Using The Isothermal Transformation Diagram For A 0 45wt C Steel Alloy Figure 10 40 Determine The Approximate Percent 1 (189.4 KiB) Viewed 36 times
Using the isothermal transformation diagram for a 0.45wt%C steel alloy (Figure 10.40), determine the approximate percentages of the microconstituents that form the final microstructure of a small specimen that has been subjected to the following time- temperature treatments. In each case assume that the specimen begins at 845∘C(1550∘F), and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenitic structure. a) Rapidly cool to 250∘C(480∘F), hold for 103 s, then quench to room temperature. b) Rapidly cool to 400∘C(750∘F), hold for 500 s, then quench to room temperature.
c) Rapidly cool to 700∘C(1290∘F), hold at this temperature for 105 s, then quench to room temperature. d) Rapidly cool to 450∘C(840∘F), hold for 10 s, then quench to room temperature. e) Rapidly cool to 625∘C(1155∘F), hold at this temperature for 10 s, rapidly cool to 400∘C(750∘F), hold at this temperature for 5 s, then quench to room temperature. a) 100% martensite, b) 100% bainite c) 100% spheroidite d) 30% martensite, 70% bainite e) 42% proeutectoid ferrite, 58% fine pearlite a) 100% martensite, b) 100% bainite c) 100% spheroidite d) 100% bainite e) 100% fine pearlite a) 100% pearlite, b) 100% bainite c) 100% spheroidite d) 30% martensite, 70% bainite e) 42% proeutectoid ferrite, 58% fine pearlite a) 90% martensite, b) 80% bainite c) 70% spheroidite d) 30% martensite, e) 34% fine pearlite
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