The document discusses the transformation of austenite upon heating and cooling in steels of various compositions. It addresses the microstructures that form from austenite decomposition such as pearlite, bainite, and martensite depending on the cooling rate. Time-temperature-transformation diagrams are presented showing the different phases that form under continuous cooling conditions or isothermal transformations. Factors that influence austenite decomposition and transformation such as alloy content, carbon content, grain size, and cooling rate are also examined.
