Turbine shaft journal damage with no corresponding babbitt damage
Turbine shaft journal damage with no corresponding babbitt damage
(OP)
Has anyone seen this? Have you seen a case where the shaft gets scored/phonographed, but the sleeve bearing has no damage?
Side info:
Oil sample clean - as far as I'm told.
I'm told the bearing was not replaced.
Only 3 year old turbine.
Scoring in the non-feed area of the pressure dam bearing.
Side info:
Oil sample clean - as far as I'm told.
I'm told the bearing was not replaced.
Only 3 year old turbine.
Scoring in the non-feed area of the pressure dam bearing.





RE: Turbine shaft journal damage with no corresponding babbitt damage
Look at the bearing surface again, you should find something embedded in it some where...
-The future's so bright I gotta wear shades!
RE: Turbine shaft journal damage with no corresponding babbitt damage
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RE: Turbine shaft journal damage with no corresponding babbitt damage
Looking at the sleeves, the grooves almost look polished. My initial thought was that something larger than the bearing clearance made it into the pressure dam area and slowly wore away at the shaft over time - therefore, no shaft cutting or raised edges to break down the babbitt. I suppose the same theory could hold true, like you say, if a hard particle entered the babbitt and slowly polished the shaft.
I'll get the sleeves looked at professionally. If wire wooling is the culprit in this case, the particle(s) is pretty small.
Thanks again.
RE: Turbine shaft journal damage with no corresponding babbitt damage
Here is a picture and description I found:
http://w
-The future's so bright I gotta wear shades!
RE: Turbine shaft journal damage with no corresponding babbitt damage
No appreciable babbitt damage in my case. I'm tending to think this may be a very minor case of wire wooling which occurs at startup when film thickness is not yet established.
Thanks again for your help, and the link.
RE: Turbine shaft journal damage with no corresponding babbitt damage
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RE: Turbine shaft journal damage with no corresponding babbitt damage
I had one machine where polymer build up in the interstage seal on a compressor machined the rotor from a six inch diameter to a three inch diameter. The polymer built up, hard stuff imbedded in it, machined the rotor like sand paper, and as the clearance opened up more polymer built up to fill the gap. The cycle repeated itself.
-The future's so bright I gotta wear shades!
RE: Turbine shaft journal damage with no corresponding babbitt damage
Have you ever seen something larger than bearing clearance get stuck in the pressure dam area and slowly polish the shaft?
RE: Turbine shaft journal damage with no corresponding babbitt damage
-The future's so bright I gotta wear shades!
RE: Turbine shaft journal damage with no corresponding babbitt damage
Just to play devil's advocate. From the link:
"The best solution is to limit the chromium content of the steel to 1.5% where surface speeds are greater than 25 m/sec."
A440 has -.8 - 1.1% so should not be susceptible. But the books aren't always right and Steve has specific experience to to the contrary.
"Identified by extensive damage to both bearing and the journal"
No extensive damage to the bearing mentioned in this case.
Also I have heard the reason they call it wire wooling is because you will often see shavings like from machining.
Once again, I defer to Steve's experience on this one. I certainly don't have any alternate theory. But just wanted to throw in those comments.
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RE: Turbine shaft journal damage with no corresponding babbitt damage
Even with A4140, perhaps there might be a possibility the shaft journal area had previously been repaired with a chrome process? We prohibit that in our repair specification for motors.
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RE: Turbine shaft journal damage with no corresponding babbitt damage
RE: Turbine shaft journal damage with no corresponding babbitt damage
Johnny Pellin
RE: Turbine shaft journal damage with no corresponding babbitt damage
I am having a wire wooling problem with a large vertical pump with a type 431 shaft sleeve and babbit tilting pad journal bearings.
We were looking into using 4140 as a replacement for the 431 shaft sleeve to solve our wire wooling problem.
You said you have seen wire wooling on 4140? I was for 4140 until I just read you post. What was the case where this happened?
Any help is appreciated...thanks
RE: Turbine shaft journal damage with no corresponding babbitt damage
So I stand corrected in that regard. Now I have seen shafts machined by debris even in 4140 steels, as I mentioned above, but that literally would not be wire wooling.
I think 4140 is probably the most common rotor material out there. Unless this is a very unusual application then you can't really go wrong with a 4140 shaft.
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RE: Turbine shaft journal damage with no corresponding babbitt damage
I am looking for proof of 4140 in shaft sleeve/shaft applications for documentation purposes (pump, turbines, etc...) before we make any material changes.....if you can be of any help in that regard I would greatly appreciate it.
RE: Turbine shaft journal damage with no corresponding babbitt damage
Automotive engines need to have their journals ground and polished in a particular direction to remove directional grinding fuzz and surface flaps and nuggets. I have to wonder if chrome steel's bad rap is related to that phenomenon, and might be remedied just as easily.
http://motorheadheaven.com/it_crankgrind.asp
go here and click on accelerated wear
http://motorheadheaven.com/it_bearingfailures.asp