QW 202.4 allows you weld dissimilar thickness material in Production with a qualified PQR(s). Not for the qualification of dissimilar thickness. The thickness Qualification range is to be taken from QW 451or QW 403.6 (if impact test is required) from the thickness used for qualification.
For qualification you need similar thickness (for full penetration groove welds). You can use dissimilar thickness but you will not get the benefit from thicker material (thickness) as the thickness T considered is based upon the tensile specimen thickness used.
Please refer Section IX Interpretation No. IX 86-43 which is nearly similar to this query.
Thanks & Regards,
Sanjeevan
----- Original Message -----
From: "Bathula Raghuram (Mumbai - PIPING)" <R.Bathula@ticb.com>
Sent: Tuesday, May 27, 2008 9:06 AM
Subject: [MW:798] Re: Dissimilar Group number/Thickness combination PQR as per QW403.5/QW403.6
Min qualified thickness can't be 1.5mm, when impact testing required.
Qualified thk range for P1G1 will be 6-12mm and P1G2 would be 12-24mm,
please refer the question again.
Dissimilar thickness combinations are quite common to qualify (in
particular for SR nozzle welds on equipment) per QW202.4
-----Original Message-----
From: Quality [mailto:quality@gpsoman.com]
Sent: Tuesday, May 27, 2008 10:28 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:797] Re: Dissimilar Group number/Thickness combination
PQR as per QW403.5/QW403.6
The qualified thickness range is 1.5mm to 12mm (2T) for P1G1to them
selves,
P1G2 to themselves & P1G1 to P1G2 combinations.
The maximum qualified weld deposit is 2t (to is deposited weld thickness
during the qualification).
If you qualify a procedure with different parent material thickness
(groove
weld), the thickness T can be considered based upon the tensile specimen
thickness (T) used for the destructive testing of the groove weld PQR.
In
short, qualification of different thickness of relatively less use in
ASME
Sec IX.
Normally none of the construction/ fabrication codes does not allow
difference in thickness more than 1.5T (of the thinnest). Any Thickness
welded above 1.5 will not be accounted in design.
Regards,
Sanjeevan
GPS
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