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Old 09-20-2006, 06:27 PM
Chris Meyer Chris Meyer is offline
Steel Addict
 
Join Date: Aug 2005
Location: Connecticut
Posts: 263
Tim Zowada's "Bending and busting steel" demo, Ashokan 2006

At the 25th annual New England Bladesmiths? Guild seminar at the Ashokan field campus of SUNY, Tim Zowada gave a demonstration entitled ?Bending and busting steel.? Tim used a machine that he designed and built to show to demonstrate Young?s Modulus (aka Modulus of Elasticity) and to show the difference in breaking points between heat treated and annealed pieces of steel. The machine uses a hydraulic jack to bend pieces of steel around a fulcrum, with a strain gauge to monitor the force necessary to make the bend, and a dial test indicator to assess the amount of permanent curve (if any) the steel acquires.

Tim?s demonstration proved that it takes much more force to bend a fully hardened piece of steel until it permanently deforms, than it does to do the same to unhardened steel of the same material and size. If I recall correctly, it took over 425 ft/lbs of pressure to deform the hardened piece, but only a little over 100 ft/lbs for the annealed piece. If anyone who was there recalls the exact numbers, please post them.

For reference, Kevin Cashen has stated; Modulus of elasticity (also called "Young's modulus) is the slope of the stress/strain line at stresses less than the yield strength. (This number will be virtually identical for any steel regardless of composition or heat treatment.)



Tim Zowada


Tim?s contraption.



Applying some force.



Bending the steel.




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