ESAB ES 95i, Operating Manual

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ESAB ES 95i
OPERATION 4-8 Manual 0-5458
Art # A-07702
Figure 4-17: Multi run vertical fillet weld
Art # A-07703
Figure 4-18: Examples of vertical fillet welds
2. Vertical Down
The E7014 electrode makes welding in this position
particularly easy. Use a 1/8" (3.2mm) electrode at 120
amps. The tip of the electrode is held in light contact
with the work and the speed of downward travel is
regulated so that the tip of the electrode just keeps
ahead of the slag. The electrode should point upwards
at an angle of about 45°.
3. Overhead Welds
Apart from the rather awkward position necessary,
overhead welding is not much more difficult that
downhand welding. Set up a specimen for overhead
welding by first tacking a length of angle iron at right
angles to another piece of angle iron or a length of
waste pipe. Then tack this to the work bench or hold in a
vice so that the specimen is positioned in the overhead
position as shown in the sketch. The electrode is held at
45° to the horizontal and tilted 10° in the line of travel
(Figure 4-19). The tip of the electrode may be touched
lightly on the metal, which helps to give a steady run.
A weave technique is not advisable for overhead fillet
welds. Use a 1/8" (3.2mm) E6012 electrode at 120
amps, and deposit the first run by simply drawing the
electrode along at a steady rate. You will notice that
the weld deposit is rather convex, due to the effect of
gravity before the metal freezes.
Art # A-07704
Figure 4-19: Overhead fillet weld
4.19 Distortion
Distortion in some degree is present in all forms of welding. In
many cases it is so small that it is barely perceptible, but in other
cases allowance has to be made before welding commences for
the distortion that will subsequently occur. The study of distortion
is so complex that only a brief outline can be attempted hear.
4.20 The Cause of Distortion
Distortion is cause by:
A. Contraction of Weld Metal:
Molten steel shrinks approximately 11 per cent in volume on
cooling to room temperature. This means that a cube of molten
metal would contract approximately 2.2 per cent in each of
its three dimensions. In a welded joint, the metal becomes
attached to the side of the joint and cannot contract freely.
Therefore, cooling causes the weld metal to flow plastically, that
is, the weld itself has to stretch if it is to overcome the effect of
shrinking volume and still be attached to the edge of the joint. If
the restraint is very great, as, for example, in a heavy section of
plate, the weld metal may crack. Even in cases where the weld
metal does not crack, there will still remain stresses “locked-
up” in the structure. If the joint material is relatively weak, for
example, a butt joint in 2.0mm sheet, the contracting weld metal
may cause the sheet to become distorted.
B. Expansion and Contraction of Parent Metal in the
Fusion Zone:
While welding is proceeding, a relatively small volume of the
adjacent plate material is heated to a very high temperature and
attempts to expand in all directions. It is able to do his freely at
right angles to the surface of the plate (i.e., “through the weld”),
but when it attempts to expand “across the weld” or “along the
weld”, it meets considerable resistance, and to fulfil the desire
for continued expansion, it has to deform plastically, that is, the
metal adjacent to the weld is at a high temperature and hence
rather soft, and, by expanding, pushes against the cooler, harder
metal further away, and tends to bulge (or is “upset”). When the
weld area begins to cool, the “upset” metal attempts to contract
as much as it expanded, but, because it has been “upset”, it
does not resume its former shape, and the contraction of the new