Impact Testing--Is conversion between Izod and Sharpy Possible?

John P McCarron

Registered
Hello Colleagues,

I have a challenge in relation to Charpy and Izod test results can a Charpy result be converted to an equivalent Izod result? I am receiving mixed messages the tests are totally different for test piece size, notch etc and i cannot see how they can be equivalent is there some sort of conversion table that I am not aware of?

I see on the internet that there is a formula that converts Izod results to Charpy but not Charpy to Izod and I not sure that the formula is valid for the Izod to Charpy value??

My thoughts are that if a material is tested by a mill and released via a Charpy Impact test result then that is a capability test performed on the material for release testing purposes. I cannot see how the value would be acceptable if the material specification requests the test to be performed to the Izod method?

Any thoughts on this would be greatly appreciated.

Best Regards,

John
 

Steve Prevette

Deming Disciple
Leader
Super Moderator
Any thoughts on this would be greatly appreciated.

Best Regards,

John

I suggest this is more of an engineering question than a lab KPI question. Here is a good article (well, advert) on the technical differences:
Impact Testing Izod and Charpy - Impact Solutions (impact-solutions.co.uk) , with a key drawing below. The geometries are quite different on the two tests. I'd be very wary of trying to determine equivalencies without a professional engineer opinion. My undergrad was in Civil Engineering so I do understand (and performed) the Charpy test, but must admit I had not heard of the IZOD test before.

Impact Testing--Is conversion between Izod and Sharpy Possible?
 

Jim Wynne

Leader
Admin
My thoughts are that if a material is tested by a mill and released via a Charpy Impact test result then that is a capability test performed on the material for release testing purposes. I cannot see how the value would be acceptable if the material specification requests the test to be performed to the Izod method?
I don't think there's a reliable conversion method, if for no other reason than there are different dynamics involved in the two methods. That being said, if you have specified one method or the other in your purchase order, and what you get is the wrong results, you should go back to the supplier and ask for the appropriate testing to be done. Don't accept the supplier's reference to conversion factors--they need to do what was specified.
 
Top Bottom