This article lets you know about WPS qualification for fillet welds – pressure retaining as well as non-pressure retaining ones. At the end, a couple of paragraphs also address the subject of performance qualification for pressure retaining fillet welds.
Procedure Qualification For Fillet Welds
We know that, ordinarily, the WPS qualification for a fillet joint can be done through a fillet weld test coupon as well as a groove weld test coupon. QW 451.3 lists the tests required when the qualification is done on a fillet weld test coupon. The tests required when the coupon is a groove weld, are of course listed in QW 451.1 and QW 451.2.
The objective of this article is to address whether WPS qualification for all kinds of fillet joints can be done through a fillet weld test coupon. Or, is WPS qualification for only non-pressure retaining fillet joints permitted through a fillet test coupon?
QW 451.3 does not say that fillet weld test coupon is only for non-pressure retaining welds only. Even QW 202.3, which refers us to QW 451.3, does not say particularly loudly that the fillet test coupon option is only for non-pressure retaining fillet joints.
Consider the text given in QW 202.2(c). It starts with: “WPS qualification for fillet welds may be made on groove-weld test coupons…”. Note the words “may be”. They tell us that this is an option. The alternate is that we can carry out WPS qualification for fillet welds through fillet weld test coupons too.
The paragraph goes on to say that a groove weld procedure can be used to weld fillets of all sizes, on base metals of all thicknesses and diameters …blah blah blah. Thus far there is nothing in the paragraph that might address the objective of this article.
The penultimate sentence of QW 202.2(c) says: “Non-pressure retaining fillet welds, as described in other Sections of the Code, may as an alternate be qualified with fillet welds only.”
This does imply that the alternate of fillet weld test coupon is only permitted for non-pressure retaining fillet welds, and not pressure retaining ones. The WPS qualification for pressure retaining fillet welds must therefore be done through a groove weld test coupon only.
The message would have got emphatically hammered home had the paragraph stated that – Pressure retaining fillet joints shall be qualified only through groove welds. However, in QW 202.2(c), the message has been delivered subtly.
This is noticeable throughout the BPVC. The Code believes in economy of expression. At all times, the intent is communicated across through a subtle and measured tone.
ASME Interpretation Settles The Debate
This matter has been further affirmed by the Committee though an Interpretation IX-89-87, which firmly establishes that pressure retaining fillet welds must be qualified by means of groove weld test coupons only. This leaves no room for further doubt.
2021 Edition Establishes It Firmly
Important Note: The 2021 edition of Section IX has included a revision of this paragraph QW 202.2 (c). The issue discussed above has been addressed with greater clarity. It now begins with – “WPS qualification for fillet welds shall be made on groove‐weld test coupons…”. This firmly establishes that the first choice for method for establishing a WPS qualification for fillet welds is groove-weld coupon.
The last line of QW 202.2 (c) in 2021 edition says that – “Nonpressure‐retaining fillet welds, as defined in other Sections of the Code, may as an alternate be qualified with fillet weld qualification tests.” This confirms the understanding just established in the above paragraphs.
Welder Qualification For Pressure Retaining Fillet Welds
- It is worth mentioning that this stipulation has not been imposed for welder performance qualifications. A welder qualified through a fillet weld test coupon of QW 303.2 is very much qualified to weld fillets of both kinds – pressure retaining, as well as non-pressure retaining ones. The QW 303.2 makes no distinction between pressure retaining and non-pressure retaining fillet welds. A welder qualified through a fillet weld coupon gets qualified to weld on fillet welds, that’s all.
- ALSO, a welder who prepares the fillet weld WPS qualification test coupon also gets qualified to weld all kinds of fillet welds: pressure retaining as well as non-pressure retaining ones.
This gets further reaffirmed through an Interpretation: IX-83-103 (qs 2).
Important Note: This held true until 2021 edition of Section IX. A new paragraph has been inserted under QW 301.2, in 2021 edition. This paragraph says that a welder who prepares the fillet weld WPS qualification test coupon gets qualified for welding on only non-pressure retaining fillet welds.
So the new understanding with respect to welder qualification through a fillet weld coupon is as follows:
- A welder qualified on a performance qualification test coupon in accordance with QW 303.2 is qualified to weld on all kinds of fillet welds: pressure retaining as well as non-pressure retaining ones.
- A welder qualified by virtue of having prepared a fillet weld procedure qualification test coupon is only qualified to weld on non-pressure retaining fillet welds.
This is curious though. A welder qualification is only concerned with sound deposition of weld metal, it has nothing to do with pressure-retaining or non-pressure retaining welds.
So, this was about WPS qualification for fillet joints – pressure retaining and non-pressure retaining. Would you like to add something? Please do leave your thoughts in the comments section below.
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