The relationship between inclusion clustering and embrittlement of ferritic spheroidal graphite cast iron at intermediate low temperatures

Shiao, F. T.; Lui, Truan-Sheng; Chen, Lihui; Song, Jenn‐Ming

doi:10.1080/13640461.2001.11819432

Cited by 2 publications

(5 citation statements)

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“…3.1 Effect of solidification cooling rate on the variation of eutectic cell morphologies From previous investigations, [8][9][10] it is clear that the tensile properties of SG cast iron at elevated temperatures are strongly dependent on the feature of the eutectic cell morphology. Figure 3 shows the electrochemically-etched ferritic SG cast iron, the morphology of the eutectic cell wall is marked by arrows.…”

Section: Resultsmentioning

confidence: 99%

“…This was the dominant factor causing a deterioration in tensile properties after the specimen suffered a cyclic heating process. [8][9][10][11][12][13][14] In this case, in spite of the tensile tested be performed at room temperature, ductility deterioration caused by intergranular fracture was identified. This raises the questions of how the dispersed MgO inclusions affect the intergranular fracture behavior, and the effect of the eutectic cell wall morphology during these severe cyclic heating/ cooling processes on reliability.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Microstructural Refinement on Ductility Deterioration of High Silicon Ferritic Spheroidal Graphite Cast Iron Caused by Cyclic Heating

2003

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This investigation applies cyclic heating and cooling to elucidate the effect of microstructural refinement on the tensile elongation deterioration of ferritic spheroidal graphite cast iron. In order to eliminate the oxidation factor, the cyclic heating/cooling test was performed in a 1:33 $ 0:133 Pa ambient vacuum atmosphere with cyclic heating at a maximum temperature of 1023 K. Severe embrittlement accompanied by intergranular fracture occurred after the ferritic spheroidal graphite cast iron was subjected to a certain number of heating and cooling cycles. A fair amount of inevitable inclusion particles were found to agglomerate in the eutectic cell boundary region, and so the cyclic heating induced embrittlement can be recognized to be strongly dependent on the solidification cooling rate of the materials. Based on experimental evidence, the cracking evolution can be divided into three steps: (1) crack initiation from the vicinity of the eutectic cell boundary at the surface, (2) crack linking and major crack formation, and (3) major crack inward extension. Cyclic heating cracks are mainly initiated at the eutectic cell boundary where a fair amount of MgO inclusions dispersed, and consequently propagated along the annealed eutectic cell boundary. While investigating the plastic deformation behaviors around the above mentioned MgO inclusions pertaining to the crack initiation and crack propagation, typical etch pit evidence was observed in the vicinity of the cell boundary area.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Microstructural Refinement on Ductility Deterioration of High Silicon Ferritic Spheroidal Graphite Cast Iron Caused by Cyclic Heating

2003

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“…Here, ferritic-pearlitic castings were free from 673 K embrittlement, and 3.9% Si HSI had less than 5% elongation between 300 and 500 °C. For the latter, GJS-400-18 iron lower carbon equivalents also led to increased inclusion clustering; owing to the temperature difference between the liquidus and solidus temperature [31]. Unfortunately, no 673 K properties were investigated for this GJS-400-18, but at very low temperatures (−75 °C), fracture initiated around the graphite instead of in Mg-rich inclusions at the grain boundary [31].…”

Section: Intergranular and Transgranular Embrittlementmentioning

confidence: 98%

“…For the latter, GJS-400-18 iron lower carbon equivalents also led to increased inclusion clustering; owing to the temperature difference between the liquidus and solidus temperature [31]. Unfortunately, no 673 K properties were investigated for this GJS-400-18, but at very low temperatures (−75 °C), fracture initiated around the graphite instead of in Mg-rich inclusions at the grain boundary [31]. For normal ferritic iron, the encountered 673 K embrittlement was shown to be dependent on strain rate, chemical composition and temperature [32,33].…”

Section: Intergranular and Transgranular Embrittlementmentioning

confidence: 99%

“…Consequently, for normal ferritic irons, the drop below 10% elongation (with intergranular fracture) occurred between 300 • C (573 K) and 500 • C (773 K) for low strain rates of 4.4 × 10 −5 to 2.8 × 10 −4 [32,33]. For high strain rates of 1.4 × 10 −2 and 2 × 10 −2 , the drop below 10% elongation (with intergranular fracture) occurred between 400 • C (573 K) and 680 • C (973 K) [31,32].…”

Section: Intergranular and Transgranular Embrittlementmentioning

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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The relationship between inclusion clustering and embrittlement of ferritic spheroidal graphite cast iron at intermediate low temperatures

Cited by 2 publications

References 4 publications

Effect of Microstructural Refinement on Ductility Deterioration of High Silicon Ferritic Spheroidal Graphite Cast Iron Caused by Cyclic Heating

Effect of Microstructural Refinement on Ductility Deterioration of High Silicon Ferritic Spheroidal Graphite Cast Iron Caused by Cyclic Heating

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

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