Section IX of ASME BPVC is a qualification standard for welding procedures and welding operators. It is a very widely used standard today.
In some places, it is a statutory requirement – that is, it is mandated by law. In other places, it is adopted by companies for welding qualifications. Sometimes it becomes compulsory by virtue of being a contract requirement.
ASME Section IX is a consummately technical document. A remarkably consistent set of rules have adorned its pages for over 8 decades. When we first come across it, it appears verbose and long-winded. As you become more and more familiar with its intent, the simplicity and clarity of intent gets you hooked.
The economy of expression, the strong-mindedness with which the requirements are conveyed start to becomes visible.
Unlike how it might seem to a beginner, it is a pretty simple Code to refer. It keeps things quite uncomplicated. It keeps in mind that its role is limited to only the welding qualifications. It does not try to assume the role of the construction code.
It goes with the thinking that the construction code knows best about an application.
Also, it conveys repeatedly that it is a minimum set of requirements towards a goal. It relies heavily on the welding engineer to take into account the requirements of the application. And write WPS and qualify welders keeping the requirementsof application in mind.
In this article, I have tried to put together some interesting aspects about Section IX. I come across these pieces of information while browsing old editions, the interpretations database on ASME website, listening and reading the writings of greats like Mr. Walter Sperko, and general welding related welding forums on the internet.
Some historical aspects of ASME Section IX dominate the majority of this article. You would enjoy it if you are a Section IX enthusiast. Do share your thoughts in the comments section below.
When did ASME Section IX come into existence?
Boiler code committee has been in existence since 1911. In 1914 this committee published the first edition of Boiler Code which contained some requirements on welding as well.
The Boiler Code took the form of Boiler & Pressure Vessel Code in 1928, when it got divided into various construction codes such as Section I, Section VIII, etc. The welding qualifications related requirements were contained in the construction codes itself.
In 1941, the welding qualifications related requirements probably became too elaborate, and could not be contained in each of the construction codes. A separate Section code was needed to address the requirements of welding qualifications alone. And thus was born the Section IX, in 1941.
What was the 1941 Edition of Section IX Like?
The 1941 edition contained only 47 pages (compare it to the 350 pages long treatise that it is today!). Five of these pages contained requirements of welding rods (there wasn’t a Section II Part C back then). Only mild steel covered electrodes featured in it.
The basic intent (or, the objective) of the ASME Section IX was the same even back then. Like it does today, it sought to address requirements for: 1. the content of welding procedure specifications; 2. qualification of welding procedure specifications; and 3. qualification of welding operators that would use those procedure specifications.
Similar to the present day BPVC, the requirements expected from the production welds were addressed only in the construction codes (not in Section IX). As mentioned above, Section IX only addressed what a WPS should contain, how to qualify a procedure, and how to qualify a welder (or welding operator as was called back then).
The 1941 edition comprised of only three welding processes: Shielded metal arc welding, oxy-fuel welding, and carbon-arc welding.
Brazing as a joining process was introduced only in the year 1960. Then onwards, the ASME Section IX got its title as Welding and Brazing Qualifications. The plastic fusing joining process was added only 9 years back, in 2013.
What did the WPS format look like? Was it same back then?
The ASME Section IX specified a non-mandatory (just like it does today) WPS format back in 1941 as well. The format was in the form of a narrative text with blanks in the text. The user was required to fill the blanks appropriately.
What about the variables for procedure qualification? Were they same back then?
The 1941 edition contained fewer variables than the present day edition, but far more conservative in nature. For a procedure qualification, the following essential variables were specified:
- Change in electrode classification.
- Change in electrode diameter.
- Change of more than +15% in mean current/voltage.
- Change of more than +25% in number of passes deposited in a groove.
- Change in type of groove (U-groove to V-groove etc.).
- Decrease in the included angle of a groove.
- Decrease in root gap or root opening.
- Increase in root face (or land, as it is called in some countries).
- Addition or deletion of a backing strip.
- Change in welding position.
- Decrease in preheat temperature.
- Change in PWHT temperature range.
- Change in base metal thickness (qualified BM thickness would be normally ‘2T’, except qualification on a BM of more than an inch thickness qualifies unlimited thickness).
- Change in base metal P-Number.
Anyone familiar with Section IX would notice that most of these are no longer essential variables today. Some of them are, but a broad range of these variables is permitted for production welds. The above variables meant that the procedure qualification coupon had to be essentially a replica of the production weld.
A notable relief from the tight rules was the stipulation regarding the qualified base metal thickness, as seen in serial number 13 above.
The tests required to qualify a groove weld were the same as today, four bend tests and two tensile tests.
The ASME Section IX in 1941, just like it does today, also contained a table listing P-Numbers for various base metals.
Another notable feature was that the procedure qualification coupon for a fillet weld could be done only through a fillet weld. In today’s edition, a groove weld qualifies all fillet welds. Back then, it wasn’t so.
Welder Qualifications Per 1941 Edition
The following paragraphs discuss a few aspects surrounding the subject of welder performance qualifications in accordance with the 1941 edition of ASME Section IX.
What were the variables for welder qualification?
There were a total of four variables for welding operators.
A notable variable for performance qualifications was the ‘O-number’.
The ‘O-numbers’ were assigned to different base metals. Carbon steel and low alloy steel base metals had one O-number, and stainless steels had another (the non-ferrous metals were introduced to ASME Section IX only in the year 1948). The O-number pertained to the qualification of operators, hence the term ‘O-number’.
This meant that an operator qualified with base metals of one O-number was qualified to weld on production jobs with only that O-number.
Another essential variable for the welding operators was the filler metal specification. Meaning that an operator qualified with one electrode specification was qualified to weld with only that electrode specification.
This is highly restrictive, it must be said. In comparison, the rules are much more liberal today. We have F-numbers today. Per QW-404.15, a welder qualified with a filler metal having a certain F-number is qualified to weld with all fillers metals having that F-number, and then some.
Another essential variable for welding operators was the change of progression from uphill to downhill and vice versa. This one has continued till today. Today, this variable is enshrined in Section IX in the form of QW-405.3.
Another variable is the change in position. Testing in any position qualified flat position. Testing in 5G qualified flat, vertical, and overhead positions.
This one has continued till today as well, with some modifications. Today it finds a place as an essential variable for welder qualifications, in QW-405.1.
1952 – Variables For Welder Qualification Separated from those of Procedure Qualification
The rules for welder qualifications were clearly separated from those of procedure qualifications only in the year 1952. This meant that the variables for welder qualification were to be treated exclusively from those for procedure qualification. The two would have no relation to each other.
And that is the way it has stayed to this day.
Testing For Welder Qualification Coupons
One face bend and one root bend was specified for thicknesses below 1 inch base metal thickness. For above one inch BM thickness, four side bend specimens were specified. A welder qualified on a coupon having BM thickness of one inch or more would be qualified to weld unlimited thickness.
Today of course this value is half an inch (13 mm). That is, a welder who has deposited at least 13 mm in the qualification coupon with a minimum of three layers is qualified to deposit unlimited thickness in the production welds.
The acceptance criteria for the bend tests were: No cracks exceeding 1/8 inch (3 mm) in length are permitted. Corner cracks are acceptable. This is same as the criteria specified in QW-163, when the welders are qualified through the visual + mechanical testing route in accordance with QW-304.
Other Interesting Facts about Welder Qualifications in 1941
Here are some more interesting facts on the subject of welder qualifications as per the 1941 edition.
Welder was called welding operator
Note from the above paragraphs that the welder was called a welding operator. The welding machines in those times were bulky. A diesel driven motor would turn a generator which would produce current and voltage that would enable welding.
The whole set up was a big machine. So it is understandable that the person who operated would be called an operator.
Separate Qualification for Fillet Welds
Another interesting thing is that the 1941 edition compulsorily required separate qualifications for fillet welds. This means that a welder wanting to make fillet welds in production must be qualified on a fillet weld coupon during his performance qualification test.
The testing specified for fillet weld coupons included the bend tests! (as opposed to the fracture test and macro-graphs specified in the 2021 edition).
Under today’s rules, this has been relaxed of course. Per QW-452.6, a welder qualified on a groove weld is qualified to weld all fillet sizes, on base metals of all thicknesses and diameters.
Retesting Was Permitted
Another interesting feature that has continued unchanged is the matter of re-test. The 1941 edition allowed retesting if one or more of the specimens failed to meet the acceptance criteria, but with twice the number of specimens. If the welder underwent some training, he could retake the test. In such case, doubling the number of specimens would not apply.
This is the exact same direction that appears in the 2021 edition of Section IX too.
Validity Lasted Only Three Months
We know that, as per the rules of 2021 edition of Section IX, a welder’s qualification remains valid for six months from the date of completion of welding. After this time period, the validity of his qualification is said to have expired unless he engages on welding with that process in the six months period.
Well, this period of validity was three months per the 1941 edition. The changeover to six months was done in mid-1980s.
Welding Positions Have Stayed Same Since 1941
The welding positions in the present day edition of Section IX are defined under QW-461. These same positions were described in the 1941 editions as well. This is one aspect in which the Section IX has stayed consistent over 80 years! The same 1G, 2G… for groove welds, and 1F, 2F… for fillet welds are described in the 2021 edition as well.
The only exception is the 6G position, which did not exist in the 1941 edition.
In fact, the wonderfully difficult to understand diagram in Figure QW-461.1 today, existed in the same configuration in 1941 too!
Here are a few interesting questions that occur to any welding engineer that uses Section IX.
What Does the ‘P’ in P-Number Stand for?
P-number has been around since the 1941 days. Back then, there was another number called ‘O-number’. The P number related to the classification of materials according to their welding characteristics (same as today). The P numbers were related to the procedure qualifications. Hence the term ‘P-number’.
Why is There No P-number 2 in the Present Day Edition?
There is no P-number 2 in the 2021 edition. In fact, it disappeared from Section IX many editions ago. There is a P-number 1, and then there is P-number 3, and so on. But no P-number 2.
In the early days, the P-number 2 was assigned to wrought iron. Today, wrought iron is not used any longer (at least for the commercial purposes to the best of my knowledge). Due to this reason, the P-number 2 has becomes obsolete.
What does ‘SFA’ Stand for in SFA Specifications?
After a few years of the 1941 edition, sometime in the mid 1960s, the work of writing material specifications for electrodes was given to American Welding Society (to lessen some load probably). The ASME did not do the work of writing the material specifications by itself. So it outsourced this work.
The AWS came up with filler metal specifications under the banners A5.1, A5.2, and so on. These fillers would be reviewed by the standards committee II (i.e. the committee of Section II of today’s BPVC) and adopted (if found fit) for use on the boilers and pressure vessels. Not all filler metals were adopted. The ones that were adopted were special.
These special filler metals were deemed fit for construction of the boilers and pressure vessels, and included in the fold of BPVC under the material specifications titled SFA 5.1, SFA 5.2, and so on. The ‘SF’ stands for special filler, while the rest of it (A5.1, A5.2, etc.) remains identical to the original title assigned by the AWS.
What does QW in Section IX stand for?
Although I am not sure, I have heard some experts use ‘Quality Weld’ when referring to QW in Section IX.
1974 – A Seminal Year for Section IX
The Section IX acquired a form resembling its present day form in the year 1974. This was when the variables were delineated into essential, non-essential, and supplementary essential variables.
The most important change in the 1974 edition was the stance adopted by Section IX with regards to the welding position for procedure qualification. Welding position ceased to be an essential variable for procedure qualification.
This meant that a procedure qualified in any position could be used to support welding in any other position. This applied except for the cases when toughness was a consideration. In qualifications where toughness tests were done, welding still continued to be restricted through the clause QW-405.2. This was until 2019 when this restriction too was lifted.
So, from 2019 onwards, position is not an essential variable for procedure qualifications at all, regardless of whether toughness is a requirement or not.
Why did position stop being an essential variable for procedure qualifications in 1974?
Well, it was determined that changing the position of the weld did not affect the mechanical properties of the weld. If a welder is skilled enough to deposit a sound weld in out of position welds, the weld will still have desired mechanical property. In other words, position should be a variable for the welder qualifications only.
It was also in 1974 when it was clearly established that only those variables that affected mechanical properties of the weld should be considered as essential variables for procedure qualifications.
And on the other hand, the variables that affected soundness of the weld should be considered as essential variables for performance qualifications.
It was established in 1974 that the welding position related to the soundness of a deposit, not its mechanical properties.
Incremental Changes since 1974 Onwards
The changes to Section IX since 1974 have been gradual and incremental. The basic framework has stayed same though.
With each revision, new base metals get added. New welding processes are introduced as they come into existence with advancements in the technology developed by humans.
Year 2000 – Another Important Year
The year 2000 was another important year. The SWPSs published by AWS were permitted by Section IX in this year, for the purpose of fabrication activities in accordance with BPVC.
The SWPSs are the procedure specifications that address welding of the very commonly used materials. The use of SWPS saves the fabricator from going through the hassle and expenditure of carrying out a procedure qualification. The fabricator has to only demonstrate in a demonstration coupon that they are able to supervise and control the use of SWPS properly.
The SWPS is as good as the regular WPS developed by the fabricator. An inspector cannot refuse the use of a SWPS, because it is expressly permitted by the code. However, SWPSs are not permitted for the cases where toughness is a consideration. For such applications, the WPS has to be developed through the regular route.
There are around 33 SWPSs available in the mandatory appendix E of the 2021 edition. Today, if anyone needs to develop a procedure qualification to support a production weld(s), the SWPSs is the first place they should look to satisfy their requirement.
Year 2013 – The Part QF Gets Added
The Part QF regarding the plastic fusing was introduced in the Section IX in the year 2013. This was also the year in which the Part QG was introduced for the first time.
The Part QG contains administrative requirements that are commonly applicable to all the three joining processes: welding, brazing, and plastic fusing. These requirements include establishing the scope of Section IX, defining a WPS, PQR, WPQR, defining the variables (essential, non-essential, and supplementary essential), the organizational responsibility, ownership transfers of the personnel, WPSs, and PQRs, establishing applicability of qualifications made to previous editions, and a few general definitions.
Earlier these requirements were included in the respective part for that joining process. For example, the requirements for welding were included in the Part QW, those of brazing were included in the Part QB, and so on. When the Part QF got introduced, there became too much multiplicity of the administrative requirements.
So a separate portion named Part QG was introduced that would address common administrative requirements for all the three joining processes.
Interpretations to ASME Section IX
Interpretations have been cited extensively across this website. Here are a few observations that I formed after consulting a large number of interpretations on the asme website.
When did Interpretations Come Into Being? Are Interpretations Issued Every Year?
Interpretations began to be issued in 1977. Since then interpretations are issued almost every year, in response to the inquiries asked by people from all over the world. The interpretations database can be accessed on the asme website here.
On this database, one can see interpretations from almost every year, except 1984, 1985, 1987, 1988, 1990, 1991, 1993, 1994, 1996, 1997, 1999, 2000, 2002, 2003, 2005, 2006, 2008, 2009, 2011, 2012, 2014.
Role of Interpretations in Section IX
Interpretations are not only an instrument for the Section IX committee to literally provide interpretations to the Code, but also a trigger for making revisions/additions to the code.
Sometimes, an interpretation may trigger the committee to make revisions to the code to remove an ambiguity that may have been noticed while issuing the interpretation. Sometimes, a revision becomes compulsory to support the intent that may have been formulated by the committee while issuing an interpretation. Such interpretations are called Intent Interpretations.
The interpretations database is a goldmine of information for anyone wanting to understand the intent of Section IX on various matters.
Interpretations are a powerful tool for the committee to convey its intentions. That the committee attaches a lot of importance to interpretations becomes clear when the biggest experts on Section IX in the world refer us back to instances of 40 year old interpretations to establish a point. The understanding conveyed by an interpretation is considered as good as the Section IX itself.
Sometimes, the intent of the Section IX on certain aspects can be understood only through the interpretations. Anyone who ever aspired to understand Section IX with any degree of clarity must familiarize themselves with the world of interpretations.
It is to be noted that only the Section IX committee can issue interpretations. Any retired personnel that are not presently part of the committee cannot issue interpretations. Anybody who is presently not a part of the committee can only express their opinions.
Use of Minimum Words in Replying to Interpretations Inquiries
A notable feature of interpretations is that most of them contain only a ‘yes’ or ‘no’ by way of a reply. The economy of expression is visible throughout the Section IX, but it takes an extreme form in interpretations.
While the economy of expression is appreciation worthy, sometimes it is frustrating. The committee does not bother telling why or how behind their answer. Not just this, the committee also does not bother telling what the correct answer should be. An interesting case in point is the committee’s reply to Interpretations IX-16-38 and IX-17-66. Both contained exactly same set of questions, perhaps asked by the same inquirer.
The answers given by the committee were ‘no’ to the questions asked in IX-16-38. The same questions were asked again with a couple of words changed, in IX-17-66. This time the answers were ‘yes’. The poor fellow would have waited a full year to get confirmation to his understanding!
Does the Committee Respond to ALL Questions?
There are a set of rules/conditions that all inquiry submittals must conform to. These rules can be found on the cstools website of the asme. A link to these rules is here.
The committee does not respond to questions that ask ‘why’ behind a requirement. Also, inquiries seeking a review of the calculations/drawings/qualifications are not entertained. The requests seeking the committee’s assistance in performing code related functions (such as material selection, design, calculations, testing, inspection, etc.) are also not entertained.
So that is all I had to offer in this article. Before I close the article – a sincere thank you to Mr. Walter Sperko for his writings, if he ever reads this.
Please share your thoughts in the comments section below.