The eutectoid phase transition in the iron carbon system takes place at 727 C. The three components in equilibrium at this temperature are Austenite, g, with the composition Fe - 0.77 wt % C, Ferrite, ...

However, the microstructure of each zone of weldment varies in shape, size and amount with changing the austempering temperature and holding time. In general, microstructure at 300 °C reveals needle ...