About Titanium

GENERAL

Titanium is the fourth most abundant structural metal in the earth's crust, exceeded only by aluminum, iron, and magnesium. The ore can easily be seen as black beach sand where it is chemically bound with oxygen and iron. While titanium has been accessible to man since prehistoric times, it has taken modern metallurgy to transform these black sands into a usable metallic form. Today, this metal is processed into common material sizes. Shapes are produced by extrusion, investment casting and forging. Products are available in the low strength commercially pure grades as well as high strength alloys designed to meet exacting needs. In this country, shipments of titanium mill products now exceed 35 million pounds annually. Usage is primarily based on applications requiring high strength, light weight, and corrosion resistance.

USES

Titanium is the material designers reach for when nothing else will do. In the United States, over 70% of the titanium produced is consumed by the aerospace industry where the high strength to density ratio makes it a basic material of choice. The fastest growth, however, is occurring in the marine, industrial, and commercial sectors. The many unique properties of titanium are utilized in applications ranging from medical implants to high performance sports equipment.

SPACE VEHICLES - JET ENGINES - HEART VALVES BALLISTIC ARMOR - DEEP SEA SUBMERSIBLES - RACING CAR COMPONENTS - BICYCLE FRAMES

PROPERTIES

Titanium can often bridge the gap between aluminum and steel by providing many of the properties of each. Like aluminum, titanium has a low density and is non magnetic. At the same time, titanium has the high strength characteristics of steel coupled with corrosion resistance that is superior to stainless steel. Deep sea submersibles are designed with titanium pressure hulls utilizing this combination of properties.

MAGNETIC PROPERTIES

Titanium, like aluminum, is non magnetic and does not become magnetized when exposed to natural backgrounds or imposed magnetic fields. It is an ideal material for electronic containment cases and military applications where a non magnetic signature is required.

DENSITY

Titanium is more than 40% lighter than steel. For comparative analysis, Aluminum is approximately 0.12 lbs./cu.in., Steel is approximately 0.29 lbs./cu.in., and Titanium is approximately 0.16 lbs./cu.in.

CORROSION RESISTANCE

Titanium's outstanding corrosion resistance is due to the formation of a tightly adherent oxide film on its surface. When damaged, this thin invisible layer immediately reforms, maintaining a surface which is completely resistant to corrosive attack in sea water and all natural environments. This oxide is so resistant to corrosion that titanium components often look brand new even after years of service.

STRENGTH and HARDNESS

Commercially pure titanium grades are relatively soft and comparable in strength to aluminum. Strength and hardness can be increased by the addition of other elements such as aluminum, vanadium, oxygen, iron, chromium, molybdenum, etc. By far, the most common alloy in use today is Ti-6Al-4V, which contains 6% aluminum, 4% vanadium, and approximately 90% titanium. In the annealed condition, ultimate tensile strength is a minimum of 130,000 psi with a hardness in the Rockwell C (RC) 32 range. Heat treatment can increase the strength to 160,000 psi and a peak hardness of Rc 38. For additional strength, more highly alloyed grades are available at strength levels over 225,000 psi with peak hardness values up to Rc 48.

DURABILITY and HOLDING SHAPE

A durable material is one that will last, in spite of hard wear and frequent use. High strength, good ductility, toughness, corrosion resistance, fatigue strength, and wear resistance are necessary for durability. High strength titanium alloys have a unique combination of these properties. For this reason, titanium components, whether they be aerospace or industrial, are normally designed never to be replaced. Further, high strength titanium alloys are unique in maintaining their shape, even under high stress. This is due to a lower modulus of elasticity in combination with a high yield strength. A small diameter heat treated bar, for example, would be difficult to bend out of shape - even with the help of a vise.