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Adhesive wear can be found between surfaces during frictional contact and generally refers to unwanted displacement and attachment of wear debris and material compounds from one surface to another. Two separate mechanisms operate between the surfaces.
Abrasive wear is caused by
particle contaminants in the lubricant. Particles may
originate internally due to poor quality control during the
manufacturing process. Particles also may be introduced from
the outside during servicing or through inadequate filters,
breathers, or seals. Internally generated particles are
particularly destructive because they may become
work-hardened during compression between the gear teeth. The
following guidelines should be observed to prevent abrasive
wear in gear units:
Remove internal contamination from new
gearboxes. Drain and flush the lubricant before initial
start-up and again after 50 hours of operation. Refill
with the manufacturers recommended lubricant. Install
new filters or breathers.
Use surface-hardened gear teeth, smooth
tooth surfaces, and high-viscosity lubricants. Maintain
oil-tight seals and use filtered breather vents,
preferably located in clean, nonpressurized areas.
Use good housekeeping procedures.
Use fine filtration for circulating-oil
systems. Filtration to 3 m (120 -in.) has proven
effective in prolonging gear life.
Unless otherwise recommended by the gear
manufacturer, change the lubricant in oil-bath systems
at least every 2500 hours or every 6 months.
When warranted by the nature of the
application, conduct laboratory analysis of lubricants.
Analysis may include spectrographic, ferrographic, acid
number, viscosity, and water content.