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
0.32
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
Density
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
| Ti | 76 to 81.2 | |
| Mo | 14 to 16 | |
| Al | 2.5 to 3.5 | |
| Nb | 2.2 to 3.2 | |
| Si | 0.15 to 0.25 | |
| Fe | 0 to 0.4 | |
| O | 0 to 0.17 | |
| C | 0 to 0.050 | |
| N | 0 to 0.030 | |
| H | 0 to 0.015 | |
| res. | 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