Lost & Foundry

This article focuses on an ancient art form exhumed by modern engineering tools that makes hyperefficient gas turbines. IGT makers, such as GE, Siemens Westinghouse, and Alstom Power, use Howmet’s blades and vanes in the “hot sections” of their gas engines. Extreme inlet temperatures and the promise of greater efficiencies keep Howmet engineers seeking ways to implement advanced cooling designs, higher- temperature alloys, and stronger airfoils. Developing directionally solidified crystals was an important step in the improvement of turbine blade strength—one taken over 30 years ago. For directionally solidified casting, both the mold and the metal are kept at similar temperatures, around 2700 or 2800°F. Aside from the technological leaps that have been made in lost wax casting to produce ever larger, stronger, hotter, and more complex IGT components, it is still very much an elemental process.