Production Weld Impact Tests (UG-84(i))

[RPRad]

Do you have to do Production Weld impact test if you: A)Have ordered your material already impact tested (yes it is required to meet the MDMT) B)Have qualified Section IX weld procedures which includes impact testing well below the current MDMT and further includes PWHT

Basically I have a thick shell (SA516 Gr. 70N) material(2.5")and a couple of thick nozzles which do not meet the MDMT exemption for a MDMT of -20F (my coincident factor is high due to the design and Corr Allow conditions). Obviously I am not exempted under UG-20(f), the material was ordered impact tested and came from the material manufacturer impact tested to -50F. My current weld procedures cover both weld zone impact testing down to -50F and PWHT which I am required to do in this case because of thickness

It almost appears that I need to use UCS-67(a)to exempt myself out of UG-84(h) and subsequently UG-84(i) in order to not do the production tests

Perhaps I am interpreting wrong but I dont see the point of doing production tests if my material and weld procedures are both impact tested well below the MDMT...this could not be the intent of the Code...there are situations (ie heavy weld passes) where I could see doing this but this doesnt strike me as one of them

Anybody know the intent of the Code in this case, in talking to other manufacturers they rarely do production test as well...but admittedly most agree interpretation appears confusing...is there an ASME interpretation that covers this situation?

 

[CWEng]

In general, if the base metal requires impact testing, so will your WPS, and production impact test would be required.

If you order material meeting UCS-66(g)it will already be impact tested, but is considered exempt. It's a fine line between material the requires impact testing vs material that is already impact tested, so is therefore exempt. It would be the difference between using SA-105 tested at -50F (not exempt) and using SA-350 LF2 tested at -50F (exempt). If you use exempted base metal and use the correct filler metal testing meeting UCS-67(a)(3), that is one way to avoid production impact testing, since production impact testing is not required if the WPS is exempt from impact testing.

Another way to not have to do production impact testing, is design a vessel small enough to not need butt welds. use pipe, slip on flanges, flat heats, etc. That way you do not have a category A or B joint, which are the only ones that require production impact tests. This is usually cost prohibitive though if your vessel has any size to it.

You would probably also find the ABSA impact testing summary informative:

https://www.absa.ca/media/1495/ab-511_impact_testing_enigma.pdf

 

[RPRad]

Pretty much the conclusion I came to as well...most I talk to try avoiding it by skating through with a combination of UCS-66(g) and UCS-67(a)(3) as you indicated. Just seems kind of odd arguing to exempt the weld procedure from impact testing on one hand yet you always make sure your WPS has you covered on the other hand. I dont recall this being so muddy...was it clearer in earlier versions of the Code (ie pre 2004 maybe)

I actually did come across the ABSA document when I was pondering this, it certainly helps clear it up some...nicely organizes the Code sections....tells you what they think of the issue when they put the word "Enigma" in the title

I am just trying to understand what the reasoning was behind essentially making production testing mandatory every time you need to bring in impact tested material...basically over an inch thick. It just seems to me if your weld procedure and materials are all impact tested already I dont see the benefit or need for the production testing to be done (particularly with P1 (G1 and G2) materials)...I wont disagree that there are circumstance where production testing would be pertinent