VideRime Staff asked 5 years ago
In a hardening process, the hypo-eutectoid steel is
a) Heated from 30°C to 50°C above the upper critical temperature and then cooled in still air
b) Heated from 30°C to 50°C above the upper critical temperature and then cooled suddenly in a suitable cooling medium
c) Heated from 30°C to 50°C above the upper critical temperature and then cooled slowly in the furnace
d) Heated below or closes to the lower critical temperature and then cooled slowly
