Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding

0583056 - ÚPT 2025 RIV CZ eng C - Conference Paper (international conference)
Šebestová, Hana - Horník, Petr - Mika, Filip - Mikmeková, Šárka - Ambrož, Ondřej - Mrňa, Libor
Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding.
METAL 2023. 32nd International Conference on Metallurgy and Materials. Conference Proceedings. Ostrava: TANGER, 2024, s. 302-307. ISBN 978-80-88365-12-9. ISSN 2694-9296.
[METAL 2023. International Conference on Metallurgy and Materials /32./. Brno (CZ), 17.05.2023-19.05.2023]
R&D Projects: GA TA ČR(CZ) FW01010293
Grant - others:AV ČR(CZ) StrategieAV21/17
Program: StrategieAV
Institutional support: RVO:68081731
Keywords : laser welding * high-strength steel * microstructure * heat input * ferrite stabilization
OECD category: Mechanical engineering
https://www.confer.cz/metal/2023/4646-microstructure-modifications-of-al-si-coated-press-hardened-steel-22mnb5-by-laser-welding

Weld microstructure depends on the characteristics of welded materials and parameters of welding technology, especially on the heat input that determines the peak temperature and the cooling rate. When the coated sheets are welded, the effect of the chemical composition of the coating must be also considered even though its thickness is only a few tens of microns. During 22MnB5+AlSi laser welding experiments, the ferrite-stabilizing elements of coating modified the weld metal microstructure. Ferrite appeared in a quenched weld metal. The rapid cooling rate accompanying welding with a focused beam limited the homogenization of the weld metal which resulted in the formation of ferritic bands in the regions rich in Si and especially in Al. On the other hand, a high level of homogenization was reached when welding with the defocused beam. The ferritic islands uniformly distributed in the weld metal were formed at 0.4 wt% and 1.6 wt% of Si and Al, respectively. The doubled heat input reduced the Al content to 0.7 wt% insufficient for the ferrite formation at still relatively high cooling rates. Predicting the distribution of ferrite in the weld metal is challenging due to its dependence on various factors, such as cooling rate and the volume of dissolved coating, which may vary with any modifications made to the welding parameters.
Permanent Link: https://hdl.handle.net/11104/0351050