ASTM E8 and 316L

[matkenmd]

For ASTM A240 thick, hot rolled, annealed plate UNS S31603 (316L)

What material issues may cause a properly run ASTM E8 to report an estimated Elastic Modulus (Youngs) significantly lower than expected? (28-31Mpsi)

What testing issues may cause a good piece of material to show a very low modulus? How common is this?

Looking at the shape of the developed stress-strain curves, what can one tell to help explain a large deviation in modulus?

Yield and Ultimate strengths are within spec. Chemistry and Hardness are nominal.

 

[CoryPad]

Elastic modulus determination via tension testing can be difficult. Testing equipment and procedure are more likely the cause(s) than material properties. Things like strain rate, electronics sampling rate, specimen and fixture alignment, preloaded vs. slack specimens, the list is large.

 

[EdStainless]

And the mechanical testing issues only get worse with low strength high ductility metals. In a well run tensile curve for 316 there is almost no straight portion to use, add in a little slack or zero offset and you can get about any number imaginable for modulus.

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