Subsized Charpy V Notch Values

[bulldog2002]

We have customer requirements that state we need to achieve CVN values of 27j @ -50 on weldments. Upon testing our weldments a testing lab used subsized samples (5mm x 5mm x 20mm), is there a mathmatic way to correlate the subsized CVN results back to a standard size sammple (10mm x 10mm x 20mm).

 

[metengr]

Look here;

http://www.twiprofessional.com/content/ksplm002.html

 

[salmon2]

I am not aware of a math model for this. You can expect that the min will be more than half of 27j because subsize Charpy tends to be more ductile than full size just like plane stress case. By the way, the full size should be 10x10x55mm.

 

[salmon2]

The best way to find out is to refer your design code or your customer. Last resort: ASTM A370 Table 9 specifies 14J for half size which is equivalent to 27j of full size. This is pretty much a linear correlation and a lot of codes differ from this depending on application.

 

[bulldog2002]

Thank you both for your input and knowledge, both were a great help.

And yes I was confused on the standard size.

 

[Guest102023]

If it is for Code procedure qualification (or production test blocks) you need to follow that. For example, UG-84 in Section VIII-D1. The penalty for subsize samples (less than 80% IIRC) is applied as a reduction in test temperature.

For carbon steels at that temperature, there is a substantial penalty for specimens that are 50% of full size.