Turning processes and mechanism of compacted graphite iron used for high performance engine

Meng, Fanning; Zhang, Zhenyu; Wu, Bin; Hu, Wei; Ai, Xiaonan; Meng, Xiangdong; Ding, Ze; Zhang, Lezhen

doi:10.1016/j.jmapro.2021.06.014

Cited by 15 publications

(3 citation statements)

References 27 publications

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“…Since its first observation in 1948 [2] as a type of cast iron, compacted graphite iron (CGI) was used in numerous industrial applications, including in internal combustion engines (cylinder heads, blocks, brake drums [3], and exhaust manifolds [4]), machinery, and pipes. CGI has a strong potential in the automotive industry, especially diesel engines [5], benefiting from its toughness, thermal-fatigue durability [6], heat resistance [7], and competitive price.…”

Section: Introductionmentioning

confidence: 99%

Effect of Graphite Morphology on the Thermomechanical Performance of Compacted Graphite Iron

Cao

Baxevanakis

Silberschmidt

2023

Metals

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Compacted graphite iron (CGI) has gained significant attention in automotive industry applications thanks to its superior thermomechanical properties and competitive price. Its main fracture mechanism at the microscale—interfacial damage and debonding between graphite inclusions and a metallic matrix—can happen under high-temperature service conditions as a result of a mismatch in the coefficients of thermal expansion between the two phases of CGI. Macroscopic fracture in cast iron components can be initiated by interfacial damage at the microscale under thermomechanical load. This phenomenon was investigated in various composites but still lacks information for CGI, with its complex morphology of graphite inclusions. This research focuses on the effect of this morphology on the thermomechanical performance of CGI under high temperatures. A set of three-dimensional finite-element models was created, with a unit cell containing a single graphite inclusion embedded in a cubic domain of the metallic matrix. Elastoplastic behaviour was assumed for both phases in numerical simulations. The effect of graphite morphology on the thermomechanical performance of CGI was investigated for pure thermal loading, focusing on a high-temperature response of its constituents. The results can provide a deeper understanding of the correlation between graphite morphology and CGI fracture mechanisms under high temperatures.

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Section: Introductionmentioning

confidence: 99%

Effect of Graphite Morphology on the Thermomechanical Performance of Compacted Graphite Iron

Cao

Baxevanakis

Silberschmidt

2023

Metals

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“…Compacted graphite iron (CGI) was often used to manufacture heavy engine parts, for example, cylinder head, for its comprehensive mechanical properties [34]. While, valve seats in cylinder heads would experience severe wear during long-term service at high temperature, which would inhibit the effective working of the engine further.…”

Section: Introductionmentioning

confidence: 99%

Influence of Plasma Arc Current on the Friction and Wear Properties of CoCrFeNiMn High Entropy Alloy Coatings Prepared on CGI through Plasma Transfer Arc Cladding

Gao

Liu

et al. 2022

Coatings

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High-entropy alloys receive more attention for high strength, good ductility as well as good wear resistance. In this work, CoCrFeNiMn high-entropy alloy (HEA) coatings were deposited on compacted graphite iron through plasma transfer arc at different currents. The microstructure and wear properties of the CoCrFeNiMn HEA coatings were investigated. The coatings are composed of single phase with FCC structure. The CoCrFeNiMn HEA coating had the highest microhardness of 394 ± 21.6 HV0.2 and the lowest wear mass loss when the plasma current was 65 A. All of the HEA coatings had higher friction coefficients than that of the substrate. There were adhesive, abrasive and oxidation wear forms in the HEA coatings with the wear couple of N80 alloy. The HEA coating presented higher friction coefficient and better wear resistance than compacted graphite iron.

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“…The tensile strength and hardness of vermicular graphite cast iron are between that of nodular graphite cast iron and gray cast iron, but the heat fatigue resistance and machinability are better than those of nodular graphite cast iron [1][2][3]. Moreover, the good casting performance, wear resistance, and compactness make it widely used in working environments of high mechanical thermal stress, such as in large diesel engines with high power density [4][5][6]. Vermicularity is one of the most important parameters for evaluating vermicular graphite cast iron.…”

Section: Introductionmentioning

confidence: 99%

Influence of FeS2 and FeSi75 in Double-Chamber Sample Cup on Thermal Analysis Curve and Graphite Morphology of Molten Iron

An-li

Tian

Shi

et al. 2023

Metals

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In the production of vermicular graphite cast iron, the allowable range of residual magnesium content in molten iron after treatment is very narrow, amounting to only 0.008%. Therefore, thermal analysis technology was used to quickly evaluate the vermiculation and inoculation level of molten iron at the furnace itself, thus allowing the molten iron to be adjusted in time. The additives in the sample cups play a crucial role in obtaining cooling curves with remarkable characteristics. In this study, either FeS2 or FeSi75 additives were added to one chamber of a double-chamber sample cup made of resin sand, in which the cavities of the double chambers were spherical with diameters of 30 mm. The thermal analysis curves of molten iron in the double-chamber sample cup were acquired using a double channel temperature recorder, and the solidified spherical samples were analyzed quantitatively. The influence of FeS2 or FeSi75 additives on both the cooling curves of molten iron and the graphite morphology were investigated. The experiment’s results indicated that when 0.05% FeS2 is added to one chamber of the sample cup, the cooling curve changes to the solidification pattern of gray cast iron. The continuous increase in the FeS2 additive has little influence on the shape of cooling curves, and the graphite changes form from vermicular to flaked. When the amount of FeS2 is increased from 0.05% to 0.10%, the resulting graphite changes from D-type and E-type to A-type and B-type. When the amount of FeS2 reaches 0.20%, the morphology of graphite is short and thick. With the increase in the amount of FeSi75 additive, the amount of spherical graphite in the sample cup increases gradually, and the vermicularity decreases gradually from 89% to 46%. With the increase in FeSi75 additive from 0 to 0.45%, we observed that the average diameter of graphite decreases from 23 μm to 19 μm and then increases to 22 μm. The eutectic recalescence temperature shows a decreasing trend, and the cooling curve gradually changes from a hypoeutectic to a eutectic pattern. The addition of 0.05% FeS2 or 0.45% FeSi75 to one chamber is more appropriate for a double-chamber sample cup with two spherical cavities with diameters of 30 mm. This lays a foundation for the optimization of additives when using the double-chamber sample cup for thermal analysis of vermicular graphite cast iron.

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Turning processes and mechanism of compacted graphite iron used for high performance engine

Cited by 15 publications

References 27 publications

Effect of Graphite Morphology on the Thermomechanical Performance of Compacted Graphite Iron

Effect of Graphite Morphology on the Thermomechanical Performance of Compacted Graphite Iron

Influence of Plasma Arc Current on the Friction and Wear Properties of CoCrFeNiMn High Entropy Alloy Coatings Prepared on CGI through Plasma Transfer Arc Cladding

Influence of FeS2 and FeSi75 in Double-Chamber Sample Cup on Thermal Analysis Curve and Graphite Morphology of Molten Iron

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