You can set diameter d, density p, length l

Mass m is PI of d over 2 squared times l times p

Reference density 4.51g/cm3

In your millimeters, it should be m=0.0354d^2*l

For example, the mass of 65 mm titanium rod m=0.0354*65^2*l=149.58*l

That's 149.58 grams per centimeter

At present, the annual production of titanium alloy has reached more than 40,000 tons, and nearly 30 kinds of titanium alloy trademarks. The most widely used titanium alloys are ti-6al-4v (TC4), ti-5al-2.5sn (TA7) and industrial pure titanium (TA1, TA2 and TA3). Titanium alloy is mainly used in the production of aircraft engine compressor components, followed by rockets, missiles and high-speed aircraft layout. By the mid-1960s, titanium and its alloys were already in common industrial use, making electrodes for the electrolytic industry, condensers for power stations, heaters for oil refining and desalination, and pollution control equipment. Titanium and its alloys have become a corrosion resistant layout data.

In addition, it is also used to produce hydrogen storage data and shape recall alloys. Titanium alloy is a new important material used in the aerospace industry. Its specific gravity, strength and operating temperature are between aluminum and steel. The amount of titanium alloy in aero engines usually accounts for 20% ~ 30% of the total weight of the layout. It is mainly used to make compressor components, such as cast titanium fans, compressor discs and blades, cast titanium compressor cases, intermediate cases, bearing shells, etc. The spacecraft primarily USES the high specific strength, corrosion resistance and low temperature resistance of titanium alloy to make various pressure vessels, fuel storage tanks, fasteners, instrument bands, frames and rocket casings. Sputnik, lunar module, manned spacecraft and space shuttle also use titanium alloy plate welding parts.