Multi Process Welding Procedures QW200.4 and QW451.1
Base Metal
approval range for the above welded joint is 4.76mm To 52mm Ref QW451.1
If the
joint is made of more than one welding process then the maximum deposited
thickness each process in the above example is (2 x Deposited Weld Metal t)
:- GTAW 12mm and SMAW 52mm (This is because t = T for this process as t >
19.1mm QW451.1)
If the
SMAW deposit in the above qualification was less than 19.1mm, assume 18mm and
GTAW 8mm then to weld a joint 52mm thick with 8mm GTAW and 44mm SMAW is not
permitted as maximum SMAW deposit would be 36mm
You can
delete the SMAW and qualify an all GTAW weld
4.76mm To 12mm thick or delete the GTAW and weld SMAW 4.76mm to 52mm
thick, providing all the essential, non essential and supplementary variables
are applied to the WPS. (Note the
procedure allows the SMAW to be used as a root run but not the welder
qualification.)
When
tested the deposited weld metal of each process must be included in the tension
and bend test specimens and impacts where applicable. Note it is acceptable for the impact test for the GTAW to contain
some SMAW in the test specimen.
PICK and MIX QW200.4 b
[Note restrictions in QW451.1 notes (1)]
This
applies to test coupons 13mm and thicker and welding processes SMAW, SAW, GTAW,
GMAW. A WPS consisting of several
processes can be created from different PQR’s, but the maximum thickness of
base metal covered by this WPS can’t exceed 2 x the thickness of the thinnest
test coupon used for each PQR and each process can’t exceed 2 x its deposited
thickness. This applies even if all the
processes used for that coupon are not required in this WPS. However the base metal thickness of the PQR
used for the root does not have to be considered if the WPS is single sided
QW200.4 b
Note test
coupons 38mm and above approve deposited weld metal and also base metal
thickness up to 200mm max QW451.1.
(QW403.7 Processe GTAW,SMAW,GMAW,SAW)
EXAMPLE
Can the
proposed PQR be made from the above example + PQR 2 + PQR 3.
Consider
individual deposited thickness 2 x t
GTAW 12mm > 6mm. SMAW 60mm > 39mm. GMAW 66mm > 20mm All OK
Consider
Plate thickness 2 x T
SMAW 60mm <65mm Fail. GMAW 66mm > 65mm OK. GTAW not considered.
SMAW procedure can’t be used for proposed PQR
WELDER PERFORMANCE QUALIFICATIONS
If you
want to weld a 30mm plate and your welder qualifications only go up to 15mm use
two welders. You can’t use one welder
with two different qualifications for the same process