Look at the yield and ultimate stresses I posed and say that you need more material with Titanium. That might be general, but looking up 4340 (the stuff that caspian uses) and comparing that to high strength Ti with 10% Vandium, we see that the yield stresses are 10 ksi off, 170 compared to 160. That isn't anwhere close to failing on a properly designed part. It really isn't much different in stregth. Ok?
Yes, both materials will not fail in something as mundane as a pistol slide because the stresses involved don't even approach maximum operational properties of the material but regardless (ignoring the host of hardened metal parts inside besides the slide and frame), the chart makes comparisons based on one unit of density of these materials, not volumetric so it defaults to the argument about volume and mass. Titanium has more volume but is stonger by mass and it meets somwhere in between and still falls below steel.
Maximum hardness, enlongation, modulus of elasticity, shearability, compressional strength, machinability, castability, etc--there are countless reasons that come into play when selecting a material. Yield/ultimate tensile strength is hardly and end-all argument for one material over another. Materials used in firearms are far from representative of what takes place in industry. AISI 4340 is a rather generic steel regardless of how Caspian advertises it. By contrast, we've been contracted to use it for mundane end-purposes like commercial adjustable table feet. It's great steel, but nothing magical because it's chosen by a high end 1911 manufactuer. Same with titanium.
It isn't unusual to have generic steel over 40-45 Rc, and alloys specifically for bearing surfaces, cutlery, and other high impact/wear purposes are easily around the 55-60Rc. Steel-based tooling (your generic HSS tool steel variants) can push to about 65Rc. For contrast, a titanium alloy like 6Al-4V can be pushed to the low 40's Rc, MUCH softer by comparison even if it is hardened to it's upper limits and titanium is more difficult to harden due to it's poor thermal properties. If titanium alloys can achieve the same hardness, they would be used in cutlery and wear applications. It isn't.
Again, I am not putting down titanium, but every metal and alloy has its purposes. As mentioned, aluminum used to be a "wonder metal" because it was incredibly difficult to produce in quantity. I'm just tired of being bombarded with titanium tennis rackets, golf clubs, and firearms promising the impossible.
The big problem with Ti is the expense - it's gone way up already and is going to cost more and more as China and India buy it all up.
All metals have gone up in price as 3rd world nations start developing their industry. Some of the exotic stuff like nickel and cobalt superalloys have really jumped up a few notches as it's not that widespread and available in quantity.
