BAAE 2010 - Iron Carbon Equilibrium Diagram PDF

The Iron Carbon Equilibrium Diagram By : Group 2  Meet Group 2: 01 Anjali Ragbir 02 Cristian Garcia 03 Chénicqwa Bain 04 Yzabelle Morris  Project Overview By the end of this presentation, you should be able to: Understand the Iron-Carbon Diagram I...

The Iron Carbon Equilibrium Diagram By : Group 2  Meet Group 2: 01 Anjali Ragbir 02 Cristian Garcia 03 Chénicqwa Bain 04 Yzabelle Morris  Project Overview By the end of this presentation, you should be able to: Understand the Iron-Carbon Diagram Identify the different phases of iron in this diagram. Identify the varying changes in the structure based on the rate of cooling. Describe the changes in the grain structure as the temperature and carbon content increases. Identify important points, regions, and transitions in the diagram. What is an Iron-Carbon Phase Diagram? Allows the prediction of a compound's properties depending on the carbon content and how the material it is heated and cooled. Consists of two axes: temperature on the y-axis and percentage of carbon by weight on the x-axis. Phases of the Iron Carbon diagram Alpha (α) Iron/Ferrite Phase Gamma (γ) Austentite Phase Cementite Phase Delta (δ) ferrite Phase Ledeburite Phase Pearlite Phase Martensite Phase The Iron-Carbon Equilibrium Diagram  Points to Note Eutectoid Point Eutectic Point The point at which The point at which liquid austenite turns into iron and carbon solidify into pearlite ledeburite. Occurs at around Occurs at 1148°C and 4.3% 800°C and 0.8% carbon concentration carbon. The Iron-Carbon Equilibrium Diagram  Key Terms to Understand Face-Centred Cubic Structre Body-Centred Cubic Structre Atoms organised in a Atoms organised in a cube. cube. Each corner of the cube has Each corner of the cube an atom. has an atom. Each face of the cube has an A single atom in the atom in the centre. centre Advantages of FCC and BCC Face-Centred Cubic Structre Body-Centred Cubic Structre Atoms organised in a Atoms organised in a cube. cube. Each corner of the cube Each corner of the cube has an atom. has an atom. Each face of the cube has A single atom in the an atom in the centre. centre Key Terms to Understand Grains/ Grain Structure The structure of a metal is The grain structure of a metal made of individual structures varies based on: called grains. composition of the metal Grains form when the the way in which the developing crystals of a metal is forged. cooling metal are confined by eachother. The Iron-Carbon Equilibrium Diagram The Phases of Iron  Alpha (α) Fe/ Ferrite Ferrite is an iron that contains a small amount of carbon. At room temperature, ferrite is magnetic, relatively soft and ductile. It has a body-centred cubic structure.  Alpha Ferrite α-ferrite forms by the slow cooling austenite when the temperature drops below 912°C. As it is cooling, its carbon solubility decreases It absorbs a maximum of 0.025% of carbon at the eutectoid temperature of 727 C. Ferrite has a relatively coarse grain structure, which can vary based on cooling rates.  Gamma Austenite Austenite is formed when ferrite is heated above 912°C. As the temperature increases up to 1394°C, austenite becomes stable. The body-centred cubic structure transforms into a face-centred cubic structure.  Gamma Austenite Austenite has 2.1% carbon at 1147°C y-austenite is non-magnetic, soft, and ductile. Austenite grains are uniform and fine, especially when formed at higher temperatures or during rapid cooling.  Delta Ferrite Delta Ferrite only exists at temperatures above 1394°C. Delta Ferrite (δ-Fe) forms at high temperatures during the solidification of iron and exists mainly in specific alloying conditions As molten iron cools, it may first form delta ferrite if the cooling is gradual enough.  Delta Ferrite Delta Ferrite has a solubility of 0.1% carbon. It has a body-centred cubic structure. The grain structure of delta ferrite is coarse due to its formation at high temperatures, which influences the formation of larger grains. It remains stable at high temperatures, providing structural integrity during processes like casting.  Cementite Cementite is a hard and brittle intermetallic compound made up of carbon and iron. It is found in hypereutectoid steels with a carbon content > 0.76% Cementite forms along grain boundaries before pearlite transformation. image showing cementite in 9310 alloy steel Its structure is crystalline and at most times forms in discrete particles or continuous networks  Cementite Properties include: Profound Hardness thus enhancing wear resistance Provides significant strength to steels but reduces ductility Due to the extreme hardness and resistance of Cementite, it can be applied to various industries to be used in the manufacture of high-carbon steel, wear resistant parts and cutting tools.  Pearlite This is a eutectoid mixture of ferrite (α) and cementite (Fe₃C). Pearlite is formed at 0.76% carbon when steel cools below 727°C. It is made up of a complex structure of alternating layers of ferrite and cementite. There are two main types: Coarse Perlite Fine Pearlite Image showing microstructure of pearlite steel  Pearlite Coarse pearlite is formed during slow cooling, with widely spaced layers Fine pearlite forms in the process of fast cooling, with tightly packed layers Properties: Retains ductility more than cementite alone Hardness increases with thinner finer layers Provides a balance of strength and toughness within steels  Pearlite The application of Pearlite can be seen used in structural steels, industrial, machinery and automotive gears as well as, railway tracks due to its toughness and strength.  Ledeburite Ledeburite is formed when austenite solidifies with a carbon content of approximately 4.3% during the cooling process. Ledeburite is made up of 2 primary phases, cementite (Fe₃C) and austenite (γ-Fe) it forms during the eutectic solidification process in the iron- carbon system where the liquid phase solidifies into a two-phase structure of cementite and austenite.  Ledeburite When heating ledeburite above 272°C it may transform into austenite as the cementite is dissolved heating may result in grain growth which may decrease the hardness and improve ductility slow cooling may result in a finer grain structure which may form pearlite with the presence of cementite rapid cooling may not provide enough time for austenite to turn into pearlite, this may result in a brittle substance.  Liquid phase In the iron-carbon diagram, the liquid phase exists at high temperatures above 1130°C, where the alloy is fully molten. The liquid phase can accommodate varying amounts of carbon, up to about 4.3% in cast iron. As it cools, the liquid begins to solidify and can form different microstructures  Liquid phase Depending on the cooling rate and carbon content. The behaviour of the liquid phase is crucial for casting processes and influences the final properties of the solidified material.  Key Regions Steel Hypoeutectoid Steels (0.02 - 0. 76% Carbon) Eutectoid Steels (0.76% Carbon) Hypereutectoid Steels (0.76- 2.14% Carbon)  Key Regions Cast Iron Cast Irons (2.14% – 6.67% Carbon) Summary  Sources BorTec. (2023, January 24). Iron-Carbon-Phase-Diagram explained » BorTec. https://bortec-group.com/glossary/iron-carbon-phase- diagram/#:~:text=The%20AHIECF%20polyline%20is%20called,cementite%20(Fe3C). Plieth, W. (2008). Corrosion and corrosion protection. In Elsevier eBooks (pp. 291–321). https://doi.org/10.1016/b978-044452792-9.50012-9 The Iron Carbon Phase Diagram. (n.d.). https://www.tf.uni- kiel.de/matwis/amat/iss/kap_6/illustr/s6_1_2.html Velling, A. (2024, January 26). Iron-Carbon Phase Diagram Explained. Fractory. https://fractory.com/iron-carbon-phase- diagram/#:~:text=The%20carbon%20in%20iron%20is,and%20%CE%B4%20phases%20 of%20iron.  Sources George Gray. (2020, April 7). Heat Treating : Metal & Alloy Structures - Iron-Carbon Phase Diagram (VIDEOCLIPS) [Video]. YouTube. https://www.youtube.com/watch? v=tYk5NMylHc0 tec-science. (2023, October 1). Iron-Carbon Phase Diagram | Creating | Steel | Cast Iron | hypo-eutectoid | hyper-eutectoid[Video]. YouTube. https://www.youtube.com/watch? v=b581J_SmCM4 Does Anyone Have Questions?  Questions 1. What is the eutectoid Point? 2. What is the difference between alpha ferrite and delta ferrite? 3. Which phase has a face-centred cubic structure? 4. What is the importance of the Iron-Carbon Diagram? Thank You