PRCI Hot Tap, 800 - 500C relationship to heat sink test

By Asa504 Date 08-16-2016 05:26

Hi All, g'day from down under!

New to the forums.

I've got a question I've struggled to have answered in all places I've looked.

I'm heavily involved in the in-service welding of most of our networks and transmission natural gas pipelines in Australia, specialising in thin wall pipe, but I've had an problem with one of the reports that PRCI prints out that I cant answer.

We conduct heat sink capacity tests (250 - 100C) on our pipelines for simulating conditions when we produce a PQR for the ISW. Its also possible to run a model in PRCI for a heat sink capacity however the report (as in all the reports) states the "Minimum Cooling Time" from 800 - 500C.

Firstly I wanted to clarify if this title is not an error in the software and they didn't actually mean 250 - 100C?
We all know that 800 - 500C is a very critical temperature for resultant microstructure and brittleness (our HACC issues), so I'm not 100% sure this is actually a typo.
If this report is correct, then I cant find the relationship between 800 - 500C and 250 - 100C.

Obviously I cant measure 800 - 500C on site!, and I've heard there is a relationship between the two time measurements however PRCI's HSC result is pretty useless without knowing this relationship.

Does anyone have good insight to this?

I know that Bill Bruce and Matt Boring are the guys I should be talking to but I don't have a contact for them and I'm interested in hearing what others think also.

Many thanks,
Aaron

By js55

Date 08-16-2016 15:40

Bill Bruce
DNV
614-734-6128

By Asa504 Date 08-17-2016 02:48

thanks js.
I don't suppose you have an email address?

By jarsanb (***)

Date 08-17-2016 14:43

Definitely contact either of the two you mentioned (B. Amend also). You have the EWI hot tap forum as well (not a lot of activity).

http://hottap.ewi.org/resources/hot_tap/

I'm struggling to see the relevance of 800 - 500C monitoring during procedure qualification. You've mentioned procedure qualification, so you've more than likely addressed burn through temps (982C id max), will complete all required testing including hardness measurements, compared the thermal cooling capacity of production situations to qualification simulation, CE's, and more than likely are applying low hydrogen processes/electrodes - H4's. Throw in pass sequence if necessary. How can you control or predict the amount of time you will be in 800 to 500C? Seems like any mechanical issues would be verified through the qualification process and measurement of such temps wouldn't be necessary. But the gentlemen you've mentioned know far, far more than I do.

By js55

Date 08-17-2016 19:07

Bill.Bruce@dnv.com