Normalization of Subsize Charpy results 2

[Guest102023]

I frequently encounter Charpy impact energy reported as J/cm**2. I assume this is based on the fracture area and not the overall area of the test specimen. I am attempting to normalize data from '2.5t' specimens to a result for a full size specimen (10 x 10 mm, with 2 mm notch depth, leaving 0.8 cm fracture area). Again I am guessing '2.5t' indicates a 2.5 mm thick specimen.
Someone please clarify!

Note this is not a question about test temperature compensation (as in ASME VIII-1, UG-84).

 

[Guest102023]

I think what I am actually asking is:

how is J(ft-lbf) related to J/cm**2 (ft-lbf/sq.in.) for standard and subsize Charpy specimens?

 

[ulyssess]

J/cm**2 is related to the nominal cross section below the notch.
Charpy-V: value in J/cm**2 = value in J divided by 0.8
27 J = 34 J/cm^2
Charpy-U: value in J/cm**2 = value in J divided by 0.5
These relations are valid for all specimen (standard or reduced-size section).
The indication in J/cm^2 or ft-lbs/sq.in. is not in conformance with actual standards like ISO 148-1 or ASTM A370.

 

[Guest102023]

Thanks ulyssess, you've confirmed my suspicion that J/cm**2 is non-standard. I found no reference to that in ASTM A370 and other documents.