MIL-DTL-83420M
4.4.7.1 Use of acoustic, electronic device for first wire break test. The load shall be
increased to 80 percent on the test specimen. If no ping (see 6.4.8) is heard, the specimen has
passed the test. If one or more pings are heard, the wire rope specimen shall be unraveled and
the broken wires shall confirm failure of the specimen. If no broken wires are found, the
specimen has passed the test.
4.4.8 Protective coating.
4.4.8.1 Tin or zinc coating, composition A.
4.4.8.1.1 Preparation of specimens. For qualification, three specimens not less than 12
inches long shall be cut from the wire before the wire rope is fabricated. These specimens shall
be cut from each size of wire to be used in making each lot of wire rope. Optionally, three
12-inch samples of the wire rope may be cut off and used for specimens.
4.4.8.1.2 Tin-coated wire. The weight of tin coating on samples of tin-coated wire shall
be determined by first selecting a sample of the coating, weighing the sample, establishing the
percentage of tin present through the use of atomic absorption, and then multiplying the sample
weight by the percent of tin present (as determined by the atomic absorption).
4.4.8.1.3 Zinc-coated wire. The weight of coating on samples of zinc-coated wire shall
be determined in accordance with ASTM A 90/A 90M.
4.4.9 Low temperature flexibility for type II, composition A and B. The jacketed wire
rope for qualification testing shall be subjected to -65 °F (-54 °C) for a period of 24 hours in a
straight position. After this time and while still at the specified temperature, the sample shall be
evenly and uniformly bent over a test sheave with the same dimensions as the endurance sheave
for the particular size wire rope. Bending shall be accomplished in a period of not less than 8
seconds and not more than 12 seconds, and the wire rope shall be bent at least 180 degrees in the
groove of the sheave. After flexing, straighten the wire rope out and allow to warm to room
temperature in four to six hours, then examine the flexed area under a magnification of 20 x
power. There shall be no evidence of cracks or separation of the nylon jacket from the wire
rope.
4.4.10 Resistance to fluids on type II, composition A and B. For qualification testing,
totally immerse a separate 3-inch unsealed length of nylon jacketed wire rope in each of the
fluids listed below for four hours. Remove, wipe dry, and record appearance of each one of the
specimens. Deleterious effects such as softening, cracking, or separation shall be cause for
rejection. A separate test specimen shall be used for each fluid test.
a.
MIL-PRF-5606
Hydraulic fluid
b.
MIL-DTL-5624
Jet fuel JP-4 and JP-5
c.
MIL-PRF-7808
Lubrication oil
d.
SAE AMS 1424
Deicing/Anti-icing fluid
e.
MIL-H-19457
Hydraulic fluid (skydrol 500A, or equivalent)
f.
MIL-PRF-87937
Cleaning compound
14
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business