hi all,
according to QW-404.5, in ferrous metals a change in the chemical composition of the weld deposit from one A number to any other A number in table QW-442 is an essential variable. only qualification with A No. 1 shall qualify for A No. 2 and vice versa.
best regards
n4v4rr0
Don't forget there are several ways allowed in QW-404.5 to determine A-Number. For GTAW, SMAW or GMAW, most people seem to use the chemical composition from the filler metal specification or manufacturer's test reports, per (b) or (c). Below are the different methods allowed. My understanding of the A-Number concept is that it is a method of reducing the number of welding procedure qualifications required, the same as the use of P-Numbers is intended. Otherwise, you might have to qualify any change in AWS classification.
From QW-404.5:
The weld metal chemical composition may be determined
by any of the following:
(a) For all welding processes — from the chemical
analysis of the weld deposit taken from the procedure
qualification test coupon.
(b) For SMAW, GTAW, and PAW—from the chemical
analysis of the weld deposit prepared according to
the filler metal specification, or from the chemical composition
as reported either in the filler metal specification or
the manufacturer’s or supplier’s certificate of compliance.
(c) For GMAW and EGW—from the chemical analysis
of the weld deposit prepared according to the filler
metal specification or the manufacturer’s or supplier’s
certificate of compliance when the shielding gas used
was the same as that used to weld the procedure qualification
test coupon.
(d) For SAW — from the chemical analysis of the
weld deposit prepared according to the filler metal specification
or the manufacturer’s or supplier’s certificate of
compliance when the flux used was the same as that used
to weld the procedure qualification test coupon.
In lieu of an A-Number designation, the nominal chemical
composition of the weld deposit shall be indicated
on the WPS and on the PQR. Designation of nominal
chemical composition may also be by reference to the
AWS classification (where such exists), the manufacturer’s
trade designation, or other established procurement
documents.