ANS:A - spherodising

To improve the machinability of steel, it is generally subjected to spheroidizing. Spheroidizing is a heat treatment process used to improve the machinability of steels, particularly high-carbon steels. In this process, the steel is heated to a temperature below the critical range and then held at that temperature for an extended period. This allows the cementite (Fe3C) in the microstructure to decompose into small, rounded particles, known as spheroids. These spheroids are dispersed in a matrix of ferrite, which results in a softer and more ductile material. The spheroidized steel is easier to machine due to reduced tool wear and improved chip formation.