Page 231 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

216 Chapter Three

requirement. Secondly, one or more of the specific conditions to be used
in the production may deviate from the prequalified requirements. In
either case, a test weld must be made prior to the establishment of the
final WPS. The first step in qualifying a welding procedure by test is to
establish the procedure that is desired to be qualified. The same sources
cited for the prequalified WPS starting points could be used for WPSs
qualified by test. These will typically be the parameters used for fabri-
cation of the test plate, although this is not always the case, as will be
discussed later. In the simplest case, the exact conditions that will be
encountered in production will be replicated in the procedure qualifica-
tion test. This would include the welding process, filler metal, grade of
steel, joint details, thickness of material, preheat values, minimum
interpass temperature level, and the various welding parameters of
amperage, voltage, and travel speed. The initial parameters used to
make the procedure qualification test plate beg for a name to define
them, although there is no standard industry term. It has been suggested
that “TWPS” be used where the “T” could alternatively be used for tem-
porary, test, or trial. In any case, it would define the parameters to be
used for making the test plate since the validity of the particular para-
meters cannot be verified until successfully passing the required test.
The parameters for the test weld are recorded on a procedure qualifica-
tion record (PQR). The actual values used should be recorded on this
document. The target voltage, for example, may be 30 V but, in actual
fact, only 29 V were used for making the test plate. The 29 V would be
recorded.
After the test plate has been welded, it is allowed to cool and the
plate is subjected to the visual and nondestructive testing as pre-
scribed by the code. The specific tests required are a function of the
type of weld being made and the particular welding consumables. The
types of qualification tests are described in D1.1-98, paragraph 4.4.
In order to be acceptable, the test plates must first pass visual
inspection followed by nondestructive testing (NDT). At the contrac-
tor’s option, either RT or UT can be used for NDT. The mechanical
tests required involve bend tests (for soundness) macroetch tests (for
soundness), and reduced section tensile tests (for strength). For quali-
fication of procedures on steels with significantly different mechanical
properties, a longitudinal bend specimen is possible. All weld metal
tensile tests are required for unlisted filler metals. The nature of the
bend specimens, whether side, face, or root, is a function of the thick-
ness of the steel involved. The number and type of tests required are
defined in D1.1-98, Table 4.2, for complete joint penetration groove
welds; D1.1-98, Table 4.3, for partial joint penetration groove welds;
and D1.1-98, Table 4.4, for fillet welds.
Once the number of tests has been determined, the test plate is sec-
tioned and the specimens machined for testing. The results of the tests

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