The instantaneous temperature rise in the contact zone caused by friction and sliding as each tooth pair passes through mesh. Added to the bulk temperature of the gear, it gives a contact temperature that is compared with a critical value for the lubricant to judge scuffing risk. It peaks at the tooth tips and roots, where sliding velocity is greatest.
Flash temperature at the pinion tip is over the oil's scuff limit, add tip relief or go to a heavier EP oil.
Also heard as
- Blok flash temperature
- flash temp
Related terms
Scuffing
Sudden adhesive damage where tooth surfaces weld and tear apart because the oil film broke down.
Tip relief
A slight removal of material near the tooth tip so each tooth enters mesh smoothly under load.
Lambda ratio
Oil film thickness divided by combined surface roughness, showing how well the lubricant separates the teeth.