QuesTek Innovations LLC has been awarded a Small Business Innovation Research (SBIR) Phase II project from the U.S. Army to demonstrate the application of QuesTek-designed Ferrium C61 steel to the forward rotor shaft of the CH-47 Chinook helicopter. The 2-year contract is valued at $729,958.

Working in conjunction with the Army, Boeing and key industry suppliers, the forward rotor shaft will be re-designed to be made of C61 and one or more prototype shafts will be produced. It is expected that the weight of this large shaft can be reduced by 15-25%, because the fatigue strength and key static mechanical properties of C61 core material are more than 30% greater than those of incumbent alloy 9310. C61 can also tolerate much higher operating temperatures (such as may occur in an emergency “oil-out” situation) because its tempering temperature is 600°F greater than that of 9310.

Manufacturing operations such as forging, thermal processing, and machining will be optimized for this part during this project. Total thermal processing and manufacturing operations are expected to be simplified because C61 was specifically designed to use modern vacuum carburizing technology and combine the carburization and austenization steps, thus eliminating numerous manufacturing steps. The very high hardenability of C61 also permits a mild gas quench, thus reducing part distortion and allowing less grind stock and subsequent machining. C61 is also highly resistant to grinding burn damage during production, due to its high tempering temperature.

QuesTek’s initial production and sales licensee for C61 is Latrobe Specialty Steel Company of Latrobe, PA, as announced on Nov. 20, 2009. QuesTek anticipates awarding additional production and sales licensees for C61 as market demand builds. Applications for C61 beyond helicopter rotor shafts can include other integral drive shafts, gear assemblies, and power transmission components in hightemperature, high-performance, or weight- or space-sensitive applications, such as aerospace, racing, offroad, commercial and military vehicles.

Charlie Kuehmann, President and CEO of QuesTek, commented: “We thank the Army for this Phase II award, and the opportunity to further demonstrate how our integrated, applied approach to computational materials design rapidly generates and inserts valuable new materials. We also thank our project partners for their active participation applying new materials to help improve the performance, capacity and durability of critical products and platforms such as the CH-47 Chinook helicopter.”