STRUCTURE AND MECHANISM OF THE FORMATION OF GRANULAR BAINITE IN STEEL20KH2NACH

At the present time the structure of granular bainite is widely used i n heat treatment. The novel technologies include spheroidizing treatme nt of rolled stock from steel 20Kh2NACh. The composition of the steel provides a structure of granular bainite in rolled strips up to 10 mm wide with their cooling in still air from the temperature attained at the end of hot rolling. After a high-temperature tempering of the stri ps for 4 h the granular bainite transforms into granular pearlite whic h is optimum for cold forging. The available published data on the str ucture of granular bainite are insufficient for explaining the causes of the accelerated transformation. In this connection, it is interesti ng to investigate the phase composition, the microstructure, and the t ransformation mechanism of granular bainite.