Lowering the Heat - The Development of Reduced SPF Temperature Titanium Alloys for Aircraft Production

摘要

Boeing has had seven years of high rate production of SPF titanium parts. The effect of 900℃ forming temperature on die life, part surface finish and alpha case formation has been documented, which has shown that there would be a great advantage in forming at a lower temperature. This paper investigates in detail the SPF properties of three new alloy developments, SP700 from NKK/RMI (USA), fine grain Ti-6-4 from VSMPO (Russia) and sub-microcrystalline Ti-6-4 from IMSP (Russia). All these alloys are formable at around 760℃. The relationship between temperature and SPF stress, elongation, oxygen contamination and formability is examined and compared between the alloys. In addition, the probability of the alloy being implemented is discussed.