Question

Given a plain carbon steel which has 8 % primary (or pro eutectoid) carbide, determine both overall carbon content and ferrite content. a. Assume that the steel was at equilibrium just above the eutectoid temperature and then cooled immediately to 600°C and held for 5 seconds, then quenched. What microconstituents would there be in the structure and how much of each? (Assume the cooling behavior follows the TTT curve shown)

this is the TTT curve

Answer 1

9239 T 727°C Pro- eutectoid Carbide Topal 0,022% 0.77% 6.67% % wt Carbons 69 Co-0.022 Primary Carbide = 0,08 0.77-0.022 - Co=0.881 % Wt Carbon a => Carbon content Total ferente content Co 6.67 -0.081 6.67 -0.022 Mtotal- a 0.991 -99.17 Eutectoid ferrite = mtoru-a primary-a -0.991 - (1 - 0,08) a primary = 0,071 Carbide

800 * 100% Austenite a 600" 50% Austenite - 50% fine Pearlite 400 50% Fine Pearlite + 50% Bainite SOY Final constituents 50% Fine Pearlite + 50% Bainite.