Cast Iron Inoculation Enhanced by Supplementary Oxy-sulfides Forming Elements

Riposan, Iulian; Stan, Stelian; Uta, Valentin; Stefan, Ion

doi:10.1007/s11665-017-2869-2

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…It has been found that three groups of elements play an important role in nucleating graphite in industrial gray cast irons: a) Al and Zr, as strong deoxidizing elements promote early forming microinclusions; b) Mn and S to support MnS type sulfide formation; and c) Ca, Ba and Sr, as inoculating elements act in the first stage by forming various oxides that can subsequently nucleate sulfides and in the second stage by changing the lattice parameters of the subsequently nucleated (Mn,X)S compounds [5][6][7]. The amount of inoculant added are in the range from 0.05 to even 1.0 wt.% of the mass metal and depends on the carbon equivalent, sulfur levels, thin sections of casting, raw materials and the time at which the inoculant is added relative to the melting process [8,9]. The Standard ASTM A247 establishes a test method that covers the classification of graphite in cast irons in terms of type, distribution, and size by visual comparison to reference photomicrographs.…”

Section: Introductionmentioning

confidence: 99%

Archives of Metallurgy and Materials

Reyes-Castellanos

Cruz-Ramírez²,

García

et al. 2020

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Low manganese and sulfur gray irons were produced by adding inoculant base Fe-Si with small amounts of Al and Ca in the ladle. The effect of the cast thickness, inoculant amount and shakeout time of the green sand molds were studied on the graphite flake formation by microscopically techniques. A thermodynamic analysis was carried out for the cast iron produced with the FactSage 7.2 software. Stability phase diagrams were obtained for both gray cast irons to different manganese (0.1 to 0.9 wt.%) and sulfur (0.01 to 0.12 wt.%) amounts to 1150°C. It was shown that lower amounts of manganese and sulfur allow forming the 3Al 2 O 3 •2SiO 2 , Al 2 O 3 , and ZrO 2 solid compounds. The thermodynamic results match with those obtained by SEM-EDS. It is possible to form MnS particles in the liquid phase when the solubility product (%Mn) × (%S) equals 0.042 and 0.039 for heats A and B, respectively.

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Section: Introductionmentioning

confidence: 99%

Archives of Metallurgy and Materials

Reyes-Castellanos

Cruz-Ramírez²,

García

et al. 2020

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Effect of La–O–S complex inoculant on microstructure and mechanical characteristics of ductile iron

Feng

Sun

et al. 2022

J Mater Sci

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Effect of Holding Time on Populations of Microparticles in Spheroidal Graphite Irons

Michels

Pires

Ribeiro

et al. 2022

Metall Mater Trans B

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Non-metallic microparticles in spheroidal graphite irons are a product of the inoculation and the Mg-treatment of the liquid melt. Besides the influence on the mechanical properties of these iron–carbon–silicon alloys, they are also responsible for the nucleation and the morphology of the graphite phase. The present investigation is undertaken to study holding time effects of a (Ba, Ca, Al)–ferrosilicon (called Ba-inoculant) and (Ca, Al)–ferrosilicon (called Ca-inoculant) inoculants on the overall distribution of microparticles. Using the 2D to 3D conversions method, which is typically used for graphite nodules, the non-metallic microparticles’ statistical parameters, such as size distributions and number densities, are quantified. The total number of particles is similar after Mg-treatment and inoculation for Ca-inoculant but not for Ba-inoculated samples, which lose approximately 25 pct of microparticles after 1 minute of holding time. Iron treated with the Ca-inoculant loses about 37 pct of its nodules after 5 minutes, while the Ba-inoculated melts maintain their performance even after 10 minutes. Based on extrapolating the trend of the undercooling, Ba-inoculated samples would reach the uninoculated undercooling values in 48 minutes, while Ca-inoculated samples in only 11 minutes. By evaluating the size distributions of the non-metallic microparticles, the Ostwald ripening hypothesis or particle aggregation can be verified. The results suggest that sulfides are more critical for graphite nucleation since they can be correlated with the graphite number densities. However, due to the small difference in the microparticle population of the uninoculated sample with Ca-inoculated samples, other aspects of the fading mechanism need to be considered, such as transient metastable states, since the central hypothesis of loss of inclusions cannot alone explain the decrease in the nucleation frequency of graphite.

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Cast Iron Inoculation Enhanced by Supplementary Oxy-sulfides Forming Elements

Cited by 4 publications

References 18 publications

Archives of Metallurgy and Materials

Archives of Metallurgy and Materials

Effect of La–O–S complex inoculant on microstructure and mechanical characteristics of ductile iron

Effect of Holding Time on Populations of Microparticles in Spheroidal Graphite Irons

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