Iron metals, alloys, and steels

These steels account for over 90% of all steel production, There are numerous varieties, depending upon carbon content and method of production. In one classification, there are killed steels, semikilled steels, rimmed steels, and capped steels, These are described in considerable detail under Iron Metals, Alloys, and Steels. 

AUSTENITE. The solid solution based upon the face-centered cubic form of iron. The most important solute is usually carbon, but other elements may also be dissolved in the austenite, See also Iron Metals, Alloys, and Steels. 

BLOOM, In surface-coating technology, bloom is a whitish, filmy layer that appears on films of paints, varnishes, or lacquers due to contamination from the atmosphere. The term is also applied to a filmy layer deposited on a photographic plate by tap water, which can be removed by rubbing the plate with wet cotton. The term bloom is used in metallurgy to denote a mass of malleable iron from which the slag has been removed See also Iron Metals, Alloys, and Steels. 

CARBIDES. A binary solid compound of carbon and another element. The most familiar carbides are those of calcium, tungsten, silicon, boron, and iron (cemcntitc) Two factors have an important bearing on the properties of carbides (1) the difference in electronegativity between carbon and the second elemenl. and (2) whether the second element is a transition metal. Saltlike carbides of alkali metals are obtained by reaction with acetylene. Those ohlained from silver, copper, and mercury sails are explosive. See also Carbon and Iron Metals, Alloys, and Steels. 

EQUILIBRIUM DIAGRAM. A diagram showing the phase fields of an alloy system under the conditions of complete equilibrium using as coordinates the temperature, the compositions in terms of the components, and the pressure. The most frequently used equilibrium diagrams in metallurgy are drawn with the pressure considered constant. See iron-carbon diagram under iron Metals, Alloys, and Steels. See also Distillation. 

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. 

See also Allays Iron Metals, Alloys, and Steels Metals ( The) and Periodic Table of the Eiemeots. 

PASSIVITY. When iron is immersed in concentrated nitric acid, there is no visible reaction (Keir, 1790). although dilute nitric acid results in a marked reaction with iron, Upon removal of the iron from the concentrated nitric acid and immersion in copper sulfate solution, the iron is not plated by copper, although this occurs with ordinary iron. Iron in such a condition is described as passive iron, and the phenomenon is known as passivity. See also Iron Metals, Alloys, and Steels... 

STAINLESS STEEL. See Iron Metals, Alloys, and Steels. 

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