Menu (ESC)

Grade 21 (R58210) Titanium

Grade 21 titanium is a titanium alloy formulated for primary forming into wrought products. R58210 is the UNS number for this material. Additionally, the ASTM designation is Titanium Grade 21.

It has a fairly high density among wrought titaniums. In addition, it has a fairly low heat capacity and a fairly high melting temperature.

The properties of grade 21 titanium include three common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare grade 21 titanium to: wrought titaniums (top), all titanium alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

140 GPa 20 x 106 psi

Elongation at Break

9.0 to 17 %

Fatigue Strength

550 to 660 MPa 80 to 95 x 103 psi

Poisson's Ratio


Reduction in Area

22 %

Shear Modulus

51 GPa 7.5 x 106 psi

Shear Strength

550 to 790 MPa 79 to 110 x 103 psi

Tensile Strength: Ultimate (UTS)

890 to 1340 MPa 130 to 190 x 103 psi

Tensile Strength: Yield (Proof)

870 to 1170 MPa 130 to 170 x 103 psi

Thermal Properties

Latent Heat of Fusion

410 J/g

Maximum Temperature: Mechanical

310 °C 590 °F

Melting Completion (Liquidus)

1740 °C 3170 °F

Melting Onset (Solidus)

1690 °C 3070 °F

Specific Heat Capacity

500 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

7.5 W/m-K 4.3 BTU/h-ft-°F

Thermal Expansion

7.1 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

60 % relative


5.4 g/cm3 340 lb/ft3

Embodied Carbon

32 kg CO2/kg material

Embodied Energy

490 MJ/kg 210 x 103 BTU/lb

Embodied Water

180 L/kg 21 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

110 to 180 MJ/m3

Resilience: Unit (Modulus of Resilience)

2760 to 5010 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

32 points

Strength to Weight: Axial

46 to 69 points

Strength to Weight: Bending

38 to 50 points

Thermal Diffusivity

2.8 mm2/s

Thermal Shock Resistance

66 to 100 points

Alloy Composition

Titanium (Ti)Ti 76 to 81.2
Molybdenum (Mo)Mo 14 to 16
Aluminum (Al)Al 2.5 to 3.5
Niobium (Nb)Nb 2.2 to 3.2
Silicon (Si)Si 0.15 to 0.25
Iron (Fe)Fe 0 to 0.4
Oxygen (O)O 0 to 0.17
Carbon (C)C 0 to 0.050
Nitrogen (N)N 0 to 0.030
Hydrogen (H)H 0 to 0.015
Residualsres. 0 to 0.4

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM B861: Standard Specification for Titanium and Titanium Alloy Seamless Pipe

ASTM B381: Standard Specification for Titanium and Titanium Alloy Forgings

ASTM B265: Standard Specification for Titanium and Titanium Alloy Strip, Sheet, and Plate

ASTM B348: Standard Specification for Titanium and Titanium Alloy Bars and Billets

Titanium and Titanium Alloys: Fundamentals and Applications, Christoph Leyens and Manfred Peters (editors), 2003

Titanium, 2nd ed., G. Lutjering and J. C. Williams, 2007

Aerospace Materials, Brian Cantor et al. (editors), 2001