WPS FOR DIFFERENT P-NO./G-NO.

Question

WPS FOR DIFFERENT P-NO./G-NO.

sadra (Petroleum)

(OP)

28 Dec 02 14:39

HELLO,
WE HAVE A PROBLEM IN WELDING OF MATERIAL WITH SAME P-NO. BUT
DIFFERENT GROUP NOS.
AS WE FOLLWD ASME SECTION IX WE FOUND IN QW403.5 THAT IF THERE IS NOT ANY CHANGE IN ESSENTIAL VARIABLES EXEPT IN GROUP NO. THEN WE CAN QUALIFY PROCEDURE FOR WELDING OF THE SAME MATERIAL WITH THE SAME P-NO. AND GROUP NO. AND THEN IT QUALIFIES WELDING OF TWO TYPE OF MATERIALS WITH THE SAME P-NO. BUT DIFFERENT GROUP NOS.
THIS PROBLEM IS SPECIALLY IN WELDING OF PIPES TO FLANGE AND FITTING WHICH HAVE DIFFERENT GROUP NOS. AND EMPHESISE THAT ALL ESSENTIAL VARIABLES (ELECTROD,FILLER,...) ARE THE SAME AND DIFFERENCE IS JUST IN GROUP NOS.

GRoberts (Materials) · Answer 1 · 2002-12-30 15:41:04

The main question is whether the base metal you are welding has impact property requirements or not.

If it does not, then since Group # is a supplementary essential variable in ASME Sectin IX you can basically ignore it for the purposes of weld procedure qualification.  One P No. welded to the Same P No. would qualify all of the metals of that P No. regardless of which group they are in.

If the material does have impact property requirements, then the group number becomes an essential variable.  You can only weld the specific group numbers you qualified.

Metalguy (Materials) · Answer 2 · 2003-01-02 23:34:07

Sadra,

Is your "problem" a real "physical" problem or a code/paper one? If an actual welding problem, what is it-eg. cracking, etc. Many more specifics would be required.

sayee1 (Materials) · Answer 3 · 2003-02-07 06:43:03

Sorry for the very late reply on this one, but QW403.5 states that if you qualify a procedure for eg between SA 106 Grade B and SA105, i.e. P1 Gr1 to P1 Gr2, but want to use this procedure for welding of a P1 Gr1 to P1 Gr 1 /P1 Gr2 to P1 Gr 2, where all the esential variables are the same, then the WPS can still be used. Similarly if I have two procedures for welding P1 Gr1 to P1 Gr 1 and P1 Gr2 to P1 Gr 2 where the two procedures have no change in essential variables, I can ue these two PQRs for supporting a WPS for welding P1 Gr1 to P1 Gr2 . But as GRoberts said this is a supplementary requirement i.e. only if there is impact test requirements.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

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WPS FOR DIFFERENT P-NO./G-NO.