Effect of Process Parameters on the Melting Ratio in Overlap Pulsed Laser Welding

A study of melting ratio in overlap pulsed laser welding has been done on St14 carbon steel sheet to investigate the effect of process parameters. Pulse duration, pulse energy, pulse frequency, and travel speed were varied in the experimental procedure. The results of the melting ratio have been presented by reforming the related formulas. Formulas have been modified based on overlapping and preheat effect factors. A new parameter is defined to show the actual energy entrance to the spot region in overlapping pulsed laser welding. It is shown that keyhole formation in pulsed laser welding has an essential role in increasing the melting ratio. Moreover, it is shown that the role of pulse energy is more effective on the melting ratio than pulse duration and overlapping process variables. The effect of overlapping has been studied by varying the travel speed and pulse frequency separately, and an optimum range of overlapping for maximizing the melting ratio in the full penetration keyhole mode was established.