Page 308 - Root Cause Failure Analysis

296 Root Cause Failure Analysis

fretting corrosion Surface damage usually in an air environment
between two surfaces, one or both of which are
metals, in close contact under pressure and
subject to a slight relative motion; also known as
chajng corrosion.
friction Resistance to sliding, a property of the interface
between two solid bodies in contact. Friction
wastefully consumes energy and wear changes
dimensions.
full-fluid film The ideal state of lubrication where the film
remains thick and prevents contact between the
surface peaks, which is apparent in a
microscopic examination of two surfaces; also
referred to as thick-jilm lubrication.
fuse An expendable device for opening an electric
circuit when the current therein becomes
excessive. The device contains a section of
conductor that melts when the current through it
exceeds a rated value for a definite period of
time.
Disk or wheel with teeth around its periphery,
either on the inside edge (i.e., internal gear) or
on the outside edge (Le., external gear), used to
provide a positive means of power transmission.
gearbox The gearing system by which power is
transmitted from the source to the rotating shaft
or axle.
gland A device for preventing leakage at a machine
joint, as where a shaft emerges from a vessel
containing a pressurized fluid; also referred to as
a packed-stufJing box.

hard blue A temporary coating used on mating parts to
evaluate fit and wear patterns.
head The height of a column of fluid necessary to
develop a specific pressure.
hydraulic Operated or effected by the action of water or
other low-viscosity fluid.

hydraulic curve A plot with total dynamic head as the vertical
axis and discharge volume or flow as the
horizontal axis.