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Related to Pearlite: Bainite, cementite


A lamellar aggregate of ferrite (almost pure iron) and cementite (Fe3C) often occurring in carbon steels and in cast iron.



(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.


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



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.
References in periodicals archive ?
They are of steel CS700 which structural components are ferrite and pearlite (in plates and grains) and are noticeable in fractures.
After hot rolling, the developed steel exhibits a ferrite and pearlite structure, as described above.
Predicted nodularity and pearlite content of test castings and an Audi 3,01 V6 TDI CGI crankcase were used for the coupling of local microstructures with durability values and validated by measurements.
Cement, Fly ash (not necessarily), glass fiber or steel wire, aggregate (optional: sand, stone, blast furnace slag, pearlite, ceramisite, pumice, and other slag).
For this particular case of study it is expected that ferrite, which is softer than pearlite, undergoes higher plastic deformation in its microstructure (Al Abbasi 2013).
The first stage is the pearlite dissolution and the second stage is the ferrite to austenite transformation, which finishes at [Ac.
This transformation occurs in the cementitic lamellas in the pearlite of the original rail or wheel into a mixture of coarse deformed particles which the effects of enormous deformation further divide into ultra-fine grain structures.
Image analysis of pearlite spheroidization based on the morphological charact-erization of cementite particles.
The gray cast iron HT200 in this test is widely used in as met al matrix, Its microscopic structure is flake graphite + pearlite (Figure 1), depending on the molding process divided bionic coupling unit into laser surface melting unit (LMU).
These crystals are characterised by a troostite structure, with individual areas of plate-shaped pearlite.
Among the 93 specific topics are texture development in aluminum friction stir welds, combining two x-ray diffraction settings for determining the texture of small sheared samples, the relative preference for strain localizations in ultra-low-carbon steel, eutectoid point shift and orientation relationships between ferrite and cementite in pearlite in a high magnetic field, texture and microscopic evolution during the asymmetric rolling of magnesium alloys, and modeling rolling texture of twinned copper single crystals.