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Pearlite

About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.


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Journal ArticleDOI
J.D. Embury1, R.M Fisher1
TL;DR: In this article, an empirical model has been developed to relate the flow stress of the drawn wire to the spacing of substructural barriers in terms of the drafting strain, which indicates that this type of strengthening mechanism is operative in the case of drawn iron wire of commercial purity.

510 citations

Journal ArticleDOI
TL;DR: In this paper, a ferritic steel precipitation-strengthened by manometer-sized carbides was developed to obtain a high strength hot-rolled sheet steel having tensile strength of 780 MPa grade with excellent stretch flange formability.
Abstract: A ferritic steel precipitation-strengthened by manometer-sized carbides was developed to obtain a high strength hot-rolled sheet steel having tensile strength of 780 MPa grade with excellent stretch flange formability. Manganese in a content of 1.5% and molybdenum in a content of 0.2 % were added to 0.04 % carbon Ti-bearing steel in order to lower austenite-ferrite transformation temperature for fine carbides and to retard generating of pearlite and large cementites, respectively. Tensile strength of hot-rolled sheet steel increased with titanium content and it was achieved to 800 MPa in a 0.09 % Ti steel. Microstructure of the 0.09 %Ti steel was ferrite without pearlite and large cementites. Fine carbides of 3 nm in diameter were observed in rows in the ferrite matrix of the 0.09 % Ti steel with transmission electron microscope. The characteristic arrangement of the nanometer-sized carbides indicates that the carbides were formed at austenite-ferrite interfaces during transformation. By energy dispersive X-ray spectroscopy, the carbides were found to contain molybdenum in the same atomic concentration as titanium. Crystal structure of the nanometer-sized carbides was determined to be NaCI-type by X-ray diffractometry. The calculated amount of precipitation-strengthening by the carbides was approximately 300 MPa. This is two or three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels. Based on the results obtained in the laboratory investigation, mill trial was carried out. The developed hot-rolled high strength sheet steel exhibited excellent stretch flange formability.

420 citations

Journal ArticleDOI
TL;DR: In this paper, Bolling's method of transformation in a steep temperature gradient was used for drawing wire and strip in dies designed to minimize macroscopically nonuniform deformation, and cross sections of the drawn wires and strip were examined by conventional and high-voltage transmission electron microscopy.
Abstract: Pearlite with its lamellae oriented mainly parallel to the longitudinal direction was prepared by Bolling's method of transformation in a steep temperature gradient. The Fe-0.7 pct Mn-0.9 pct C pearlite was drawn into wire and also into strip in dies designed to minimize macroscopically nonuniform deformation. Cross sections of the drawn wires and strip were examined by conventional and high-voltage transmission electron microscopy and were analyzed by quantitative metallography for a) average interlamellar spacing, b) distribution of interlamellar spacings, and c) orientation relationship between the cementite lamellae and the slip systems in the ferrite. The strength of pearlite is proportional to the reciprocal square root of the average interlamellar spacing, and the proportionality constant analogous to the Hall-Petch constant (k) is related to the strength of the cementite lamellae. If the stress for the propagation of slip through the cementite is assumed constant, a Hall-Petch type of equation can be derived for the strengthening of the pearlite against slip in the ferrite by piled-up groups of dislocations. Evidence for the plastic deformability of cementite is presented; sufficiently thin cementite plates were fully plastic. The exponential strain hardening of drawn pearlitic wires and of rolled pearlite is explained in terms of locally inhomogenous deformation revealed by the lack of fragmentation of the lamellae.

353 citations

Journal ArticleDOI
TL;DR: In this paper, an excellent combination of elongation over 30% and high strength about 100kgf/mm2 is achieved in processing of a 0.4C-1.8Mn steel by intercritical annealing, rapid cooling into bainite transformation temperature to soak several minutes.
Abstract: An excellent combination of elongation over 30% and high strength about 100kgf/mm2 is achieved in processing of a 0.4C-1.5Si-0.8Mn steel by intercritical annealing, rapid cooling into bainite transformation temperature to soak several minutes. This combination is caused by transformation induced plasticity of retained austenite. Sufficient amount of stable austenite is a requisite for the good ductility. For the rapid cooling after annealing, the soaking temperature for the best combination of strength and ductility is immediately above Ac1. On the other hand, a delay before rapid cooling provides good properties if the soaking temperature is near Ac3 and the subsequent cooling is performed at a lower rate before pearlite transformation; in this case the critical cooling rate is reduced. These phenomena are discussed in terms of the growth of ferrite and the diffusion of alloying elements inclusive of Mn during slow cooling.

349 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of cold wire drawing on the structure of a pearlitic steel containing 0.7 wt% of carbon and subjected to a strain of approximately 3.5 has been studied.

335 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023148
2022326
2021218
2020271
2019291
2018221