Notes On Major Changes In ASME Section IX: 2021 Edition

A new edition of ASME Section IX was published in second half of the year 2021. This article lists my observations on some of the noteworthy changes in this latest edition. Please note that not all changes have been discussed, only the ones I found interesting have been included. Also, editorial changes have not been discussed.

major changes in ASME Section IX 2021 edition

Changes in Article II: Welding Procedure Qualifications

The following are the major changes that have been introduced in the 2021 edition, regarding procedure qualifications.

Qualified Thickness For GMAW in short-circuiting transfer mode

The qualified base metal thickness when using GMAW in short-circuiting transfer mode, and when qualification coupon thickness is less than ½ in. (13 mm), an increase in base metal thickness beyond 1.1 times that of the qualification test coupon – requires requalification of procedure.

This essential variable, which appeared in Table QW-255 (for GMAW) and expanded in QW 403.10,has been revoked.

QW 403.10 no longer appears under the Table QW 255.

Likewise, the qualified weld metal thickness when using GMAW (short-circuiting transfer mode) and when deposited weld metal thickness is less than ½ in. (13 mm), “an increase in deposited weld metal thickness beyond 1.1 times that of the qualification test coupon” requires requalification of the procedure.

This essential variable too, which appeared in Table QW-255 (for GMAW) and expanded in QW 404.32,has been revoked.

QW 404.32 no longer appears under the Table QW 255.

Both QW 403.10 and QW 404.32 continue to appear in Article IV – Welding Data. QW 404.32 also appears under Table QW 355 for performance qualification with GMAW process, so it will continue to appear there.

The QW 403.10 will probably continue to remain there, or will be deleted in next edition. However, it is no longer referred in QW 255, and is therefore meaningless now. Let us see why this change might have been introduced.

The short circuiting transfer mode in GMAW process produces lack of fusion defects, which become more likely as the thickness increases. This is why, the qualified thickness had been restricted for both procedure qualifications as well as performance qualifications.

However, essential variable for procedure qualification (per QW 401.1) means that a change in it must affect mechanical properties. The 1.1 times thickness had been more concerned with the soundness of deposition. In recognition of this anomaly, the Committee, in 2021 edition, has removed this restriction from procedure qualifications, while continuing to retain it for performance qualifications.

Exemption From Supplementary Essential Variables For P-No. 8, P-No. 21-26, and P-No. 41-49 materials

The supplementary essential variables in Section IX did not make any separate provision for above mentioned materials. They were applicable equally to all kinds of materials.

The 2021 edition of Section has brought in a big ticket change for these materials – this set of P-Numbers includes austenitic stainless steels, aluminium and aluminium-base alloys, and nickel and nickel-base alloys.

Almost none of the supplementary essential variables, barring one or two, is now applicable to these materials. An exemption that goes – “This variable does not apply to a WPS qualified for welding base metals that are assigned to P-No. 8, P-Nos. 21 through 26, and P-Nos. 41 through 49.” is now visible in the body of most of the supplementary essential variables.

Let us take a quick look at the supplementary essential variables for SMAW process. As can be seen in the table below, only QW 404.12 is properly applicable to these materials.

Supplementary essential variableApplicable for P-No. 8, P-No. 21-26, and P-No. 41-49 materials?
QW 403.5 – ø Group NumberApplicable to P-No.8 metals.   P-No. 21-26 and P-No. 41-49 are non-ferrous, therefore they do not have any group number assigned to them. QW 403.5 for these metals is practically same as QW 403.11 (ø P-No. qualified), which is an essential variable.
QW 403.6 – T Limits impactExempted in 2021 edition
QW 404.7 – ø Diameter > ¼ in. (6 mm)Variable deleted in 2021 edition
QW 404.12 – ø ClassificationYes, applicable.
QW 405.2 –  ø PositionVariable deleted in 2019 edition
QW 406.3 – Increase > 100°F (55°C) (IP)Exempted in 2021 edition
QW 407.2 – ø PWHT (T & T range)Exempted in 2021 edition
QW 409.1 – > Heat inputExempted in 2021 edition
QW 409.4 – ø Current or polarityExempted in 2021 edition
QW 410.9 – ø Multiple to single pass/sideExempted in 2021 edition

The toughness of materials in this set (P-No. 8, P-No. 21-26, and P-No. 41-49) is not affected by these variables. This makes some sense too. Most of these materials have a FCC microstructure that packs in more atoms per unit volume. That increases toughness. The microstructure remains austenitic thanks to metallurgy, regardless of changes in the above variables. Hence it makes sense to remove these variables for these materials.

However, an inadvertent oversight has occurred while making this change.

The variables QW 409.4 (change of current or polarity) and QW 410.9 (change of multiple passes to single pass per side) act as non-essential variables too, when toughness is not a requirement.

By inserting the line – “This variable does not apply to a WPS qualified for welding base metals that are assigned to P-No. 8, P-Nos. 21 through 26, and P-Nos. 41 through 49” – in these variables gives off the meaning that these variables are not required to be addressed under any circumstances!

This is not perhaps what the committee would have intended.

Non-essential variables are required to be addressed too (mandated in QG 101) on a WPS (although a change in them does not require procedure requalification) because they help the welder in making the weld.

This was probably an oversight which will get corrected in the next edition of Section IX.

Change Of Electrode Diameter To More Than ¼ in. (6 mm)

QW 404.7, which is a supplementary essential variable, says that a change in nominal diameter of the electrode to over ¼ in. (6 mm) will require requalification of the procedure.

The 2021 edition of Section IX has deleted this variable. QW 404.7 is no longer a supplementary essential variable.

This has been done because QW 409.1 (also a supplementary essential variable) anyway restricts use of higher electrode diameter over that qualified.

Suppose that you have qualified a PQR by using a dia 5/32 in. (4.0 mm) for preparing the test coupon. Then, using this PQR – you can only write WPS using 5/32 in. (dia 4.0 mm) or lower. Because using a higher diameter will entail requiring higher current/voltage than what is required for a dia. 5/32 in. (4.0 mm) electrode, (meaning higher heat input) which would violate QW 409.1.

So, indirectly, QW 409.1 prevents using any higher diameter of electrode (let alone dia ¼ in.) anyway, regardless of QW 404.7. So QW 404.7 was basically redundant, and was justifiably removed.

Are Supplementary Essential Variables Applicable To Fillet Welds

Indeed they are. This requirement is enforced through a ‘General Note’ that appears under the Table QW 451.4, which lists the qualified ranges for production fillet welds when they have been qualified through a groove weld tests. This general note was introduced under this table in 2013 edition, and conveyed that “Supplementary essential variables apply when notch toughness is required by other Sections.”.

The committee probably thought that ‘notes’ under a table is not a prominent enough place for important requirements to be mentioned at. An important piece of information should figure in the body of the text.

So this note has been deleted, and the information contained in it now appears under QW 251.2. The note had been deleted in the 2019 edition itself, but its content has made an appearance elsewhere only in 2021 edition.

In fact, information contained in a large number of notes under many tables has now been shifted to the body of the text from 2019 edition onwards.

WPS Qualification For Pressure Retaining Fillet Welds

Section IX intends that the WPS qualification for pressure retaining fillet welds be done only on groove welds. The first line of QW 202.2 (c) was preventing this message from getting conveyed with absolute clarity. The line went like “WPS qualification for fillet welds may be made on groove-weld test coupons…”. The word ‘may’ implied that it is a choice.

The 2021 edition corrects this ambiguity, and now says – “WPS qualification for fillet welds shall be made on groove-weld test coupons…”. This hammers home the point without ambiguity. It now means that for any fillet weld, WPS qualification through the groove weld route is the Section IX’s first choice. The fillet weld test coupon is a choice available only for non-pressure-retaining fillet welds.

I have explained this whole matter in another article, which may be accessed here.

Changes in Article III: Welding Performance Qualifications

The following are the major changes that have been introduced in the 2021 edition, regarding performance qualifications.

Welder Qualified Through Fillet Weld Procedure Qualification Coupon

We know that Section IX permits procedure qualification for fillet production welds through groove weld test coupons as well as fillet weld coupons. Although, procedure qualification for a pressure-retaining fillet weld must be done only through a groove weld. This is given in QW 202.2.

However, welder performance qualifications – which mainly concern with a welder’s ability to deposit a sound weld, did not have any such stipulation. We had following understanding:

  1. A welder qualified on a fillet weld performance qualification test coupon in accordance with QW 303.2 is qualified to weld on fillet welds of both pressure-retaining as well as non-pressure-retaining type.
  2. A welder qualified by virtue of having prepared a fillet weld procedure qualification test coupon (which meets requirements of QW 200) also gets performance qualified to make fillet welds, within the limits of QW 304. This also meant that this welder is qualified to weld on both pressure-retaining as well as non-pressure-retaining fillet welds. This was further confirmed by IX-83-103.

The 2021 edition of Section IX has introduced a change in QW 301.2, which alters the above understanding slightly. There is no change in the understanding established by point number ‘1’ above. However, with regard to the point number ‘2’, the change in Section IX now means that a welder qualified by virtue of having prepared a fillet weld procedure qualification test coupon is qualified to weld only on non-pressure-retaining fillet welds.

This is a little curious. First of all, the pressure retaining aspect of a weld has more to do with the procedure qualification than the performance qualification.

Second, this change has been introduced only for welders qualified through procedure qualification test coupons, and not for performance qualification test coupons. I wonder if this is a conscious step, or an oversight. The only difference between these two coupons is that the performance coupon involves fracture test too, in addition to the macro-etching examination which is common to both coupons.

Qualified Range For Welding Operator Need Not Be Recorded On WOPQ-Record.

QW 301.4 – which previously listed that the performance qualification record for both welders and welding operators must record four things: i) essential variables per QW 350/ QW 360; ii) type of tests done; iii) test results; iv) ranges qualified. The formats given at QW 484A/QW 484B accordingly contained provisions to record these four things.

The 2021 edition of Section IX indicates that – for welding operator qualifications, only the first three things need be recorded. The range qualified is not included as a requirement for the qualification record. For welder qualification, no such change is told.

This is a little curious. Why would Section IX not want ranges qualified on a welding operator qualification record (WOPS-record)? The reason is not quite apparent.

Moreover, the format for WOPQ at QW 484B continues to indicate column for ‘Ranges Qualified’, which makes the change further curious.

Welder Qualification For Zirconium Using GTAW By Volumetric Examination

Section IX allows welders using GTAW process to qualify by volumetric examination when welding aluminum, aluminum-based alloys, titanium, and titanium-based alloys (P-No. 21-26, P-No. 51-53).

The 2021 edition adds zirconium (P-Nos. 61, 62) as well, to this list. Likewise for welding operators.

Overhaul Of QW 322

Clause QW 322 has been revised in entirety.

The earlier edition said that a welder’s validity gets extended by six months if he has welded with that process under the supervision and control of the qualifying organization.

The 2021 edition now says that the validity gets extended if he merely welds with that process. The words ‘supervision and control’ have been removed.

Section IX from 2019 edition onwards intends that the people under whose supervision and control a welder prepares his performance qualification coupon should be qualified themselves too. The words ‘supervision and control’ in QW 322 probably conveyed that the people responsible for updating continuity should be qualified too.

Updating of continuity is a clerical work, and can be done by anybody. Section IX does not require any special qualification for such persons. Hence these words have been removed.

Further, the second paragraph under QW 322.1 conveys that welding with either manual or semi-automatic with a process extends the continuity for both manual and semi-automatic welding with that process. For a welding operator engaged in machine or automatic welding extends his continuity for machine or automatic welding.

The word ‘both’ is missing.

This means that engaging on machine welding extends the operator’s continuity for machine welding only, and engaging on automatic welding extends the operator’s continuity for automatic welding only. Did the Committee really intend this?

If they did, the wording could have been definitely clearer.

Welder Qualification For Tube-to-tubesheet Welds

Section IX has always allowed that if the code of construction does not require compliance to demonstration mock-ups of QW 193.2 for performance qualification for tube-to-tubehseet welds, the qualification of welder/welding operator can be done on either a groove weld test coupon in accordance with QW 303.1, or the demonstration mock-up of QW 193.2.

The 2021 edition of Section allows such qualification to be done on a fillet weld test coupon also (if the production tube-to-tubesheet weld is a fillet weld), if the code of construction does not require compliance to demonstration mock-ups of QW 193.2. This choice has been given at QW 387 (c)(3).

Non-mandatory Appendix D Deleted

The Appendix D had contained a listing of materials, sorted P-number wise. All materials with one P-Number were bunched together. This was basically a regurgitation of QW 422, which is structured ‘SA’ specification wise. Same data was repeated at two places, and probably was only meant for easy reference of data.

This Appendix has been deleted now, perhaps because referring data has become very easy today, with the help of computers. One Ctrl+F search can find any P-Number and any material specification within a second. So, Appendix D served no real use for anybody.

Miscellaneous Observations

What is the difference between ‘Code’ And ‘code’?

One of the revisions in 2021 edition of Section IX is that the word ‘Code’ has been revised to ‘code’ in QG 101 – para 2. The matter must have been pertinent enough to: i) merit a change, ii) appear as one of the serial numbers under ‘summary of changes’.

What is the difference between ‘code’ and ‘Code’? Which form of the word should be used under what circumstances?

To the best of my knowledge: ‘Code’ is used when referring to a particular code, while ‘code’ is used when referring it generically. When ‘code’ is used, the authors didn’t have any one particular code in mind, and the word can refer to any code in general.

Also, when the text implies one of the sections of BPVC, then too the word ‘Code’ is used instead of ‘code’.

The above understanding is of course not mentioned anywhere, it is only inferred. Most of the instances of usage of this word in Section IX follow the above understanding, however – not all. Some examples in which the usage of the word does not conform to the above understanding can be seen in paragraphs QG 100 (b), QG 100 (e), QG 106.1 – para 1, QG 106.2 – para 2 etc.

So these were a few observations on the changes done to ASME Section IX 2021 edition. Do feel free to share your thoughts on the matter in the comments section below.

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