10) What is the name of the heat treatment process, where the metal is heated and quenched in water or oil?

11) Which is a kind of surface hardening process?

12) How much time is allowed normally in soaking zone for a 10mm thick metal piece while hardening?

13) What is colour of a metal piece when heated to 250 Degree C while doing the tempering process?

14) What is the purpose of tempering a steel?