DEVELOPMENT OF SHORT MALLEABLIZING HEAT TREATMENT CYCLE

Abstract

Malleable iron is characterized by containing graphite in an aggregated or nodular shapes in the matrix of ferrite. It possesses strength at par with low carbon steels, making it suitable for wide range of applications like automotive parts, agricultural equipments, pipe fittings, valve components and couplers. Malleable iron is widely used due to its advantages such as excellent surface finish, good dimensional control, good machinability, better tool =life and it allows freedom of desi.gn along with good casting characteristics. But the main expenditure in manufacturing malleable iron castings is the long annealing- procedure involved. Various researches are going in this field to reduce the malleabalizing time by employing different addition and using alloying elements. The present investigation is an attempt to reduce the malleabalizing time. In this work an effort has been made to decrease the time required for first stage of graphitization by applying the process accelerated annealing in which malleable iron castings are subjected to hardening prior to graphitizing. annealing.