Do you know how many types of titanium alloys are there?
Pure Titanium, From Grade 1 to Grade 4
Grade 1
It is the first of four grades of industrially pure titanium. It is the softest and most malleable of these grades. It offers maximum formability, excellent corrosion resistance and high impact toughness. Grade 1 is the material of choice for any application requiring ease of formability and is commonly used as titanium plate and titanium tubing.
Grade 2
Due to its diverse availability and wide availability, Grade 2 titanium is known as the “workhorse” of the commercial pure titanium industry. It has many of the same qualities as Grade 1 titanium, but is slightly stronger. Both are equally resistant to corrosion. This grade offers good weldability, strength, ductility and formability. This makes Grade 2 titanium rods and plates the first choice for many applications such as construction, power generation, and the medical industry.
Grade 3
This grade 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 primary corrosion resistance, such as aerospace, chemical processing, marine industries, etc.
Grade 4
It is considered the strongest of the four types of commercially pure titanium. It is also known for its excellent corrosion resistance, good formability and weldability. Used in some fuselage components, cryogenic vessels, heat exchangers and other applications that require high definition.
Common Titanium Alloys
At room temperature, titanium alloys have three matrix structures, and titanium alloys are divided into the following three categories: Alpha Alloys, Alpha-Beta Alloys, and Beta Alloys.
1. α Titanium Alloys
Commercially pure titanium and alpha alloys of titanium are non-heat treatable and have very good welding characteristics.
Forms Available:
Bar, Forgings, Plate, Sheet Extrusions
It is a single-phase alloy composed of α-phase solid solution. Whether it is at room temperature or at a higher practical application temperature, it is α-phase, with a stable structure, higher wear resistance than pure titanium, and strong oxidation resistance.
At a temperature of 500 ℃ ~ 600 ℃, it still maintains its strength and creep resistance, but can not be strengthened by heat treatment, and the strength at room temperature is not high.
2. β Titanium Alloys
Titanium Beta or near Beta Alloys are:
Fully heat treatable Generally weldable
Capable of high strengths Possess good creep resistance up to intermediate temperatures
In the solution-treated condition, excellent formability can be expected from Beta Alloys
Common Titanium Beta Alloys include:
Grade 5 – 6Al-4V
Titanium Grade 5 is the most commercially available of all titanium alloys. It offers an excellent combination of high strength and toughness. Grade 5 titanium has good welding and fabrication characteristics.
- High Strength Titanium
- Heat Treatable
- Good Ductility
- Good Fabricability
- Good Weldability
Grade 5 accounts for 50% of the world’s total titanium consumption. Its usability lies in its many benefits. Ti6Al-4V can be heat treated to increase its strength. It can be used in welded structures at service temperatures up to 600°F. The alloy combines high strength with light weight, useful formability and high corrosion resistance. The availability of Ti6AI-4V makes it the best alloy for use in multiple industries such as aerospace, medical, marine and chemical processing industries.
Grade 9 – 3Al-2.5V
It is made of pure titanium with about 3% aluminum and about 2.5% vanadium added. This alloy generally has excellent corrosion resistance, high strength and good welding properties. Gr9 titanium alloy is widely used in aerospace, shipbuilding, chemical equipment and other fields, especially where high-performance materials are required in high temperature and corrosive environments. The properties of Gr9 titanium alloy make it an ideal structural material that can be used to manufacture a variety of parts and components.
Grade 23 – 6Al-4V ELI
Ti 6AL-4V ELI or Grade 5 ELI grade is a higher purity form of Ti 6Al-4V. It can be made into coils, strands, wires or flat wires. It is the first choice for any situation where high strength, light weight, good corrosion resistance and high toughness are required. It has excellent damage tolerance to other alloys. These advantages make Ti 6Al-4V ELI grade the ultimate dental and medical titanium grade. Due to its biocompatibility, good fatigue strength and low modulus, it can be used in biomedical applications such as implantable components.
It is a single-phase alloy composed of a β-phase solid solution, which already has high strength before heat treatment. After quenching and aging, the alloy is further strengthened, and the room temperature strength can reach 1372 ～ 1666 MPa. However, its thermal stability is poor, so it is not suitable for use at high temperatures.
3. （ α + β）Titanium Alloys
Titanium Alpha Beta alloys are heat treatable and most of them are also weldable. The typical properties of Titanium Alpha Beta Alloys are:
Medium to high strength levels;
High temperature creep strength is not as less than most alpha alloys;
Limited cold forming but hot forming qualities are normally good;
The most commonly used Titanium Alpha Beta Alloy is Ti 6Al-4V. Titanium 6Al-4V has been developed in many variations of the basic formulation for numerous and widely differing applications.
Grade 7
Grade 7 Titanium contains 0.12 to 0.25% palladium. The small quantity of palladium added gives it enhanced crevice corrosion resistance at low temperatures and high pH.
Mechanically and physically the same as Grade 2, except that the interstitial element palladium has been added to make it an alloy. Grade 7 offers excellent weldability and workability and is the most corrosion-resistant of all titanium alloys. Therefore it is mainly used as components in chemical processes and production equipment.
Grade 12 – Ti-0.3-Mo-0.8Ni
Titanium Grade 12 alloy is similar to Titanium Grades 2 and 3 except that Titanium Grade 12 has 0.3% molybdenum and 0.8% nickel. This offers enhanced corrosion resistance.
Applications:
Chemical processing, Desalination, Power generation, Industrial Standards
Forms Available
Tube, ASME SB-338
Grade 11 – Ti-0.15Pd
Very similar to Grade 1, except that a small amount of palladium is added to enhance corrosion resistance, making it an alloy. This corrosion resistance can be used to prevent crevice corrosion and reduce acids in chloride environments. Other useful properties include optimal 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 required.
Titanium Grade 11 has similar physical and mechanical properties to Titanium CP Grade 2.
- Excellent Weldability Titanium
- Excellent Fabricability
- Physical Properties Similar to CP Grade 2
- Mechanical Properties Similar to CP Grade 2
- Highly resistant to corrosion
It is a two-phase alloy with good comprehensive properties, good structural stability, good toughness, good plasticity, and high-temperature deformation properties, which can be processed by hot pressure, quenched, and aged to strengthen the alloy.
The strength after heat treatment is about 50% to 100% higher than that of the annealed state. This alloy has high high-temperature strength and can work for a long time at a temperature of 400 ° C to 500 ° C, and its thermal stability is inferior to that of alpha titanium alloy.
Among the 3 types of titanium alloys we mentioned above, the most commonly used are alpha titanium alloy and alpha+beta titanium alloy; alpha titanium alloy has the best machinability, followed by alpha+beta titanium alloy, and beta titanium alloy is the worst.