MIL-W-14969 (MU)
Categories
Defects
Method of
Code No.
Inspection
Critical:
None defined.
4.3.3.1 Microexamination. - Major Defect - Code No. 01002
(see Dwg. 9238882). For ductile. iron, a test lug shall be cast
representing the last metal poured from each ladle treated with the
modularizing agent. The test casting and microexamination shall be
in accordance with ASTM-A-445. Failure of the test lug to conform
to the microstructure requirements of ASTM-A-445 shall be cause for
rejection of the castings from the ladle represented by the test lug.
4.3.3.2 Hardness Test
4.3.3.2.1 Ductile Iron Nose Casting Hardness Test - Major
Defect - Code No. 01003. - To insure compliance with the mechanical
properties requirements, each nose casting from a sample shall be
subjected to a hardness test with a Brinell Hardness Tester. The
sample, 10 per cent minimum, representative of extreme furnace
environment , shall be selected from each heat treat batch when a
batch type furnace Is used for final heat treatment. When a con-
tinuous type furnace Is used for final heat treatment, from which a
10% min. sample will also be selected, a heat treat batch will be
considered a quantity of castings not to exceed 4 hours production.
The castings which constitute the sample shall be collected at reg-
ular continuous intervals throughout the 4 hour cycle. The heat
treat batch thus constituted shall form the basis for selecting
castings for the tension test hereinafter prescribed. The test
shall be performed as specified in 4.4.2 using equipment in accord-
ance with 4.3.4.
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