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The permanent mold was made of Ferro Casting Ductile as a result of sand casting. Permanent mold is mold that can be used repeatedly. This permanent mold is used to produce tensile test specimens. Tensile test specimens are made of gray cast iron. This study aims to determine and analyze the effect of spheroidal graphite on the hardness and toughne...
In general, during the production of compacted graphite iron (CGI), the active residual magnesium reduces and the effect of inoculation fades after magnesium treatment. In this paper, characteristics of the thermal analysis curve of CGI are compared with those of ductile iron and grey cast iron. The fading effect on the compacted graphite percentag...
Citations
... The ITACA [31] thermal analysis consisted of recording the crystallisation curve and determining its first derivative in real time. Based on the courses of these curves, the following parameters were determined: ...
This study shows that the inoculation process of a molten alloy is crucial in disposing of porosity-type defects. A thermal analysis is used to assess the physico-chemical state of a molten alloy, which can be an indicator of the inoculation effect. A modern thermal analysis should be able to perform a quick data-analysis and provide information about any possible problems in a casting if it is poured with the analysed alloy. The time of the transmission of this information depends on whether we can make a decision and introduce changes to the metallurgical process. An important piece of information that can be obtained in this way is a message about the possibility of the appearance of porosity in a cast iron casting. In such a situation, an operator can react by applying an additional dose of inoculant. The porosity that is indicated by the thermal analysis systems can be either gaseous or shrinkage in nature. The research that is presented in this paper is based on two industrial castings that are made of cast iron with reduced sulphur content, in which shrinkage porosity occurred and was detected during the mechanical machining of the castings. As a result of laboratory tests in which iron powder was introduced along with an inoculant, a mixture was developed that, when applied under industrial conditions, eliminated the porosity defects by increasing the number of austenite dendrites. The ITACA thermal analysis system was used at each stage of the research, which allowed for the faster and more precise determination of the appropriate amount of the inoculant mixture that was used.
... The cooling curves generated during solidiication of alloys can be further analysed by the use of irst-order and second-order derivatives to ind out the temperature arrest points. The thermal analysis cooling curves can be used for optimisation of inoculation in ductile iron [8]. ...
... In order to study the effect of the post-inoculation, some cups contained the same proportion of inoculant (referred to the mass) as used for the blocks. The cooling curves were then analyzed following the procedure described by Vaucheret et al. (2009) and using the Itaca ® thermal analysis software so as to determine the eutectic temperatures (the labels used in this work follow those used by Serthucha et al. (2009)) and other important parameters such as VPS (the angle of the derivative that indicates the speed of passing from the semi-solid to the solid state; the lower the value, the fewer shrinkage cavities in the matrix), PAE (eutectic precipitation of austenite; this parameter relates to the efficiency of eutectic precipitation, measured in seconds. High values are therefore ideal, as they guarantee castings with no porosity or micro-shrinkage. ...
The effects of inoculation sequence and inoculant chemical composition on heavy-section castings microstructure, with particular attention to chunky graphite, were investigated. The combinations of inoculant types with inoculation sequences were chosen basing on foundry experience.Thermal and chemical analyses were used to control the experimental foundry processes. Metallurgical analyses were performed by means of optical and field-emission gun scanning electron microscope and important microstructural parameters were measured and correlated with the results coming from tensile tests. In-stream inoculation with inoculant containing Bi and rare earths was found to drastically reduce the formation of chunky graphite. This result was attributed to the major fading resistance of such inoculant compared to the standard ones, confirmed both by nodule fraction measurements and sub-micrometric aggregates of Bi detected at the spheroid centre in the central part of the casting.
In this work, the effects of casting orientation (horizontal, side, and vertical), section thickness (4–16 mm) and composition (Cu, Mn) were investigated on the cooling rate, microstructure, and mechanical properties (tensile strength, yield strength, elongation, hardness) of hypereutectic ductile iron castings. Overall, horizontal castings were found to cool faster than side and vertical castings. Thermal analysis (using cooling curves) showed a wide difference among the four sections. Thinner sections exhibited significant undercooling and thereby carbide formation, leading to poor ductility. The combined effect of Cu and Mn showed an increase in the amount of pearlite to 82% and nodularity to 94% along with a reduction in nodule count to 323 and the amount of ferrite. Also, increased tensile strength (659 MPa) and hardness (264 BHN) were observed along with a drop in ductility to 2.5% in 4 mm thin section, helping offset carbide formation. Thermal analysis was found to be a useful tool in understanding the combined effect of orientation, thickness variations and processing parameters.
