Page 41 - Handbook of Structural Steel Connection Design and Details

Fasteners and Welds for Structural Connections

26 Chapter One

the weld usually is about 45° relative to horizontal and vertical
surfaces.
Vertical with the axis of the weld nearly vertical. (Welds are made upward.)
Overhead with the face of the weld nearly horizontal. The electrode
is nearly vertical, and welding is performed from below the joint.
Where possible, welds should be made in the flat position. Weld metal
can be deposited faster and more easily and generally the best and most
economical welds are obtained. In a shop, the work usually is positioned
to allow flat or horizontal welding. With care in design, the expense of
this positioning can be kept to a minimum. In the field, vertical and
overhead welding sometimes may be necessary. The best assurance of
good welds in these positions is use of proper electrodes by experienced
welders.
AWS D1.1 requires that only the flat position be used for submerged-
arc welding, except for certain sizes of fillet welds. Single-pass fillet
welds may be made in the flat or the horizontal position in sizes up to
1
5 ⁄16 in with a single electrode and up to ⁄2 in with multiple electrodes.
Other positions are prohibited.
When groove-welded joints can be welded in the flat position,
submerged-arc and gas metal-arc processes usually are more economi-
cal than the manual shielded metal-arc process.
Designers and detailers should detail connections to ensure that
welders have ample space for positioning and manipulating electrodes
and for observing the operation with a protective hood in place.
3
Electrodes may be up to 18 in long and ⁄8 in in diameter.
In addition, adequate space must be provided for deposition of the
required size of the fillet weld. For example, to provide an adequate land-
ing c, in, for the fillet weld of size D, in, in Fig. 1.12, c should be at least
3
5
D + ⁄16. In building column splices, however, c = D + ⁄16 often is used for
welding splice plates to fillers.
1.3.5 Weld procedures
Welds should be qualified and should be made only by welders, welding
operators, and tackers qualified as required in AWS D1.1 for buildings.
Welding should not be permitted under any of the following conditions:

Figure 1.12 Minimum landing for a fillet weld.

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