GEARENCH U120-12 PETOL HYDRA-TORK - Manual (Page 9)

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Abrasives - Accelerated wearing and scoring of the articulating chain members (pins
and plates) may occur, with a corresponding reduction in chain strength. Due to
inaccessibility of the bearing surfaces (pin surfaces and plate apertures), wear and
scoring are not readily noticeable.
These conditions, when coupled with normal chain wear and inherent residual stress
(normally in the chain as constructed), can result in environmentally assisted failure. It is
impossible to predict chain life under complex conditions, as the degree of hostility and its
effects are dependent on many variables such as temperature, time of exposure, concentration
of corrosive atmosphere or medium, degree of abrasive wear, etc.. Establishing the degree
and frequency of unpredictable dynamic loading is also difficult.
Normal Life Expectancy
A leaf chain's normal life expectancy can be expressed as a maximum percent of elongation.
This is generally between 2% and 3% of pitch. As the chain flexes back and forth, the
bearing joints (pins and inside link plates) gradually wear from articulation. As with all steel
bearing surfaces, the precision hardened steel joints of leaf chain require a constant film of
oil between mating parts to prevent wear and to resist corrosion.
Lubrication
One of the most important but often-overlooked factors is adequate lubrication. In addition
to reducing internal friction, maintaining a film of oil on all chain surfaces will inhibit rusting
and corrosion, This is important as corrosion of highly stressed, hardened steel chain
components can cause a major reduction in the load capacity of leaf chain and result in link
plate cracking.
Protection from corrosion is important in storage as well as in service. The factory lubricant
applied to PETOL CHAIN is a "Fingerprint Neutralizing Water-Displacing Corrosion
Preventative". This is an excellent rust and corrosion inhibitor for chains in storage. When
installing these chains new, do not attempt to steam clean or degrease this lubricant. A grade
of SAE 30 or 40 weight, nondetergent motor oil should be used as supplemental lubricant
and a film of this oil should be maintained on all surfaces and internal bearing joints. Also,
do not attempt to paint new chains. Though painting may help inhibit corrosion, it will seal
off critical clearances and restricts oil from reaching the pin surfaces where it is needed for
good joint lubrication.
When operating in dusty environments, lubricated chains will accumulate a paste-like
buildup of grime. At periodic intervals, this buildup should be removed by cleaning and the
chain should be immediately relubricated. Do not use caustic or acid type cleaners; use a
stiff brush and a certified safe petroleum base solvent.