In a recent issue [April 2015] of this newsletter, you included an article about laser welding with filler wire. What is the process you go through to determine the optimum welding speed and wire speed?
The answer begins with the weld specification. To determine the optimum wire speed and welding speed, first we will typically create a ‘bead on plate’ weld without filler material to find the welding speed that results in full penetration. Then the weld speed that gives the specified widths of the top bead, waist (center of the weld), and bottom bead is considered the baseline weld from which we also define the wire speed.
For reference, the example featured in the previous issue of the newsletter was butt welding 4 mm thick Inconel 718. We determined that if there was no gap in the butt joint, a welding speed of 1 m/min and wire speed of 1 m/min would produce the required weld profile. Since there was a gap (0.1-0.2mm), we would increase the wire speed and reduce the welding speed. In this case (with a 0.1-0.2 mm gap), we found through a few combinations of lower weld speed and higher wire speed that a weld speed of 1.5 m/min and wire speed of 0.7 m/min consistently produced the required weld profile without any porosity.