Exploded Graphite Versus Chunky Graphite
- صفحه اصلی
- Exploded Graphite Versus Chunky Graphite
The fatigue strength of smooth specimens can also be determined by casting defects such as microshrinkage cavities. Fig. 11.19 shows an example of cavities observed in FCD400-M as shown in Figs. 11.11b and 11.20 shows its extreme value distribution [29], in which the distribution of graphite nodules is also shown for comparison.For irregularly shaped cavities, a r e a max is …
WhatsApp: +86 18221755073
It allows a sound fatigue assessment of the fatigue strength of as‐cast ductile irons containing solidification defects, such as low nodule count, exploded, chunky and spiky graphite, or ...
WhatsApp: +86 18221755073
In addition, some "degenerated" morphology, such as spiky, exploded, or chunky graphite, can result from incorrect melt treatment or unfavorable cooling conditions. Some typical examples of ...
WhatsApp: +86 18221755073
Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite...
WhatsApp: +86 18221755073
In heavy section castings, several different graphite morphologies such as vermicular, spiky, coral, exploded and chunky graphite are formed during solidification step [19]. Chunky graphite consists of large blocks of branched and interconnected network within eutectic cells. It is usually found at the thermal centers of heavy sections at the ...
WhatsApp: +86 18221755073
Exploded graphite, mainly due to an excess of rare earth additions, Fig. 1; Chunky graphite, due to an excess of rare earth additions, Fig. 2; Compacted graphite, mainly due to low residual ...
WhatsApp: +86 18221755073
A pattern including five 200 mm × 200 mm plates with thicknesses ranging from 10 to 200 mm was designed (Fig. 1) to enable investigation of the influence of different solidification times on chunky graphite formation.The thermal moduli, i.e. the relation between volume and cooling surface area (V/A), of the 10-, 25-, 50-, 100- and 200-mm plates were 8, 13, 19, 26 …
WhatsApp: +86 18221755073
Different mechanisms have been proposed for the formation of exploded graphite. Considering that nodularizers facilitate nucleation into basal planes with growth mainly occurring in the prismatic ...
WhatsApp: +86 18221755073
1 Chunky Graphite in Low and High Silicon Spheroidal Graphite Cast Irons–Occurrence, Control and Effect on Mechanical Properties Jon Sertucha 1,*, Garikoitz Artola 1, Urko de La Torre 1 and Jacques Lacaze 2,* 1 Azterlan, Basque Research Technological Alliance, Aliendalde Auzunea 6, 48200 Durango, Spain; [email protected] (G.A.); [email protected] (U.d.L.T.)
WhatsApp: +86 18221755073
lamellar graphite can be prevented, whereas by exceeding a critical amount of Ce exploded and chunky graphite will be formed [2]. There are different investigations about critical amounts of trace elements affecting graphite morphology in ductile cast iron as reviewed by Reynaud [3]. Buhr [2] reported that already small
WhatsApp: +86 18221755073
The effects of RE and Sb contents on the morphological changes of graphite (especially the appearance of chunky graphite and exploded graphite) were studied using a test block which was solidified with the simulated time for heavy-walled ductile casting. The followings were confirmed in this study.
WhatsApp: +86 18221755073
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 been reported that …
WhatsApp: +86 18221755073
It allows a sound fatigue assessment of the fatigue strength of as‐cast ductile irons containing solidification defects, such as low nodule count, exploded, chunky and spiky graphite, or ...
WhatsApp: +86 18221755073
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 the beginning of the eutectic …
WhatsApp: +86 18221755073
chunky and exploded graphite. The imprecise term degenerated graphite along with mixing of chunky, compacted and exploded graphite can generate confusion. With the recent boom in wind energy it has become more common to make large ductile iron castings. In these large and …
WhatsApp: +86 18221755073
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 ...
WhatsApp: +86 18221755073
That fewer and larger nodules are more prone to degenerate is well known, this has been recently evidenced by X-ray computerized tomography (4D-XCT) [24] and theorized for the case of exploded ...
WhatsApp: +86 18221755073
A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 1 6, I s s u e 4 / 2 0 1 6, 5 9 - 60 59 Table 3. Chemical composition of inoculants
WhatsApp: +86 18221755073
The microstructure of chunky graphite is shown in Fig. 1. We believe that the possible causes of the generation of chunky graphite are very slow solidi˜cation5), excess amount of elements such as Si 6 –9 ), Ni, Ce8 10, and Al8), and inappropriate inoculation11). The presence of chunky graphite affects the tensile
WhatsApp: +86 18221755073
Degenerative (or, "chunky") graphite is likely to form in late-solidifying sections of ductile iron castings, especially where the section thickness is greater than 50 mm. At other times we find chunky graphite during the …
WhatsApp: +86 18221755073
The whole set of available data of chunky graphite fraction versus recalescence for the cylindrical castings is plotted in Figure 12. As expected, and described above, there is a clear trend for an increased recalescence when chunky graphite becomes more and more prevalent. ... Lacaze J. A possible mechanism for the formation of exploded ...
WhatsApp: +86 18221755073
As discussed earlier for metamorphic graphite, helical growth can lead to the formation of holes in the middle of graphite aggregates. This is illustrated in Fig. 11-b for the case of chunky graphite. Growth through the foliated dendrites mechanism is also shown in Fig. 11-c for a different region of the chunky graphite.
WhatsApp: +86 18221755073
In the first group are chunky graphite (CHG) and exploded graphite (EG) whereby EG is an intermediate between regular nodular graphite and CHG. 7, 8 Intercellular lamellar graphite (ILG ...
WhatsApp: +86 18221755073
Abstract 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. The understanding of this graphite degeneration is however limited, and the above conclusions are still controversial. To get further insight into this topic, ductile cast iron melts have been prepared …
WhatsApp: +86 18221755073
for nodular graphite degeneracy known as chunky graphite [4, 5]. Chunky graphite consists of interconnected strings of graphite [6–8] and often appears as rounded cells very much like coral graphite. The difference between these two forms being that the overall or apparent graphite growth direction is along the basal c axis for chunky and
WhatsApp: +86 18221755073
This work deals with experimental determination of high cycle fatigue properties of EN-GJS-400 ductile cast iron containing chunky graphite. Constant amplitude axial tests were performed at room temperature under a nominal load ratio R = 0.In order to evaluate the influence of chunky graphite morphology on fatigue life, fatigue tests were carried out also on a second …
WhatsApp: +86 18221755073
In the first group are chunky graphite (CHG) and exploded graphite (EG) whereby EG is an intermediate between regular nodular graphite and CHG.7,8 Intercellular lamellar
WhatsApp: +86 18221755073
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 ...
WhatsApp: +86 18221755073
eutectic growth, which results in exploded or even chunky graphite. Possible reasons are long solidification times, high amounts of Si and the presence of Ce in the melt.1
WhatsApp: +86 18221755073
Abstract: 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 ... [24] and theorized for the case of exploded graphite [25]. Finally, using the fact that chunky graphite precipitates during coupled growth with
WhatsApp: +86 18221755073
graphite), exploded graphite, chunky graphite, etc. In comparison to steel, while there is no large difference when it comes to tensile strength, ductile iron has greater yield strength.
WhatsApp: +86 18221755073
chunky graphite but also lead to some spiky graphite when no rare earth is added. Chunky graphite negatively a ects the room temperature mechanical properties, though much more in the case of low silicon spheroidal graphite cast irons than in high silicon ones. Spiky graphite has been found to be much more detrimental and should thus be avoided ...
WhatsApp: +86 18221755073
Chunky graphite morphology negatively affect the mechanical properties of cast iron due to undercooling and presence of trace elements. Sertucha et al. showed the eutectic undercooling versus growth rate for chunky graphite (CHG) and nodular graphite (spheroidal) in a recent publication. From this figure it is seen that chunky graphite forms at ...
WhatsApp: +86 18221755073
Exploded graphite, mainly due to an excess of rare earth additions, Fig. 1; Chunky graphite, due to an excess of rare earth additions, Fig. 2; Compacted graphite, mainly due to low residual magnesium and/or rare earth (high temperatures or long holding time), Fig. 3;
WhatsApp: +86 18221755073
Chunky graphite is a degenerate form of spheroidal graphite, so this casting should have been a spheroidal graphite casting (probably around GJS400). The appearance corresponds to an "exploded graphite sphere". The degeneration of the graphite form is promoted by slow cooling and therefore also by ...
WhatsApp: +86 18221755073Graphite particle parameters that were evaluated using image analysis. 4.2. Graphite Size and Count Characteristics. According to the Figure 1 microstructures, there was a big difference in graphite phase characteristics, mainly as an effect of the mold media thermal properties but also the wedge casting wall thickness variation ().Generally, a higher solidification cooling rate in …
WhatsApp: +86 18221755073چه بخواهید با ما کار کنید و چه علاقه مند به کسب اطلاعات بیشتر در مورد محصولات ما هستید، مایلیم از شما بشنویم.