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Effect of graphite particles

Effect of graphite particles

(OP)
Hello,

What is the effect of graphite particles (coming out of machined cast iron) on the gear box life.

Please note that we do hot alkali wash the cast iron part before assembly. However, the black color is still seen on some places on the surface.
We need to use tissue paper and manually clear those spots.

I am wondering whether we really need to do the manual cleaning operation.

Your opinion please

RE: Effect of graphite particles

If the black crud really is only pure graphite powder, then it is actually a very decent lubricant.  (Dry graphite powder is the traditional lubricant of choice in locks.)  If any other fine substances are in the black crud, then it can be expected to provide some nice trash to accelerate wear if you leave it in place.  Even the seemingly harmless graphite powder can burden the additives in the lube oil, and that may be another good reason to just get everything as clean as possible anyway.

Valuable advice from a professor many years ago:  First, design for graceful failure.  Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs.  Only then can practicality and economics be properly considered.

RE: Effect of graphite particles

Graphite won't be a problem, metals and abrasives are.  

RE: Effect of graphite particles

Some classes of machinery call for painting sumps, etc with products very oil and temperature resistant to seal in all manner of foundry debris.  For a little while GE's Glyptal was popular for painting high performance engine engine block and cylinder heads.  Glyptal is owned by someone else now.

http://www.glyptal.com/Distributor.htm

Dan T

RE: Effect of graphite particles

smurali1,

Depending upon what type of cast iron you are referring to, the graphite residue may or may not be detrimental.  With grey iron, the graphite is in the form of flakes and is not really abrasive in nature.  With ductile iron, the graphite is in the form of nodules, and these nodules are very abrasive due to an outer layer of silicon carbide that can form over each nodule during casting.

Hope that helps.
Terry

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