Papers by Keyword: Gray Iron

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Authors: Wilson Luiz Guesser, Luis Carlos Guedes, Ailton L. Müller, Vagner B. Demetrio, Alexsandro Rabelo
Abstract: Fatigue strength and fracture of high strength cast irons, gray iron grade 300 and CGI grade 450, used for producing lightweight cylinder blocks, were studied. The results show endurance ratios of 0.27-0.28 and 0.38 for gray irons and CGI, respectively. The fracture surfaces in cast irons in general show the predominance of graphite and graphite/matrix interface; however, in CGI there is a larger proportion of fractured pearlitic matrix than in gray iron. This fact, and the differences in the morphology of the graphite/matrix interface, flat in gray iron, rough in CGI, explain the higher results of fatigue strength in CGI compared to gray iron. The results of fatigue strength are compared with the literature and with previous works.
Authors: B. Garda, Francis Durand
Authors: Jarosław Chmiel, Robert Jasionowski, Dariusz Zasada
Abstract: A results of test of erosion and corrosion resistance of pearlitic gray cast iron (grade EN GJ 400) are showed. The NaCl solutions and of ethylene glycol solutions were used as the test environment. Examination were performed at varying cavitation load, in the range 2,8 ÷ 20 W/cm2.
Authors: Attila Diószegi, Rubén Lora, Vasilios Fourlakidis
Abstract: Dynamic coarsening of austenite dendrite in lamellar cast iron has been studied for a hypoeutectic alloy. The common morphological parameter to characterize dynamic coarsening, secondary dendrite arm space has been replaced by the Modulus of primary dendrite ( MPD ) and the Hydraulic diameter of the interdendritic space ( DHydIP ) to interpret the dynamic coarsening with respect to the local solidification time. The obtained results demonstrate the coarsening process of both the solid and liquid phase. The interdendritic space is increasing as the contact time between the solid and liquid phase increases. The ratio between the DHydIP/MPD is strongly dependent on the precipitated fraction primary austenite indicating clearly the morphology variation during coarsening. The interrupted solidification method demonstrate that the observed coarsening process is not only a combination of the increasing fraction precipitated solid phase and the rearrangement of the solid liquid interphase curvature but the volume change due to density variation is also contribute to the coarsening process. Keywords: dendrite morphology, hydraulic diameter, interdendritic space, gray iron.
Authors: Vasilios Fourlakidis, Rubén Lora, Attila Diószegi
Abstract: Investigation of dynamic coarsening in lamellar cast iron is extended over a wide interval ranging from hypoeutectic to eutectic composition. The dendrite morphology is defined on as-cast samples produced under various cooling rates. The as-cast morphology is considered being close to the one at the end of solidification. The obtained relations describing the coarsening process as a function of local solidification time and fraction austenite are compared to results obtained from interrupted solidification experiments. By using the Modulus of primary dendrite (MPD) and the Hydraulic diameter of the interdendritic space (DHydIP) become possible to characterize the coarseness of a wide range of lamellar cast irons solidified under various cooling rates.
Authors: Xin Zhao, Xiao Ling Yang
Abstract: Gray iron was hot-compressed on a Gleeble 3500 machine. The effect of hot compression on mechanical properties of gray iron was studied. The result shows that gray iron with the sandwich structure of graphite and ferrite matrix is prepared after more than 45% reduction of hot compression. The mechanical properties of 80% hot-compressed gray iron are significantly enhanced: tensile strength from 117MPa to 249MPa, and total elongation from 0 to 5.2%. The tensile fracture surface presents ductility characters after more than 45% reduction of hot deformation. The increase of the strength and ductility of the hot-compressed gray iron is caused by delamination toughening.
Authors: Vasilios Fourlakidis, Vasile Lucian Diaconu, Attila Diószegi
Abstract: This paper investigates the effect of different carbon contents and cooling rates on gray iron tensile properties as well on the formation of different microstructure features. Four heats with increasing amount of carbon were cast. Every heat constituted of three cylinders, each of them surrounded by different materials which provided a wide range of solidification rates. The casting specimens were subjected to tensile test measurements and to microstructure examination. The results indicate a clear correlation between cooling rates, ultimate tensile strength (UTS), carbon content and eutectic cell size. Microscopic analysis shows also a relation between the primary phase’s fraction and the number of the eutectic cells.
Authors: Ke Ping Zhang, Jian Long Huang, Jing Feng Wu
Abstract: In this study, the abrasive testing machine which was similar to the roller mills was used. It used orthogonal test design and cast iron as the wear material. The main factor effected wear results such as abrasive particle size, rotation speed and rolling gap between the metal materials surface of two rollers were considered in order to find out the best value of each factor and optimize the condition of wheat grinding. Furthermore the wear properties of grain powder on cast iron and wear mechanisms were discussed. The results showed that powder size is the most important factor of the wear properties, the gap is the secondary factor and rotation speed is third. The wear loss is minimal while size is 0.2mm, gap is 0.5mm and rotation speed is 181± 2r/min.
Authors: Mihai Chisamera, Iulian Riposan, Stelian Stan, C.B. Albu, C. Brezeanu, Rod Naro
Abstract: Inoculation comparisons were made between Calcium-bearing FeSi75 and a new complex alloy tablet (CAT) inoculant to compare their effects on late inoculation. Thermal analysis was used to study the solidification behavior and how FeSi75 and the CAT inoculants affect graphite nucleation. Quick-cup addition rates for FeSi75 ranged from 0.1% to 0.3% while the CAT, was added in much smaller amounts, 0.01 to 0.03%. Thermal analysis of the base low sulphur iron (0.02 %S) was characterized by excessive eutectic undercooling. It was found that an addition of 0.03% of the CAT had inoculation efficiency comparable to 0.2% to 0.3% Ca-FeSi75 in reducing the level of undercooling, recalescence and the maximum recalescence rate. A greater negative peak of the first derivative at the end of solidification process, that would minimize micro-shrinkage tendencies, was also obtained.
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