The document discusses various surface heat treatment and case hardening processes. It describes the purposes of these processes as producing a wear resistant hard surface, improving corrosion resistance and heat resistance, serving as an ornamental finish, and increasing the useful life of components made from low cost materials. It then lists and defines common processes like carburizing by adding carbon, nitriding by adding nitrogen, cyaniding by adding both carbon and nitrogen, carbonitriding by adding both carbon and nitrogen, and other processes like induction hardening and flame hardening. It further explains that nitriding is a process that diffuses nitrogen into the surface of a metal to create a case-hardened surface, and these processes are commonly used on low-carbon,

1. SURFACE HEAT TREATMENT
(OR)
CASE HARDENING
Prepared by
K.sengottaiyan

2. Purpose
 To produce a wear resistant hard
surface
 To improve corrosion resistance
 To improve heat resistance
 To serve as an ornamental finish
 To increase the useful life of the
component made from a low cost
material

3.  Carburising-by the addition of carbon
 1. PACK Carburising 2. LIQUID
Carburising 3.GAS Carburising
 Nitriding- by the addition of nitrogen
 Cyaniding- by the addition of both
carbon and nitrogen
 Carbonitriding- by the addition of both
carbon and nitrogen
 Induction Hardening
 Flame Hardening
 Vacuum and Plasma hardening.

8.  Nitriding is a heat treating process
that diffuses nitrogen into the surface
of a metal to create a case-hardened
surface. These processes are most
commonly used on low-carbon, low-
alloy steels. They are also used on
medium and high-carbon steels,
titanium, aluminium and molybdenum.