Re: [ST] Shot peen, and others

[jwratmaster@xxxxxxxxx (Jonathan West)]

Sheep Dawg barked:
<snip>
3. The cranks are plasma nitrided. This is a low temperature process
unlike traditional nitriding, which requires heat. The cranks are placed
in a low-pressure chamber containing an atmosphere of pure N2. There's a
voltage potential between the cranks and the inside of the chamber that
ionizes the nitrogen allowing it to penetrate the surface of the steel.
I used to know a bit about the chemistry of this process, but it was too
long ago and I've fried too many brain cells since then. 
Whether it's BS or not that Triumph is one of only three mfrs doing this
I couldn't say.
<snip>

Sheep Dawg,
To clarify, you are partially correct in your original statement that
Triumph are one of 3 manufacturers that plasma nitrides their cranks.
In fact, what you probably meant to say was that Triumph are one of 3
OEM's (Porsche and Mercedes too?)that do their own "IN HOUSE" plasma
nitriding.  Most others farm it out as it is a very expensive process
for such a small part of the final product.  The plasma nitriding takes
no less than 24 hours per batch (I think Triumph's machine holds 24?
cranks per batch) at 520 C degrees.  The current in the Hydogen/Nitrogen
atmosphere forms a coating on the crank for hardening which penetrates
the crank at a rate proportional to the lenght of time of exposure.    
I'm no metallurgist but I did stay at a Holiday Inn Express last night.

Jonthan West
2 Dawgs...


     *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
      The ST/RS Mailing list is sponsored by Jack Lilley Ltd.
          http://www.TriumphNet.com/st/lilley for more info
   http://www.TriumphNet.com/st for ST, RS and Mailing List info

=-=-=-= Next Message =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=