Mould-reaction with gypsum bonded refractory investments.

Three series of standard tensile test specimens were produced using the nickel-base Ticonium Premium 100 alloy cast into a gypsum-bonded investment. For the first series an average weight metal ingot was used and cast at the temperature determined by the sensing head of the casting machine. For the second series a larger ingot was used, whilst for the third an elevated casting temperature was employed. The degree of investment breakdown resulting from mould reaction was assessed visually and by sulphur determination.