Civil Engineering Reference
In-Depth Information
5
Welding symbols 3
Spot and seam welds, surfacing, and steep
flanked butt welds
The symbols for resistance and arc spot and seam welds are shown
with reference lines (ISO) to indicate clearly the position of the
symbols in relation to the line. AWS symbols would be similarly
placed on the reference line for resistance welds and below the line
for arc welds. These symbols are shown in
Fig. 5.1(a)
and
(b)
.
Figure 5.1(a)
shows
spot welds
. The upper illustration shows a
resistance spot weld or projection weld requiring access from both
sides. The lower illustration shows an arc spot weld made from one
side of the joint. The reference line is on one side of the symbol.
Figure 5.1(b)
illustrates
seam welds
. The upper illustration shows
a resistance seam weld requiring access from both sides of the joint.
The lower illustration shows an arc seam weld made from one side
of the joint.
Arc spot and arc seam welding processes are rarely used and, by
common usage, spot and seam welding mean resistance welding.
Figure 5.1(c)
indicates
surfacing
. In this symbol, the arrow line
points to the surface to be coated with weld metal.
ISO 2553 does not explain how to indicate the extent of the
surface coating which is essential information.
AWS A2.4-98 gives detailed instructions on how to show the area
to be coated on a plan view; this is described in Section 14.
Figure 5.1(d)
shows
steep flanked butt welds
. ISO 2553 includes
two symbols representing a steep flanked single-V butt weld and a
steep flanked single-bevel butt weld. The edge preparations for these
welds are shown in ISO 9692-1: 2003 with bevel angles of 5-20° for
a butt weld and 15-30° for a bevel butt weld. The welds have a
backing strip.
These symbols are not included in the AWS standard and are not
really necessary because the welds are, in fact, single-V and single-
bevel butt welds.
They can be indicated as such by including the symbol for a
backing strip (shown in Fig. 8.1 on page 16). Both symbols in Fig.
5.1(d) have a horizontal line at the bottom. The lines vary slightly
in length. This difference is pointless because, as in the case of the
fillet weld symbol, the symbols would be placed with the lines
directly on the reference line.
There are no examples of the application of these symbols in ISO
2553.
