Ferrites iron-carbon alloys

Hel] Heller, W., Brauner, J., Investigations on the Diffusion and Precipitation of Carbon in Ferritic Iron-Nickel Alloys by Measuring the Damping Capacity (in German), Arch. Eisenhuettenwes., 35(11), 1105-1110 (1964) (Experimental, Kinetics, Interface Phenomena, Phase Relations, 13)... 

A detailed electron microscopic examination has been made on high purity C-Fe-V alloys with particular reference to the aging behavior prior to the hardness peak in the temperature range of 500-600°C [1966Ray]. Precipitation of vanadium carbide on aging has been studied in a ferritic iron-vanadium alloy containing a small amount of carbon by [1973Hei]. 

Pearlite p3r(-o)- lit [F perlite, fr. perle pearl] (1888) n. The lamellar mixture of ferrite and cementite in slowly cooled iron-carbon alloys occurring normally as a principal constituent of both steel and cast iron. Same as perlite. 

The lamellar mixture of ferrite and cementite in slowly cooled iron-carbon alloys occurring normally as a principal constituent of both steel and cast iron. 

Ferrous alloys are those in which iron is the prime component, but carbon as well as other alloying elements may be present. In the elassification scheme of ferrous alloys based on carbon content, there are three types iron, steel, and cast iron. Commercially pure iron contains less than 0.008 wt% C and, from the phase diagram, is composed almost exclusively of the ferrite phase at room temperature. The iron-carbon alloys... 

The development of microstrnctnre for many iron-carbon alloys and steels depends on a eutectoid reaction in which the austenite phase of composition 0.76 wt% C transforms isothermally (at 727°C) into a-ferrite (0.022 wt% C) and cementite (i.e., a + FejC). 

The microstructural product of an iron-carbon alloy of eutectoid composition is pearlite, a microconstituent consisting of alternating layers of ferrite and cementite. The microstructures of alloys having carbon contents less than the eutectoid (i.e., hy-poeutectoid alloys) are composed of a proeutectoid ferrite phase in addition to pearlite. Pearlite and proeutectoid cementite constitute the microconstituents for hypereutec-toid alloys—those with carbon contents in excess of the eutectoid composition. 

The microstructure of an iron-carbon alloy con-O sists of proeutectoid ferrite and pearlite the mass... 

The mass fractions of total ferrite and total ce-O mentite in an iron-carbon alloy are 0.91 and 0.09,... 

For iron-carbon alloys of other compositions, a proeutectoid phase (either ferrite or cementite) coexists with pearhte, as discussed in Section 9.19. Thus, additional... 

Yet another microconstituent or phase called martensite is formed when austenitized iron-carbon alloys are rapidly cooled (or quenched) to a relatively low temperature (in the vicinity of the ambient). Martensite is a nonequilibrium single-phase structure that results from a diffusionless transformation of austenite. It may be thought of as a transformation product that is competitive with pearlite and bainite. The martensitic transformation occurs when the quenching rate is rapid enough to prevent carbon diffusion. Any diffusion whatsoever results in the formation of ferrite and cementite phases. 

We now discuss the mechanical behavior of iron-carbon alloys having the microstructures discussed heretofore—namely, fine and coarse pearlite, spheroidite, bainite, and martensite. For all but martensite, two phases are present (ferrite and cementite), and so an opportunity is provided to explore several mechanical property-microstructure relationships that exist for these alloys. 

FE On the basis of the accompanying isothermal O transformation diagram for a 0.45 wt% C iron-carbon alloy, which heat treatment could be used to isothermally convert a microstructm-e that consists of proeutectoid ferrite and fine pearlite into one that is composed of proeutectoid ferrite and martensite ... 

Soft magnetic materials are characterized by high permeabiUty and low coercivity. There are sis principal groups of commercially important soft magnetic materials iron and low carbon steels, iron—siUcon alloys, iron—aluminum and iron—aluminum—silicon alloys, nickel—iron alloys, iron-cobalt alloys, and ferrites. In addition, iron-boron-based amorphous soft magnetic alloys are commercially available. Some have properties similar to the best grades of the permalloys whereas others exhibit core losses substantially below those of the oriented siUcon steels. Table 1 summarizes the properties of some of these materials. 

Iron Low-carbon steels Low-carbon alloy steels Decarburised malleable Chromium 980-1 050 (Halide) 1. Gaseous 2. Semi- gaseous 3. Pack 25-75 urn Solid-solution (ferritic) 20-25% Cr Ductile (200-300 HV) Weldable Heat treatment acceptable ... 

The scheme E involves dead roasting of the concentrate by which Fe203 forms and the nickel content is oxidized to nickel ferrite (NiFe204). This material is selectively reduced to produce an iron-nickel alloy which is then leached in an ammoniacal ammonium carbonate solution for nickel recovery, leaving hematite as a leach residue. 

In binary alloy systems, a eutectoid alloy is a mechanical mixture of two phases which form simultaneously from a solid solution when it cools through Ihe eutectoid temperature. Alloys leaner or richer in one of the metals undergo transformation from the solid solution phase over a range of temperatures beginning above and ending al the eutectoid temperature. The structure of such alloys will consist of primary particles of one of the stable phases in addition to ihe eutectoid. lor example ferrite and pearlite in low-carbon steel. See also Iron Metals, Alloys, and Steels. 

Strong Attraction Steels carbon, alloy, tool Cast Irons gray, ductile, malleable Cobalt Nickel Stainless Steels ferritic, duplex, martensitic, martensitic precipitation hardening... 

In many processes, carbon is present as the primary or secondary oxidant. Where carbon is the primary oxidant, the principal reaction is that of carburization or the dissolution of carbon into the metal matrix. The solubility of carbon in metals varies widely, being very low in Ni, Cu, Co, and ferritic iron but quite substantial in austenitic iron. Carburization of alloys, principally steels, is a common treatment for developing a hard and strong surface on components that are exposed to contact wear during service. The theory and techniques for this are clarified in the literature. ... 

Corrosion of Stainless Steels in Acids Stainless steels are iron-based alloys with chromium as the main alloying element. The most interesting alloys for technical applications are ferritic stainless steels, austentic stainless steels, and duplex stainless steels. The distinction between the stainless steels comes from their different crystallographic structures. Ferritic-martensitic stainless steels and martensitic stainless steels have less nickel and a higher carbon content and can be hardened by heat treatment. The corrosion behavior of these steels is mainly influenced by the formation of carbides, which generally increase the corrosion rate. 

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. 

Swi] Swinden, D.J., Woodhead, J.H., Kinetics of the Nucleation and Growth of Proeutectoid Ferrite in Some Iron-Carbon-Chromium Alloys , J. Iron Steel Inst., London, 209, 883-899 (1971) (Morphology, Phase Relations, Experimental, Kinetics, 40)... 

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