Scuffing
Scuffing turns up in 2 fields: tribology, gears. Here is what it means to the people in each one.
Scuffing in tribology
Sudden, severe adhesive damage where the oil film fails and sliding surfaces locally weld and tear.
A form of severe adhesive wear on gear teeth, cam followers and piston rings, triggered when the flash temperature in the contact breaks down the lubricant film. The surface shows a matte, torn band running in the sliding direction, often at the tip and root of gear teeth where sliding is highest. It can happen within minutes of an overload or a viscosity mix-up. EP additives, higher viscosity and smoother finishes prevent it.
"Tooth tips are scuffed on the first-stage pinion, somebody put a 150 in a box that calls for 320."
Scuffing in gears
Sudden adhesive damage where tooth surfaces weld and tear apart because the oil film broke down.
A failure in which the lubricant film collapses under high load, speed and sliding, so the metal surfaces bond and tear, leaving rough, dull bands of radial streaks in the sliding direction. It concentrates at tips and roots, where sliding is highest, and can happen within minutes of overload or lube failure. Contributing factors are flash temperature, oil viscosity and additives, surface finish and missing tip relief.
"Scuffing at the tips of every tooth, radial streaks, that's oil film breakdown, not fatigue, what did they fill it with?"