Inspection slang for a frost-like matte area on a hardened surface where micropitting has started. Under a magnifier the frosted band resolves into countless tiny pits. On gears it often appears first in the dedendum of the pinion or near the tip, and it is worth photographing and trending because it can either stabilize or grow into macropitting.
Heard on the job
Couple of teeth have frosting below the pitch line, no pits yet, take photos and we'll look again next stop.
Also heard as
- frosted
- gray staining
Related terms
Micropitting
Fatigue damage made of tiny pits, about 10 to 20 microns deep, that turns gear and bearing surfaces dull gray.
Pitting
Rolling contact fatigue that leaves visible craters on gear teeth or bearing races.
Scuffing
Sudden, severe adhesive damage where the oil film fails and sliding surfaces locally weld and tear.