The role of boron content in high alloy white cast iron (Ni-Hard 4) on microstructure, mechanical properties and wear resistance

Çöl, Mustafa; Koç, Funda Gül; Öktem, Hasan; Kır, Durmuş

doi:10.1016/j.wear.2015.12.007

Cited by 32 publications

(14 citation statements)

References 20 publications

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“…B may combine with the N dissolved in the molten metal forming particles of BN that can act as heterogeneous nucleating agents of graphite [23]. B can also form carbides, thereby improving the wear resistance of the material [24,25]. Nb tends to reduce the eutectic cell, which could result in graphite of smaller size that is more uniformly distributed [19,26].…”

Section: Introductionmentioning

confidence: 99%

Control over the Percentage, Shape and Size of the Graphite Particles in Martensitic White Castings Alloyed with Cr, Nb and Mg

et al. 2019

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This paper presents the results obtained regarding the control by manufacturers of the percentage, shape, and size of the precipitated graphite in the working layer of duplex work-rolls used in hot strip mill finishing stands. This working layer is manufactured in a martensitic white cast iron alloyed with Cr and Nb to promote the precipitation of M3C and MC carbides, which provide a high wear resistance. The thermal cycling behavior of this layer also has a decisive influence on its service life. In this context, the percentage of graphite and its morphology play a very important role against said thermal cycling. With the aim of studying their effect on the sphericity of graphite, the analyzed industrial manufacturing factors worth highlighting include the liquidus temperature, the %Si, the use of an FeSi inoculant with traces of Lanthanum, inoculation with different amounts of FeB and SiCaMn, and the addition of Mg. At the periphery of the working layer, it was found that the use of the FeSi inoculant with traces of La promoted an increase in the density of counts of graphite, and that inoculation with FeB and the addition of 0.02% Mg diminished the nodularity of the graphite. Furthermore, throughout the entire thickness of the working layer, an increase in the amount of SiCaMn of up to 0.6 kg/T produced an increase in the size of the graphite particles and a marked improvement in their nodularity.

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Section: Introductionmentioning

confidence: 99%

Control over the Percentage, Shape and Size of the Graphite Particles in Martensitic White Castings Alloyed with Cr, Nb and Mg

et al. 2019

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“…Previous research concludes that additions of B promote an increase in the percentage of carbides and an increase in wear resistance. However, their addition could affect the flexural strength of the material [18]. Moreover, the addition of Mg and other elements such as Ca and La promote the precipitation of graphite with a nodular morphology [19].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Fracture Strength in the Working Layer of Rolls Manufactured in Ni-Hard Cast Iron Alloyed with Mo, Nb and Mg

Cofiño-Villar

Álvarez-Antolín

Lozano

2018

Metals

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One of the main in-service failure mechanisms of the work-rolls used in hot strip mill finishing stands is surface spalling. The indefinite chill double-poured rolls usually comprise of a peripheral working layer made of crushed Ni-hard cast iron and a grey cast iron core, mostly pearlitic matrix with spheroidal graphite. To enhance its wear resistance, the working layer can be alloyed with Mo and Nb. The possible cracking and spalling of the surfaces of these work-rolls is strongly influenced by the presence of carbides and the continuity of their network. The flexural and impact toughness tests are reliable testing methods to assess these properties. The aim of this paper is to identify those manufacturing factors that have a significant effect on the flexural strength and toughness of this material, correlating the results with the volume fraction of precipitated carbides. It is worth highlighting, among the analysed factors are the liquidus temperature, the %Si, the use of an inoculant with traces of Lanthanum, and inoculation with different amounts of FeB, SiCa and Mg. Inoculation with SiCa is found to have a positive effect on the toughness of the material, breaking up the continuity of the carbide network, while FeB is found to act as a heterogeneous nucleant for NbC precipitation. However, high FeB contents reduce flexural strength and do not have a significant effect on the hardness of the material. To enhance the fracture toughness of the working layer, a liquidus temperature in the 1270–1275 °C range is recommended, as well as inoculating the ladle with Mg, 3 kg/T FeB and 0.6 kg/T SiCa.

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“…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]. Another new manufacturing factor included in this study was the % Ni.…”

Section: Introductionmentioning

confidence: 77%

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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The role of boron content in high alloy white cast iron (Ni-Hard 4) on microstructure, mechanical properties and wear resistance

Cited by 32 publications

References 20 publications

Control over the Percentage, Shape and Size of the Graphite Particles in Martensitic White Castings Alloyed with Cr, Nb and Mg

Control over the Percentage, Shape and Size of the Graphite Particles in Martensitic White Castings Alloyed with Cr, Nb and Mg

Enhanced Fracture Strength in the Working Layer of Rolls Manufactured in Ni-Hard Cast Iron Alloyed with Mo, Nb and Mg

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

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