Page 244 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

Welded Joint Design and Production 229

Figure 3.22 Effect of filler metal strength level. (Courtesy of The
Lincoln Electric Company.)

case, notice that the weld controls. If the weld is properly designed,
the base metal will not be overstressed. With matching weld metal,
the loading on both the weld and the base metal is essentially the
same. But, in the case of the overmatching combination, the weld has
20% more capacity than the base metal. If a designer overlooked load-
ing on the base metal, the connection could easily be overlooked.
It should be noted, however, that all filler metal combinations will
overmatch A36. Particular caution should be taken when sizing PJP
groove welds on this steel to ensure that the base metal allowables
are not exceeded.
Another area of potential problem is the slightly overmatched alloy
filler metals used on A588. For PJP groove welds subject to shear
loading, weld sizes that are determined based upon E80 filler metal
will result in an overstressing of the base metal. However, the prob-
lem is eliminated when design calculations are made based on E70
filler metal. This is the recommended approach since some acceptable
filler metals for weathering applications are classified E70. The base
metal will not be overstressed, and the fabricator will have the flexi-
bility of employing either E70 or E80 filler metal.

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