The eyes of common perception do not see far The eyes of common perception do not see far. Too often we make the most important decisions based only on superficial information – Norma Cenva (unpublished laboratory notes)

Problem 10.14 List all phases that can be present in steels (do not include the alloy carbide phases or consider stainless steels); describe how each can be formed. AUS - heat above A1 FE - cool AUS slowly to below A1 CM - cool AUS slowly to below A1 MAR - quench to below ms (also - liquid & -ferrite)

Problem 10.14 For these phases, which can occur in: hypoeutectoid steels hypereutectoid steels a eutectoid steel AUS, FE, CM, MAR

Problem 9.55 Compute fractions of proeutectoid ferrite and pearlite for Fe-0.25C alloy. Why was this problem assigned? Understand the terms proeutectoid ferrite and pearlite Learn to use the equilibrium Fe-C diagram See that diagram tells amounts of microconstituents The concept is important; resulting nos. are not (as far as course is concerned)

Problem 9.55 Compute fractions of proeutectoid ferrite and pearlite for Fe-0.25C alloy. Gives proeut. FE fraction: (0.77-0.25)/0.75 = 0.69

Problem 9.55 Compute fractions of proeutectoid ferrite and pearlite proeut. FE fraction = 1

Problem 9.55 Compute fractions of proeutectoid ferrite and pearlite proeut. FE fraction = 0.25 proeut. FE fraction = 0

Problem 9.57 Total FE = 0.9, total CM = 0.1. Hypo or hyper? Why was this problem assigned? Use the terms hypoeutectoid, hypereutectoid Total FE, total CM? (where's the beef?) More contact with Fe-C diagram

Problem 9.57 Total FE = 0.9, total CM = 0.1. Hypo or hyper? Total FE = 0.9 = (6.67-x)/6.65 x = 0.68

Problem 10.14 Use TTT curves predict microstructures when steel is cooled as specified Why was this problem assigned? Understand TTT curves Connect cooling process with microstructure Recognize variety of microstructures possible

Problem 10.14 Use TTT curves predict microstructures when steel is cooled as specified ~ 2/3 P, 1/3 MAR Transformation of AUS not complete till almost 105 s

Problem 10.14 Use TTT curves predict microstructures when steel is cooled as specified Roughly 2/3 bainite + 1/3 MAR

Problem 10.14 Use TTT curves predict microstructures when steel is cooled as specified Tempered MAR