Work hardening requires a lot of deformation to occur, IOW if you bent
the beam into a pretzel and then straightened it back out again, so I
think that would be somewhat unlikely.
What I did wonder about and I'm somewhat unsure about would be heat
treatment. The tool could be heated to varying degrees during its life
and that could change its level of heat treatment without leaving much
evidence of what had happened. (I looked this up on wikipedia and they
said that E isn't changed by heat treating.)
I recall seeing E listed as 30,000,000 psi for steel, but in our
industry it is commonly used as 29,000,000 psi. (I thought I had read
somewhere that steel alloys could vary in stiffness by 6 or 8 % from
max. to min., but I couldn't find it again with a little bit of searching.)
>> E for steel and steel
>> alloys is in a
>> fairly narrow range.
> Ok, my mistake. I thought work hardening, etc. would change the Young's
> modulus slightly, but I guess not. I wonder then, how it is that old
> bourdon-tube gauges typically change scale as well as zero.
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