oil-harden

[ oil-hahr-dn ]
/ ˈɔɪlˌhɑr dn /

verb (used with object) Metallurgy.

to quench (steel) in a bath of oil.
Compare water-harden.

Origin of oil-harden

First recorded in 1900–05

British Dictionary definitions for oil hardening

oil hardening

noun

a process of hardening high-carbon or alloy steels by heating and cooling in oil Compare air hardening