MIL-A-21180D
3.4.1.1.2 Soundness. Unless otherwise specified in the contract or order, the severity of the
discontinuities shall not be greater than that shown in Table II for the applicable quality standard
specified. Discontinuities revealed by the radiograph of the casting shall be matched to the
comparable ASTM E 155 reference radiograph for a particular discontinuity. The matching
reference radiograph indicates the relative severity of the discontinuity, and that number shall be
equal to or less than the number in Table II. Where "none" appears in Table II, none of the
applicable discontinuities shall be permissible in the castings.
3.4.1.1.3 Mechanical properties. Once conformance to Table II is established, conforming
castings shall exhibit mechanical properties meeting the applicable requirements of Tables III and
IV or as specified in the casting drawing, when tested in accordance with 4.5.4. Specimens for
the tension test shall represent as a minimum those locations subjected to high stresses, or
identified as critical, and other locations (see 4.4.2.4.2) containing the most severe discontinuities
within specified standards. From the latter locations specimens shall be removed when requested
by the purchaser (see 6.2.1). Castings which exhibit soundness and mechanical properties, both of
which are borderline, shall be cause for disapproval of foundry control.
3.4.1.1.3.1 Mechanical properties of large castings. Where the casting is large (over 100
pounds poured weight), specimen blanks shall be removed in accordance with 4.4.2.4.4.
Specimens shall be tested for compliance with Tables III and IV, or as specified on casting
drawing, as applicable. All specimens made from excised blanks or gates, or from integrally cast
test bars shall exhibit properties representative of the properties of locations within the casting
adjacent to those locations from which blanks for these specimens were removed.
3.4.1.1.4 Surface quality. Foundry control castings shall not contain cracks, cold shuts, or
foreign material in excess of that allowed by the applicable radiographic quality grade specified,
when inspected in accordance with 4.5.3. When specified (see 6.2.1), surface roughness in any
location shall not exceed the maximum specified for that location.
3.4.1.1.5 Electrical conductivity. When applicable, the foundry control casting shall meet
the requirement of 3.4.4.
3.4.2 Production castings.
3.4.2.1 Radiographic requirements. After the foundry practices of 3.2 have been established,
castings shall be radiographically inspected as specified in 4.5.2. Acceptance shall be by
comparison with the applicable standard set of radiographs contained in ASTM E 155 or with
other standards approved by the purchaser (see 6.6). Radiographic indications shall be identified
in terms of the discontinuities listed in Table II. Acceptance shall be made in accordance with the
grade specified on the engineering drawing (see 1.2.3). When no grade is specified, Grade C shall
apply.
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