9) Which is the suitable nitriding process for all alloyed and unalloyed steels?

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?