Modeling of Distribution of Visible and Non-Visible Graphite Nodules Embedded in the Surface Layer of Ductile Cast Iron

2010 ◽  
Vol 659 ◽  
pp. 453-458
Author(s):  
Tamás Réti ◽  
Mihály Réger ◽  
Ágnes Csizmazia ◽  
Imre Czinege
Keyword(s):  
Cast Iron ◽  
Surface Defects ◽  
Defect Formation ◽  
Structural Parameters ◽  
Ductile Cast Iron ◽  
Graphite Nodule ◽  
Image Analyzer ◽  
Local Surface ◽  
Cast Irons ◽  
Surface Damages

The graphite nodule count and size distribution are important structural parameters in the quantitative characterization of the microstructure of ductile cast irons. In several cases, it is observed that local surface damages (cracks or microchip formations) are generated by the final manufacturing process (superfinishing operation), and these defects are originated basically from the hidden (invisible) graphite nodules located directly below surface. Based on measured data obtained by an image analyzer, a stereological model and a simulation algorithm have been developed to analyse the correspondances between the graphite morphology and the defect formation. This method makes it possible to establish a correlation between the microstructure parameters and the occurrence of local surface defects on ductile cast iron components.

scholarly journals Pearlite Stabilisation by Copper on Ductile Cast Iron

2010 ◽  
Vol 457 ◽  
pp. 151-156 ◽  
Author(s):  
Masato Tsujikawa ◽  
Norikazu Matsumoto ◽  
Koji Nakamoto ◽  
Yoshisada Michiura
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Copper Content ◽  
Carbon Diffusion ◽  
Ductile Cast Iron ◽  
Graphite Nodule ◽  
Eutectoid Reaction ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Matrix Microstructure

In ductile cast irons with copper, cementite stability was investigated against an annealing heat treatment used to obtain a fully ferritic matrix. Copper controls cast-iron mechanical properties, but its role in the matrix microstructure formation remains unclear. Some reports suggest the copper layer around graphite or cementite. They can be barrier to carbon diffusion at eutectoid reaction, however it is difficult to understand the mechanism of pearlite stability by copper. To confirm the existence of the barrier and effect of copper addtion, ten 9-mm-thick spheroidal graphite cast iron castings were prepared with different copper contents of 0.16 wt% – 0.69 wt%. The samples’ as-cast microstructures included spheroidal graphite, ledeburite, and pearlite. The pearlite fraction degreases to about 10% by heat treatment for ordinary ductile irons without intentional copper addition. The samples’ copper content and the pearlite fraction after heat treatment are not linearly related. The retained pearlite increased suddenly with increased copper content greater than 0.4 wt%. However, even the sample with the highest copper content showed no precipitation of a copper solid solution around graphite nodule or cementite.

Influence of Ca-Ba and Sr Base Inoculants on Metallurgical and Mechanical Properties of Grey and Ductile Cast Irons

2018 ◽  
Author(s):  
Dhruv Patel ◽  
Devendra Parmar ◽  
Siddharthsinh Jadeja
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Uniform Distribution ◽  
Ductile Cast Iron ◽  
Grain Structure ◽  
Spheroidal Graphite ◽  
Primary Carbide ◽  
Cast Irons ◽  
Melt Temperature ◽  
Nodular Graphite

Microstructural adaptation of cast iron alloys by inoculation is a well-known practice to swell their mechanical properties. In foundries, several inoculants have been used to refine grain structure, and to obtain uniform distribution of graphite flakes. Inoculation is one of the most critical steps in cast iron production. The effectiveness of inoculants depends on melt temperature, method of addition, type of inoculants, and holding time. In this paper, the effect of Ca-based, Ba-based, Ca-Ba based and Sr-based inoculants on microstructure and tensile properties of grey cast iron IS-210 and spheroidal graphite iron IS-1862 is reported. Results showed both Ca and Ba based inoculants were effective in obtaining uniform distribution of flaky and nodular graphite in IS-210, and IS-1862 cast irons, respectively. But in a case of Sr-based inoculant were highly effective for increase the nodularity of SG cast iron as well as succeed supreme yield strength for both grey and ductile cast iron. The amounts of ferrite in the as-cast matrix are excess with controlled granulometry for elimination of primary carbide in Sr-based inoculant.

scholarly journals INVESTIGATION ON TRIBOLOGICAL BEHAVIOR OF DUCTILE CAST IRONS WITH NANOSIZED PARTICLES

2019 ◽  
Vol 3 ◽  
pp. 84
Author(s):  
Julieta Kaleicheva ◽  
Valentin Mishev ◽  
Manahil Tongov
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Titanium Nitride ◽  
Tribological Behavior ◽  
Ductile Cast Iron ◽  
Titanium Carbonitride ◽  
Nanosized Particles ◽  
Cast Irons ◽  
Nickel Deposition ◽  
Graphite Phase

The work in this study is focused on investigation of the tribological behavior of ductile cast iron with nanosized particles: titanium nitride TiN; titanium nitride 30% + titanium carbonitride 70% (30%TiN+70%TiCN). The ductile cast iron composition is: Fe-3,55C-2,67Si-0,31Mn-0,009S-0,027P-0,040Cu-0,025Cr-0,08Ni-0,06Mg wt%. Before the addition to the melt nanosized particles were coated with nickel by the electroless nickel deposition method EFFTOMNICKEL .The nickel coating on the nanosized particles ensures their wetting in the melt as well as their uniform distribution into the cast. The optical and quantity metallographic observations and wear test are performed to study the influence of the nanoparticle additives on the cast iron tribological properties. It is observed that the quantity proportion changes between pearlite, ferrite and graphite phase in the cast iron structure. The graphite shape is retained the same, but the nanosized additives decrease the average diameter of the graphite spheres Dmid and increase the quantity of the graphite phase in the structure of ductile cast irons. The cast iron wear resistance in the presence of nanosized additives of (TiN+TiCN) and TiN increases to 55–69% in comparison to wear resistance of the cast iron without nanoparticles.

scholarly journals Influence of nickel addition and casting modulus on the properties of hypo-eutectic ductile cast iron

2019 ◽  
Vol 55 (2) ◽  
pp. 283-293 ◽  
Author(s):  
E. Colin-García ◽  
A. Cruz-Ramírez ◽  
G. Reyes-Castellanos ◽  
J.A. Romero-Serrano ◽  
R.G. Sánchez-Alvarado ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Cooling Rate ◽  
Ductile Iron ◽  
Ductile Cast Iron ◽  
Strength Ratio ◽  
Cast Irons ◽  
Microstructural Changes ◽  
Nodule Count ◽  
Nickel Addition

The effect of the casting modulus on the distribution and features of graphite in hypo-eutectic ductile iron unalloyed and alloyed with nickel (0.88 wt %) was studied. The cooling rate of the casting plates of 25.4, 12.7 and 8.5 mm in thickness with a casting modulus of 6.87, 4.46 and 3.31 mm, respectively promotes several microstructural changes, such as cementite precipitation and a noticeable nodule count increment. The nickel addition suppressed the cementite formation and improved the nodule count and nodularity for the three casting modulus evaluated. The nickel addition increased the nodule count in 69, 67 and 128 % for the modulus of 3.31, 4.46 and 6.87 mm, respectively, regarding the unalloyed ductile iron. It was found that the biggest casting modulus produced the biggest nodules with the lowest nodule count for both ductile cast irons. Further to the improvements in the graphite features, the nickel addition allowed to keep almost constant the yield and tensile strength ratio for the different casting modulus.

In situ synchrotron investigation of degenerate graphite nodule evolution in ductile cast iron

2021 ◽  
pp. 117367
Author(s):  
T. Wigger ◽  
T. Andriollo ◽  
C. Xu ◽  
S.J. Clark ◽  
Z. Gong ◽  
...  
Keyword(s):  
Cast Iron ◽  
Ductile Cast Iron ◽  
Graphite Nodule

Mechanical Properties and Thermal Expansion Characteristics of Low Thermal Expansion Ductile Cast Iron with same Nickel Equivalent (NiE)

2010 ◽  
Vol 457 ◽  
pp. 380-385
Author(s):  
Minoru Hatate ◽  
Tohru Nobuki ◽  
Shoji Kiguchi ◽  
Kazumichi Shimizu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Thermal Expansion ◽  
Cast Iron ◽  
Coefficient Of Thermal Expansion ◽  
Solution Treatment ◽  
Ductile Cast Iron ◽  
High Dimensional ◽  
Cast Irons ◽  
Low Thermal Expansion

Low thermal expansion ductile cast iron is expected to become a new structural material with high dimensional stability against temperature change. We tried to develop a new low thermal expansion ductile cast iron by means of adding C and Si to Superinver alloy. In this study we prepared four kinds of ductile cast irons whose Co contents vary from 0% to 12 %, and investigated about the effects of Co content and solution-treatments on several main characteristics such as coefficient of thermal expansion and mechanical properties. The results obtained are as follows: With increase of Co content the amount of martensite increases but this martensite can be inverse-transformed to austenite totally or greatly by solution-treatment followed with water-quenching. In the case of Co content less than some 9 % the ability of relatively larger plastic deformation can be expected in inverse-transformed austenite.

Application of Inclined Cooling Plate to Fabrication of Semi-Solid Cast Iron

2007 ◽  
Vol 544-545 ◽  
pp. 195-198 ◽  
Author(s):  
Sung Yong Shim ◽  
Hwan Goo Seong ◽  
Jin Ho Jeong ◽  
Su Gun Lim
Keyword(s):  
Cast Iron ◽  
Solidification Rate ◽  
Optical Microscope ◽  
Peak Hardness ◽  
Image Analyzer ◽  
Cast Irons ◽  
Cooling Plate ◽  
Relative Extent ◽  
Iron Specimen ◽  
Semi Solid

The influence of angles of inclined cooling plate on cast structure and mechanical properties of cast iron was investigated experimentally in 3.1 wt.% C containing hypoeutectic semisolid cast irons fabricated by flowing the molten melt over the inclined cooling plate and pouring into a preheated permanent mold. The variables used in this study were angles of the cooling plate (5 ~ 15 deg) and the mold temperatures (500~700 deg). The microstructure of resultant specimens were characterized by measuring grain sizes of primary austenite and its solid fraction, using an optical microscope equipped with a digital image analyzer. It was shown that the spherical-like austenite (1.4 aspect ratio) was formed at the cast iron specimens prepared in employing a 10 deg angle of the inclined cooling plate. This was ascribed to the relative extent of duration time of the flowing melt which determine the solidification rate of the melt. The peak hardness and impact values were achieved in the semi-solid cast iron specimen with relatively more spherical austenite. The measured values were approximately 44HRC and 1.71 J/cm2.

scholarly journals Structure Distribution in Precise Cast Iron Moulded on Meltable Model

2015 ◽  
Vol 15 (4) ◽  
pp. 69-74 ◽  
Author(s):  
B. Skrbek ◽  
K. Policar
Keyword(s):  
Quality Improvement ◽  
Cast Iron ◽  
Ductile Cast Iron ◽  
Spheroidal Graphite ◽  
Flake Graphite ◽  
Cast Irons ◽  
Remanent Magnetism ◽  
Measurement Results ◽  
Mechanical And Physical Properties ◽  
Grey Cast

Abstract Topic of this work is to compare metalurgy of cast irons poured into sand moulds and into shell molds at IEG Jihlava company and from it following differencies in structures of thin- and thick-walled castings. This work is dealing with investigation and experimental measurement on surfaces and sections suitable thin- and thick-walled investment castings at IEG Jihlava. Cast irons with flake graphite (grey cast iron) and cast irons with spheroidal graphite (ductile cast iron). Both mechanical and physical properties are determined using calculations from as measured values of wall thicknesses L and Lu, Vickers hardness and remanent magnetism. Measurement results are discussed, findings are formulated and methods for castings metallurgical quality improvement are recommended finally.

Graphite nodule morphology as an indicator of the local complex strain state in ductile cast iron

2013 ◽  
Vol 52 ◽  
pp. 524-532 ◽  
Author(s):  
Isabel Hervas ◽  
Mohamed Ben Bettaieb ◽  
Anthony Thuault ◽  
Eric Hug
Keyword(s):  
Cast Iron ◽  
Strain State ◽  
Ductile Cast Iron ◽  
Graphite Nodule ◽  
Local Complex ◽  
Complex Strain ◽  
Nodule Morphology

scholarly journals Methodology for Determination of Degree of Nodularity in a Ductile Cast Iron GGG 40 by Ultrasonic Velocity Test

2018 ◽  
Vol 26 (26) ◽  
pp. 10-16
Author(s):  
Douglas Agnoletto ◽  
Guilherme Vieira Braga Lemos ◽  
Arthur Bortolini Beskow ◽  
Cleber Rodrigo de Lima Lessa ◽  
Afonso Reguly
Keyword(s):  
Cast Iron ◽  
Ultrasonic Method ◽  
Iron Alloy ◽  
Ductile Cast Iron ◽  
Cast Irons ◽  
Ultrasonic Sound ◽  
Time Savings ◽  
Carbon Iron ◽  
Microstructural Examination

Cast iron alloys combine many elements such as carbon, iron, silicon, magnesium and can be usually classified according to their microstructure in ductile, gray, compacted, white, and malleable. Each one has particularities in terms of properties and applications. Hence, this study aims to evaluate the degree of nodularity (%) in a ductile cast iron alloy GGG 40. In this context, a methodology to investigate the degree of nodularity was proposed. The ultrasonic method was used to determine the amount of ductile graphite as well as for parts release and thus facilitated the industrial operational execution. The effect of ultrasonic sound was investigated in sixtyseven ductile cast irons, and these analyses were further compared to the level of nodularity observed by metallography. Finally, based on the findings, the cast iron quality was guaranteed, leading to time-savings, avoiding the microstructural examination, and thus promoting cost reductions.

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