Product Code: ICA12_1005

A Comparative Study Between the Low Carbon Steel and the Galvanized Steel Welding
Authors:
Seung Hwan Lee, Center for Lasers and Plasmas for Advanced Manufacturing, Univ. of Michigan at Ann Arbor; Ann Arbor MI USA
Jyoti Mazumder, Center for Lasers and Plasmas for Advanced Manufacturing, Univ. of Michigan at Ann Arbor; -
Presented at ICALEO 2012

In this paper, a comparative study between the low
carbon steel and the galvanized steel welding is
reported to observe temporal evolution of keyhole
since the keyhole variation is decisive for the weld
quality and the zinc coating causes the instability of the
keyhole in the galvanized steel welding. Galvanized
steel sheets and bare steel sheets are welded together to
investigate the phenomena under the same
experimental conditions. The reflective topography is
used to visualize the temporal evolution of the keyhole.
The keyhole size and the flow pattern are monitored in
both cases using a high-speed camera. The elongated
keyhole and the irregular shape of the seam edge are
observed in the galvanized steel welding compared
with the bare steel case. A three-dimensional numerical
simulation is conducted to investigate the keyhole
variations in both cases. This numerical study shows
that the zinc vapor induces the expansion of the keyhole.
The result is combined with the experimental result to
validate the zinc-induced pressure which exerts to the
keyhole wall. The welded sample, along with welding
direction, is cut and analyzed. In the sample, porosity is
found in the zone of the overlapped zinc coating. The
porosity results from the exerted pressure to the rear
keyhole found in the simulation results. This study
may suggest guidelines in prediction of manufacturing
process of the galvanized steel welding for better weld
quality.