6 BASIC WELDING GUIDE
0463 815 001
- 56 -
© ESAB AB 2021
Rate of travel
After the arc is struck, your next concern is to maintain it, and this requires moving the electrode
tip towards the molten pool at the same rate as it is melting away. At the same time, the electrode
has to move along the plate to form a bead. The electrode is directed at the weld pool at about
20° from the vertical. The rate of travel has to be adjusted so that a well-formed bead is
produced.
If the travel is too fast, the bead will be narrow, strung out and may even be broken up into
individual globules. If the travel is too slow, the weld metal piles up and the bead will be too large.
Making welded joints
Having attained some skill in the handling of an electrode, you will be ready to make welded
joints.
Butt welds
Set up two plates with their edges parallel, as shown below, allowing 1/16 in. - 3/32 in. (1.6 mm -
2.4 mm) gap between them and tack weld at both ends. This is to prevent contraction stresses
from the cooling weld metal pulling the plates out of alignment. Plates thicker than 1/4 in. (6.4
mm) should have their mating edges beveled to form a 70° to 90° included angle. This allows full
penetration of the weld metal to the root. Using a 1/8 in. (3.2 mm) E7014 electrode at 100 A,
deposit a run of weld metal on the bottom of the joint.
Do not weave the electrode, but maintain a steady rate of travel along the joint sufficient to
produce a well-formed bead. At first you may notice a tendency for undercut to form, but keeping
the arc length short, the angle of the electrode at about 20° from vertical, and the rate of travel
not too fast, will help eliminate this. The electrode needs to be moved along fast enough to
prevent the slag pool from getting ahead of the arc. To complete the joint in thin plate, turn the
workpiece over, clean the slag out of the back and deposit a similar weld.
Figure 58: Butt weld
1 Tack weld
Figure 59: Weld build up sequence
Heavy plate will require several runs to complete the joint. After completing the first run, chip the
slag off and clean the weld with a wire brush. It is important to do this to prevent the slag being
trapped by the second run. Subsequent runs are then deposited using either a weave technique
or single beads laid down in the sequence shown above. The width of the weave should not be
more than three times the core wire diameter of the electrode. When the joint is completely filled,
the back is either machined, ground or gouged out to remove slag which may be trapped in the
root, and to prepare a suitable joint for depositing the backing weld. If a backing bar is used, it is
