Steam turbine rotor cracks
Steam turbine rotor cracks
(OP)
Hi,
We have a few very small cracks on our steam turbine discs. Does anyone have any experience in assessing these?
Thanks.
We have a few very small cracks on our steam turbine discs. Does anyone have any experience in assessing these?
Thanks.





RE: Steam turbine rotor cracks
It really does make a difference when you're looking for service providers!
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If we learn from our mistakes I'm getting a great education!
RE: Steam turbine rotor cracks
RE: Steam turbine rotor cracks
But why should I guess that based on so little information given by you.
Have you ever had any boiler priming issues?
rmw
RE: Steam turbine rotor cracks
Thanks for your response. I'm not in the US, but in Australia. Have you seen small cracks on rotors?
Thanks.
RE: Steam turbine rotor cracks
- Turbine manufacturer
- Turbine rating
- Turbine configuration (reheat or non-reheat, condensing or non-condensing, single casing or multiple casings, etc.)
- Inlet and exhaust steam conditions
- Year when unit was placed initial service
- Location and orientation of the cracks, including which rotor and which disc(s)
RE: Steam turbine rotor cracks
But they were on the LP rotors mainly in the high/low teeth area of the diaphragm packing fits between the stages, all stages of the LP.
Does this come any where close to where your cracks are?
rmw
RE: Steam turbine rotor cracks
We are working with the manufacturer to remedy this, and hence I am limited what information I can disclose at this stage. The small cracks are in the discs of the LP.
I am interested in the scale of the cracks you have found in the past, and how this limited the life of the rotor.
I would be more comfortable continuing this discussion in private.
Cheers
RE: Steam turbine rotor cracks
telling your manufacturer something you gained from an internet posting (not to diminish the expertise on this forum) could cause you some embarrasement or worse.
RE: Steam turbine rotor cracks
For your case, I would recommend to do nothing by yourself. Best way is to contact the owner of design. Even if you can provide data for dimensions, working conditions, it is impossible just to say it can withstand the loading, vibrations, etc... without having as much information as the design owner.
Regards
RE: Steam turbine rotor cracks
Further to what thgirw said, you may get some support from the OEM depending on the youth of the unit but if it's an older unit, they will tend to suggest you buy a new rotor. Even though there may be plenty of life left in it.
Good luck
RE: Steam turbine rotor cracks
RE: Steam turbine rotor cracks
RE: Steam turbine rotor cracks
Our crack was at the base/root of the disc. The rotor is a one piece forged rotor. and the crack was right around the upstream root of the stage 3 disc. The max depth was around 22mm.
Interesting project! If anyone else has seen cracks in this location in a one piece forged rotor I'm very interested in what was found in the way of causes.
We do have a history of non perfect steam chemistry , but don't have cracking elsewhere around the rotor, such as at the blade roots. Makes us think that there may be other contributing causes as well as steam chemistry.
Chris
RE: Steam turbine rotor cracks
Glad your back up & running. What are you using for chemicals. You may want to change over to all volitale water treatement. Using phosphate you may be carring over. Next ouytage inspect your dryers in both drums. Get sodium analyzers installed pronto. Good luck mate.
RE: Steam turbine rotor cracks
Best of luck,
RE: Steam turbine rotor cracks
Machine appears to operate well without stage 3.
Cheers
Chris