pearlite

pearl·ite

P0136300 (pûr′līt′)n.1. A mixture of ferrite and cementite forming distinct layers or bands in slowly cooled carbon steels.2. Variant of perlite.

pearlite

(ˈpɜːlaɪt) n1. (Metallurgy) the lamellar structure in carbon steels and some cast irons that consists of alternate plates of pure iron and iron carbide2. (Minerals) a variant spelling of perlite pearlitic adj

pearl•ite

(ˈpɜr laɪt)

n. 1. a microscopic lamellar structure found in iron or steel, composed of alternating layers of ferrite and cementite. 2. perlite. [1885–90] pearl•it′ic (-ˈlɪt ɪk) adj.

Thesaurus

Noun

pearlite - a lamellar mixture of cementite and ferrite formed during the cooling of austenite; a constituent of steel and cast ironcast iron - an alloy of iron containing so much carbon that it is brittle and so cannot be wrought but must be shaped by castingsteel - an alloy of iron with small amounts of carbon; widely used in construction; mechanical properties can be varied over a wide rangecementite, iron carbide - a chemical compound that is a constituent of steel and cast iron; very hard and brittleferrite - a solid solution in which alpha iron is the solventglobular pearlite, granular pearlite - if steel or iron cool very slowly the cementite may occur in globules instead of in layerslamellar mixture - a mixture in which substances occur in distinct layers

Translations

perlite

Pearlite

pearlite

[′pər‚līt] (geology) perlite (metallurgy) A lamellar aggregate of ferrite (almost pure iron) and cementite (Fe₃C) often occurring in carbon steels and in cast iron.

Pearlite

(in metallurgy), a structural component of iron-carbon alloys (steels and cast irons) that consists of a eutectic mixture of two phases, ferrite and cementite. In alloy steels the two phases that combine to form pearlite are different carbides.

Pearlite is a product of the eutectic decomposition of austenite upon relatively slow cooling of iron-carbon alloys below 723°C. In this process, γ-iron is transformed into α-iron, in which the solubility of carbon is only about 0.02 percent. The excess carbon precipitates as cementite or carbides.

A distinction is made between lamellar and granular pearlite. In the former, which is more common, both phases are present as lamellas; in the latter, rounded granules, or globules, of cementite are arranged against a background of ferrite globules. As supercooling proceeds, the number of pearlite colonies increases; that is, the number of sections of the piece of metal in which ferrite and cementite or carbide lamellas are uniformly oriented increases. Furthermore, the lamellas of pearlite become thinner as the temperature drops.

The mechanical properties of pearlite depend primarily on the interlamellar distance, that is, the total thickness of the two adjacent lamellas. Decreasing this distance increases ultimate strength and yield strength and decreases the ductile-to-brittle transition critical temperature. The structure of pearlite facilitates mechanical working of steel. Certain dispersed varieties of pearlite are sometimes called sorbite or troostite.

REFERENCE

Bunin, K. P., and A. A. Baranov. Metallografiia. Moscow, 1970.

R. I. ENTIN

perlite

A siliceous volcanic rock; under heat it expands to 15 to 20 times its original volume, forming an excellent lightweight aggregate; used in plaster or gypsum wallboard, as loose-fill thermal insulation, and as an aggregate in concrete.

pearlite

pearl·ite

pearlite

pearl•ite

Pearlite

pearlite

Pearlite

REFERENCE

perlite

pearlite

Words related to pearlite

noun a lamellar mixture of cementite and ferrite formed during the cooling of austenite

Related Words