The pattern design for evaluation of castability of nickel-chromium alloys

To find a pattern design that would provide a higher degree of discrimination for castability of nickel-chromium alloys using a polyester sieve cloth pattern, four shaped patterns were chosen. The results as calculated by t-test indicated that patterns No. 2 and No. 3 can discriminate the castability of nickel-chromium alloys over almost the total range of the casting temperatures, but that pattern No. 3 is a better discriminator for the castability. Pattern No. 1 can only discriminate the castability at lower casting temperatures. Pattern No. 4 can only discriminate the castability at higher casting temperatures. The percent castability value calculated from the number of complete square segments and the areas of the four patterns are highly linear correlations, so it is reasonably accurate to calculate the castability only from counting the number of complete square segments. Beryllium-containing nickel-chromium alloy is more castable than non-beryllium-containing alloy and the higher casting temperatures appear to result in better castability.