from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A mixture of ferrite and cementite forming distinct layers or bands in slowly cooled carbon steels.
- n. Variant of perlite.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A two-phased lamellar structure composed of alternating layers of alpha ferrite and cementite that occurs in some steels and cast irons, having a pearlescent appearance.
- n. Alternative form of perlite.
from the GNU version of the Collaborative International Dictionary of English
- n. A glassy volcanic rock of a grayish color and pearly luster, often having a spherulitic concretionary structure due to the curved cracks produced by contraction in cooling. See Illust. under perlitic.
from The Century Dictionary and Cyclopedia
- n. The eutectoid of Steel.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a lamellar mixture of cementite and ferrite formed during the cooling of austenite; a constituent of steel and cast iron
The name perlite (also spelled pearlite) comes from the French word perle which means pearl, in reference to the “pearly” luster of classic perlite.
The name perlite (also spelled pearlite) comes from the French word perle which means pearl, in reference to the "pearly" luster of classic perlite.
The cementite, although adding to the tensile strength, is very brittle and the strength of the pearlite is the combination of the ferrite and cementite.
This structure of thin sheets has received the name "pearlite," because of its pearly appearance under sunlight.
He suggested to me a theoretical problem left over from his work during the war on the cooling of steel through the austenite-pearlite transition, and I learned a fair amount of metallurgy in order to understand the physical basis of the phenomenon.
When cooled slowly below 670 degrees, martensite yields a heterogeneous mixture of pearlite and ferrite (or cementite, if the original mixture contained between 0.8 per cent. and two per cent. of carbon).
Any of these operations not only allows the transformations from austenite to pearlite to proceed, but also relieves internal stresses in the steel.
Tiny white granules of pure iron (ferrite) have small accumulations of dark-etching pearlite interspersed between them.
If the steel be then cooled, the austenite breaks up into new crystals of ferrite, cementite and pearlite; and in general if the temperature has not gone far above the critical, and cooling is not excessively slow, a very fine texture will result.
At that moment, in fact, the ferrite, cementite or pearlite which previously existed has lost its identity by everything going into the solid solution called austenite.
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