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Titanium
Grades
The
various Titanium Grades as defined by
ASTM and ASME are numbered from 1 and
upwards where all numbers except 6 and
8 are represented.
Most of
the grades are of alloyed type with various
additions of for example aluminium, vanadium,
nickel, ruthenium, molybdenum, chromium
or zirconium for the purpose of improving
and/or combining various mechanical characteristics,
heat resistance, conductivity, microstructure,
creep, ductility, corrosion resistance
etc. etc.
Palladium
(Pd) and ruthenium (Ru), Nickel (Ni) and
molybdenum (Mo) are elements which can
be added to the pure titanium types in
order to obtain a significant improvement
of corrosion resistance particulary in
slightly reducing environments where titanium
otherwise might face some problems due
to insufficient conditions for formation
of the necessary protective oxidefilm
on the metalsurface. The formation of
a stable and substantially inert protective
oxidefilm on the surface is otherwise
the secret behind the extraordinary corrosion
resistance of titanium .
The mechnical
properties of commercially pure titanium
are in fact controlled by "alloying"
to various levels of oxygen and nitrogen
to obtain strength levels varying between
approximately 290 and 550 MPa. For higher
strength levels alloying elements, e.g.
Al and V have to be added. Ti3Al2,5V has
a tensile strength of minimum 620MPa in
annealed condition and minimum 860 MPa
in the as cold worked and stress relieved
condition. The CP-titanium grades are
nominally all alpha in structure, whereas
many of the titanium alloys have a two
phase alpha + beta structure. There are
also titanium alloys with high alloying
additions having an entire beta phase
structure. While alpha alloys cannot be
heat treated to increase strength, the
addition of 2,5% copper would result in
a material which responds to solution
treatment and ageing in a similar way
to aluminium-copper.
| Common
ASTM/ASME Titanium Grades |
| Grade |
Description |
| Grade
1 |
Unalloyed
titanium, low oxygen, low strength |
| Grade
2 |
Unalloyed
titanium, standard oxygen, medium
strength |
| Grade
3 |
Unalloyed
titanium, medium oxygen, high strength |
| Grade
4 |
Unalloyed
titanium, high oxygen, extra high
strength |
| Grade
5 |
Titanium
alloy (6% aluminum, 4% vanadium) |
| Grade
7 |
Unalloyed
titanium plus 0.12% to 0.25% palladium,
standard oxygen, medium strength |
| Grade
9 |
Titanium
alloy (3% aluminum, 2.5% vanadium),
high strength. Mainly aerospace applications |
| Grade
11 |
Unalloyed
titanium plus 0.12% to 0.25% palladium,
low oxygen, low strength |
| Grade
12 |
Titanium
alloy (0.3% molybdenum, 0.8% nickel),
high strength |
| Grade
13 |
Titanium
alloy (0.5% nickel, 0.05% ruthenium),
low oxygen |
| Grade
14 |
Titanium
alloy (0.5% nickel, 0.05% ruthenium),
standard oxygen |
| Grade
15 |
Titanium
alloy (0.5% nickel, 0.05% ruthenium),
medium oxygen |
| Grade
16 |
Unalloyed
titanium plus 0.04% to 0.08% palladium,
standard oxygen, medium strength |
| Grade
17 |
Unalloyed
titanium plus 0.04% to 0.08% palladium,
low oxygen, low strength |
| Grade
18 |
Titanium
alloy (3% aluminum, 2.5% vanadium
plus 0.04% to 0.08% palladium), |
| Grade
19 |
Titanium
alloy (3% aluminum, 8% vanadium, 6%
chromium, 4% zirconium, 4% molybdenum) |
| Grade
20 |
Titanium
alloy (3% aluminum, 8% vanadium, 6%
chromium, 4% zirconium, 4% molybdenum)
plus 0.04% to 0.08% palladium |
| Grade
21 |
Titanium
alloy (15% molybdenum, 3% aluminum,
2.7% niobium, 0.25% silicon) |
| Grade
23 |
Titanium
alloy (6% aluminum, 4% vanadium, extra
low interstitial, ELI) |
| Grade
24 |
Titanium
alloy (6% aluminum, 4% vanadium) plus
0.04% to 0.08% palladium |
| Grade
25 |
Titanium
alloy (6% aluminum, 4% vanadium) plus
0.3% to 0.8% nickel and 0.04% to 0.08%
palladium |
| Grade
26 |
Unalloyed
titanium plus 0.08% to 0.14% ruthenium,
standard oxygen, medium strength |
| Grade
27 |
Unalloyed
titanium plus 0.08% to 0.14% ruthenium,
low oxygen,low strength |
| Grade
28 |
Titanium
alloy (3% aluminum, 2.5% vanadium)
plus 0.08% to 0.14% ruthenium |
| Grade
29 |
Titanium
alloy (6% aluminum, 4% vanadium with
extra low interstitial elements (ELI)
plus 0.08% to 0.14% ruthenium |
|
|
