Grade 5

Grade 5, also known as Ti6Al4V, Ti-6Al-4V or Ti 6-4, is the most commonly used alloy. It has a chemical composition of 6% aluminium, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium.[5] It is significantly stronger than commercially pure titanium while having the same stiffness and thermal properties (excluding thermal conductivity, which is about 60% lower in Grade 5 Ti than in CP Ti).[6] Among its many advantages, it is heat treatable. This grade is an excellent combination of strength, corrosion resistance, weld and fabricability.

 

Ti-6Al-4V

Category : Titanium Alloy

Class : Wrought

Type : Alpha-beta alloy

Designations : United States: ASTM B265 Grade5, ASTM B348 Grade5, ASTM B381 Grade5, MIL-T-9046, MIL-T-9047, AMS 4928, AMS 4911, AMS 4906, AMS 4965

 

Grade 5 titanium is the workhorse of all the titanium grades. It is also know as Ti-6AL-4V or simply Ti 6-4. Its high strength, light weight and corrosion resistance enables Ti 6-4 to be used in many applications. The most comon market is aerospace. The alloy is also "age hardenable" by heat treatment to achieve even higher strengths.

 

Market Applications

Aerospace, Medical, Marine, Chemical Processing

 

Physical Properties

Table 1. Typical physical properties for Ti6Al4V.

Property Typical Value

Density g/cm3 (lb/ cu in) 4.42 (0.159)

Melting Range °C±15°C (°F) 1649 (3000)

Specific Heat J/kg.°C (BTU/lb/°F) 560 (0.134)

Volume Electrical Resistivity ohm.cm (ohm.in) 170 (67)

Thermal Conductivity W/m.K (BTU/ft.h.°F) 7.2 (67)

Mean Co-Efficient of Thermal Expansion 0-100°C /°C (0-212°F /°F) 8.6x10-6 (4.8)

Mean Co-Efficient of Thermal Expansion 0-300°C /°C (0-572°F /°F) 9.2x10-6 (5.1)

Beta Transus °C±15°C (°F) 999 (1830)

 

Mechanical Properties

Table 2. Typical mechanical properties for Ti6Al4V.

Property Minimum Typical Value

Tensile Strength MPa (ksi) 897 (130) 1000 (145)

0.2% Proof Stress MPa (ksi) 828 (120) 910 (132)

Elongation Over 2 Inches % 10 18

Reduction in Area % 20

Elastic Modulus GPa (Msi) 114 (17)

Hardness Rockwell C 36

Specified Bend Radius <0.070 in x Thickness 4.5

Specified Bend Radius >0.070 in x Thickness 5

Welded Bend Radius x Thickness 6

Charpy, V-Notch Impact J (ft.lbf) 24 (18)

 

Fabrication

Weldability – Fair

Forging – Rough 982°C (1800°F), finish 968°C (1775°F)

Annealing - 732°C (1350°F), 4hr, FC to 566°C (1050°F), A.C. F.C. not necessary for bars

Solution Heat Treating – Forgings

Ageing – 904-954°C (1660-1750°F), 5 min-2hrs, W.Q. 538°C (1000°F), 4hr, A.C.