Effect of homogenisation treatment on segregation of silicon in ferritic ductile irons: a colour metallographic study

Yeung, C. F.; Zhao, He; Lee, Wing Bun

doi:10.1179/026708399101506427

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…The real Si segregation will be between these extremal predictions and depends on cooling rate and graphite nodule number. 26 So, thermodynamic prediction well-fitted experimentally observed negative Si segregation.…”

Section: Simulation and Experimental Procedures Alloy Simulation And ...supporting

confidence: 65%

Control of High-Temperature Static and Transient Thermomechanical Behavior of SiMo Ductile Iron by Al Alloying

et al. 2022

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Silicon and molybdenum (SiMo) ductile iron is commonly used for exhaust manifolds because these components experience thermal cycling in oxidizing environment, which requires resistance to fatigue during transient thermomechanical loads. Previous studies have demonstrated that alloying elements, such as Al, to SiMo ductile iron reduces the amount of surface degradation during static high-temperature exposure. However, deterioration of sphericity of the graphite nodules and a decrease in ductility could affect the tendency of cracking during thermal cycling. In this article, the effect of Al alloying on static and transient thermomechanical behavior of SiMo ductile iron was investigated to optimize the amount of Al alloying. A thermodynamic approach was used to confirm the effect of the Al alloying on the phase transformations in two SiMo cast irons, alloyed by 1.8% Al and 3% Al. These two alloys were cast in a laboratory along with the baseline SiMo ductile iron. Several experimental methods were used to evaluate the dimensional stability, physical properties, static oxidation, and failure resistance during constrained thermal cycling testing to compare their high-temperature capability. Experimental results verified that Al alloying increases the temperature range and decreases volume change during eutectoid transformation, which together with enhancement of oxidation protection improved the dimensional stability. Thermocycling tests showed that the number of cycles to failure depends on the amount of Al alloying and the applied high-temperature exposure during each cycle. SEM/EDX, high-resolution TEM and µCT analysis were used to verify the mechanism resulting from the Al alloying protection. It was shown that an optimal level of Al alloying for balancing oxidation and thermal cracking resistance depends on thermomechanical conditions of application.

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Section: Simulation and Experimental Procedures Alloy Simulation And ...supporting

confidence: 65%

Control of High-Temperature Static and Transient Thermomechanical Behavior of SiMo Ductile Iron by Al Alloying

et al. 2022

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“…Therefore, the content of silicon must be controlled in the production of heavy-section ductile cast iron. Generally, a suitable addition of silicon can obviously improve the graphite sphere grade and nodularity of heavy section ductile iron [9]. However, when the content is 2.74 wt.%, the aggregation of chunky graphite occurs, as shown in Figure 5b4.…”

Section: Figurementioning

confidence: 99%

“…S.I. Karsay and E. Campomanes [4][5][6][7][8][9] studied the influence of silicon content on ductile iron, and found that lower silicon content can reduce the performance of chunky graphite iron, especially in its capacity to demonstrate good impact performance at low temperatures. The proper content of silicon can increase the nodularity and improve the mechanical properties of heavy section ductile iron, and inhibit graphite floatation and chunky graphite formation [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Effects of Silicon on Mechanical Properties and Fracture Toughness of Heavy-Section Ductile Cast Iron

Song

Guo

Wang

et al. 2015

Metals

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Abstract:The effects of silicon (Si) on the mechanical properties and fracture toughness of heavy-section ductile cast iron were investigated to develop material for spent-nuclear-fuel containers. Two castings with different Si contents of 1.78 wt.% and 2.74 wt.% were prepared. Four positions in the castings from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties' testing. Results show that the tensile strength, elongation, impact toughness and fracture toughness at different positions of the two castings decrease with the decrease in cooling rate. With an increase in Si content, the graphite morphology and the mechanical properties at the same position deteriorate. Decreasing cooling rate changes the impact fracture morphology from a mixed ductile-brittle fracture to a brittle fracture. The fracture morphology of fracture toughness is changed from ductile to brittle fracture. When the Si content exceeds 1.78 wt.%, the impact and fracture toughness fracture morphology transforms from ductile to brittle fracture. The in-situ scanning electronic microscope (SEM) tensile experiments were first used to observe the dynamic tensile process. The influence of the vermicular and temper graphite on fracture formation of heavy section ductile iron was investigated. OPEN ACCESSMetals 2015, 5 151

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Ferrite Growth During Cooling Through the Ferrite-Austenite-Graphite Field in SGI

García

Carazo

Boeri

2019

Metall Mater Trans A

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Effect of homogenisation treatment on segregation of silicon in ferritic ductile irons: a colour metallographic study

Cited by 3 publications

References 4 publications

Control of High-Temperature Static and Transient Thermomechanical Behavior of SiMo Ductile Iron by Al Alloying

Control of High-Temperature Static and Transient Thermomechanical Behavior of SiMo Ductile Iron by Al Alloying

Effects of Silicon on Mechanical Properties and Fracture Toughness of Heavy-Section Ductile Cast Iron

Ferrite Growth During Cooling Through the Ferrite-Austenite-Graphite Field in SGI

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