I can also supply a bit of the why, from what I remember of the exhibit at the Wright-Patterson air force base museum. The SR-71 needed a specific grade of tit

I can also supply a bit of the why, from what I remember of the exhibit at the Wright-Patterson air force base museum. The SR-71 needed a specific grade of titanium, something of extreme purity. Only the USSR sold that purity with regularity, I believe what I read said something like 90%+ of what they bought from other suppliers had to be discarded