Analysis: titanium rod conversion formula

We all know that "titanium bolts, titanium rods, titanium shaped pieces"? In fact the main material for these products is derived from a name of 'titanium' metal to the elements. It is grayed out, atomic number 22, relative atomic mass 47.87. And it in nitrogen combustion, high melting point. Wherein the titanium rods, its conversion formulas we do not know understand how much?
Note: the diameter d, the density p, the length l
Mass m = π (d / 2) ^ 2 * l * p
Reference density 4.51g / cm3
Take your millimeters, it should be m = 0.0354d ^ 2 * l
For example 65 mm titanium bar stock mass m = 0.0354 * 65 ^ 2 * l = 149.58 * l
That is, every centimeter 149.58g
The above conversion formula Titanium round bar, it is worth learning from. For blunt titanium and titanium-based alloy is a new structural materials, mainly for the aerospace industry and the maritime industry. It is said, from the discovery of titanium element to obtain the finished product, which lasted a hundred years. The titanium really get use to recognize the true face of its original, it should be attributed to something in the past of the 1940s.