Page 226 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

Welded Joint Design and Production 211

weld type. All welds are required to deliver a certain yield and/or
tensile strength, although the exact level required is a function of the
connection design. Not all welds are required to deliver minimum
specified levels of notch toughness. Acceptable levels of undercut and
porosity are a function of the type of loading applied to the weld.
Determination of the most efficient means by which these conditions
can be met cannot be left to the welders, but should be determined by
knowledgeable welding technicians and engineers who create written
welding procedure specifications and communicate those require-
ments to welders by the means of these documents. The WPS is the
primary tool that is used to communicate to the welder, supervisor,
and inspector how a specific weld is to be made. The suitability of a
weld made by a skilled welder in conformance with the requirements
of a WPS can only be as good as the WPS itself. The proper selection
of procedure variable values must be achieved in order to have a WPS
appropriate for the application. This is the job of the welding expert
who generates or writes the WPS. The welder is generally expected to
be able to follow the WPS, although the welder may not know how or
why each particular variable was selected. Welders are expected to
ensure welding is performed in accordance with the WPS. Inspectors
do not develop WPSs, but should ensure that they are available and
are followed.
The D1.1-98 Structural Welding Code—Steel requires written weld-
ing procedures for all fabrication performed. The inspector is obligated
to review the WPSs and to make certain that production welding
parameters conform to the requirements of the code. These WPSs are
required to be written, regardless of whether they are prequalified or
qualified by test. Each fabricator or erector is responsible for the
development of WPSs. Confusion on this issue apparently still exists
since there continue to be reports of fabrication being performed in
the absence of written welding procedure specifications. One preva-
lent misconception is that if the actual parameters under which weld-
ing will be performed meet all the conditions for “prequalified” status,
written WPSs are not required. This is not true; according to the code,
the requirement is clear.
The WPS is a communication tool, and it is the primary means of
communication to all the parties involved regarding how the welding
is to be performed. It must therefore be readily available to foremen,
inspectors, and the welders.
The code is not prescriptive in its requirements regarding availabili-
ty and distribution of WPSs. Some shop fabricators have issued each
welder employed in their organization with a set of welding proce-
dures that are typically retained in the welder’s locker or tool box.
Others have listed WPS parameters on shop drawings. Some company

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