The picture looks like its the thrust disc which would be made of steel. When assembled and installed this disc would be sandwiched between the active and inactive (or normal and counter) thrust bearing pads. The pads should be faced with babbit which is much softer than steel: if there is excessive thrust loading then the babbit should wear first - is my understanding of your picture correct? Do you have any pictures of the pads themselves?

Wow! - what are your thrust pads made of???? That's pretty bad wear on the thrust collar. I am VERY surprised that you didn't get any temperature increase with that sort of rubbing. How long has this been going on, when did you last inspect the thrust collar?

Hope the machine is running OK now?

This message has been edited. Last edited by: cheddar-caveman,

Quotes from posting:

(i) Allowable tolerance = 0.25 mm max.

(ii) so we found a deep (appprox. 0.5mm) cut in the inactive side thrust collar

Those two add up to give about 0.75mm of clearance and this doesn't take account of any wear to the thrust pad which must have been substantial - because babbitt is so soft compared to steel, I would suggest that the babbitt loss should at least equal the loss of steel say ~0.5mm - the additional axial movement due to loss of babbitt doesn't appear in your reports of measured clearance (~0.62mm)- are you 100% that your thrust monitor setup is correct?


Another quote:
When axial probe is showing counter side reading, governor valves are automatically opened meaning that machine becomes inefficient upon this counter side movement and governor allows more steam to cover the speed reduction

Is it possible that the speed reduction occurs due to the thrust disc being ground out?

Another quote:

Only once we found scored thrust bearing on the counter side. But it was due to reduced oil pressure caused by an increase in flow path of oil on the outer periphery of composite bearing.

Well, taken at face value, its looks like its happened again. Are you sure that the diagnosis of the original problem (i.e. reduced oil pressure) was correct?

Whilst you have provided description of most of the symptoms (eventually), I don't believe you have provided enough information to identify the cause.

Maybe you should consider talk to the OEM and call upon his experience.