You are correct in that steel is harder and stiffer than titanium. Steel is also more re-usable, smelt-able than titanium.
However, when it comes to fatigue (which I assume, you are referring to fracture strain) titanium has a significant edge. The fracture strain for steel is roughly 15%, but for titanium alloys, it often reaches and exceeds 50%.
I don't say this to contradict you, but to point out that as with most things in life, "it depends".
A better argument for steel is it requires 5-10 kwhr/kg to produce vs 60kwhr/kg for aluminum and 250kwhr/kg for titanium. So for the same energy you get 6 times more steel than aluminum and 25 times more than titanium. Which seems to say when the properties of steel are acceptable it's the cheaper option.
Like steel, titanium alloys have a distinct non-zero fatigue limit, and thus can be engineered to have infinite fatigue lives. Though the exact details differ and steel or titanium can be better depending on exactly what the conditions are.
softfalcon|2 years ago
However, when it comes to fatigue (which I assume, you are referring to fracture strain) titanium has a significant edge. The fracture strain for steel is roughly 15%, but for titanium alloys, it often reaches and exceeds 50%.
I don't say this to contradict you, but to point out that as with most things in life, "it depends".
Source: https://www.ulbrich.com/blog/titanium-versus-steel-a-battle-....
Gibbon1|2 years ago
https://solar.lowtechmagazine.com/2009/06/how-much-energy-do...
petertodd|2 years ago