Flight Qualification of Titanium F-14A Airframe Components Manufactured by Hot Isostatic Pressing (HIP).

摘要

This program established that fuselage braces (Part No. A51B21683) manufactured by the hot isostatic pressing (HIP) process can satisfy flight requirements for forged parts. The HIP braces withstood 24,000 equivalent flight hours (four design lives) without failure. The projected cost saving related to the utilization of the HIP process in manufacturing of these parts is in the range of 30 to 40%. Ti-6Al-6V-2Sn titanium alloys consolidated by HIP exhibited excellent fracture toughness and elongation characteristics, and obtained K sub ic and percent elongation values in the range of 69-74 ksi sq root of in and 15-16%, respectively. Representative F sub tu and F sub ty values were approximately 3% below the current design specifications for forgings. However, these values can be increased by minor modifications in the oxygen content within allowable limits. Mechanical properties exhibited isotropic characteristics. Reproducibility studies indicated that current tight tolerances for machined components may have to be relaxed to assure that all dimensions of hot isostatically pressed (HIP'd) parts meet design specifications. Experimental welds on HIP and vacuum annealed materials met radiographic and ultrasonic acceptance criteria. Utilization of the HIP process in manufacturing fatigue-critical airframe components will depend on availability of high-quality powders with certified purity standards to insure freedom from inclusions.