Mechanical and microstructural characterization of Nodular Cast Iron (NCI) with Niobium Additions

Souza, Tânia Nogueira Fonseca; Nogueira, Rogéria Alves Perilo Sousa; Franco, Francis José Saldanha; Aguilar, Maria Teresa Paulino; Cetlin, Paulo Roberto

doi:10.1590/1516-1439.249413

Cited by 17 publications

(6 citation statements)

References 10 publications

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“…It can be concluded that the standard speed makes the crack rate in materials proportionate with its fracture standard. In this research, jagged and dimple fractures that were found in the fracture microstructure and the high elongation define the ductile fracture at 1.5 mm/s speed [4]. Figure 3 shows the cleavage appearances that make it brittle.…”

Section: The Description Of Tensile Test Resultsmentioning

confidence: 64%

Crosshead Speed Effects on Ferro Casting Ductile (Fcd) Tensile Strength and Fault Morphology

Andoko¹

2019

MM SJ

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Nodular cast iron or Ferro casting ductile (FCD) is the developmental result of grey cast iron. Nodular cast iron has mechanical properties similar to carbon steel, which are better than the mechanical properties of grey cast iron. The 1.5 mm/s crosshead speed created a tensile strength of 549.8 N/mm 2 . It gradually declined to 401.4 N/mm 2 at 4.5 mm/s and 302.6N/mm 2 at 9 mm/s. Differentiation in strain rates at the speed variations caused the decline in tensile strength, creating energy lost due to the plastic deformation that resulted in the quick break in the specimen. The increase in strain rates influenced the yield strength results. These occurrences meant that the slower pullout generated a more static material. Thus, there was no declination in the tensile strength. Observed from the fault morphology results, a variant with 1.5 mm/s speed had ductile fractures, 4.5 mm/s speed variant had a combination of ductile-brittle fractures and 9 mm/s speed variant had brittle fractures.

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Section: The Description Of Tensile Test Resultsmentioning

confidence: 64%

Crosshead Speed Effects on Ferro Casting Ductile (Fcd) Tensile Strength and Fault Morphology

Andoko¹

2019

MM SJ

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“…For all HSDI samples with different Nb content, a change in the phase fraction in the metallic matrix was observed, as well as the presence of small irregular particles randomly distributed and corresponding to polygonal primary NbC carbides. These particles form before the casting due to the high affinity between Nb and C atoms, so they are called primary carbides [18,21,22,[24][25][26][27][28][29][30][31]. Unlike other carbide-forming elements (Mo, Cr, and V), precipitation of NbC carbides occurs randomly throughout the material rather than by positive segregation.…”

Section: Microstructural Analysismentioning

confidence: 99%

“…Additionally, Nb has low solubility, especially in ferrous alloys with relatively high carbon content, such as cast iron. The presence of these particles in DI has been reported to improve corrosion resistance and provide good wear resistance with little change in austenite stability and graphite refinement [21][22][23][24][25][26]. However, the effects of a combination of high Si and Nb content on DI have not been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Determination of Corrosion Resistance of High-Silicon Ductile Iron Alloyed with Nb

Valdez

Navarro

Valdés

et al. 2023

Metals

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In this study, the effects of Nb on the microstructural characteristics, hardness, and corrosion resistance of high-silicon ductile cast iron (HSDI)-3.6 wt.% Si were investigated. Samples from different castings with 0–0.9 wt.% Nb were obtained and compared to a commercial ductile iron. Microstructures showed that the amount of ferrite in the matrix increased with increasing Nb content, from 34% for unalloyed HSDI to 88% for HSDI-0.9 wt.% Nb. The presence of randomly distributed NbC carbides was identified by EDX for all the samples alloyed with Nb, and the hardness of the HSDI increased with the Nb content. To evaluate the influence of the Nb content on the corrosion resistance of HSDI, potentiodynamic tests were carried out in a solution of H2SO4. The highest corrosion rate on HSDI was obtained for the HSDI-0.3 wt.% Nb sample, with 2802 mills per year, due to the amount of pearlite present and the lowest presence of NbC carbides, compared to the HSDI-0.9 wt.% Nb, with 986 mills per year. This behavior was attributed to the ferrite matrix obtained because of a high Si content in the DI, which delayed the anodic dissolution of the alloy and suppressed the pearlitizing effect of Nb for contents greater than 0.3 wt.%, as well as to the effect of NbC carbides, which acted as inhibitors.

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“…However, this behaviour appears to have been modified by the type of microstructure developed in the samples on addition of CNSA. (Souza et al, 2014). It is envisaged that the corresponding modest level of hardness conferred on the samples will be beneficial in curtailing the conventional cast irons wear rate in service (Hatate et al, 2001).…”

Section: F Hardnessmentioning

confidence: 99%

Investigation of the Nodularisation Propensity of Calcined Cashew-Nut Shell-Ash in Cast-Iron Melt Graphite

Sekunowo¹,

Ugboaja²,

Tiamiyu³

2021

Nig. J. Technol. Dev.

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Production of ductile iron using ferrosilicon-magnesium master alloy in melt treatment is currently fraught with challenges bothering on cost and availability. In this study the suitability of cashew nut shells ash (CNSA) as a viable alternative to magnesium master alloys employed in the treatment of molten cast iron for enhanced mechanical properties was studied. The carbonized CNSA used varied from 2-10 wt. % to treat different heat batches; CA1-CA5 containing varied amount of CNSA, CaO and FeSi in the molten cast iron. The cast samples were subjected to both mechanical characterisation (tensile, hardness and impact) and microstructural analysis using Instron electromechanical machine, impact tester and scanning electron microscope (SEM) coupled with energy dispersive spectroscope (EDS). Results show that the 8 wt. % CNSA addition demonstrated the best mechanical properties comparable to ASTM A536 ferritic ductile cast iron. Specifically, the 8 wt. % CNSA cast samples exhibited 433 MPa tensile strength, 144HRC hardness and ductility of 14.7%. Contributions to improved mechanical properties may be attributed to the development of sufficient fractions of graphite nodules during melt treatment with CNSA. These outcomes are a boost both to the production of quality ductile irons and a cleaner environment. Keywords: Nodularisation, ductile-iron, cashew-nut, ferrosilicon-magnesium alloy, mechanical properties

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Mechanical and microstructural characterization of Nodular Cast Iron (NCI) with Niobium Additions

Cited by 17 publications

References 10 publications

Crosshead Speed Effects on Ferro Casting Ductile (Fcd) Tensile Strength and Fault Morphology

Crosshead Speed Effects on Ferro Casting Ductile (Fcd) Tensile Strength and Fault Morphology

Determination of Corrosion Resistance of High-Silicon Ductile Iron Alloyed with Nb

Investigation of the Nodularisation Propensity of Calcined Cashew-Nut Shell-Ash in Cast-Iron Melt Graphite

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