Arc Voltage:

It determines the type of metal transfer by effecting the rate of droplet transfer across the arc. The arc voltage to be utilized depends on base metal thickness, type of joint, electrode composition and size, welding position, shielding gas composition, type of weld and other factors.

Arc Travel Speed:

Arc travel speed influenced weld bead size and penetration. There is a certain value of travel speed at which the weld penetration is maximum. If this value is lowered, the weld pool becomes shallower and larger and the advancing arc impinges on this weld pool instead of on the base metal. The result is a shallower penetration and a wider weld bead. As the travel speed is enhanced, the heat input rate of the arc is reduced. The result is decreased penetration and narrower weld bead. While the travel speed is excessive, undercutting take place along the edges of the weld bead, because the deposition of filler metal is not adequate to fill the path melted by the arc.