TM 1-1500-204-23-6
Table 2-1. Bolt and Screw Markings - CONT
Classification or
Marking
Material
Physical characteristics
specification
Steel, nickel
TS: 125,000 psi min up to
AISI 4340, grade L43
chromium
4-inch dia inclusive
ASTM A320
molybdenum
TS: 125,000 psi min
MIL-S-1222
1/4 inch to 2-1/2 inch dia
RH C25-34
TS: 115,000 psi min
over 2-1/2 inch dia
RH. C22-34
Alloy steel
125,000 to 145,000 psi
NAS380
NAS1347
Close tolerance
Close tolerance shank
and/or head
NAS380
Close tolerance shank
and/or head, high strength
160,000 to 180,000 psi
NAS380
Alloy
Close tolerance shank
and/or head, 125,000
to 145,000 psi
NAS380
Rolled threads after heat
treatment
NAS380
Aluminum alloy
TS: 62,000 psi min
NAS380
MIL-13-6812 (AL-24)
Aluminum alloy 2024
TS: 62,000 psi min
MIL-S-1222 (2024)
in T4 temper
1/4 inch dia
and over
Aluminum alloy 6061
TS: 42,000 psi min
MIL-S-1222 (6061)
in T6 temper
1/4 inch dia
and over
2-14
