At 11:47 AM 3/3/2000 +1100, Neil Cotty wrote:
>.... I can get a crank here for about $130USD - not too bad. John Black
suggested I get the crank cryogenically blah blahed. <G> What do you think?
....
I'm a mechanical engineer, but this is almost out of the realm of reality.
As I recall the (really high tech) cryogenic treatment is supposed to help
surface hardness. but I don't know it it would do anything good for
brittleness or reducing stress cracks.
If I was to suggest anything along the lines of heat treatment to improve
the life of a really old crankshaft, it would be a heat tempering process.
You warm it up to a fairly low heat treating temperature, like for
annealing, but I don't know the exact temperature. You hold it at that
temperature for a very long time, like for a week or more, and then let it
cool gradually, like maybe while burried in a box or sand. This has the
same affect as would be desireable for new castings or forgings, it
relieves internal stresses in the metal. In the case of an old crankshaft
that should take a couple of decades away from its appearant age.
Barney Gaylord
1968 MGA witn an attitude
http://www.ntsource.com/~barneymg
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