Titanium Grades

Titanium classification

1 Commercially Pure Titanium Grades

Grade 1 titanium is the softest grade of titanium, which makes it very formable. It offers high ductility while still maintaining the necessary impact toughness. This grade is most often used in plates, tubing, piping, and a range of other applications where a higher level of weldability and formability is important.

 

For slightly stronger metal, there is Grade 2 titanium. It is still very moldable, but has a higher tensile strength. Grade 2 titanium is very widely available, which makes it more affordable than other grades. The common product forms include everything from bar and billet to plate and wire.

 

Grade 3 titanium is not used nearly as much as grade 2, but it still has its uses. It is stronger than grades 1 and 2, features good weldability, and has extremely high corrosion resistance.

 

Grade 4 titanium is the purest grade of titanium, but it is also the least moldable. Still, it has good cold formability, and it has many medical and industrial uses because of its great strength, durability and weldability. Grade 4 titanium is most commonly found in surgical hardware, heat exchangers, and CIP equipment.

2 Titanium Alloys

Grade 5 also known as Ti6Al4V, Ti-6Al-4V or Ti 6-4

It has a chemical composition of 6% aluminium, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium. It is significantly stronger than commercially pure titanium (grades 1-4) while having the same stiffness and thermal properties (excluding thermal conductivity, which is about 60% lower in Grade 5 Ti than in CP Ti). Among its many advantages, it is heat treatable. This grade is an excellent combination of strength, corrosion resistance, weld, and fabricability.

This alpha-beta alloy is the workhorse alloy of the titanium industry. The alloy is fully heat treatable in section sizes up to 15 mm and is used up to approximately 400 °C (750 °F). Since it is the most commonly used alloy–over 70% of all alloy grades melted are a sub-grade of Ti6Al4V, its uses span many aerospace airframe and engine component uses and also major non-aerospace applications in the marine, offshore, and power generation industries in particular."

Grade 6 contains 5% aluminium and 2.5% tin. It is also known as Ti-5Al-2.5Sn. Ti 5Al-2.5Sn is a non-heat-treatable alloy that can achieve good weldability with stability. It also possesses high temperature stability, high strength, and good corrosion resistance. It has a uniquely high creep (plastic-like strain over long periods, usually caused by extreme temperatures) resistance. Ti 5Al-2.5Sn is mostly used in aircraft, jet engines, and airframe applications.

 

Grade 7 contains 0.12 to 0.25% palladium. This grade is similar to Grade 2. The small quantity of palladium added gives it enhanced crevice corrosion resistance at low temperatures and high pH.

 

Grade 9 contains 3.0% aluminium and 2.5% vanadium. This grade is a compromise between the ease of welding and manufacturing of the "pure" grades and the high strength of Grade 5. It is commonly used in aircraft tubing for hydraulics and in athletic equipment.

 

Grade 12 has a strength that is similar to the 300 series steels, and it has a very high formability and weldability, making it a good choice for various fabricated applications. It is also known as Ti 3 AI 2.5. Ti 3 Al 2.5 is most commonly used in the manufacturing industry, specifically in equipment. It is highly resistant to corrosion and can be formed by heat or cold. Grade 12 titanium alloy is used the most in the following industries and applications:

Shell and heat exchangers, Hydrometallurgical applications, Elevated temperature chemical manufacturing, Marine and airfare components.

 

Grade 18 contains 3% aluminium, 2.5% vanadium, and 0.04 to 0.08% palladium. This grade is identical to Grade 9 in terms of mechanical characteristics. The added palladium gives it increased corrosion resistance.

 

Grade 23, also known as Ti-6Al-4V-ELI or TAV-ELI

It contains 6% aluminium, 4% vanadium, and  0.13% (maximum) Oxygen. ELI stands for Extra Low Interstitial. Reduced interstitial elements oxygen and iron, improve ductility and fracture toughness, with some reduction in strength. TAV-ELI is the most commonly used medical implant-grade titanium alloy. Due to its excellent biocompatibility, corrosion resistance, fatigue resistance, and low modulus of elasticity, which closely matches human bone, TAV-ELI is the most commonly used medical implant-grade titanium alloy. It also has a unique biocompatibility property that makes it popular for many medical and dental applications, including: surgical staples, ligature clips, pins and screws and more. It has also found work in airframe components and ballistic armour. It is available in most common product forms, including seamless pipe and tubing.

 

Grades 33 and 34

They contain 0.4% nickel, 0.015% palladium, 0.025% ruthenium, and 0.15% chromium. Both grades are identical, but for a minor difference in oxygen and nitrogen content. These grades contain 6 to 25 times less palladium than Grade 7 and are thus less costly, but offer similar corrosion performance thanks to the added ruthenium.

 

Grade 38 contains 4% aluminium, 2.5% vanadium, and 1.5% iron. This grade was developed in the 1990s for use as an armour plating. The iron reduces the amount of Vanadium needed as a beta stabiliser. Its mechanical properties are very similar to Grade 5, but it has good cold workability similar to Grade 9.