Impact test in PQRT??

[bmoorthy]

The MDMT of the vessel is -45 deg C. The vessel is 2" thick. material A 516 Gr 70 (Impact tested at -46 Deg C).

The main seams (Category A, B, C, D)are welded with GMAW and GMAW +SAW Combination. (All Groove PQRs Impact tested at -46)

The externals (Ladder, Platform) Fillets are welded with SMAW and FCAW.


Is it mandatory to have Groove Qualification (For Impact)
or Is it OK to have just Fillet Qualification for SMAW and FCAW.

Code of Construction ASME Sec VIII Div 1. Qualification done to ASME Sec IX.

Project or Purchase/Client Spec does not address the above issue.

Is there an explicit reference in ASME Sec VIII Div 1 or In Sec IX that calls for impact test qualification, when only fillet is involved.

 

[metengr]

You need to have an impact qualified WPS - fillet or otherwise for any welding to the pressure boundary of the vessel -see ASME Section VII, Part UG-84 (a) General. Also review UG-84 (f), which describes impact testing of weldments. Review Part UCS-66 (b) which provides thickness criteria for using impact exemption curves related to corner, fillet or lap welded joints.

Per ASME Section IX, QW-202.2 (c) fillet welds can be qualified separately as fillet welds provided they are non-pressure retaining welds. However, you still are dealing with welding to an impact qualified base material based for a MDMT of -46 deg C.

Since QW-451.4 allows fillet welds to be qualified by groove-weld tests, the impact qualified groove weld test using the SMAW and FCAW processes is the way to proceed. The groove weld coupon can be impact qualified and apply to fillet welds.