The carbon steels listed in the table below were soaked at 1000 ˚C for 1 hour to form austenite and were cooled slowly, under equilibrium conditions to room temperature. Refer to the Fe-Fe3C phase diagram to answer the following questions for each of the carbon steel compositions listed in the table below:
(a) Determine the amounts of the phases present;
(b) Determine the C content of each phase; and
(c) Plot the C content of pearlite, α, and Fe3C versus yield strength. Based on the graph, discuss the factors influencing yield strength in steels with < 1% C.
Carbon %Yield Strength (MPa)
0.2 ................................. 295
0.4 ................................. 353
0.6 ................................. 372
0.8 ................................. 376
0.95 ............................... 379