Abstract:
The absence of proper understanding and facilities for heat treatment, specifically surface
treatment techniques has retarded the development of tooi and die industry in Sri Lanka. Thus
there has been a growing interest among the local tool manufacturers and users for new heat
treatment techniques.
It has been shown that the surface properties for Dies and Moulds can be enhanced by
nitriding and this technique was first used in early 1920’s. Since then much development has
taken place and now the technique can be applied to a greater variety' of steels than it was
originally thought possible. However nitriding is still in its infancy as far as the local industry
is concerned.
Nitriding is basically the introduction of atomic nitrogen from a surrounding medium
into the surface of steel by diffusion. In contrast to most heat treatment procedures nitriding
changes both the chemical composition and the structure of the layer thereby enabling the
properties to vary in a wider range. Extreme hardness, retention of hardness at elevated
temperatures, improved fatigue strength and corrosion resistance are some of the properties
imparted by nitriding.
This paper describes the work carried out towards developing a suitable nitriding
technique adaptable by the local medium and small scale industries with due regards to
economy and safety aspects. It is expected to carry out industrial trials to assess the efficiency
of the proposed setup.
