crack in PSV spring
crack in PSV spring
(OP)
Hi,
we are suffering from PSV spring crack
Material: 17-7 PH stainless steel
operating temperature: 221 F
set pressure: 1760 psig
size: 2"
service: boiler feed water, good quality and well treated
There is some corrosion in the spring but it is not on the carbon steel piping!
See attached photo
Any one can help on why it fails???
we are suffering from PSV spring crack
Material: 17-7 PH stainless steel
operating temperature: 221 F
set pressure: 1760 psig
size: 2"
service: boiler feed water, good quality and well treated
There is some corrosion in the spring but it is not on the carbon steel piping!
See attached photo
Any one can help on why it fails???





RE: crack in PSV spring
I'm guessing the spring itself, thanks to its location, is not as not as the piping, so isn't guaranteed to stay dry.
Dip the next replacement in Dykem, twice.
Or insulate the valve so the spring stays warm.
Or specify plastic-coated springs.
Mike Halloran
Pembroke Pines, FL, USA
RE: crack in PSV spring
RE: crack in PSV spring
This is often overlooked in spring design because the normal design practice is to only design it for torsion about it's section as a result of the compression.
Any chance the spring is being twisted about the longitudinal axis?
RE: crack in PSV spring
RE: crack in PSV spring
RE: crack in PSV spring
RE: crack in PSV spring
RE: crack in PSV spring
There is no much salts in the treated water
Conductivity is 6400 micro simens/cm
Chloride < 2000 ppm
There is no indication of bending or permanent deformation
Oxygen < 10 ppb
I dont think 17-7 PH is not suitable for this service
What kind of metallurgical testing will help on this??
RE: crack in PSV spring
If you can remove the cracked spring and send it to a metallurgical lab it can be destructively examined to determine the cause of failure. Otherwise, all you can do is guess.
RE: crack in PSV spring
RE: crack in PSV spring
RE: crack in PSV spring
RE: crack in PSV spring
I am waiting for experts !
RE: crack in PSV spring
RE: crack in PSV spring
<<<
Don't tell the lab what tests to run.
Ask them to tell you why the parts failed.
Mike Halloran
Pembroke Pines, FL, USA
RE: crack in PSV spring
You have been given sound advice by MikeHalloran and others. You have several possible damage mechanisms. If I could tell you exactly why it failed based solely on a public internet forum, I would quit my day job and become very wealthy.
RE: crack in PSV spring
You should engage a competent materials lab. They will be able to propose an initial workscope to you based on the information you provide. Good luck!
RE: crack in PSV spring
Mr. Failure, you are the most guy who could understand me..
anyway I showed it to a corrosion specialist and he commented it looks like hydrogen crack