I may be overthinking it... true
From a KPI point of view for that same example, would it be fair to say that the number of times the valve operates would be a plant KPI, how often the procedure is followed would be a process KPI, and the percentage of operators trained in the procedure a...
All,
In the process safety space, I often hear of these three factors (People, Plant, Process). What is slightly confusing to me is the delineation between the three. For example, is a procedure covering valve operation process or plant related?
Does anyone have any clear definitions of these...
Based on information from metalinfo.com, 15CrMoG appears similar to P11 in composition. I couldn't find an exact match for 12CrMoVG, but the 12CrMoV designation in Chinese standards refers to 0.5Cr 0.5Mo 0.25V steel, which I understand is not so common in the states.
However, the prudent course...
With regards to special filler, within power generation repairs to Cr/Mo steels with austenitic filler materials (Inconel, 308) without PWHT are not uncommon. The thinking being that the austenitic weld structure affords more ductility and avoids cracking in the base material. I don't believe...
It will depend on the chemistry regime you choose but generally for make-up, chloride limits tend to be around the single digit ppb mark. Drum measurements for units with reheat do vary as you have found, generally from 10-100 ppb.
EPRI suggests conductivities rather than chloride levels are a...
Concur with metengr - shape, size are the two main features used to distinguish carbide pullout/creep cavities. You can sometimes use the distribution of the indications as a check, if you have good knowledge on how you expect creep damage to progress in your examined material.
Metengr,
Thanks for the info. How does the 7 year period fit in with the typical outage program in the US?
Davefitz,
From the what I have read, the CMV materials are a lot more problematic than standard CrMo, particularly with regards to Type IV and reheat cracking. We have MDRs with heat...
Have a query with regards to high energy piping, on thermal power stations and creep damage.
There is much data available with regards to how to classify creep damage - we tend to adopt the VGB TW-507 criteria for the relevant materials, which is essentially a 1 (no creep voids) to 5...
Ed,
I can't seem to find a UNS - from my google searching, the grade seems to be reasonably popular in Asia, but not the US.
The designation I have seen is KS D 3698 grade STS 304J1 - I believe this is a Korean standard.
Also, composition wise:
http://www.zpsspzpc.com/english/about/?148.html...
Is anyone familiar with above grade and how it's corrosion resistance compares to 304, particularly in regards to SCC? From what I gather, the grade has slightly lower cr and ni, with a 1-2% addition of Cu. supposed to have better workability characteristics.
Thanks
Thanks to everyone for their feedback.
Ultimately we are going to be OK with 0.5 hr PWHT for thin wall tube:
- Qualification testing will show suitable properties are obtained
- Industry experience - 0.5 hr for thin wall tube is OK
- Metengr link to the EPRI document suggests oxide scaling can...
I'm sure the question has been asked before, but what is the minimum hold time for PWHT on P91? The question is pertinent to thin sections (1/2" and lower say).
I believe ASME VIII (UCS-56) suggests it is possible to do as little as 15 mins on thin sections (<1/4"). However, I've seen some...
Does anyone have much experience with the above topic? Specifically, has anyone run successful life assessment programs at their plants based on creep pip measurements on pipework? Concerned about the quality of the measurements, given how easily the tips may be damaged and how accurate the...
See
thread794-302393
Have just been informed by some experienced power station personnel that this was reasonably common practice (using a lower alloy content - F11 - to perform capping runs to a F22 stub weld) to improve ductility and reduce the onset of fatigue cracking. Any truth to that...
Folks,
Have a stainless steel fitting, small valve welded to a pipe section, maybe about 3/4" in diameter.
The operating conditions it sees internally are 260C, 600 kPa.
Was told by operating personnel that the line suffered from an impact, which caused failure.
Material analysis has shown...
Finished up the investigation. Turns out the valve was (unintentionally) throttling, which lead to the damage observed. On closer inspection, damage was consistent with flow-accelerated corrosion.
The seat was a thermally sprayed chrome carbide (on what amounted to a carbon steel substrate)...
Part 1 of ISO 3834 (in particular annex A) will help you select what quality level you require. I don't think you will find any standards/documents that say welding management of gas pipeline shall be to ISO 3834 part 2. Essentially, it is left up to the client and it comes down to the risk of...
Haven't worked with ball valve failures too much, so I thought I should ask for some thoughts on this forum.
Came across a recent failure of a 1" NB ball valve, the downstream set had experienced severe gouging in a 180 deg arc. The gouging was sharp and distinct. Outside the gouge, the...
Two Questions:
1. What factor(s) limit the use of cast iron in higher temperature applications? Is it the debonding of the graphite phase from the matrix?
2. Is there any difference in the max servicable temperature for gray iron vs ductile iron? If so, why?
Questions are regarding use of cast...
