Section IX supplemental variables 1

[HgTX]

Need a sanity check.

QW-251.2 appears to say that the supplementals (e.g., additional restrictions on minimum thickness & maximum heat input) kick in automatically whenever Charpies are required.

We have WPS/PQR provided by a sub. They have Charpies, but don't seem to have worried about the thickness & HI limitations--and the customer's engineer doesn't seem to have worried about this either, even though they critiqued other aspects of the WPS. Sub says they've had no end of customers' engineers reviewing their procedures, closely enough to require spelling correction on electrode trade names, and no one has ever made them cut their thickness range to start at the tested thickness, and cut the electrical parameters down to what was on the PQR (which would be a big cut, and not a good one for performance, if they ran their PQR in the comfortable middle).

So I sanity-checked with a buddy at yet another company and he said more or less the same, that he's never required from a sub nor been required by a customer to work to the supplementals unless said supplementals have been written into the contract.

So, am I overreading 251.2? Or is that an instruction to the EOR for when they should be specifying the supplementals and it's not an automatic requirement? Or is there an automatic requirement that just gets underenforced by the WPS-reviewing engineer community? I don't want to force the sub to run additional tests (or worse, force them into an abnormally low part of their operating range) if this isn't normal practice.

Hg

 

[metengr]

If the weld procedure specification has been qualified with impact testing and impact tests are not required as part of the contract or engineering specification for the work to be performed, you can ignore the Supplementary Essential Variables part of the WPS review.

If the work requires the weld region to meet minimum impact requirements, then yes, the WPS must be reviewed and supplementary essential welding variables would require close review.

 

[Mr168]

When I review a WPS to a given Code or set of specifications (including this exact situation), I make sure they meet all of those requirements. If they are indicating that the WPS and PQR are qualified to Section IX, is impact qualified, and it does not adequately address all the supplemental variables, then I have them either add the supplemental variables, or remove the text indicating that it is qualified with impacts.

While you can ignore it, I find all too often that someone ignores incorrect information on a WPS because it's not applicable to a specific scope of work, only to find that later on that something did require impacts, and Joe Schmoe used that WPS without thinking twice about it. Once the nonconformance is issued, the finger of blame comes back to the procedure reviewer, because it was "approved" and said "impact qualified" on it somewhere.

 

[HgTX]

I'm hearing that on recent projects, a Major Engineering Firm requested that CVN testing be added, and even they didn't invoke the supplementals for thickness & HI.

Is this really something that engineers tend not to know about?

Or have my contacts just been travelling in the wrong circles of Major Engineering Firms?

Hg

 

[metengr]

HgTX;

Is this really something that engineers tend not to know about?

Yes, it is called either inexperience or lack of understanding related to proper use of welding procedures. Unless you are involved day in and day out, procedure reviews can miss items and most important the wrong procedure can be pulled for a specific job.

 

[Duwe6]

Gotta keep reading the pertinent sections of the Code. I got sent to the -50°F stuff in B31.3 this very morning. NOBODY can quote all this stuff from memory and be 100% accurate. Gotta match the Design stuff against the correct Code. It's tedious, but EVERYBODY seems to be letting anybody with a fresh Eng degree and some facility with CAD design major, sophisticated items. The shiny-faced kids miss all manner of subtle but brutally expensive things to skip, like thickness or service driven [think NaOH & amine] PWHT; customer or Code-driven NDT; the need for Weld Procedures before fabrication welding starts, for the oddball materials that they JUST HAVE to use to build with, etc.

If they are going to turn the kids loose, the "things to check for" list needs to be taped above each computer keyboard.

 

[DekDee]

Agree totally with the previous postings.
Just finished an offshore module that required impact testing on Carbon, Duplex and Super Duplex.
Piping Engineers had approved 6 x low temp welding procedures prior to my arrival.
Took one look at them and knew there was a serious problem.
Firstly, thickness ranges noted on WPS's were in accordance with ASME IX and not B31.3 so the WPS's didn't even cover all the material thicknesses to be welded in production.
Secondly, electrical variables listed (when heat input was calculated)clearly exceeded the heat inpts from the PQR's so were not even code compliant,
Regards,
DD

 

[gtaw]

A good point has been introduced, that is ASME Section IX is not a standalone code section. The basic requirements of how the WPS and welders are qualified are addressed by Section IX. However, the applicable construction code, i.e., Section I, Section VIII, B31.3, etc. must be reviewed for potential modification to the requirements of Section IX. For instance, the construction code will specify when notch toughness testing, i.e., Charpy Impact testing, is required. The construction code may also include restrictions that are not addressed or may be permitted by Section IX. An example would be the joint design, a nonessential variable per Section IX. However, B31.3 for the High Pressure category will not permit the use of permanent backing.

A WPS that is qualified for notch toughness must restrict the thickness range as per Section IX and it must be supported by a PQR that includes the results of the impact testing. However the same PQR can be used to write a second WPS that is not qualified for notch toughness with extended thickness ranges.

When the WPS is written to include notch toughness, all the essential variable, supplementary essential variables, and nonessential variables must be addressed and limited to the appropriate thickness ranges. The supporting PQR must address all essential and supplementary essential variables. I always record the nonessential variables on the PQR as well because they serve as the foundation for the nonessential variables listed on the WPS. To expand upon that, once I have recorded the arc voltage, amperage, wire feed speed, etc. on the PQR, I have a rational basis (data) to support the parameters listed on the production WPS.



Best regards - Al

 

[stanweld]

I have had pipe fabricators impact test qualify welds, in my presence or trusted welding inspector's presence, on production materials when I knew that the heat input specified on the submitted WPS, in accordance with the supporting PQR heat inputs recorded thereon, were irrational for the actual work. In all such cases the heat inputs actually being used were substantially greater than that specified on the WPS. When impact testing is required by the contract specifications/construction Codes, it is always a good idea to audit production welding to assure compliance, especially when excessively low heat inputs are defined.

Reviews by novices in any engineering field are always dangerous and unfortunately that seems to be more common today.