Magnetized in Steam Turbine

Sounds like your problem may be more electrical than magnetic, are you sure it's properly grounded?

https://www.power-eng.com/1997/08/01/stray-currents-can-damage-turbine-bearings/#gref

http://www.iffcokandla.in/data/polopoly_fs/1.2501926.1438111752!/fileserver/file/515530/filename/Aiche-23-024.pdf

Sounds like you're using a bad brush design or poor quality...

It sounds like your brush is intended to allow eddy currents induced by the ferrous metals in the turbine to drain to ground without going through and pitting the bearings of the turbine.

Did you have the bearings changed recently, particularly prior to brush failures starting? They may have replaced an electrically isolating bearing with one that's not isolating or vice versa.

The best source to answer this uncertainty and your initial question is to contact the turbine manufacturer. They may have a recall or simple upgrade that can solve your problem. But be prepared, they may only say the system is already long after the expected lifetime and full replacement is the only frugal answer.

The parts giving you trouble is their mass a factor in why they were made from that material? Is there any other reason why they can't be manufactured from non-ferrous metal, carbon fiber reinforced ceramic, or even a polymer?

In the presence of steam, there may be an accelerated level of corrosion occurring from differential metals in contact with each other. Which is something which might otherwise not been expected to show up until the end of its useful life.

If, as it has been suggested that those parts were designed to have eddy currents, then Carbon fiber (with, or without some interwoven metal strands) may be a viable substitute.

If not, and they can be 3-D printed from a different material, then you might want to contact Oak Ridge National Laboratory and ask for their 3-D Printing facility to see what they might be able to do for you.

Something is fundamentally wrong if there are <...electromagnetic currents...> strong enough to cause this level of problem.

What has been the outcome of the telephone calls made to the equipment manufacturer about it?

What is stopping having a representative from the manufacturer visit site and sort the problem out once and for all?

https://preserve.lehigh.edu/cgi/viewcontent.cgi?article=3002&context=etd

Lehigh University

Lehigh Preserve

Theses and Dissertations

1-1-1985

Steam turbine - generator shaft grounding.

Bernard Michael Ziemianek

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Reading theses/dissertations can be a cost effective way to circumvent paywalls. If you do not mind reading, that is.

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Here's a paywalled article:

https://search.informit.com.au/documentSummary;dn=393616813253361;res=IELENG

Prevention of Homopolar Generation in Steam Turbines by Reducing Residual Magnetism

Transactions of the Institution of Professional Engineers New Zealand: Electrical/Mechanical/Chemical Engineering Section
Volume 14 Issue 2 (Jul 1987)

Moutter, Simon P; Campbell, Gary J

Abstract: Homopolar generation caused by residual magnetism build-up can result in severe bearing damage in steam turbine generating sets. Experience with this phenomenon at New Plymouth Power Station, New Zealand, is described and mechanisms for the magnetic field build-up and bearing current flow are explained. The theory for electromagnetic demagnetising of steam turbines is presented along with a fast and inexpensive method of implementing the theory using readily available equipment. The theory and practice are supported by the results of a successful steam turbine demagnetising operation carried out at New Plymouth.