlight the importance of controlled heat input for optimising microstructures and stress states, informing advanced rail maintenance strategies like repair welding and grinding. This work contributes to improving the performance, safety, and sustainability of railway components.
Source: Materials & Design
Authors: Björn Andersson, Erika Steyn, Johan Ahlström
Institution: Chalmers University of Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,650
OpenAlex ID: W4411136175