Answer Happy

Using Figure 10.40, the isothermal transformation diagram for a 0.45wt%C steel alloy, specify the nature of the final microstructure (in terms of the microconstituents present) of a small specimen that has been subjected to the following temperature treatments. In each case assume that the specimen begins at 845∘C and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenitic
a) Rapidly cool to 700 degrees C, hold for 100,000 s, then quench to room temperature. b) Rapidly cool to 650 degrees C, hold for 3 s, then quench to room temperature. a) all spheroidite, b) proeutectoid ferrite + pearlite + martensite a) proeutectoid ferrite, b) all spheroidite + pearlite + martensite a) all spheroidite, b) proeutectoid ferrite + pearlite a) spheroidite, b) pearlite + martensite