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MIL-A-46100D (MR)
w/INT. AMENDMENT 2
decarburization shall be removed from the areas where the tests are to be made. However,
no more that 0.060 inches shall be removed from the test area. Hardness tests shall be made
on the surfaces of pieces cut from the plate after heat treatment.
4.6.2.1 Rockwell hardness tests. For plates less than 3/16 inch in thickness, Rockwell - C
hardness tests (HRC) shall be substituted for HB tests. Tests shall be conducted in
accordance with ASTM El8 and the readings shall be converted to HB.
4.6.3 Charpy V-notch impact tests. At least four Charpy V-notch impact test specimens
shall be taken from the sample and shall be prepared and tested in accordance with ASTM
E23. Charpy V-notch impact test specimens shall be taken in both the TL orientation and in
the LT orientation from locations midway between the top and bottom surfaces of the plate
and at least 4 inches or 2T; whichever is less, from any quenched edge as well as outside
the heat affected zone of any thermally-cut edge. The largest attainable subsize Charpy
V-notch impact specimens shown in figure 7 of ASTM E23 shall be used.
4.6.4 Bend test. The bend test shall be conducted in accordance with ASTM E290 using
method Arrangement C.
4.6.5 Ballistic tests. Ballistic testing of armor plate shall be conducted at a Government test
facility specified in the contract or order (see 6.2). Testing shall be conducted in accordance
with the requirements of the appendix of this specification.
4.6.6 Ultrasonic examination.
4.6.6.1 Inspection equipment. The ultrasonic soundness inspection equipment shall
conform to ASTM A578.
4.6.6.2 Procedure. Unless otherwise specified (see 6.2), the ultrasonic examination shall be
carried out in accordance with ASTM A578 with the following exceptions.
(a) Scanning shall be continuous over 100% of the plate surface.
(b) Scanning rate shall be at a speed where recordable discontinuities can be detected.
(c) The testing frequency shall be a minimum of 2 megahertz (MHz).
(d) Any area within a plate where a discontinuity produces a continuous total loss of back
reflection accompanied by continuous indications on the same plane that cannot be
encompassed within a circle whose diameter is 1 inch shall be cause for rejection of that
plate. All discontinuities shall be evaluated using a frequency of 2 megahertz (MHz).
4.6.6.3 Certification of inspection personnel. Unless otherwise specified (see 6.2),
personnel performing ultrasonic inspection shall comply with the qualification
requirements of NAS 410 as determined by QSTAG 335 (see 6.11).
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