TITANIUM ALLOY
Ti - 4AI - 4Mo - 2Sn - 0.5Si (Ti-550)
ASTM GRADE (UNS NO.)
(UNASSIGNED)
Chemical Composition (wt. %)
(Max. values unless range is shown) 		3.0-5.0AI; 1.5-2.5Sn; 0.12Fe; 3.0-5.0Mo; 0.3-0.7Si; 0.03N; 0.05C; 0.16-0.20O; 0.015H
TENSILE PROPERTIES
Guar.R.T.
Min.
Typical R.T.
Typical Elevated Temp. Properties
93°C(200°F)
204°C(400°F)
315°C(600°F)
Ultimate Strength
MPa (ksi)
1103 (160)
1145 (166)
1096 (159)
979 (142)
876 (127)
Yield Strength,
0.2% offset
MPa (ksi)
958 (139)
1021 (148)
938 (136)
800 (116)
683 (99)
Elongation in 51 mm
(2") gage length
(%)
9
12
15
16
17
Reduction in Area -
Bar, Billet & Forging only
(%)
20
36
—
—
—
OTHER MECHANICAL PROPERTIES
 

Stress to Rupture
in Time Shown

Stress
MPa (ksi)
—
841 (122)
Time-Hrs. at Temp. (°C)
—
100 (399)
Stress & Time to
Produce Elongation
Shown (creep)
Stress
MPa (ksi)
752 (109)
710 (103)
703 (102)
517 (75)
Time-Hrs. at Temp. (°C)
1000 (100)
100 (300)
1000 (300)
100 (399)
Creep
(%)
0.05
0.10
0.10
0.10
Charpy V-Notch
Impact @ R.T.
Joules
(ft-lbs)
23 (17)
Bend Radius Under 1.78 mm (0.070") thick
Hot formable only
1.78 mm (0.070") and over

Hot formable only
Welded Bend Radius
—
Nominal Hardness
37 HRC
PHYSICAL PROPERTIES
  
Nominal Beta
Transus
°C (°F)
975 (1787)
Coefficient of
Thermal Expansion
10-6/°C
(10-6/°F) 		0-100°C (32 -212°F)

8.8 (4.9)
0-315°C (32-600°F)
9.2 (5.1)
0-538°C (32-1000°F)
10.1 (5.6)
0-648°C (32-1200°F)
—
0-816°C (32-1500°F)
—
Density
g/cm3 (lbs/in3)
4.6 (0.166)
Melting
Point,
Approx.
°C (°F)
—
Electrical
Resistivity
@ R.T.
10-6 ohm·cm
(10-6 ohm·in)
159 (63)
Modulus of
Elasticity ­
Tension
GPa (103 ksi)
114 (16.5)
Modulus of
Elasticity ­
Torsion
GPa (103 ksi)
—
Thermal
Conductivity
W/m·°C (BTU/hr·ft·°F)
7.5 94.35)
Specific
Heat
J/Kg·°C (BTU/lb·°F)
—
Weldability
Limited
Industry Specifications
Ta-46, -47 and -48;