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Titanium Alloys - Ti6Al4V Grade 5

Chemical Formula

Ti6Al4V

Topics Covered

Background

Ti6Al4V ELI (Grade 23)

Composition

Key Properties

Physical Properties

Mechanical Properties

Fabrication

Applications

Background

This alpha-beta alloy is the workhorse alloy of the titanium industry. The alloy is fully heat treatable in section sizes up to 15mm 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.

The addition of 0.05% palladium, (grade 24), 0.1% ruthenium (grade 29) and 0.05% palladium and 0.5% nickel (grade 25) significantly increase corrosion resistance in reducing acid, chloride and sour environments, raising the threshold temperature for attack to well over 200°C (392°F).

Ti6Al4V ELI (Grade 23)

The essential difference between Ti6Al4V ELI (grade 23) and Ti6Al4V (grade 5) is the reduction of oxygen content to 0.13% (maximum) in grade 23. This confers improved ductility and fracture toughness, with some reduction in strength. Grade 23 has been widely used in fracture critical airframe structures and for offshore tubulars. Mechanical properties for fracture critical applications can be enhanced through processing and heat treatment. Grade 29 also having lowered level of oxygen will deliver similar levels of mechanical properties to grade 23 according to processing.

Composition

Table 1. The composition of Ti6Al4V Grade 5.

 

Content

C

<0.08%

Fe

<0.25%

N2

<0.05%

O2

<0.2%

Al

5.5-6.76%

V

3.5-4.5%

H2(sheet)

<0.015%

H2(bar)

<0.0125%

H2(billet)

<0.01%

Ti

Balance

Key Properties

Physical Properties

Table 2. 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 3. 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

 

5.0

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.

Applications

As mentioned previously, this alloy is the most popular of the titanium alloys. It is used for a range of applications in the aerospace, marine, power generation and offshore industries.

 

Source: Titanium Information Group.

 

For more information on this source please visit Titanium Information Group.

 

Date Added: Jul 30, 2002 | Updated: Apr 1, 2014
Comments
  1. Jaroslav Přidal Jaroslav Přidal Czech Republic says:

    We need to coat Ti6Al4V ELI (grade 23) at 300 centigrades instead of 250 centigrade.I am intersted what is the difference in mechancal properties of this material at 250 oC and 300 oC. Can anybody help us? Thanks.
    jara.pridal@mikropur.cz

  2. Gunner Munk Gunner Munk Denmark says:

    We have a design temperature of -20 Celsius to +50 Celsius.
    Is there any difference in mechanical properties?
    Please send answer to my mail gm@munk-technologies.dk
    Thank you.
    Gunner Munk

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