Effect of Cooling Rate on Graphite Morphology and Mechanical Properties in High-Silicon Ductile Iron Castings

Bauer, Branko; Pokopec, Ivana Mihalic; Petrič, Mitja; Mrvar, Primož

doi:10.1007/s40962-020-00432-3

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…Furthermore, in comparison with nonvibrational casting, the nodularity percentages of 0.9 mm and 1.8 mm amplitude castings are increased by 3.8% and 8.1%, whereas the standard deviations of the castings dropped by 45% and 75%, respectively. In applying vibration to the cast metals [13,44] , the basic harmonic motion creating periodic tension pressure in liquid metals could lead to improve nodularity, thus it enhanced mechanical properties, such as elongation, damping capacity, impact energy [44,45] .…”

Section: Nodularitymentioning

confidence: 99%

Microstructural analysis of EN-GJS-450-10 ductile cast iron via vibrational casting

Yüksel

2020

China Foundry

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C ast irons are the most widely used engineering materials in the world with 71% of total metal casting all over the world, followed by non-ferrous and steel castings with 17% and 9%, respectively, following World Casting Census [1, 2]. Among the cast iron family, ductile, or spheroidal cast irons exhibit outstanding properties, such as castability, strength/weight ratio, and corrosion resistance [3]. With these well-developed features, the production of ductile iron was increased substantially in the last decade comparing with other cast iron groups [2]. Also, ductile irons are suitable for mass production such as components of windmills [4-6]. Whether the matrix of the ductile iron will be ferritic, pearlitic, or both, the type of graphite could be controlled with the addition of alloying elements [7-12]. Some other techniques, such as electromagnetic, ultrasonic vibrations were developed to modify the

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Section: Nodularitymentioning

confidence: 99%

Microstructural analysis of EN-GJS-450-10 ductile cast iron via vibrational casting

Yüksel

2020

China Foundry

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“…The deviation, using a sphere as a reference of graphite particles, was noticeably increased by Si-alloying (from 2.5 up to 5.5%Si) when a characteristic of the graphite particles appeared to be a larger perimeter, resulting in a large category [IV, V, VI forms, ISO 945] [ 8 , 9 , 10 , 11 ]. According to [ 12 , 13 , 14 ], the 3.5% Si ductile iron showed good nodularity. In contrast, with increasing silicon content to 4.5%, significant graphite degeneracy occurred, with the appearance of chunky graphite, negatively affecting the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Graphite Nodularity Evaluation in High-Si Ductile Cast Irons

et al. 2022

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Ferritic high-Si ductile cast irons replace an unstable mixed ferrite-pearlite matrix with a unique combination of high elongation, strength and hardness (ideal for automotive drive train components) and resistance to oxidation and corrosion at high temperatures (automotive exhaust and turbocharger systems). The present paper analyses the graphite parameters of 4.5%Si, un-inoculated ductile cast iron (4.7%CE, 0.035%Mgres) as an effect of the casting section size. The structure is characterized by 10.5–11.2% graphite and 464–975 nodules/mm2, at more than 70% ferrite and no carbides, including at 3 mm wall thickness. The lower the wall thickness is, the higher the nodule count is and, consequently, the higher the ferrite amount is. The Roundness Graphite Shape Factor (RSF = 0.65–0.68) illustrates the presence of Slightly Irregular Spheroidal Graphite (Form V ISO 945). There is a big difference between the graphite nodularity evaluated according to ISO 16112:2017 [CGI] (NG1 = 79–86%) and according to ISO 945-4-2019 (DI) (NG2 = 65.2–74.6%), both of them based on RSF. Graphite Nodularity (NG3), calculated with the ISO 945-4-2019 [DI] formula, but replacing RSF with SSF, Sphericity Graphite Shape Factor, has an intermediary position. The higher the imposed minimum RSF or SSF is, the lower the Graphite Nodularity (NG4, NG5): 80–90% for min. 0.50 (minimum Form IV or Intermediate Graphite), 60–80% for min. 0.60–0.65 (minimum Form V graphite) and 35–70% for min. 0.80 (minimum Form VI graphite). The SSF is more representative than the RSF for Si-alloyed ductile cast iron, so it is recommended to use a graphite nodularity calculus considering SSF instead of the RSF formula (stipulated by ISO 945-4-2019), with SSF replacing RSF.

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“…Adding a small amount of magnesium can change graphite from a lamellar shape to discrete graphite spheroids with an associated marked increase in mechanical properties (Doru, 2017). Recent research by Bauer et al, (2020aBauer et al, ( , 2020b has indicated that adding bismuth and changing the cooling rate can also change the graphite shape. However, elimination of graphite to improve the corrosion resistance of high silicon iron-based alloys has not previously been described in similar studies.…”

Section: Introductionmentioning

confidence: 99%

Effect of electrolysis parameters on corrosion resistance of extra-low carbon high silicon iron-based alloy

Zhang

Xiao

Yang

et al. 2021

ACMM

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Purpose High silicon iron-based alloys possess excellent corrosion resistance in certain specific media, but the effects of electrolysis parameters on corrosion resistance remain unknown. This study aims to guide the development and application of an extra-low carbon high silicon iron-based alloy (ECHSIA) in electrode plates. Design/methodology/approach The corrosion resistance of ECHSIA and a conventional high-silicon cast iron (CHSCI) was analyzed through experimental characterizations. The morphology was observed by scanning electron microscopy. The influence of electrolysis parameters on the corrosion resistance of ECHSIA was investigated through corrosion experiments. The relationship between the electrolysis parameters and the corrosion resistance of ECHSIA was statistically investigated using the grey correlation analysis method. Findings The corrosion resistance of the ECHSIA is better than that of the CHSCI. The corrosion rate showed an increasing tendency with the increase in the nitric acid concentration (CHNO3), electrolyte temperature and current density. The grey correlation analysis results showed that the CHNO3 was the main factor affecting the corrosion rate of the ECHSIA. Originality/value An ECHSIA with a single ferrite microstructure was prepared. This study provides a guideline for the future development and application of ECHSIAs as electrode plates.

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Effect of Cooling Rate on Graphite Morphology and Mechanical Properties in High-Silicon Ductile Iron Castings

Cited by 12 publications

References 8 publications

Microstructural analysis of EN-GJS-450-10 ductile cast iron via vibrational casting

Microstructural analysis of EN-GJS-450-10 ductile cast iron via vibrational casting

Graphite Nodularity Evaluation in High-Si Ductile Cast Irons

Effect of electrolysis parameters on corrosion resistance of extra-low carbon high silicon iron-based alloy

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