[Shotimes] Fretting

[Dave Ulring]

So given I have some amount of corrosion present, any
suggestions on the best method to remove it and what
protective lubricant to apply if any when
reassembling?

Thanks,

Dave
--- Jason Hartberger <at3hartberger@mail.com> wrote:

>  From the Navy publication on Corrosion (actually
> it's from chapter four 
> of the Aviation Maintenance Ratings [AMR, NAVEDTRA
> 14022] if you're 
> interested, but it's from the 504 originally)
> states:
> 
> Fretting corrosion is a limited but highly damaging
> type of corrosion. It is caused by a slight
> vibration,
> friction, or slippage between two contacting
> surfaces
> that are under stress and heavily loaded. It is
> usually
> associated with machined parts. Examples of these
> parts are the area of contact of bearing surfaces,
> two
> mating surfaces, and bolted or riveted assemblies.
> At
> least one of the surfaces must be metal. In fretting
> corrosion, the slipping movement on the contacting
> surface destroys the protective films that are
> present
> on the metallic surface. This action removes fine
> particles of the basic metal. The particles oxidize
> and
> form abrasive materials, which further agitate
> within
> a confined area to produce deep pits. Such pits are
> usually located in an area that increases the
> fatigue
> failure potential of the metal. Early signs of
> fretting
> corrosion are surface discoloration and the presence
> of
> corrosion products in lubrication. Lubrication and
> securing the parts so that they are rigid are
> effective
> measures to prevent this type of corrosion.
> 
> Yes, the navy has a publication on everything. Yes,
> even proper condom 
> usage. If it exists, the navy has it documented at
> length. *sigh*
> 
> Jason
> 
> George Fourchy wrote:
> > On Thu, 17 Feb 2005 17:36:04 -0500, Jim & Debbie
> Leyden wrote:
> > 
> > 
> >>It is a condition known as
> >>"fretting" that occurs when two metal parts work
> against each other.  
> > 
> > 
> > Interesting....
> > 
> > I've had several engines apart in the front, and
> the only one that had anything like
> > this sort of appearance was mine, with all the
> fine metal filings from the crank and
> > key spread out all over the place.  It sure looks
> like small spots of rust on that
> > sprocket in the picture.
> > 
> > Why doesn't this condition occur all the time, or
> at least, more often?
> > 
> > By the way, dictionary.com does not have this
> definition for this word....I checked
> > there, just to see if there were synonyms I could
> check out to find out more about
> > the process.
> > 
> > 
> > 
> > George
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