(Solved): Using the continuous-cooling and isothermal transformation diagrams for a eutectoid Fe-C alloy sho ...

Using the continuous-cooling and isothermal transformation diagrams for a eutectoid Fe-C alloy shown below (this page and next), perform the following tasks. (a) Cool continuously at a rate of -85-90 °C/s from -760 to 300 °C and then hold at 300 °C for 3 hours. Estimate the amount of each constituent in the microstructure following this treatment. (b) If it is desirable to produce 25% of tempered martensite following the first step (i.e., the continuous cooling) in treatment (a), describe the subsequent steps to achieve this. (c) If a full (i.e., 100%) tempered martensitic microstructure is desirable, describe the conditions for achieving it in terms of both continuous cooling rate and sample size. (d) What treatment do you propose to do if a fully annealed steel is still too hard for processing (e.g.. forging)? Plot the microstructure after such a treatment, marking any dimension that is important.