lõikeriista (lõikuri) kulumiskõvera normaalkulumistsoonile järgnev tsoon, kus kulumine järsult kiireneb (vrd normaalkulumistsoon, sissetöötlustsoon), the tertiary region of cutting tool wear in which cutting temperatures are high, and the general efficiency of the machining process is substantially reduced (compare: steady-state wear region, break-in region)