Excellent High-Temperature
Strength, Low Thermal Expansion
Characteristics, and
Good Oxidation Resistance
HAYNES® 242® alloy is an age-hardenable
nickel-molybdenum chromium
alloy which derives its
strength from a long-range ordering
reaction upon aging. It
has tensile and creep strength
properties up to 1300°F (705°C)
which are as much as double
those for solid solution strengthened
alloys, but with high
ductility in the aged condition.
The thermal expansion characteristics
of 242 alloy are much
lower than those for most other
alloys, and it has very good
oxidation resistance up to 1500°F
(815°C). Other attractive features
include excellent low cycle
fatigue properties, very good
thermal stability, and resistance
to high-temperature fluorine and
fluoride environments. |
Fabrication |
HAYNES 242 alloy has very good forming and welding characteristics in the annealed condition. It may be forged or
otherwise hot-worked by
conventional techniques, and it
is readily cold formable.
Welding may be performed in
the annealed condition by
standard gas tungsten arc
(GTAW) or gas metal arc
(GMAW) techniques. Use of
matching composition filler
metal is suggested. For further
information on forming and
fabrication, contact Haynes
International. |
Heat-Treatment |
| HAYNES 242 alloy is furnished
in the annealed condition,
unless otherwise specified. The
alloy is usually annealed in the
range of 1900-2050°F (925-1120°C), depending upon
specific requirements, followed
by an air cool (or more rapid
cooling) before aging. A water
quench is recommended for
heavy section components.
Aging is performed at 1200°F
(650°C) for a period of 24-48
hours, followed by an air cool. |
Available in Convenient Forms |
HAYNES 242 alloy is produced
in the form of reforge billet, bar,
plate, sheet, and wire welding
products, all in various sizes.
Other forms may be produced upon request. |
Applications |
HAYNES 242 alloy combines
properties which make it
ideally suited for a variety of
component applications in
the aerospace industry. It will
be used for seal rings,
containment rings, duct
segments, casings, fasteners,
rocket nozzles, pumps, and
many others. In the chemical
process industry, 242 alloy
will find use in high-temperature
hydrofluoric acid vapor-containing
processes as a
consequence of its excellent
resistance to that environment.
The alloy also displays
excellent resistance to high-temperature
fluoride salt
mixtures. The high strength
and fluorine environment-resistance
of 242 alloy has
also been shown to provide
for excellent service in
fluoroelastomer process
equipment, such as extrusion
screws. |
Chemical Composition, Percent |
Ni |
Mo |
Cr |
Fe |
Co |
Mn |
Si |
Al |
C |
B |
Cu |
|
65a |
24.0-26.0 |
7.0-9.0 |
2.0* |
2.5* |
0.80* |
0.80* |
0.50* |
0.03* |
0.006* |
0.50* |
| *Maximum aAs Balance |
| |
|
New Long-Range-Order Strengthening Mechanism |
HAYNES® 242® alloy derives its
age-hardened strength from a
unique long-range-ordering
reaction which essentially
doubles the un-aged strength
while preserving excellent
ductility. The ordered
Ni2(Mo,Cr)-type domains
are less than a few hundred
Angstroms in size, and are
visible only with the use of
electron microscopy. |
 |
| Transmission electron micrograph showing long-range-ordered domains (dark lenticular particles) in
242® alloy. (Courtesy Dr. Vijay Vasudevan, University of Cincinnati). Sample was solution heat
treated at 2012°F (1100°C) and aged for 100 hours at 1200°F (650°C). |
