Variation of Tensile Properties of High Silicon Ductile Iron

Hammersberg, Peter; Hamberg, Kenneth; Borgström, Henrik; Lindkvist, Joachim; Björkegren, Lars Erik

doi:10.4028/www.scientific.net/msf.925.280

Cited by 11 publications

(6 citation statements)

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“…The metallurgical parameters or mechanisms that are significant for tensile strength remain elusive. For GJS-600-10 HSI, the use of adapted runners and filters was paramount in achieving the required elongations [8]. Conversely, the impact data in Figure 1 indicate that mimicking the elongation-only approach entails significant risk.…”

Section: Effect Of Elongation and Impact Properties On High Silicon Ductile Ironmentioning

confidence: 99%

“…Based on the elongation data to the left in Figure 1, GJS-500-14 was produced with 3.5 to 4.5% Si and GJS-600-10 was produced with 4 to 5% Si if the specification limits stipulated in EN1653 were followed [6]. HSI castings with 4 to 5% Si partially adhering to GJS-600-10 were nearly independent of key casting process parameters like nodularity, nodule count and carborn eqivalent, CE, when determining, ultimate tensile stress (UTS or R m ), yield strength (R p ) and elongation (A%) [7,8]. The metallurgical parameters or mechanisms that are significant for tensile strength remain elusive.…”

Section: Effect Of Elongation and Impact Properties On High Silicon Ductile Ironmentioning

confidence: 99%

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Influence of Strain Rate, Temperature and Chemical Composition on High Silicon Ductile Iron

Borgström¹

2021

Minerals

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Today, the use of solution hardened ductile iron is limited by brittleness under certain conditions. If chassis components are subjected to loads having high strain rates exceeding those imposed during tensile testing at sub-zero temperatures, unexpected failure can occur. Therefore, it is the purpose of this review to discuss three main mechanisms, which have been related to brittle failure in high silicon irons: intercritical embrittlement, the integrity of the ferritic matrix and deformation mechanisms in the graphite. Intercritical embrittlement is mainly attributed to the formation of Mg- and S-rich grain boundary films. The formation of these films is suppressed if the amount of free Mg- and MgS-rich inclusions is limited by avoiding excess Mg and/or by the passivation of free Mg with P. If the grain boundary film is not suppressed, the high silicon iron has very low elongations in the shakeout temperature regime: 300 to 500 °C. The integrity and strength of the ferrite are limited by the reduced ordering of the silicumferrite with increasing silicon content, once the “ordinary” ferrite is saturated at 3% silicon, depending on the cooling conditions. Finally, the graphite damaging mechanisms are what dictate the properties most at low temperatures (sub −20 °C).

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Section: Effect Of Elongation and Impact Properties On High Silicon Ductile Ironmentioning

confidence: 99%

Section: Effect Of Elongation and Impact Properties On High Silicon Ductile Ironmentioning

confidence: 99%

Influence of Strain Rate, Temperature and Chemical Composition on High Silicon Ductile Iron

Borgström¹

2021

Minerals

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“…Despite the highest content of silicon (4.55-5.25% Si), the third group is characterized by an intermediate Px level (1.52-1.72), due to the higher incidence of presence of the minor elements. Then it could be concluded that the favorable effect of high silicon content in ferrite formation allows the tolerance of higher amounts of pearlite and carbide stabilizing elements in the chemical composition of the High-Si ductile cast irons [1,2,14,15].…”

Section: Chemical Compositionmentioning

confidence: 99%

Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Stan

Anca

Stan

et al. 2021

Metals

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The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (<3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

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“…An improvement of the machinability, maintaining or even improving the mechanical properties of the ferritic-pearlitic SGI, was the starting point for the first investigations on these high Si cast irons. 1,2 The European Standard EN-1563:2012 introduced three new grades of fully ferritic SGI, characterized by a higher Si content that induces a strengthening of the ferrite by solid solution: Si solid solution strengthened full ferritic ductile iron grades (SSF DI). The guidance values for the chemical composition are presented in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Damping Behaviour of High Silicon Nodular Cast Iron

Pereira

Anjos²,

Alonso

et al. 2023

Inter Metalcast

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This work focused on producing and characterizing high silicon cast irons (microstructural analysis, tensile properties, damping capacity, elastic properties). Moreover, it also evaluated the influence of RE alloying on damping capacity. The samples present a step-casting geometry to verify the cooling rate’s impact on their microstructures and, consequently, on the mechanical properties. The high Si SGI presented a fully ferritic matrix (i.e. pearlite < 5%) with uniform dispersed graphite nodules; however, those also RE alloyed showed a lower nodularity. The results show an average increase, relative to the base SGI, of 33% for tensile strength and 55% for yield strength (section thicknesses between 45 and 25 mm). A damping capacity increase was observed, reaching a maximum increase of 32% with the addition of RE. The beneficial impact lies in the possibility of increasing the damping capacity of SGI, without compromising its tensile strength, by balancing the graphite degeneration (induced by RE alloying) and strengthening the ferritic matrix (promoted by the high Si content).

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Variation of Tensile Properties of High Silicon Ductile Iron

Cited by 11 publications

References 1 publication

Influence of Strain Rate, Temperature and Chemical Composition on High Silicon Ductile Iron

Influence of Strain Rate, Temperature and Chemical Composition on High Silicon Ductile Iron

Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Damping Behaviour of High Silicon Nodular Cast Iron

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