Effect of boron on microstructure of directionally solidified high chromium white irons

Corrêa, R. R.; Bedolla-Jacuinde, A.; Mejı́a, I.; Cardoso, E.; Hernández, B.

doi:10.1179/136404611x12965641181767

Cited by 14 publications

(9 citation statements)

References 20 publications

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“…Recent studies have confirmed that an increase in the content of B reduces the volume fraction of graphite and deteriorates the spheroidal morphology [10]. In White Cast Irons, B tends to segregate principally at the Austenite/Carbide interface, decreasing the proportion of proeutectic austenite versus the metastable constituent [11]. In a previous study, the 'whitening' effect of adding FeB was verified by increasing the volume fraction of Ledeburite and mixed carbides (CrFe) 3 C [12,13].…”

Section: Introductionmentioning

confidence: 86%

Optimization of Graphite Morphology in Mottled Nihard Cast Irons Inoculated with Feb and Manufactured by Centrifugal Casting

Lozano

Álvarez-Antolín

González-Pociño

et al. 2018

Metals

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The present research was focused on the identification of manufacturing factors that have an active influence on the graphite phase formation in Nihard cast irons inoculated with FeB, constituting the outer layer of duplex work rolls. These rolls are used in the finishing stands of hot-strip steel mills where the following are desired: (a) between 2.5 and 4 vol % of graphite; (b) homogeneous graphite distribution across the layer section; and, (c) a reasonable high number of graphite particles across the layer. The research methodology that followed consisted of the application of a saturated design of experiments (DOE), with seven factors, eight experiments, and resolution III. The analyzed responses obtained by quantitative metallographic techniques were: the volume fraction of graphite, Vv; the number of counts per unit area of graphite, N A ; and the graphite morphology across the layer thickness. Increasing the addition of FeB from 6 to 10 kg/T reduced the graphite volume fraction and the count number, but had no influence on its morphology. However, an increase of the liquidus temperature from 1225-1230 to 1250-1255 • C, and an increase in the amount of SiCaMn added to the ladle from 0.3 to 0.6 kg/T produced the desired compact graphite morphology.

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Section: Introductionmentioning

confidence: 86%

Optimization of Graphite Morphology in Mottled Nihard Cast Irons Inoculated with Feb and Manufactured by Centrifugal Casting

Lozano

Álvarez-Antolín

González-Pociño

et al. 2018

Metals

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“…It is known that boron in white cast iron greatly increases its hardenability, increases microhardness and overall hardness, promotes the formation of dispersed hardening refractory particles in the structure that increase wear resistance, and reduces the technological temperature of casting alloys due to the approximation of the chemical composition of the alloy to eutectic [17]. However, the increased initial content of such harmful impurities as oxygen, nitrogen, and sulfur in cast iron of ordinary quality, smelted at the vast majority of foundries, despite all the listed positive qualities of boron as a modifier, significantly limits the effectiveness of its use in its pure form.…”

Section: Introductionmentioning

confidence: 99%

Modifying Effect of a New Boron-Barium Ferroalloy on the Wear Resistance of Low-Chromium Cast Iron

Aubakirov

Issagulov

Kvon

et al. 2022

Metals

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This paper presents the results of a study and analysis of the effect of modifying low-chromium hypoeutectic cast iron with a new boron–barium ferroalloy on its properties—wear resistance and impact resistance—in comparison with traditional boron- and barium-containing additives. The uniqueness and novelty of the work lies in the study of the nature of changes in the structure and wear-resistant properties of low-chromium cast iron as a result of its modifying treatment with a new boron–barium ferroalloy. In a laboratory electric resistance furnace, low-chromium cast iron was melted, and four batches of prototypes were cast. Samples of the first batch, for subsequent comparison, were made without modification. When casting the remaining three batches of samples, the cast iron was modified with three different additives: ferroboron FeB12, ferrosilicobarium FeSi60Ba20, and a new complex boron–barium modifier. In order to compare the degree of effectiveness of the applied modifiers, a metallographic analysis of the structure was performed, hardness measurements were performed on the surface of the samples, and they were subjected to abrasion and cyclic shock-dynamic impact tests. In all cases, when modifying cast iron, there was an increase in hardness, a noticeable grinding of the microstructure, and a redistribution of structural components towards an increase in the proportion of perlite and finely dispersed ledeburite. A comparative analysis of the results of testing samples for dry friction and shock showed a higher surface resistance of cast samples made of modified cast iron compared to unmodified low-chromium cast iron of the same composition. A comparative study of the parameters of wear tracks and craters on damaged surfaces established that the most optimal combination of wear-resistant qualities of low-chromium cast iron occurs when it is treated with a complex boron–barium modifier, which is also evidenced by obtaining a more favorable microstructure.

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“…During solidification of high chromium white cast irons, primary austenite dendrites, followed by a eutectic mixture of austenite and M 7 C 3 carbides or one of its transformation products form (Correa et al, 2011;Filipovic et al, 2011;Tabrett et al, 1996). The high amount of chromium in these alloys favor the formation of carbides (type M 7 C 3 in between 9.5 to 15% Cr and M 23 C 6 above 30 %Cr) and a pearlitic matrix in the absence of alloying additions (Abdel-Aziz et al, 2017; Wiengmoon et al, 2011;Zumelzu et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Yüksek Kromlu Beyaz Dökme Demi̇rlerde Faz Dengesi̇ni̇n Benzeti̇mi̇

Akyıldız¹,

Candemir²,

Yildirim³

2018

Uludağ University Journal of the Faculty of Engineering

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In this study, using the Materials Calculator software program, the pseudo binary phase diagrams (i.e. isoplethal maps) of high chromium white cast irons (~19% in weight) with different molybdenum contents were simulated. In order to test the accuracy of the calculated phase diagrams, the transformation temperatures read from the diagrams at certain compositions were compared with the phase transformation temperatures measured using Differential Scanning Calorimetry (DSC) analysis of the samples produced by casting in the same composition followed by slow cooling. With the same purpose, low temperature phases read from the phase diagrams were compared with the crystalline phases determined by X-Ray Diffraction (XRD) of the casted samples. Simulated diagrams predicted an increase in the amount of secondary M 23 C 6 carbides with increasing molybdenum content. The validity of this prediction was tested by determining the phase distribution and phase compositions in the casted samples by means of metallographic examinations and Scanning Electron Microscopy (SEM)-Energy Dispersive Spectroscopy (EDS) analyzes. When the hardness values of the samples were taken into consideration, it was seen that the hardness increased from 44.90 to 51.05 HRC with a 1% increase in Mo content and a corresponding increase in the amount of secondary carbides without any heat treatments. Results show that theoretical predictions and experimental measurements are in accord and estimating phase equilibria in multi-component systems is of practical importance.

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Effect of boron on microstructure of directionally solidified high chromium white irons

Cited by 14 publications

References 20 publications

Optimization of Graphite Morphology in Mottled Nihard Cast Irons Inoculated with Feb and Manufactured by Centrifugal Casting

Optimization of Graphite Morphology in Mottled Nihard Cast Irons Inoculated with Feb and Manufactured by Centrifugal Casting

Modifying Effect of a New Boron-Barium Ferroalloy on the Wear Resistance of Low-Chromium Cast Iron

Yüksek Kromlu Beyaz Dökme Demi̇rlerde Faz Dengesi̇ni̇n Benzeti̇mi̇

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