MP35N cold-worked cobalt-nickel alloy section-size limitation

Continuation from prior session. Annealed yield 60 ksi; with 65% cold work plus aging, up to 290–300 ksi tensile with 10% elongation and 48% RA — better than aircraft landing gear steel. But cannot be made in plates or in diameters much above 2 inches because cold-working tools fail. Available only as wire or sheet. Tom returns to it as the "if you could afford it and could make it thick" submarine hull thought experiment.

A number of things to clean up from last time. I finally found the properties of MP35N. Here are the typical room-temperature tensile properties of MP35N as a function of the amount of cold work. The yield strength in a completely annealed condition is only 60 ksi. That's nothing to write home about. Low-strength steel is 36 ksi; it's not hard to get 100 ksi steel; 60 ksi is sort of in between. But it can go up to 235 ksi with 65% cold work. And if you do an aging treatment, you can get it up to 290 or 300 ksi tensile strength. This is better than most aircraft landing gears, which are kind of the epitome of high-strength steel. Ten percent elongation and 48% reduction in area — that's pretty incredible, to get that much stretch out of something that strong.