Youngs Modulus

[SSavage]

When purchasing bolting we request the Youngs modulus as part of the mechanical testing. We have found the results vary between 150000 and 207000 MPa for carbon steel bolting purchased to ISO 10.9 and 8.8.
All other mechanical testing results are satisfactory.
Can anyone please explain such a variation?

 

[CoryPad]

My guess is insufficient stress/strain resolution or fixture alignment problems in the testing apparatus. The elastic region is very small and allows for large modulus problems. You can verify elastic modulus by other methods, such as ultrasound, beam bending, etc.


Cory

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