On Sun, 02 Aug 2009 08:54:54 -0500, RoyJ wrote:
(top posting fixed)
Jordan wrote:
I made a rear axle for my rigid-framed motorcycle out of 4140 steel,
and the thing bent in use. I was advised that heat-treatment was
optional, but not really necessary, so I didn't do that. Was this
advice wrong? The axle diameter is 9/16", and bike weight = 375 lbs. I
do sometimes hit the odd pothole, but nothing major.

Jordan
9/16" annealed 4140 will bend almost as easily as cold rolled.

BTW: there is a major advantage to the annealed 4140 in impact strength
......... but it only shows up in the -40F and below range. Sorta doubt
you will be out on a motorcycle at that temp.

But if you were, think of how much of a bitch it'd be to have the axle
fracture!

--
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