INTRODUCTION

Heat treatment is a process to control the mechanical properties of engineering materials by heating, cooling, and alloying the metal as per requirement. It deals with change in properties by alloying different elements to the metal at various temperatures. The various mechanical properties such as hardness, toughness, ductility, machinability, and grain refinement are controlled by heat treatment process. We deal only with steel and its properties. Some of the basic heat treatment process such as hardening, normalizing, annealing, tempering, with iron–carbon diagram and time–temperature–transformation diagram have been introduced.