Modelling the solidification of ductile cast iron parts with varying wall thicknesses

Revisiting Thermal Analysis of Hypereutectic Spheroidal Graphite Cast Irons

“…It is, however, striking to note that this also corresponds to an undercooling DT gra L which is on the range of value necessary for primary graphite to grow to a significant extent according to the 2D nucleation/lateral growth model. In line with this conclusion, it is worth noting that Bjerre et al [16] observed the first graphite precipitates in their 4D-XRD synchrotron experiments on an hypo-eutectic spheroidal graphite cast iron at an undercooling with respect to the graphite liquidus higher than 100°C. These findings suggest the following tentative schematic for solidification of mildly hypereutectic alloys.…”

“…The red arrow pointing to the right has been located as in Figure 3 at 28°C below the equilibrium eutectic to illustrate the similarity of this result for inoculated ( Figure 3) and for not-inoculated ( Figure 4) Mg-treated alloys. It is worth stressing that previous modeling approaches, e.g., those by Lacaze et al [14] and others, [15,16] that were based on the same understanding as proposed by Chaudhari et al [6] and described above, predicted an increase of the bulk eutectic temperature with carbon equivalent (see the T EN arrow in Figure 1). This expected increase is not consistent with experimental observations, suggesting that the modeling of solidification of hypereutectic alloys needs to be improved.…”

A graphite nodule growth model validated by in situ synchrotron x-ray tomography

“…In this section, we evaluate the feasibility of using the model to predict the development of the nodule size distribution and thus evaluate if the shape of the distribution is dominated by average nodule growth behaviour or not. Most simulations of the solidification of DCI components [29][30][31][32][33] assume that this is the case although it has not been sufficiently investigated.…”

“…J and especially the numeric pre-factor 0.9 appear to be the result of somewhat arbitrary choices which are not sufficiently supported by experimental evidence. Comparing the results of casting simulations to experimental observations has so far been the main tool applied to validate the different microstructural models [29][30][31][32][33] as direct observations of graphite growth have been unavailable. This approach has the disadvantage that it tests the thermal solver and choice of nucleation model as well as the microstructural growth model.…”

Revisiting Models for Spheroidal Graphite Growth

“…However, compared with experimentally measured temperatures and nodule size distributions it has been shown that such a solidification model underestimates the nodule number density after solidification is complete. It has been speculated this is related to an inaccurate description of the nucleation and growth conditions at the end of solidification [5,6]. It is the aim of the present paper to use results from recent experimental investigations into graphite growth and the resulting microstructure with the purpose of increasing the understanding of the factors influencing growth.…”