Titanium is a very soft, silvery white, medium-strength metal having very good corrosion resistance. It has a high strength to weight ratio, and its tensile strength increases as the temperature decreases. Titanium has low impact and creep strengths, as well as seizing tendencies, at temperatures above 800°F (427°C).
Titanium is a metal of the tin group which occurs naturally as titanium oxide or in other oxide forms. The free element is separated by heating the oxide with aluminum or by the electrolysis of the solution in calcium chloride. Its most important compound is titanium dioxide, which is used widely in welding electrode coatings. It is used as a stabilizer in stainless steel so that carbon will not be separated during the welding operation. It is also used as an additive in alloying aluminum, copper, magnesium, steel, and nickel; making powder for fireworks; and in the manufacture of turbine blades, aircraft firewalls, engine nacelles, frame assemblies, ammunition tracks, and mortar base plates.
Titanium can be machined at low speeds and fast feeds; formal; spot-and seam-welded, and fusion welded using inert gas.
Titanium has low impact strength, and low creep strength at high temperatures (above 800°F (427°C)). It can only be cast into simple shapes, and it cannot be welded by any gas welding process because of its high attraction for oxygen. Oxidation causes this metal to become quite brittle. The inert gas welding process is recommended to reduce contamination of the weld metal.
Pure titanium has a tensile strength of 100,000 psi; Brinell hardness number of 200; specific gravity of 4.5; melting point of 3300°F (1851°C); and good corrosion resistance. Alloy titanium has a Brinell hardness number of 340; tensile strength of 150,000 psi; and a high strength/weight ratio (twice that of aluminum alloy at 400°F (204°C)).
Titanium is a soft, shiny, silvery-white metal burns in air and is the only element that burns in nitrogen. Titanium alloys look like steel, and can be distinguished from steel by a copper sulfate solution. The solution will not react with titanium, but will leave a coating of copper on steel.
** Spark test**
The sparks from Titanium are large, brilliant white, and of medium length.