Tribological Characterization of Centrifugally Cast Graphite Cast Iron under Dry and Wet conditions

Gowda, D. S. Sake; Kumar, D. Charan; Sandeep, G.; Parthasarathy, Adithya; Chandrashekar, Subhash

doi:10.1016/j.matpr.2017.11.065

Cited by 15 publications

(10 citation statements)

References 4 publications

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“…In contrast, a spheroidal geometry reduces the evacuation of heat, but constitutes a barrier to the progression of said cracks. Furthermore, graphite performs dry lubrication functions [12], reducing the coefficient of friction between the work roll and the sheet steel to be rolled [13]. One of the quality indicators established for the working layer of these rolls is the volume fraction of graphite.…”

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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“…The presence graphite increases resistance to thermal shock. At the same time, the graphite perfor functions of dry lubrication, thus reducing the coefficient of friction between the roll a the sheet of steel [4,[14][15][16][17][18]. The aim of this study is to identify those manufacturing factors which have a sig icant effect on resistance to wear on the work layer.…”

Section: Introductionmentioning

confidence: 99%

Improvement in the Resistance to Wear of Work-Rolls Used in Finishing Stands of the Hot Strip Mills

Cofiño-Villar

Álvarez-Antolín

Alvarez-Perez

2021

Metals

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Work-rolls manufactured through the Indefinite Chill Double Poured (ICDP) method present an exterior work layer manufactured in a martensitic white cast iron alloyed with 4.5 %Ni, 1.7 %Cr, and 0.7 %Nb (wt.%). In its microstructure, there are abundant carbides of the type M3C and MC, which give high resistance to wear, and graphite particles which improve the service behaviour of the rolls against thermal cycling. The core of the rolls is manufactured in grey cast iron of pearlitic matrix and spheroidal graphite. These work-rolls are used in the finishing stands in Hot Strip Mills for rolling slabs proceeding from continuous casting at 1200 °C. Through the application of a Design of Experiments (DoE), an attempt has been made to identify those manufacturing factors which have a significant effect on resistance to wear of these rolls and to find an optimal combination of levels of these factors which allow for improvement in resistance to wear. To increase resistance to wear, it is recommended to situate, simultaneously, the liquidus temperature and the percentage of Si in the respective ranges of 1250–1255 °C and 1.1–1.15 (wt.%). Higher liquidus temperatures favour the presence of the pro-eutectic constituent rather than the eutectic constituent. The outer zone of the work layer, in contact with the metal sheet, which is being rolled, does not show the graphitising effect of Si (0.8–1.15 wt.%). On the contrary, it confirms the hardening effect of the Si in solid solution of the ferrite. The addition of 0.02% of Mg (wt.%) and the inoculation of 6 kg/T of FeB tend to eliminate the graphitising effect of the Si, thus favouring that the undissolved carbon in the austenite is found to form carbides in contrast to the majority formation of graphite.

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“…Whether the test is carried out in dry or lubricated conditions, the velocity of counter-moving parts during the test and applied load all have controlling effects on the wear behavior of alloys. For instance, gray cast iron shows much better wear resistance in lubricated conditions, obviously because of the lower friction coefficient [9][10][11][12]. Gray cast iron alloys are known to have a self-lubricating characteristic due to the presence of graphite flakes in their microstructures, making 2 of 10 them an appropriate choice for sliding components in mechanical assemblies and installations [3,13,14].…”

Section: Introductionmentioning

confidence: 99%

Wear Induced Failure of Automotive Disc Brakes—A Case Study

et al. 2019

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This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer edge of the disc brake. The cracks were rather straight with no branching. Optical microscope, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of the samples. Results showed that the root cause of crack formation, in this case, was related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wear, were recognized in the failed specimen. Moreover, the worn surface in some areas was covered with fine oxide particles. These particles appeared to have a significant contribution toward abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on the samples. Results of the pin-on-disc experiments were compared and correlated to the results obtained from the failed brake disc.

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Tribological Characterization of Centrifugally Cast Graphite Cast Iron under Dry and Wet conditions

Cited by 15 publications

References 4 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

Improvement in the Resistance to Wear of Work-Rolls Used in Finishing Stands of the Hot Strip Mills

Wear Induced Failure of Automotive Disc Brakes—A Case Study

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