Titanium

What is titanium?

Titanium ranks 9th on the list of most common elements found in the earth’s crust and 4th when it comes to most commonly used metal parts. Titanium, with the symbol Ti, has atomic number 22 in the periodic table and an atomic weight of 47.90. Titanium is sourced in the form of rutilated quartz and from the mineral called ilmenite. Rutilated quartz is mostly found in Australia, China, Canada, and the United States.

How is titanium sourced?

Titanium is obtained by combining rutilated quartz with coke or tar and chlorine gas. Heating this mixture results in titanium tetrachloride (TiCl4). A further chemical process converts TiCl4 into a so-called “titanium sponge,” which is then melted down to form titanium ingots. There are two different melting processes that we can use: vacuum arc remelting (VAR) or the so-called cold hearth furnace process.

What makes Titanium unique?

The first industry to create a demand for titanium was the military aerospace industry. They were looking for a metal with strong mechanical properties and a high density.
One of the great properties of titanium is that it is highly resistance to oxidation as oxygen actually creates a very thin film on the surface of the titanium object, thus protecting it against oxides. Because of its very high biocompatibility, titanium can be used for hip and knee replacements, dental implants, and pacemakers. Other important properties are its unique look and the fact that it is not magnetic. And lastly, titanium has a relatively high melting point and a relatively strong thermal conductivity.

The titanium grades

Titanium comes in many different grades. At a microstructural level, grades 1 – 4 are commercially pure variations in the alpha-phase and are also the softest grades of titanium. The difference between the 4 grades is the number of interstitial elements like oxygen and iron that are added to each grade.
The table below indicates the level of interstitial elements of each grade and the corresponding mechanical properties.

What makes Titanium unique?

The first industry to create a demand for titanium was the military aerospace industry. They were looking for a metal with strong mechanical properties and a high density.
One of the great properties of titanium is that it is highly resistance to oxidation as oxygen actually creates a very thin film on the surface of the titanium object, thus protecting it against oxides. Because of its very high biocompatibility, titanium can be used for hip and knee replacements, dental implants, and pacemakers. Other important properties are its unique look and the fact that it is not magnetic. And lastly, titanium has a relatively high melting point and a relatively strong thermal conductivity.

The titanium grades

Titanium comes in many different grades. At a microstructural level, grades 1 – 4 are commercially pure variations in the alpha-phase and are also the softest grades of titanium. The difference between the 4 grades is the number of interstitial elements like oxygen and iron that are added to each grade.
The table below indicates the level of interstitial elements of each grade and the corresponding mechanical properties.

The interstitial elements can be oxygen (O), iron (Fe), and nitrogen+ (N), although oxygen is the most important one. The higher the level of interstitial elements, the stronger the alloy. As the UTS (ultimate tensile strength) increases, the elongation goes down. This makes the alloy less ductile. It also means that the strength of commercially pure titanium increases per grade. In other words, grade 4 titanium is the strongest while grade 1 is the least strong.

Other grades: titanium alloys

The other grades are all alloys so they are not commercially pure. Find out more about all titanium alloys:

• Grade 1
• Grade 2
• Grade 3
• Grade 4
• Grade 5
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