Krishanubiswas department of materials science and engineering indian institute of technology, kanpur lecture 26 introduction to iron carbon phase diagram now, we are going to start with the classic iron carbon phase diagram. Mod01 lec23 iron carbon phase diagram tutorial of principles of physical metallurgy course by prof r. Iron carbon diagram with images materials engineering. Thus, this diagram see bottom most horizontal line in fig. Note that carbon lowers the freezing point of iron and that it broadens the tempera. The ironiron carbide fefe3c phase diagram in their simplest form, steels are alloys of iron fe and carbon c. Geil this monograph is a revision of the previous nbs monograph 18.
A map of the temperature at which different phase changes occur on very slow heating and cooling in relation to carbon content. It should first be pointed out that the normal equilibrium diagram really represents the metastable equilibrium between iron and iron carbide cementite. Co lead to the diffusion of c into the iron at the surface case hardened steel even a fraction of a percent of carbon can have a dramatic effect on hardness hittites needed to beat bronze in terms of hardness so their weapons could pierce bronze shields quenching also hardened steel martensite followed by tempering heating. Lecture 11 12 industrial gases free download as powerpoint presentation. Although graphite occurs extensively in cast irons, it is usually difficult to obtain. Design of steel structures video lectures, civil engineering video lectures, design of steel structures video tutorials, design of steel structures by duggal, design of steel structures by ramachandra,design of steel structures pdf. According to the diagram, point b is which of the following. Heat treatment of steel california state university. Carbon is the most common alloying element in the iron which significantly affects the allotrophy, structure and properties of iron. Phase diagrams in materials science and engineering dvd. Iron carbon diagram shows the type of alloys formed under very slow cooling, proper heattreatment temperature and how the properties of steels and cast irons can.
Courses phase diagrams in materials science and engineering. In this region the air reacts with the carbon from the coal to produce carbon dioxide and heat. Phase diagram for iron carbon system, up to about 6% carbon. A metallic substance that is composed of two or more elements austenite. Lecture 11 12 industrial gases carbon dioxide distillation. Were now going to focus in this lesson, on the iron carbon system. Mse 300 materials laboratory procedures university of tennessee, dept. Since all steels will pass through the singlephase austenite. Principles of physical metallurgy nptel online videos. Metallurgy question ironcarbon phase diagram heat treating. This helps us to understand how this control is done. Most carbon steel is less than 1 wt% c greatest tonnage produced in the 0. Iron carbon phase diagram in brief engineering insider. Ferrous metals based on iron, one of the oldest metals known to man ferrous metals of engineering importance are alloys of iron and carbon these alloys divide into two major groups.
It is also the basic understanding of the heat treatment of steels. One reason for that could be that the temperature at which pure ferrite changes to austenite is higher than that of iron carbon alloy. Lecture notes on veer surendra sai university of technology. Home forums breezeworks heat treatment pdf nptel tagged. It also covers the invariant reactions of iron carbon system. The ironcarbon equilibrium diagram total materia article. The proposed new version of the complete equilibrium phase diagram of the iron carbon system enables to reject the superposed version of the equilibrium and nonequilibrium phase diagram of iron carbon and explains clearly the presence in the microstructure of iron carbon alloys at the room temperature of. This lecture discusses the iron carbon phase diagram with different phases and reactions involved.
Iron carbon diagram shows the type of alloys formed under very slow cooling, proper heattreatment temperature and how the properties of steels and cast irons. Phase diagrams in material science engineering prof. 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. The study of the constitution and structure of iron and steel start with the iron carbon phase diagram. Unit quiz the ironcarbon system multiple choice identify the choice that best completes the statement or answers the question.
Now, we consider only a part of fefe3c diagram referring to steel. Lecture series on design of steel structures by dr. Phase diagrams in materials science and engineering. Heat treatment of steel refers to time and temperaturecontrolled processes that relieve residual stresses andor modifies material properties such as hardness strength, ductility, and toughness. If you continue browsing the site, you agree to the use of cookies on this website. Facecentered cubic iron or an iron alloy based on this structure. Cementite, chemical formula fe3c has a fixed carbon content of 6. Jan 18, 2015 heat treatment of steel refers to time and temperaturecontrolled processes that relieve residual stresses andor modifies material properties such as hardness strength, ductility, and toughness. Jan 05, 2014 principles of physical metallurgy by prof. Iron iron carbide phase diagram lecture 1for esegate.
Phase diagrams in materials science and engineering dvd media storage type. Damodar maity, department of civil engineering,iit guwahati. Austenite has a cubicclose packed crystal structure and tends to decompose into ferrite bodycentered cubic and cementite fe 3 c. Nptel provides elearning through online web and video courses various streams. The iron iron carbide fefe 3c phase diagram ferrite.
Its purpose is to provide an understanding of the heat treatment of iron and steels, principally to. At this point we only consider the area of the steel with a carbon content up to 2% maximum. So, apart from fefe3c diagram, your concepts in heat treatment may be weak. Eutectoid transformation in iron carbon phase diagram. Alloy phase diagrams pdf download closengreendangti. Hindi understanding iron carbon diagram by ravi singh. 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. 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. In their simplest form, steels are alloys of iron fe and carbon c. Microstructure in iron carbon alloys eutecticpearlite hypoeutectoid alloys hypoeutectoid steel. Other mechanical or chemical operations are sometimes grouped under the heading of heat treatment. Other mechanical or chemical operations are sometimes grouped under the. However, ductility is loss martensite is too brittle and a post heat treatment is.
Eutectoid transformation in ironcarbon phase diagram nptel. Iron carbon phase diagram in their simplest form, steels are alloys of iron fe and carbon c. Cementite is metastable, and the true equilibrium is to be between iron and graphite c. Were now going to focus in this lesson, on the ironcarbon system. Dear students we have started our discussion on ironcarbon phase diagrams and. The iron carbon phase diagram in fig 2 actually shows two diagrams namely i the stable iron graphite diagram red lines, ii and the metastable fefe3c diagram. Now, we are going to start with the classic iron carbon phase diagram. The high lattice distortion induces high hardness and strength to the steel. Log in register lost password viewing 1 post of 1 total author posts december 10, 2018 at 7. Due to the high lattice distortion, martensite has high residual stresses.
Nov 01, 2017 in their simplest form, steels are alloys of iron fe and carbon c. Mod01 lec23 iron carbon phase diagram principles of. The fefe3c diagram is not the easiest thing to understand. Conventionally, the complete fe c diagram should extend from 100% fe to 100 % carbon graphite, but it is normally studied upto 6. I guess it comes down to the electronic structure of the iron carbon system, but i guess we dont want to go to that level of detail. Cast iron is an alloy of carbon and iron and other alloying elements e. Principles of extractive metallurgy rakes h kumar email. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. 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.
This lesson talks about the iron carbon diagram reading, pearlite mixture. A phase diagram describes the state of a materials system phase diagrams are maps of the a. Fcc is a more close packed structure yet solubility of carbon in austenite which is fcc is higher. The iron carbon equilibrium diagram introduction the iron carbon diagram is the basis of two very important groups of alloys. Iron iron carbide phase diagram lecture 1for esegatepsus mechanical. 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. And the phases which are present in steels, iron carbon diagram, they are all rhyming, ferrite, austenite, cementite.
For steels, solution annealing involves heating to a sufficiently. Timetemperaturetransformation ttt curves ttt diagram is a plot of temperature versus the logarithm of time for a steel alloy of definite composition. The iron carbon diagram provides a valuable foundation on which to build knowledge of both plain carbon and alloy steels in their immense variety. What is an intuitive explanation of the ironcarbon phase. This lesson talks about the ironcarbon diagram reading, pearlite mixture. A slightly more colorful version of the iron carbon phase diagram follows. The stable condition usually takes a very long time to develop, especially in the lowtemperature and low carbon range, and therefore the metastable diagram is of more interest. Steels with a carbon concentration less than about 0. The last twothirds of the kiln is known as the reduction zone, and is where the solid iron oxides are reduced to metallic iron. The iron iron carbide diagram a map of the temperature at which different phase changes occur on very slow heating and cooling in relation to carbon, is called iron carbon diagram. Equilibrium phase diagram, ironcarbon phase diagram, lever rule, phase. Iron carbon phase diagram to refine steel from either scrap or pig iron, the amount of carbon must be carefully controlled. This lecture discusses the iron carbon phase diagram with.
Now in order for us to do that, lets go back and take a look at the iron carbon phase diagram. The actual ironcarbon diagram is far larger than the part shown here. Nptel design of steel structures nptel video lectures from. Heat treatment and properties of iron and steel thomas g. Ferrous alloys fec phase diagram the vast majority of steels are in the austenitic condition at temperatures in excess of 900 c. Greater than 1 wt% c is rare, used for razor blades, cutlery, etc. Thus, each vertical dashed line, like the solid line in fig. Dmitri kopeliovich iron carbon phase diagram describes the iron carbon system of alloys containing up to 6. 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. Ghosh,department of metallurgy and material science,iit kharagpur. Eutectoid transformation in ironcarbon phase diagram. This video describes different phases in iron iron carbide system.
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