MIL-DTL-14852D (AR)
4.4 Methods of inspection
4.4.1 Mechanical properties
4.4.1.1 Hardness. After final heat treatment but prior to
machining, the Brinell hardness test shall be performed on the
outside surface at the band seat location. The test shall be
performed using equipment and procedures as prescribed by ASTM E
10, except that a 5-second minimum dwell shall be used. A direct
reading hardness tester may be substituted for the Brinell scope
(micrometer microscope) type, provided that the same size
indenter ball and the same pressure is used and that 2000 body
forgings will have been tested by both units to establish
correlation. Continued correlation shall be assured by checking
the hardness value of one body forging each hour by measuring the
diameter of the indent with a Brinell scope, for comparison with
the dial reading.
4.4.1.1.1 Heat treatment lots. In order to determine
uniformity of heat treatment, each body forging in the heat
treatment lot (as defined by 4.3.1.1) shall be subjected to a
hardness test with a Brinell hardness tester or by any other
method of hardness testing approved by the procuring activity.
4.4.1.1.2 Stress relieved lots. To assess uniformity of
process, twenty-five cold shaped bodies from the first batch of
each stress relieved lot (as defined by 4.3.1.2) processed
through the stress relieved furnace shall be subjected to a
hardness test with a Brinell hardness tester or by any other
method of hardness testing approved by the procuring activity.
4.4.1.1.3 Tubing lot. When mechanical properties of the
tubing are altered by heat treatment or stress relief during
manufacture of components, the uniformity of process shall be
determined in accordance with 4.4.1.1.1 or 4.4.1.1.2 as
applicable.
4.4.1.1.4 Miscellaneous lots. Miscellaneous heat treatment
lots shall be subjected to a hardness test in accordance with
4.4.1.1.1. Miscellaneous stress relieved lots shall be subjected
to a hardness teat in accordance with 4.4.1.1.2.
4.4.1.2 Yield strength and percent elongation
4.4.1.2.1 Body. From the samples provided by the heat treat
or stress relieved lots two tension test specimens conforming to
the largest obtainable standard "R" type specimen, as prescribed
by ASTM E8/M8 shall be taken longitudinally from the opposite
sides of the body at midwall, in such a manner that the center of
the gage length of the machine test bar will fall in line
coincident with the center of the rotating band seat. The number
of specimens and their location are for the convenience of the
contractor and Government and shall not restrict the contractor
or Government from testing additional specimens at other
locations to determine that the mechanical properties of the
projectile body meet the drawing requirements. The criteria for
performing this test shall be prescribed in ASTM E8/8M; except
that the elongation shall be measured to the nearest thousandth
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