Equation to convert Toughness in KU in KV ? 1

[stanislasdz]

Please is there any equation to convert KU toughness in KV ?

 

[metengr]

stanislasdz;
There are no such correlations that I have seen. The Charpy KV and KU refer to notch geometry. There is no reason to make them equivalent for comparison. They must be reported as separate test results with their notch geometry.

 

[TVP]

metengr is correct-- there is no conversion of KU to KV. The geometry is different, so the results are different.

 

[stanislasdz]

Thanks guys

 

[salmon2]

I was wondering about the same thing. To be safe, use only one or do not mess them together. I have been using v-notch only

But really are they different? I will be interested to know how much difference if any. Because the notch serve as the stress raiser and help initiate the fracture, but very small energy go into that I think. The majority of energy should be the energy to propagate the fracture throughout the cross section.

 

[metengr]

salmon2;
Yes, the results will be different for notch geometry. You are confusing fracture toughness with impact energy testing in your post above. How do I know this, I had a machine shop improperly machine notched specimens and there were significant differences in results.

 

[salmon2]

Thanks, metengr. So a dramatic portion of energy in impact toughness test goes into initiating the crack? If that is true, of course, different geometries matter a lot.

Hi taking away from this discussion: is there any difference between Charpy and Izod test? Any correlation if any difference?

 

[metengr]

salmon2;
Review the paper below, it compares Izod and CVN testing.

http://nvl.nist.gov/pub/nistpubs/jres/104/6/j46sie.pdf

 

[salmon2]

metengr, thanks a lot for directing me to the interesting paper.

Now I will try to digest your comment "You are confusing fracture toughness with impact energy testing...".