Oct 03, 2018 compulsory,2 marks will be given from this iron carbon diagram theory in any exam. The ironiron carbide fefe3c phase diagram in their simplest form, steels are alloys of iron fe and carbon c. These diagrams define the regions of the stability of a phase which can exist in an alloy system under the condition of constant atmospheric pressure. Dmitri kopeliovich iron carbon phase diagram describes the iron carbon system of alloys containing up to 6. Conventionally, the complete fec diagram should extend from 100% fe to 100% carbon, but it is normally studied up to around 6. Conventionally, the complete fe c diagram should extend from 100% fe to 100 % carbon graphite, but it is normally studied upto 6. Timetemperaturetransformation ttt curves ttt diagram is a plot of temperature versus the logarithm of time for a steel alloy of definite composition. Iron carbon phase diagram, ttt diagram, cct diagram slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Iron carbon phase diagram iron shows a eutectic with carbon allowing for a lower melting alloy body centered tetragonal. Cast iron is an alloy of carbon and iron and other alloying elements e.
It can be seen that eutectic reaction takes place at 2065af. A study of the microstructure of all steels usually starts with the metastable ironcarbon fec binary phase diagram figure 1. Now in order for us to do that, lets go back and take a look at the ironcarbon phase diagram. Fe3c iron carbide called cementite because it is hard. Module 23 iron carbon system i lecture 23 iron carbon nptel hypoeutectoid steel, hypereutectoid steel, hypoeutectic white cast iron, on the basis of this diagram iron carbon alloys having less than 2. Oct 03, 2018 iron carbon phase diagram with detailed explanation. Nptel noc phase equilibria in materials nature and properties of ii mechanical engineering iron carbon equilibrium diagram metallurgy carbide phase example 1 22 because phase diagrams 1 binary eutectics. Now in order for us to do that, lets go back and take a look at the iron carbon phase diagram. The fec phase diagram is a fairly complex one, but we will only consider the steel part of the diagram, up to around 7% carbon. It also covers the invariant reactions of iron carbon system. The equilibrium constitution is the state of lowest gibbs free energy g, for a given composition, temperature and pressure. Iron carbon diagram hindigate 2019 mechanical engg. The ironiron carbide equilibrium diagram practical maintenance. Due to the high lattice distortion, martensite has high residual stresses.
Phase diagrams in materials science and engineering dvd media storage type. Ease of reduction the position of the line for a given reaction on the ellingham diagram shows the stability of the oxide as a function of temperature. Ghosh,department of metallurgy and material science,iit kharagpur. The ironcarbon diagram provides a valuable foundation on which to build knowledge of both plain carbon and alloy steels in their immense variety. The iron carbon diagram provides a valuable foundation on which to build knowledge of both plain carbon and alloy steels in their immense variety. Cementite is metastable, and the true equilibrium is to be between iron and graphite c.
However, ductility is loss martensite is too brittle and a post heat treatment is. Jan 05, 2014 principles of physical metallurgy by prof. What is an intuitive explanation of the ironcarbon phase. The iron iron carbide fefe3c phase diagram in their simplest form, steels are alloys of iron fe and carbon c.
The iron carbon diagram there are two iron carbon equilibrium diagrams. Reactions closer to the top of the diagram are the most. Mar 04, 2018 iron carbon diagram hindigate 2019 mechanical engg. Although graphite occurs extensively in cast irons, it is usually difficult to obtain. In our iron carbon phase diagram has normally presented as incomplete phase diagram, and that is what i am going to discuss first to you. An alloy in this state shows no tendency to change it is thermodynamically. The actual iron carbon diagram is far larger than the part shown here. At this point we only consider the area of the steel with a carbon content up to 2% maximum. Nov 01, 2017 steel is an alloy of carbon and iron and other alloying elements e. The part of ironcarbon alloy system diagram between pure iron and an interstitial compound, iron carbide fe3c, containing 6. Iron with higher carbon concentration exists at this point the partial diagram of cast iron would follow, but this is not of interest for our consideration here.
Carbon is the most common alloying element in the iron which significantly affects the allotrophy, structure and properties of iron. Module 23 iron carbon system i lecture 23 iron carbon system i 1 nptel phase ii. At the lowcarbon end of the metastable fec phase diagram, we distinguish ferrite alphairon, which can at most dissolve 0. L liquid phase a ferrite bcc structure ferromagnetic fairly ductile d bcc structure.
The figure given below shows the ironiron carbide equilibrium diagram labeled with the common names for the structures. A compound of iron and carbon that is very hard and brittle. According to the diagram, point b is which of the following. Mod01 lec23 ironcarbon phase diagram video lecture by prof. Ttt diagram indicates a specific transformation starts and ends and it also shows what percentage of transformation of austenite at a particular temperature is achieved.
It is an interstitial solid solution of a small amount of carbon dissolved in. The iron carbon equilibrium diagram is a plot of transformation of iron. The phase diagram of an alloy made of components a and b, for all combinations of t and x b, defines the ab system. Ironcarbon phase diagram iron shows a eutectic with carbon allowing for a lower melting alloy body centered tetragonal. Phase diagrams in materials science and engineering dvd. The iron carbon diagram also called the iron carbon phase or equilibrium diagram is a graphic representation of the respective microstructure states depending on temperature y axis and carbon content x axis. Determine the ratio of carbon monoxide to carbon dioxide that will be able to reduce the oxide to metal at a given temperature. If the percentage of the carbon is in the range of 0 to 2. Teach yourself phase diagrams and phase transformations. Ironcarbon phase diagram with detailed explanation. Ghosh, dept of metallurgical and materials engineering keywords. The high lattice distortion induces high hardness and strength to the steel. The actual ironcarbon diagram is far larger than the part shown here.
Phase diagrams metastable ironcarbon fec phase diagram. Steel is an alloy of carbon and iron and other alloying elements e. Thus, this diagram is only just a part of the complete fec equilibrium diagram. Note that carbon lowers the freezing point of iron and that it broadens the tempera. Mod01 lec23 ironcarbon phase diagram tutorial of principles of physical metallurgy course by prof r. Iron with higher carbon concentration exists at this point the partial diagram of cast iron would follow, but. Note that pearlite is not a single substance, but rather a fine mixture of ferrite essentially pure iron and cementite iron carbide a chemical compound of iron and carbon. In their simplest form, steels are alloys of iron fe and. Iron carbon phase diagram with detailed explanation.
Authors define the eutectoid point of the fec diagram with different% c example. The ironcarbon equilibrium diagram is a plot of transformation of iron. It should first be pointed out that the normal equilibrium diagram really represents the metastable equilibrium between iron and iron carbide cementite. It should be realized that gramin discussing ironcarbcn al loys, we actually are dealing with plain carbon steels and cast irons. Alloys of iron and carbon the properties of iron are affected. Consider the ttt diagram as shown and the cooling curves imposed on the ttt diagram shown in figure 9. On the basis of iron carbon diagram, we can divide iron carbon alloys into three distinct categories like cast irons, steels, cast steels. Iron carbon equilibrium diagram complete discussion with interview questions duration. It is the softest structure that appears on the diagram. The ironcarbon equilibrium diagram total materia article. It provides an invaluable foundation on which to build knowledge of both carbon steels and alloy steels, as well as a number of various heat treatments they are usually subjected to hardening, annealing.
Jul 18, 2019 phase diagram nptel pdf posted on july 18, 2019 by admin nptel noc phase equilibria in materials nature and properties of ii mechanical engineering iron carbon equilibrium diagram metallurgy carbide phase example 1 22 because phase diagrams 1 binary eutectics. Ironcarbon thephase diagram the complete ironironcarbon phase or. Mar 07, 2014 iron carbon phase diagram, ttt diagram, cct diagram slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Now, we consider only a part of fefe3c diagram referring to steel.
Phase diagrams definitions and basic concepts phases and microstructure binary isomorphous systems complete solid solubility binary eutectic systems limited solid solubility binary systems with intermediate phasescompounds the ironcarbon system steel and cast iron. Whenever an alloy passes this line, eutectic reaction must take. The much larger phase field of gammairon austenite compared with that of alphairon ferrite indicates clearly the. On the basis of ironcarbon diagram, we can divide ironcarbon alloys into three distinct categories like cast irons, steels, cast steels.
With frame as pdf go to science of welding steel go to 8. Iron carbon diagram free download as powerpoint presentation. Binary systems have two components, ternary systems three, and so on. Mar 11, 20 the iron carbon phase diagram the phase diagrams are very important tools in the study of alloys for solutions of many practical problems in metallurgy. A phase diagram or equilibrium diagram is a diagram with t and composition as axes, showing the equilibrium constitution. Compulsory,2 marks will be given from this ironcarbon diagram theory in any exam.
Metallurgy question ironcarbon phase diagram heat treating. The fec phase diagram is a fairly complex one, but we will only consider the steel part of the. Unit quiz the ironcarbon system multiple choice identify the choice that best completes the statement or answers the question. So, apart from fefe3c diagram, your concepts in heat treatment may be weak. Iron carbon phase diagram in brief engineering insider. The alloy may constituent affect its colour while fractured. Compulsory,2 marks will be given from this iron carbon diagram theory in any exam.
The fefe3c diagram is not the easiest thing to understand. And as you cool down pure iron and some amount of carbon in the material what you get is a phase that is called delta iron. If you continue browsing the site, you agree to the use of cookies on this website. Iron carbon equillibrium diagram with explanation youtube. Note that pearlite is not a single substance, but rather a fine mixture of ferrite essentially pure iron and cementiteiron carbide a chemical compound of iron and carbon. Thus, each vertical dashed line, like the solid line in fig. When we look at the phase diagram over a range of different temperatures, what we see is iron melts at a temperature of 1538 c. The iron carbon phase diagram in fig 2 actually shows two diagrams namely i the stable irongraphite diagram red lines, ii and the metastable fefe3c diagram.
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