L liquid phase a ferrite bcc structure ferromagnetic. Phase diagrams metastable iron carbon fec phase diagram. You name and describe the different phases of pure iron during the cooling process. For example, the phases found in the simple binary fec. Classification, properties and uses of carbon steels, cast iron and alloy wheels. Iron carbon diagram 2340 materials engineering university of texas rio grande valley. Fe3c iron carbide called cementite because it is hard. This diagram shows the transformations taking place in an alloy of iron carbon. Iron carbon diagram iron iron carbide phase diagram iron iron carbide phase diagram features of iron iron carbide diagram phases present. Iron carbide equilibrium diagram material science engineers academy. A phase diagram in physical chemistry, mineralogy, and materials science is a type of graph used to show the equilibrium conditions between the thermodynamicallydistinct phases. 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. Iron forms a compound with carbon called cementite, when the carbon content becomes more than the solubility limits of iron. Though, carbon in the form of graphite should from as it has lower free energy than cementite.
Phase diagrams 5 a system is at equilibrium if at constant temperature, pressure and composition the system is stable, not changing with time. 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. Chemistry stack exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. Iron carbon phase diagram with eutectoid, eutectic. This graph, which is known as iron carbon equilibrium diagram has the following important points. Iron carbon diagram 2340 materials engineering university of texas. Iron carbon diagram leaving certificate engineering notes. Ironcarbon equilibrium diagram poster hobart institute. 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. Thus, this diagram is only just a part of the complete fec equilibrium diagram. Equilibrium phase diagrams and the iron carbon system. Ironcarbon phase diagram explained with graphs fractory.
If the percentage of the carbon is in the range of 0 to 2. Due to the high lattice distortion, martensite has high residual. A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions pressure, temperature, volume, etc. Gray iron gray iron was the original cast iron, and is an iron alloy characterized by its relatively high carbon content usually 2% to 4%. What is an intuitive explanation of the ironcarbon phase.
It is also the basic understanding of the heat treatment of steels. The actual ironcarbon diagram is far larger than the part shown here. The ironcarbon equilibrium diagram total materia article. Cementite is metastable, and the true equilibrium is to be between iron and graphite c. A study of the microstructure of all steels usually starts with the metastable iron carbon fec binary phase diagram figure 1.
Iron carbon phase diagram crystal structure the atoms of liquid metal during solidification arrange themselves into a systematic pattern called a crystal structure. In mathematics and physics, a phase diagram also has an alternative meaning, as a. Iron carbon phase diagram or equilibrium diagram we all know that a pure iron metal is very weak in terms of strength. Definition of structures various phases that appear on the iron. It should first be pointed out that the normal equilibrium diagram really represents the metastable equilibrium between iron and iron carbide cementite. Now in order for us to do that, lets go back and take a look at the iron carbon phase diagram. In their simplest form, steels are alloys of iron fe and carbon c. This temperature is shown by the line gs in the phase diagram. This transformation is from pure iron to cementite carbon content 6. Equilibrium phase change temperature 100 200 300 400 500 600 700 t e m p e r a t u r e b c 0. Bcc orthorhombic iron carbon phase diagram iron shows a eutectic with carbon allowing for a lower melting alloy body centered tetragonal. The infographic given below indicates the iron carbon equilibrium diagram that represents the complete range of iron carbon alloys. The ironiron carbide fe fe 3c phase diagram ferrite. In their simplest form, steels are alloys of iron fe and.
On this diagram, the carbon percentage is shown on the xaxis and temperature on the yaxis. Ironcarbon phase diagram describes the ironcarbon system of alloys containing up to 6. Identify the major phases on the fec diagram and explain their chief characteristics. The iron iron carbide fefe3c phase diagram in their simplest form, steels are alloys of iron fe and carbon c. A simplified version of the iron carbon equilibrium diagram is shown below. It is also the basis understanding of the heat treatment of steels. Having trouble understanding the iron carbon phase diagram. A3 temperature varies from 723c to 910c depending upon the carbon content of the alloy. Steel with other elements in small amounts are called plain carbon steel and their structure. Example for hypereutectoid alloy with composition c. The main structures, significance of various lines and critical points are discussed as under. Introduction to ironcarbon equilibrium diagram structures in fec diagram iron carbon equilibrium diagram fig. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
The fefe3c diagram is not the easiest thing to understand. Material science, the iron carbon phase diagram, part 1. Martensite non equilibrium bct phase from quench of. A discussion of the solid state chemistry of iron and steel in terms of the iron iron carbide phase diagram. Material technology and testing mnf 222 chapter 5 the iron carbon system 1 material technology and testing dr. Iron carbon diagram free download as powerpoint presentation. Equilibrium phase diagrams and the iron carbon system degarmos materials and. A new version of the complete equilibrium phase diagram of the iron carbon system has been proposed, which enables to reject the conventional superposed version of the equilibrium and non. The proposed version of the equilibrium phase diagram enables to explain the. See here effects of alloying element on the properties on steel. So, apart from fefe3c diagram, your concepts in heat treatment may be weak. 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. The ironcarbon 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. Many of the basic features of this system influence the behavior of even the most complex alloy steels.
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. With frame as pdf go to science of welding steel go to 8. Calculating percentages of microstructures in equilibrium phase diagrams engineering 3. 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. The iron carbon system steel and cast iron mse 2090.
A practical guide to some descriptive solid state chemistry journal of chemical education. This article delves deep into the ironcarbon phase diagram, exploring the different states of matter along with explanations. The ironcarbon equilibrium diagram introduction the iron carbon diagram is the basis of two very important groups of alloys. Having trouble understanding the ironcarbon phase diagram. Explain and use the terms hypoeutectoid, hypereutectoid, proeutectoid, and pearlite. Dmitri kopeliovich ironcarbon phase diagram describes the iron carbon system of alloys containing up to 6. Were now going to focus in this lesson, on the ironcarbon system.
1518 1476 901 512 655 129 306 865 209 442 1322 466 1057 1136 556 384 371 1390 1518 1235 1482 700 887 224 459 910 950 1408 467 1332 1266 1515 1216 642 690 705 1480 579 563 1236 697 608 479 892 797 113