EVOLUTION OF MICROSTRUCTURE IN MICROALLOYED STEEL UNDER CONTINUOUS COOLING

The evolution of microstructure under continuous cooling is studied with the help of transmission electron microscopic observation. It is found that the phase transformation in microalloyed steel is mechanistically transient. It is also observed that at the intermediate cooling rate, some austenite is retained in the microstructure. The microstructural evolution in a microalloyed steel was studied for verification and it is observed at the cooling rate 20- 30oC/sec chunky austenite is present in the microstructure. This austenite aids in improvement of the toughness of the steel.