Carbon Steel vs Ductile iron-Compositions: Carbon content in carbon steel (<2%) is less than that of ductile iron (>3%). Also, the carbon in ductile iron is in graphite form. Ductile Iron vs Carbon Steel-Castability and Welding Characteristics: Carbon steel provides better weldability than ductile irons. However, Ductile iron has better ...
Antimony is used in ductile cast iron melts to avoid graphite degenerations like exploded graphite and chunky graphite. However, the effect of Sb in the melt on the crystallization of ductile cast iron is still unknown, therefore the aim of our investigations. The current study presents thermodynamic calculations showing that at …
TECHNICAL ARTICLE Graphite Formation and Dissolution in Ductile Irons and Steels Having High Silicon Contents: Solid-State Transformations P. Rubin1,2 • R. Larker1,3 • E. Navara4 • M.-L ...
Use of rare earths, high silicon and carbon contents, and low cooling rates are reported as possible reasons for formation of chunky graphite in ductile iron castings.
Part I of this investigation deals with the inoculation mechanisms in ductile cast iron, with particular emphasis on the theoretical aspects of heterogeneous nucleation of graphite at inclusions. It is shown that the majority of the inclusions in ductile cast iron are primary or secondary products of the magnesium treatment(e.g., MgS, CaS, …
irons with lamellar graphite), causing incomplete trans-formation into ausferrite and therefore inferior ductility in the range A 4 = 0.5–1.5%. The increasing carbon solubility …
irons with lamellar graphite), causing incomplete trans-formation into ausferrite and therefore inferior ductility in the range A 4 = 0.5–1.5%. The increasing carbon solubility in the austenite with increasing temperature (see line S–E in Fig. 1) can for ductile irons having graphite spheroids as carbon reservoirs
The quantity and morphology of spheroidal graphite have an important effect on the properties of ductile iron, and the characteristics of spheroidal graphite are determined by the solidification process. The aim of this work is to explore the precipitation and evolution of graphite nodules in hypoeutectic, eutectic, and hypereutectic ductile …
Microstructure of gray and ductile irons consists with graphite particles and the iron matrix which can be considered as a composite structure. Therefore, variation of graphite morphology and fraction over the volume of a casting can be considered as an FGM. ... This is known as the graphite flotation commonly occurred in the …
Noise Reduction: The presence of precipitated graphite in both gray and ductile iron helps dampen vibration in gears, machine tool parts, and hydraulic components. The relative damping capacity of gray iron is as much as 100 times that of steel. Ductile iron has approximately 10 times the damping characteristics of steel.
In hypereutectic nodular cast irons, primary precipitation of graphite may lead to graphite flotation in thick section castings. Graphite degeneracy such as so-called exploded graphite is then often associated with this flotation phenomenon and it appears as precipitates where the nodular form is replaced by star-like or flower-like shape. It has …
The Roundness Graphite Shape Factor (RSF), which is considered (by the international standard ISO 945-4-2019) to characterize the representative graphite morphologies in cast irons (Figure 3 b), suggests a fall within the slightly irregular spheroidal graphite (Form V ISO 945), in the 4.5%Si ductile cast iron test. For RSF < …
Ductile cast irons (DCIs) are of increasing importance in the renewable energy and transportation sectors. The distribution and morphology of the graphite …
However, for heavy section ductile iron castings, the mass fraction range of carbon equivalent should be reduced to 4.3-4.4%, otherwise, graphite floating will occur. If the heavy section ductile iron is cooled by metal mold, the carbon equivalent will be increased to 4.6-4.7%, and graphite will not float.
Iron Types (page 1), Gray & Ductile Irons. Home > Iron Types (page 1), Gray & Ductile Irons. Cast Iron Grades. For most modern automotive and consumer applications, cast iron falls into 4 separate categories: ... Doru M., et.al, "The Metallurgy and Tensile Mechanical Properties of Thin Wall Spheroidal Graphite Irons", International Journal ...
The influence of post-inoculation and of cerium and antimony additions on the solidification process and on the formation of chunky graphite in ductile iron heavy-section parts have been studied ...
The compensation of the contraction in ductile cast irons is provided by graphite precipitation. So, he showed the maximization of graphite precipitation and the minimization of austenite contraction are potentially important process variables. ... Most of these entrainment defects will float up to the top of castings due to the density ...
The aim of the present study is to evaluate the actual status of silicon-alloyed ductile cast irons, as recent knowledge on the structure formation, and to review original data obtained by the authors from recent separate publications with additional unpublished data, specifically concerning the structure peculiarities. New data were added to deeply …
Graphite is a hexagonal-closepack form of carbon that can grow in both the liquid and solid forms of iron. In theory, in irons above the eutectic composition of carbon, the graphite first nucleates in the liquid, and then continues to grow in the solid. In irons below the eutectic composition, the graphite does not start
Graphite flotation in ductile iron castings by T. N. Blackman, 1988, American Foundrymen's Society edition, in English
This manuscript summarizes recent investigation of the authors into the solidification and shrinkage defect formation of ductile and compacted graphite cast irons. The study makes use of the DAAS (direct austempering after solidification) technique, developed earlier by some of the authors, to reveal the solidification grains. In addition, …
Indeed, the ductile iron foundry, which truthfully claims not to have shrinkage concerns is the exception to the rule. Other common defects may be divided into two basic categories: -Those related to nodule shape and size, such as compacted graphite structures, exploded and chunky graphite, graphite floatation, spiky graphite and nodule alignment.
In view of the large number of compositions of steels and cast irons commercially available and the fact that their properties may be varied over a wide range by appropriate heat-treatment, it is impossible to present a brief summary table of the properties of these materials as we have attempted to do in the case of non-ferrous alloys. In Appendix IV, …
Graphite formation in the solid state is both in ductile cast irons and in steels strongly promoted by high silicon contents above 3 wt.% Si. The matrix microstructure in austempered ductile iron ...
Ferritic high-Si ductile cast irons replace an unstable mixed ferrite-pearlite matrix with a unique combination of high elongation, strength and hardness (ideal for automotive drive train components) and …
Microstructure of gray and ductile irons consists with graphite particles and the iron matrix which can be considered as a composite structure. Therefore, variation of …
The use of ductile irons in thermo-mechanically loaded components is increasing, necessitating more knowledge of material properties at intermediate temperatures. A study of the mechanical properties of ductile irons at intermediate temperatures was conducted, investigating the effect of different pearlite fractions along …
Chunky graphite appears easily in heavy-section spheroidal graphite cast irons and is known to affect their mechanical properties. A dedicated experiment has been developed to study the effect of ...
Dross in Ductile Iron: Source, Formation and Explanation ... most striking difference between grey and Ductile Irons. While essential to ... dross may be associated with graphite floatation, since ...