Titanium alloys

Titanium alloys are metals that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, bicycles, medical devices, jewelry, highly stressed components such as connecting rods on expensive sports cars and some premium sports equipment and consumer electronics.

Grade 1 Titanium is the first of four commercially pure titanium grades. It is the softest and most ductile of these grades. It possesses the greatest formability, excellent corrosion resistance and high impact toughness. Because of all these qualities, Grade 1 is the material of choice for any application where ease of formability is required and is commonly available as titanium plate and tubing. These include:

Chemical processing

Chlorate manufacturing

Dimensional stable anodes

Desalination

Architecture

Medical industry

Marine industry

Automotive parts

Airframe structure

Grade 2 Titanium is called the “workhorse” of the commercially pure titanium industry, thanks to its varied usability and wide availability. It shares many of the same qualities as Grade 1 titanium, but it is slightly stronger. Both are equally corrosion resistant. This grade possesses good weldability, strength, ductility and formability. This makes Grade 2 titanium bar and sheet are the prime choice for many fields of applications:

Architecture

Power generation

Medical industry

Hydro-carbon processing

Marine industry

Exhaust pipe shrouds

Airframe skin

Desalination

Chemical processing

Chlorate manufacturing

Grade 3 Titanium is least used of the commercially pure titanium grades, but that does not make it any less valuable. Grade 3 is stronger than Grades 1 and 2, similar in ductility and only slightly less formable – but it possesses higher mechanicals than its predecessors.

Grade 3 is used in applications requiring moderate strength and major corrosion resistance. These include:

Aerospace structures

Chemical processing

Medical industry

Marine industry

Grade 4 Titanium is known as the strongest of the four grades of commercially pure titanium. It is also known for its excellent corrosion resistance, good formability and weldability. Though it is normally used in the following industrial applications, Grade 4 has recently found a niche as a medical grade titanium. It is needed in applications in which high strength is required:

Airframe components

Cryogenic vessels

Heat exchangers

CPI equipment

Condensor tubing

Surgical hardware

Pickling baskets

Grade 5 Titanium has good tensile properties at ambient temperature and a useful creep resistance up to 300oC (570oF). Resistance to fatigue and crack propagation is excellent. Like most titanium alloys, Grade 5 has outstanding resistance to corrosion in most natural and many industrial process environments.

Grade 6 Titanium is a titanium alloy formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 3.7115 is the EN numeric designation for this material. Additionally, the ASTM designation is Titanium Grade 6. It has the lowest melting temperature and a fairly low embodied energy among wrought titaniums.

Grade 7 Titanium is mechanically and physically equivalent to Grade 2, except with the addition of the interstitial element palladium, making it an alloy. Grade 7 possesses excellent weldability and fabricality, and is the most corrosion resistance of all titanium alloys. In fact, it is most resistant to corrosion in reducing acids. Grade 7 is used in chemical processes and production equipment components.

Grade 9 Titanium  is a near alpha, alpha-beta alloy. It offers much more strength than CP titanium, and unlike Ti-6-4 can be cold worked resulting in moderately high strength and good ductility. It is as weldable as the CP grades and has excellent resistance to corrosion.

Grade 11 Titanium  is very similar to Grade 1, except for the addition of a tiny bit of palladium to enhance corrosion resistance, making it an alloy. This corrosion resistance is useful to protect against crevice erosion and reducing acid in chloride environments.

Other useful properties include optimum ductility, cold formability, useful strength, impact toughness and excellent weldability. This alloy can be used in the same titanium applications as Grade 1, especially where corrosion is a concern such as:

Chemical processing

Chlorate manufacturing

Desalination

Marine applications

Grade 12 Titanium holds an “excellent” rating for its high quality weldability. It is a highly durable alloy that provides a lot of strength at high temperatures. Grade 12 titanium possesses characteristics similar to 300 series stainless steels.

This alloy can be hot or cold formed using press brake forming, hydropress forming, stretch forming or drop hammer method. Its ability to be formed in a variety of ways makes it useful in many applications. This alloy’s high corrosion resistance also makes it invaluable to those manufacturing equipment where crevice corrosion is a concern. Grade 12 can be used in the following industries and applications:

Shell and heat exchangers

Hydrometallurgical applications

Elevated temperature chemical manufacturing

Marine and airfare components