Phase diagrams iron-carbon

Fig. 1. Iron—carbon phase diagram, where a is the body-centered cubic (bcc) a-iron, y is the face-centered cubic y-iron, and Fe C is iron carbide(3 l)...

Figure 6.3 The iron-carbon phase diagram showing the alternative production of iron and cementite from the liquid alloy, which occurs in practice, to the equilibrium production of graphite...

Fig. 11.1. The left-hand part of the iron-carbon phase diagram. There ore five phases in the Fe-FejC system L, 5, y, or and Fe3C (see Table 1 1.1).

Figure A1.37 shows the iron-carbon phase diagram up to 6.7 wt% carbon (to the first intermetallic compound, FejC). Of all the phase diagrams you, as an engineer, will encounter, this is the most important. So much so that you simply have to learn the names of the phases, and the approximate regimes of composition and temperature they occupy. The phases are ...

The polymorphism of certain metals, iron the most important, was after centuries of study perceived to be the key to the hardening of steel. In the process of studying iron polymorphism, several decades were devoted to a red herring, as it proved this was the P-iron controversy. P-iron was for a long time regarded as a phase distinct from at-iron (Smith 1965) but eventually found to be merely the ferromagnetic form of ot-iron thus the supposed transition from P to a-iron was simply the Curie temperature, p-iron has disappeared from the iron-carbon phase diagram and all transformations are between a and y. 

Cast irons, although common, are in fact quite complex alloys. The iron-carbon phase diagram exhibits a eutectic reaction at 1 420 K and 4-3 wt.<7oC see Fig. 20.44). One product of this eutectic reaction is always austenite however, depending on the cooling rate and the composition of the alloy, the other product may be cementite or graphite. The graphite may be in the form of flakes which are all interconnected (although they appear separate on a... 

Iron-carbon phase diagram, 76 196-197 Iron castings, tellurium in, 24 424 Iron(II) chloride, 74 538 Iron(III) chloride, 74 539 Iron(III) chloride hexahydrate, 74 539 Iron(II) chloride tetrahydrate, 74 538 Iron Chromate Black, pigment for plastics, 7 369t... 

Stable and metastable iron-carbon phase diagram. The behaviour of iron and iron alloys depends on the existence of its different forms and on their transformations technologically moreover the carbon content is crucial. These aspects are clearly shown in the iron-carbon phase diagram, especially in the low... 

The iron-carbon phase diagram at low weight percentages of carbon is shown in Figure 2.8. Actually, the phase boundary at 6.69 wt% carbon represents the compound iron carbide, FesC, known as cementite, so that the phase diagram in Figure 2.8 is more appropriately that of FesC-C. 

Figure 2. The iron-carbon phase diagram (part), with the dissolution and precipitation regions used in this work. Key ---, Fe-cementite and-----, Fe-graphite.

With respect to the iron-carbon phase diagram (Figure 4.16 page 102) ... 

Figure 5.45 (a) Iron-carbon phase diagram with different heating conditions A, B, and C indicated a = ferrite, y = austenite, (b) Carbon profile and model for the decarburization of plain carbon steel above 910 °C, corresponding to condition C in (a). 

Main crystalline constituents in carbon steels are ferrite, cementite, perlite, and, depending on heat treatment, bainite and martensite. Below approximately 723 °C, austenite in carbon steels is transformed into perlite and, according to the carbon content, ferrite or cementite. Thus, austenite is only present at room temperature in alloyed steels and not in carbon steels. The iron-carbon phase diagram shows the metallographic constitution for unalloyed carbon steels depending on the carbon content and the temperature. Fig. 2. 

Figure 2.1. Simplified iron-carbon phase diagram. Source Simplified iron-carbon phase diagram. Metal Prog., vol. 52. Copyright 1947 ASM International (reprinted with permission)...

TaUe2.10. Critical arrest points in iron-carbon phase diagram Point Description... 

The iron-carbon phase diagram only applies to alloys that contain only iron and carbon. But because other desired or undesired alloying elements are usually originally present from... 

A portion of the iron-carbon phase diagram is presented in Figme 9.24. Pure iron, upon heating, experiences two changes in crystal structure before it melts. At room temperature, the stable form, called ferrite, or a-iron, has a BCC crystal structure. Ferrite experiences a polymorphic transformation to FCC austenite, or y-iron, at 912°C (1674°F). This austenite persists to 1394°C (2541°F), at which temperature the FCC austenite reverts back to a BCC phase known as 5-ferrite, which finally melts... 

Several of the various microstructures that may be produced in steel alloys and their relationships to the iron-iron carbon phase diagram are now discussed, and it is shown that the microstructure that develops depends on both the carbon content and heat treatment. This discussion is confined to very slow cooling of steel alloys, in which equilibrium is continuously maintained. A more detailed exploration of the influence of heat treatment on microstructure, and ultimately on the mechanical properties of steels, is contained in Chapter 10. 

Figore 11.2 The true equilibrium iron-carbon phase diagram with graphite instead of cementite as a stable phase. [Adapted from Binary Alloy Phase Diagrams, T. B. Massalski (Editor-in-Chief), 1990. Reprinted by permission of ASM International, Materials Park, OH.l... 

Figure 11.5 From the iron-carbon phase diagram, composition ranges for commercial cast irons. Also shown are schematic microstructures that result from a variety of heat treatments. Gf, flake graphite G graphite rosettes G , graphite nodules P, pearlite , ferrite.

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