Predicting liquid quenched superalloy microstructure requires an understanding of surface heat transfer. However, the state-of-the-art relies on experience and cut and try methods to predict whether the microstructure is achievable for a given shaped specimen. This program will develop an understanding of the convective film coefficient variation around a disk shaped specimen using existing data and a finite element analysis. The Phase I goal is to demonstrate the approach and define a subsequent program of analytical and experimental work to define and verify a complete theory of predicting the coefficients based on specimen shape, quenchant type, and heat transfer enhancements. This meets a goal of Subtopic 04.04 by modeling a critical manufacturing process to permit maximum hardness quenching of near net shape superalloy materials for gas turbines leading to lower design-to-production time and cost. Completion of both program phases will increase the envelope of shapes and sizes of superalloy turbine disks that can be fully and uniformly hardened. This knowledge, equally applicable to military or commercial uses, increases the value of previously developed superalloys. Additionally, many heat transfer enhancements developed in other disciplines such as steam boilers, may become available to the quench problem.Commercial Applications:The results of this program will lead to larger disks and complicated near net shape disks achieving maximum hardness throughout their mass, thus fully exploiting the advantages of new superalloys for both military and commercial gas turbines.
