What is titanium

Titanium is the fourth most abundant structural metal in the earth's crust and is the ninth industrial metal. No other engineering metal has risen so swiftly to pre-eminence in critical and demanding markets. Titanium is number 22 on the Periodic Table, has an atomic weight of 47.90, and is represented by the symbol “Ti”. It has a density of 4.54g/cm3, a melting point of roughly 1,667°C and a boiling point of 3,287°C. Rutile and ilmenite, the two primary minerals which contain titanium, make up 24% of the earth’s crust, thus making titanium the ninth most abundant element on the planet. Titanium alloys are widely used in the aerospace, chemical, auto, medical industries.

To produce the metal, the rutile is combined with coke/tar, and chlorine gas and then is heated to create titanium tetrachloride (TiCl4). The TiCl4 is then converted through a chemical process to a “sponge” product which is then melted into an ingot form. Titanium is melted either by the vacuum arc remelting (VAR) process, or by utilization of a cold hearth furnace process. If the grade of titanium being melted is an “alloyed” grade, the alloying agents are added during the compacting process. The ingot is then processed into various forms of mill products by standard  equipment of metal working.

Titanium Chemical Composition: palladium (Pd) and ruthenium (Ru), nickel (Ni) and molybdenum (Mo) are elements which can be added to pure titanium in order to obtain a significant improvement of corrosion resistance particularly in slightly reducing environments where titanium otherwise might face some problems due to insufficient conditions for formation of the necessary protective oxide film on the metal surface. The formation of a stable and substantially inert protective oxide film on the surface is otherwise the secret behind the extraordinary corrosion resistance of titanium.

The mechanical properties of commercially pure titanium are in fact controlled by "alloying" to various levels of oxygen and nitrogen to obtain strength level varying between approximately 290 and 550 MPa. For alloying elements of higher strength levels, elements e.g. Al and V have to be added. Ti 3AL 2.5V has a tensile strength of minimum 620 MPa in annealed condition and minimum 860 MPa in cold-worked and stress-relieved condition. The CP-titanium grades are nominally all alpha in structure, whereas many of the titanium alloys have a two phase alpha + beta structure. There are also titanium alloys with high-alloying additions having an entire beta phase structure. While alpha alloys cannot be heat treated to increase strength, the addition of 2.5% copper would result in a material which responds to solution treatment and ageing in a similar way to aluminum-copper.

Titanium alloys can be grouped into four main categories. Their properties depend on their basic chemical structures and the way they are manipulated during the process of manufacturing. Some elements used for making alloys include aluminum, molybdenum, cobalt, zirconium, tin and vanadium. Alpha phase alloys have the lowest strength but are formable and weldable. Alpha plus beta alloys have high strength. Near alpha alloys have medium strength but have good creep resistance. Beta phase alloys have the highest strength of any titanium alloys but they also lack ductility.

Titanium Benefit:

High strength,

High resistance to pitting, crevice corrosion resistance,

High resistance to stress corrosion cracking, corrosion fatigue and erosion,

Cold bending for complex piping bends without fittings or flanges, high strength-to-weight ratio.

Weight saving possibilities,

Low modulus, high fracture toughness and fatigue resistance,

Suitability for coiling and laying on seabed,

Ability to withstand hot/dry and cold/wet acid gas loading,

Excellent resistance to corrosive and erosive action of high-temperature acid steam and brine,

Good workability and weldability.

Its weight-to-strength ratio is one of the most attractive properties of titanium. This metal is as strong as steel and 45% lighter, but while it's twice as strong as aluminum, it is 60% heavier. This ratio is what makes it so ideal for aerospace and other applications, but there are many other properties that make it such an important resource.

Tensile Strength – The tensile strength of titanium and its alloys range from 20,000 psi to more than 200,000 psi, but most commercial grade titanium averages around 63,000 psi.

Fatigue Strength – A titanium alloy can have a very high-cycle fatigue strength. The actual strength can be determined by the surface finish, which is why care must be taken to avoid stress concentrators.

Coefficient of Thermal Expansion – The thermal expansion properties of titanium are lower than steel, copper and aluminum. The size changes very little under extreme temperature changes.

Electrical Conductivity – Titanium is not a good conductor of electricity. As a comparison, if copper were to have 100% conductivity, titanium would be around 3%.

Corrosion Resistance – A chemically inert oxide film forms on the surface of the metal, creating a high level of corrosion resistance to most mineral acids and chlorides.

Toxicity – This metal is non-toxic in the human body and biologically compatible with human tissue and bone.

Magnetics – Commercially pure titanium and all its associated alloys are non-magnetic.