53 COMMUNICATION ISSUE Figure 3. The VDG Nomogram, used to predict solidification/shrinkage behavior in cast irons. Continued on next page were the best settings to use for that foundry, in order to accurately predict solidification results, and then use that information to solve the problem. Production records showed that for chemistry there was a variation of up to 0.3% in the carbon equivalent and the pouring temperature could change by as much as 50°F. So, we have target values, but on the shop floor we have a range of inputs. Which data best predicts the results we are seeing? For gray and ductile irons, we can predict solidification and shrinkage/expansion behavior using the VDG Nomogram. Figure 3 shows what that original nomogram looks like. Working with the nomogram manually is a tedious business, but we have incorporated the VDG Nomogram electronically into the SOLIDCast software, adding mold dilation and metallurgical quality so that the calculations are taken care of automatically when you do a simulation. The initial simulation showed no predicted problems. This was done using the highest levels of the chemistry and the lowest level of the pouring temperature. That clearly was not matching what was going on in the foundry. Using intermediate chemistry and temperature data, that is, lowering the carbon and silicon levels to the middle of the range and the middle of the expected range of pouring temperature, we see that defects are starting to occur in the simulation, but they are not really occurring in the area that we saw on the sectioned castings. If we go to the lowest level of chemistry and the highest pouring
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