Perform phase analyses for a highcarbon steel with the carbo

Perform phase analyses for a high-carbon steel with the carbon content of 1 wt%, for (a) 2000 °F; (b) 1400 °F; (c) 1333 °F + ?T; and (d) 1333 °F - ?T; (e) Describe the detailed phase transformation behaviors of the steel when we slowly decrease the temperature from 3000 °F to room temperature; i.e. at what temperature what happens.

Iron/Carbon Alloy Phase Diagram Temperature (F) Temperature (C) L = Liquid y= Austenite = Ferrite = Delta Iron 3000 F 2800 2720 S 2600 2552 2400 1539 1492 CM begins to solidify 1400 Primary Austenite begins to solidify Austenite in Liquid 2200 L+ Fe C 2055 F Austenite Solid Solution of I 130 Carbon in Gamma Iron 1800 Austentite, Ledeburite and Cementite I Magnetic Point 1 (1414 F) 910 CM y-Fe,c 1600 Austenite to Pearlite i Cementite and I Ledeburite-760 1400 1333 F 1333 F 723 1200 Pearlite and Cementite 0.025 Pearlite Cementite, Pearlite and transformed Ledeburite and Ferrite + Fe3C 1000 410---_ eanetic Change of Fesg -210 6.67 0.008% 4.3I 0 50% 083% 1% 3% 4° 5% 6% 6.5% Hypo-Eutectoid Hyper-Eutectoid CAST IRON- Carbon Content Present (by weight)

Solution

(a). At 2000⁰F there would be one phase present for 1% wt of carbon which is Austenite.

(b). At 1400⁰F there would be two phases present for 1% wt of carbon which are Austenite and cementite.

(c). In this case there would be two phases present- Austenite and Cementite.

(d). In this case there would be two phases present- Pearlite and Cementite.

(e). (NOTE- To answer this part we must have this exact phase diagram so that we can see the point of intersection of the vertical line with the curve so that we can determine the exact temperature at which different phases start to form. I don\'t have this exact phase diagram with me so I am writing the accurate procedure to solve this part with approximate temperatures at different points which I could see from the phase diagram.)

If we draw a vertical line in the phase diagram corresponding to 1% wt of carbon, it will cut the graph at various points. Now on this vertical line at 3000⁰F we can see from the phase diagram that the only phase present is Liquid. Now as we move down on this line i.e when the temperature decreases, we see that the Austenite in Liquid phase starts at nearly 2700⁰F and this phase continues to exist till 2400⁰F. At 2400⁰F, only solid Austenite phase remains and this phase continues to exist as we decrease the temperature upto 1420⁰F after which two phases start to form which are- Austenite and Cementite. The above two phases continue to exist as we decrease the temperature upto 1333⁰F. Further decreasing the temperature below 1333⁰F cause the formation of another two phases- Pearlite and Cementite and these two phases continue to exist till room temperature.