0511781 - ÚPT 2020 DE eng A - Abstract
Mrňa, Libor - Horník, Petr - Šebestová, Hana
Utilization of electric arc for preheating of special steels during laser welding.
Lasers in Manufakturing. LIM 2019. Book of Abstracts. München: WLT, 2019.
[Lasers in Manufakturing. LIM 2019. 24.06.2019-27.06.2019, München]
R&D Projects: GA TA ČR(CZ) TH04010366
Institutional support: RVO:68081731
Keywords : laser welding * preheating * arc discharge
OECD category: Mechanical engineering

Laser welding is characterized by high cooling rates. We found out both experimentally and numerically that during our welding experiments it reaches about 500 °C.s-1. Such cooling rates lead to the formation of undesirable microstructures in some steel grades affecting weld mechanical properties. In our research, we verified the control of weld cooling rate by preheating with electric arc of TIG torch placed close to the laser beam impact. The stabilization of discharge burning in the neighborhood of laser-induced plasma above the keyhole was studied experimentally and optimal stand-off position of the TIG torch towards the beam axis was found. The flow of protective gas was visualized by schlieren method. Further, the effect of DC/AC arc mode on both weld and electrode was examined. The stability of low-current (20-60 A) arc was proved during casual laser welding speed. The effect of arc preheating was examined for HSLA and creep-resistant steels.
Permanent Link: http://hdl.handle.net/11104/0302029