FF-S-85D
3.1.3.2 Optional alloy steel. The optional alloy steel shown in Table I shall
have the same chemical composition as grade 8 conforming to the requirements of
SAE-AMS-STD-66 except that it shall be hardened sufficiently to a minimum oil
quench Rockwell hardness of C50 at the center of the threaded section, one
diameter from the end of the cap screw.
3.1.3.3 Alloy steels. Alloy steels shall be oil-quenched and tempered at a
minimum temperature of 800°F.
Corrosion resisting steels.
3.1.4
3.1.4.1 Austenitic. Austenitic corrosion resisting steel screws shall be
manufactured from 300 series corrosion steel as specified in SAE-AMS-STD-66 and
meet the mechanical properties specified in 3.2.2.1. Cap screws of NASM35307 and
NASM35308 shall be made in accordance with the specification.
3.1.4.2 Ferritic and martensitic. Ferritic and martensitic corrosion resisting
steel cap screws shall be manufactured from a steel composition such as steel
numbers 410, 416, and 430 as specified in SAE-AMS-STD-66 and meets the mechanical
properties specified in 3.2.2.2. Cap screws of NASM51099, NASM51100, NASM51109,
and NASM51110 shall be made in accordance with the specification.
3.1.5 Non-ferrous material. Non-ferrous cap screws shall be manufactured from
alloys specified in Table IA (see 6.2). Cap screws of MS35309, MS35310,
MS35311, and MS35312 shall be made in accordance with the specification.
3.1.5.1 Stress relief. Cold worked naval brass screws shall be stress relieved
by heating the screws to a temperature of 600ºF, and holding at that temperature
for a minimum of one hour.
3.1.6 Self-locking element.
Non-metallic, self-locking elements shall be in
accordance with MIL-DTL-18240.
Mechanical properties.
3.2
3.2.1 Steel. Grades and mechanical properties of low carbon, medium carbon,
alloy steel, and optional alloy steel cap screws shall conform to Table I, as
applicable (see 6.2).
Corrosion resisting steel.
3.2.2
3.2.2.1 Austenitic. Unless otherwise specified in the invitation for bids,
contract or order, mechanical properties of austenitic corrosion-resisting steel
cap screws shall conform to the following for diameters through 5/8 inch:
a.
Ultimate tensile strength
80,000 p.s.i. min.
b.
Yield strength (0.2 percent offset)
30,000 p.s.i. min.
c.
Rockwell Hardness
B80 min.
d.
Elongation
30 percent min.
e.
Reduction in area
40 percent min.
For diameters over 5/8 inch, ultimate tensile strength shall be 70,000 p.s.i. min.
and have a hardness of Rockwell B74 min.
6
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