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Title:

Density of Shrinkage

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philr@selmetinc.com

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Added:

12/29/1999 10:56:56 AM

Message:

I'm in the middle of a debate concerning the interpretation of shrinkage using ASTM Reference Radiographs. With the surrounding metal in both the production and reference radiograph being 2.0 H&D and the shrink indication in the production film only half the size of the largest shrink in the ASTM film. My question is, if the density of the shrink on the production radiograph is somewhat darker than that of the referenced plate, is the indication then rejectable?

Posts:

Anonymous
Posted:
8/21/2000 10:56:42 AM
Post Subject: Density of shrinkage

When using the ASTM standards, they specifically tell you the density is not to be used for acceptance or rejection. See E446-98 paragraph 8.11. Density has always been an issue for discussion for the discontinuities but what if one void is filled with a substance and one void is all air, both the same size? You would reject the one for density but it is not truly any worse than the other. Discretion is always to be used by the interpreter when making assesments according to the casting reference radiographs but he should be fair and use the specs as intended and use the guidlines they spell out.
Anonymous
Posted:
8/15/2000 2:41:37 PM
Post Subject: shrink density

the answer does not lie in whether you get the same density onyour radigraph as the astm ref. The ref. is merely a size of discontinuity type reference at a specified sensitivety, IE 2-2t. You could use a different film and the density will vastly different but the flaw still be the same size. Remember that a radigraph is a 2d pic of a 3d object, andthe lost dimension is depth. Hope that helps... JH

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