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Gearbox designer needs to clean Titanium with Stainless insert

2004

Need help in choosing a cleaning procedure/solution for this situation: Have a Ti-6Al-4V Aluminum Housing with a 17-4PH ring gear that is pressed in. The problem is that the gear has to be lapped, then cleaned, so both materials must be cleaned at the same time. We normally use TCE for the Stainless, but heard it's not to good for the Titanium. Our customer is requiring that the parts be cleaned (however), flushed with Alchohol, then baked to remove any moisture in a clean room. Can anyone help with this or point me in the right direction?

Thanks in advance...

Scott MacIntyre
Gearbox Design - Farmingdale, New York

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You are mostly correct. Used TCE will have some breakdown into free chloride ions and some hydrochloric acid that is held in check for a while with a stabilizer/buffer. free chloride ions are detrimental to Ti. What that level is has been debated for years and the same aerostace company that mandates a low chloride level in rinse waters uses HCl acid etch and a woods nickel strike in a process of EN plating engine parts, so, what is the real truth? Alcohol has a low flash point and is quite flamable so is a risk. I have used a 50 % isopropyl alcohol [on eBay or Amazon] and DI water mixture to final rinse Ti parts with acceptable safety. Having no idea of the shape of your part and the cleaning level required it can not be said what level of rinse is required, but it very probably will take more than one and may require a pumped and filtered solution if I read you letter correctly.

James Watts
- Navarre, Florida
2004

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Some aircrafts engine manufacturers allows to vapour degrease titanium alloys using inhibeted TCE for not more than five minutes. good luck ,GOD BLESS

Khair Shishani
aircraft maintenance - Al Ain, UAE
2004