Page 230 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

Welded Joint Design and Production 215

determine soundness of the weld deposit (for example, fusion, tie-in of
weld beads, freedom from slag inclusions). The plate could be nonde-
structively tested or, as is more commonly done, cut, polished, and
etched. The latter operations allow for examination of penetration pat-
terns, bead shapes, and tie-in. Welds that are made with prequalified
WPSs that meet the physical dimensional requirements (fillet weld
size, maximum reinforcement levels, and surface profile requirements)
and are sound (that is, adequate fusion, tie-in, and freedom from exces-
sive slag inclusions and porosity) should meet the strength and ductility
requirements imposed by the code for welding procedures qualified by
test. Weld soundness, however, cannot be automatically assumed just
because the WPS is prequalified.

3.5.4 Guidelines for preparing
prequalified WPSs
When developing prequalified WPSs, the starting point is a set of
welding parameters appropriate for the general application being con-
sidered. Parameters for overhead welding will naturally vary from
those required for down-hand welding. The thickness of material
involved will dictate electrode sizes and corresponding current levels.
The specific filler metals selected will reflect the strength require-
ments of the connection. Many other issues must be considered.
Depending on the level of familiarity and comfort the contractor has
with the particular values selected, welding a mock-up may be appro-
priate. Once the parameters that are desired for use in production are
established, it is essential to check each of the applicable parameters
for compliance with the D1.1-98 code.
To assist in this effort, Annex H has been provided in the D1.1-98
code. This contains a checklist that identifies prequalified require-
ments. If any single parameter deviates from these requirements, the
contractor is left with two options: (1) the preliminary procedure can be
adjusted to conform with the prequalified constraints or (2) the WPS
can be qualified by test. If the preliminary procedure is adjusted, it
may be appropriate to reexamine its viability by another mock-up.
The next step is to document, in writing, the prequalified WPS val-
ues. A sample form is included in Annex E of the code. The fabricator
may utilize any convenient format. Also contained in Annex E are a
series of examples of completed WPSs that may be used as a pattern.

3.5.5 Qualifying welding procedures
by test
Conducting qualification tests. There are two primary reasons why weld-
ing procedures may be qualified by test. First, it may be a contractual

Downloaded from Digital Engineering Library @ McGraw-Hill (www.accessengineeringlibrary.com)
Copyright © 2009 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.