Influence of Melting Conditions on Graphite Morphology in Spheroidal Graphite Cast Iron Using Ni-C Alloys

2010 ◽  
Vol 457 ◽  
pp. 37-42 ◽  
Author(s):  
Yuji Kato ◽  
Ying Zou ◽  
Hideo Nakae
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
High Purity ◽  
Holding Time ◽  
Spheroidal Graphite ◽  
Graphite Morphology ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Group 2 ◽  
Group 1

The effects of the cooling rate, atmosphere and holding time on the graphite morphology of spheroidal graphite cast iron were studied using Ni-C alloys. Two groups of parent alloys were prepared using high purity materials, i.e., Group 1 containing the spheroidizing element of Ce, Mg or Ca, while in Group 2, S was added as an anti-spheroidizing element. For discussing the influence of the cooling rate on the graphite morphology, 0.5g of the Group 1 samples were melted and held for 15 minutes at 1673K in an Ar atmosphere, then cooled at 1000K/min or 20K/min. The results showed that perfect spheroidal graphite could not be confirmed, while irregular graphite appeared. The atmosphere was changed to Ar+3%H2 for preventing the oxidation, and the holding time was reduced to 10 minutes to prevent fading of the spheroidizing element. These results showed that the formation of spheroidal graphite was confirmed at the cooling rate of 1000K/min in both groups. Nevertheless, at the cooling rate of 20K/min, graphite morphology was only chunky or flake in both groups. In order to investigate which parameter is more important for the formation of spheroidal graphite, the atmosphere and the holding time were independently changed at the cooling rate of 1000K/min. It was found that the addition of the 3%H2 did not significantly affect the spheroidal graphite formation. Moreover, the holding times of 1min and 20min also did not significantly affect the spheroidal graphite area fraction in the Ni-C alloy, while they affected the ones containing the spheroidizing elements like Mg.

Effect of Strontium Addition in Graphite Morphology and Nodularization of Hypoeutectic Cast Iron

2020 ◽  
Vol 1000 ◽  
pp. 454-459
Author(s):  
Rahmadi ◽  
Deni Ferdian
Keyword(s):  
Cast Iron ◽  
Image Data ◽  
Optical Microscope ◽  
Spheroidal Graphite ◽  
Data Processing Software ◽  
Graphite Morphology ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Molten Cast Iron ◽  
Nodular Graphite

Nodular graphite cast iron or known as spheroidal graphite cast iron structurally has a spherical graphite morphology with a matrix consisting of a ferrite-pearlite phase. In general, cast iron has a main alloy consisting of carbon and silicon where both elements have an influence on the potential of graphitization and castability. In this work, the influence of strontium (Sr) added to molten cast iron with a composition of 0, 0.04, 0.06 and 0.08 wt% to graphite morphology were studied. The sample obtained will be carried out a characterization process by observing macro and microstructures using optical microscope equipped with image data processing software that displays graphite fraction, size, form and nodularity. Analysis showed that Sr addition increase in nodularization of graphite from 19.6 % to 31.5% at 0.08 wt% Sr addition.

Influence of Cooling Rate and Alloying Elements on Kinetics of Eutectoid Transformation in Spheroidal Graphite Cast Iron

2010 ◽  
Vol 457 ◽  
pp. 163-168 ◽  
Author(s):  
Primož Mrvar ◽  
Mitja Petrič ◽  
Jožef Medved
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Alloying Elements ◽  
Spheroidal Graphite ◽  
Eutectoid Transformation ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Short Time ◽  
Kinetics Of

Paper deals with influence of cooling rate and alloying elements on kinetics of eutectoid transformation in spheroidal graphite cast iron (SGI). Transformation of austenite can proceed into ferrite and graphite (FeFeG) and/or in pearlite (Fe  FeFe3C). Examination of eutectoid transformation was made by evaluating the “in-situ” dilatation curves together with metallographic examinations, DTA, and dilatation analyses in solid state. ThermoCalc software was applied for thermodynamic calculations of phase equilibria. Based on numerous quantitative relations, such as relation between fractions of ferrite and pearlite in the as-cast SGI that was determined by analysis of dilatometric curves and taking into account also composition of melt, ferrite/pearlite ratio in the microstructure could be determined in a very short time. Thus the melt composition could be corrected by adding Cu and/or Mn or Si, respectively, using the "in situ" dilatation analyses. Characteristic temperatures of eutectoid transformation have been established from the kinetics of austenite transformation and from temperature dependence of ferrite and/or pearlite growth. Kinetics curves that enable to determine fractions of single microstructure constituents in the microstructure as function of transformation time, mainly used for ferrite and pearlite SGI, can be well determined with physical sigmoidal Boltzmann model.

Influences of Silicon and Phosphorus Contents and Cooling Rate on JIC Fracture Toughness of Ferritic Spheroidal Graphite Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
Shinichiro Komatsu ◽  
Toshio Shiota
Keyword(s):  
Fracture Toughness ◽  
Cast Iron ◽  
Cooling Rate ◽  
Compact Tension ◽  
Graphite Nodule ◽  
Spheroidal Graphite ◽  
Test Pieces ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Curve Method

ABSTRACTThe influences of silicon and phosphorus contents and cooling rate on JIC fracture toughness of ferritic spheroidal graphite cast iron were investigated by 15mm thick compact tension test-pieces. The JIC values were measured by means of the R-curve method for most cases at 20°C, and by means of the maximum J value method for the cases at -100° C. The results obtained are summarized as follows. At 20WC, the specimens with silicon contents less than 3.2% showed the ductile Load-COD relations, but a specimen with 3.5%Si showed a brittle Load-COD relation and the JIC decreased greatly. Increasing phosphorus content between 0.006% and 0.26% made the JIC value decrease gradually and made the slope of the R-curve decrease greatly. Difference in cooling rate produced differences in graphite nodule diameters and ferrite grain sizes. At 20°C, the larger the specimen's average graphite nodule diameter was, the larger the JIC value was. At -100° C, the Jic values of all the specimens tested decreased largely, and the influences of these factors became very different from those at 20° C.

scholarly journals Influence of Graphite Morphology on Phase, Microstructure, and Properties of Hot Dipping and Diffusion Aluminizing Coating on Flake/Spheroidal Graphite Cast Iron

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 450 ◽  
Author(s):  
Yu Zhang ◽  
Yongzhe Fan ◽  
Xue Zhao ◽  
An Du ◽  
Ruina Ma ◽  
...  
Keyword(s):  
Cast Iron ◽  
Spheroidal Graphite ◽  
Temperature Oxidation ◽  
Microstructure And Properties ◽  
Graphite Morphology ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
The Matrix ◽  
Continuous Oxidation ◽  
And Diffusion

The influence of graphite morphology on the phase, microstructure and properties of hot dipping and diffusion aluminizing (HDDA) coating on flake/spheroidal graphite cast iron (FC/FCD) was investigated. The microstructure and properties of the HDDA coatings on FC/FCD were determined by the graphite morphology. The outer and inner layers of the HDDA coating comprised the Fe2Al5 and FeAl phases, respectively. The outer layer of HDDA on FCD was dense and uniform; however, some pores of different sizes were found in the outer coating on FC, resulting in looser HDDA coating. Hence, the wear resistance of the HDDA coating on FC was worse than that of the coating on FCD. During oxidation, many continuous oxidation channels were formed from the coating surface to the matrix in the HDDA coating on FC, resulting in the oxidation of graphite in the HDDA coating and the matrix. However, only exposed spheroidal graphite was oxidized in the HDDA coating on FCD. Thus, the high-temperature oxidation resistance of the HDDA coating on FC was also worse than that of the coating on FCD.

Color Etching for Characterization the Grain Orientation in Spheroidal Graphite Cast Iron

2007 ◽  
Vol 537-538 ◽  
pp. 389-396 ◽  
Author(s):  
Ibolya Kardos ◽  
Zoltán Gácsi ◽  
Péter János Szabó
Keyword(s):  
Cast Iron ◽  
Crystallographic Orientation ◽  
Grain Orientation ◽  
Test Material ◽  
Spheroidal Graphite ◽  
Metallic Materials ◽  
Additional Information ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Back Scattering

Color etching is a widely used technique for visualizing different phases in metallic materials. Its advantage to the traditional etching techniques is that it gives additional information within one phase, namely, the color shade of a given phase can change in a certain range. This paper demonstrates that, due to the physics of the color etching, the shade of a phase also depends on the crystallographic orientation of the investigated grain. As a test material, spheroidal graphite cast iron was used, and individual grain orientation was identified by automated electron back scattering diffraction (EBSD). Results showed that there is a strong correlation between grain orientation and the shades obtained by color etching.

Progress of erosive wear in spheroidal graphite cast iron

Wear ◽  
1996 ◽  
Vol 198 (1-2) ◽  
pp. 150-155 ◽  
Author(s):  
K. Shimizu ◽  
T. Noguchi ◽  
T. Kamada ◽  
H. Takasaki
Keyword(s):  
Cast Iron ◽  
Erosive Wear ◽  
Spheroidal Graphite ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron

scholarly journals Copper Enrichment around Graphite in Cu-added High-Strength Spheroidal Graphite Cast Iron

Materia Japan ◽  
2009 ◽  
Vol 48 (12) ◽  
pp. 624-624 ◽  
Author(s):  
Yasuhide Ishiguro ◽  
Kenji Ichino ◽  
Hideto Takasugi
Keyword(s):  
Cast Iron ◽  
High Strength ◽  
Spheroidal Graphite ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron
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