Advanced Structural Casting Applications for a Gas Turbine Engine

The GE T700 engine family was originally developed for the U.S. Army in the early seventies. This engine utilizes investment castings for most static structural components; however, because of limitations in the casting state-of-the-art, other components are still being produced utilizing traditional fabrication methods. This paper deals with a major undertaking to convert complex structures to precision castings without sacrificing the existing design function, weight, and performance characteristics. Significant cost benefits can be achieved by reduction in material and labor, elimination of welding, brazing and other joining operations, and reduction in inventory of component pieces and sub-assemblies. These benefits can be attained through the process of direct substitution, creative integration of several components into one casting and by replacement of sheet metal assemblies with a single complex thin-wall casting. Examples of these various benefits of structural casting applications are described. It is also apparent through this undertaking that the state-of-the-art of investment casting structural components has been advanced significantly.