DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD
Weldments of three hydrofoil strutfoil candidate materials 15-5 PH stainless steel, Inconel 718, and Rene 41 for hydrofoils were prepared. Mechanical, fatigue, corrosion fatigue, and corrosion tests were performed on these materials with various postweld heat treatments. Results of tensile, impact fatigue, stress corrosion, general corrosion, and crevice corrosion tests are presented. Weld procedures, problems, and machining difficulties are noted. The corrosion properties of Rene 41 and Inconel 718 are superior to 15-5 PH stainless steel however difficulty in welding and machining these nickelbase alloys in thick sections make their application to hydrofoils highly unlikely without further development. Although not performing as well in seawater as the other two alloys, 15-5 PH is considerably easier to fabricate and therefore warrants consideration for hydrofoil struts and foils.