|
Element |
Min |
Max |
|
Carbon |
-- |
0.03 |
|
Manganese |
-- |
0.80 |
|
Silicon |
-- |
0.80 |
|
Chromium |
7.00 |
9.00 |
|
Iron |
-- |
2.00 |
|
Aluminum |
-- |
0.50 |
|
Boron |
-- |
0.006 |
|
Copper |
-- |
0.50 |
|
Molybdenum |
24.00 |
26.00 |
|
Cobalt |
-- |
2.50 |
|
Nickel |
BAL |
|
Excellent High-Temperature
Strength, Low Thermal Expansion Characteristics, and Good Oxidation
Resistance.
Haynes alloy 242 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 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 alloy
242 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 compostion filler metal
is suggested. For further information on forming and fabrication,
contact Haynes International.
Heat-Treatment
Haynes alloy
242 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 hours, followed by an air
cool.
Available in Convenient
Forms
Haynes alloy 242 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 alloy
242 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, 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
consequese of its excellent resistance to high-temperature fluoride
salt mixtures.
The high strength and fluoride
environment-resistance of 242 alloy has also been shown to provide
for excellent service in fluoroelastomer process equipment, such as
extrusion screws.
Haynes alloy 242 is an age-hardenable material which combines excellent strength and ductility in the aged condition with good fabricability in the annealed condition. It is particularly effective for strength-limited applications up to 1300°F (750°C), where its strength is as much as double that for typical solid-solution strengthened alloys. It may be used at highter temperatures, where its solid-solution strength is still excellent, but oxidation resistance limits such uses to about 1500-1600°F (815-870°C)
Bar and Ring - Annealed and Aged*
|
Test
Temperature |
Approximate
Initial Stress, Ksi (MPa) |
||
|
10 Hours |
100 Hours |
1,000 Hours |
|
|
1000 (540) |
|
||
Hot-Rolled Plate - Annealed and Aged*
|
Test
Temperature |
Approximate
Initial Stress, Ksi (MPa) |
||
|
10 Hours |
100 Hours |
1,000 Hours |
|
|
1000 (540) |
160 (1105) |
140 (965) |
120 (825) |
|
1100 (595) |
130 (895) |
110 (760) |
93 (640) |
|
1200 (650) |
105 (725) |
90 (620) |
75 (515) |
|
1300 (705) |
86 (595) |
69 (475) |
35 (240) |
|
1400 (760) |
62 (425) |
29 (200) |
17 (115) |
|
1500 (815) |
26 (180) |
16 (110) |
11 (76) |
|
1600 (870) |
15 (105) |
11 (74) |
--- |
Cold-Rolled Sheet - Annealed and Aged*
|
Test
Temperature |
Approximate
Initial Stress, Ksi (MPa) |
||
|
10 Hours |
100 Hours |
1,000 Hours |
|
|
1000 (540) |
|
||
*Extracted from Larson-Miller plots of limited data
Bar and Rings - Annealed and Aged
|
Test
Temperature |
Ultimate Tensile
Strength |
Yield Strength at
0.2% Offset |
Elongation in
4D |
Reduction in 4D |
|
Room |
187.4 (1290) |
122.4 (845) |
33.7 |
45.7 |
Hot-Rolled Plate - Annealed and Aged
|
Test
Temperature |
Ultimate Tensile
Strength |
Yield Strength at
0.2% Offset |
Elongation in
4D |
Reduction in 4D |
|
Room |
184 (1270) |
113 (780) |
38.1 |
46.6 |
Cold-Rolled Sheet - Annealed and Aged
|
Test
Temperature |
Ultimate Tensile
Strength |
Yield Strength at
0.2% Offset |
Elongation in
4D |
|
Room |
198 (1365) |
135 (930) |
31.8 |
Cold-Reduced Sheet - As Cold-Worked and Cold-Worked plus Aged
|
Condition* |
Test
Temperature |
Ultimate Tensile
Strength |
Yield Strength at
0.2% Offset |
Elongation in
4D |
|
M.A. |
Room |
137.6 (950) |
65.3 (450) |
47 |
*M.A. = Mill Annealed; C.W. = Cold Work; Age = Standard Aging Treatment.
Haynes alloy 242 exhibits significantly lower thermal expansion characteristics than most nickel-base high-temperature alloys in the range of temperature to 1600°F (870°C). Although its expansion is greater than that for alloy 909 below 1000°F (540°C), at higher temperatures, the difference narrows considerably.
Mean Coefficient of Thermal Expansion
The following compares the mean coefficient of expansion for several alloys.
|
Test
Temperature |
Mean Coefficient
of Expansion |
||||
|
1000°F (540°C) |
1100°F (595°C) |
1200°F (650°C) |
1300°F (705°C) |
1400°F (760°C) |
|
|
Alloy 909 |
5.0 (9.0) |
5.4 (9.7) |
5.8 (10.4) |
6.2 (11.2) |
6.6 (11.9) |
Haynes alloy 242 has very good low cycle fatigue resistance, particularly in comparison to solid-solution-strengthened alloys. Results for stress-controlled tests are given below.
Stress-Controlled LCF Properties (Hot-Rolled Rings)
The following test results were generated from hot-rolled and fully heat-treated rings destined for actual gas turbine engine part applications. Testing was performed in the tangential direction utilizing a round test bar geometry with a double notch design (K(t)=2.18.). Loading was uniaxial, with a stress reversal factor R= 0.05, and a cycle frequency of 20 cpm (0.33 Hz).
|
Maximum Stress |
Cycle to Failure at 1200°F (650°C), N(f) |
|
|
Ksi (Mpa) |
242 alloy |
Alloy 909 |
|
110 (760) |
845 |
2,835 |
* No crack observed at
198,030 cycles. 8 mil (200um) crack observed at 200,000 cycles.
**
No crack observed at 45,800. 8 mil (200um) crack observed at 47,770
cycles.
The following are results from standard vacuum furnace hot hardness tests. Value are given in originally measured DPH (Vickers) units and conversions to Rockwell C/B scale in parentheses.
|
Material |
Vickers Diamond Pyramid Hardness (Rockwell C/B Hardness) |
||||
|
800°F (425°C) |
1000°F (540°C) |
1200°F (650°C) |
1400°F (760°C) |
1600°F (870°C) |
|
|
242
alloy |
271
(Rc 26) |
263
(Rc 24) |
218
(Rb 95) |
140
(Rb 75) |
78 |
Haynes alloy 242 has excellent retained ductility and impact strength after long-term thermal exposure at temperature. Combined with its high strength and low thermal expansion characteristics, this makes for very good containment properties in gas turbine static structures. The graphs below show the retained room-temperature tensile elongation and impact strength for 242 alloy versus other relevent materials after a 4000 hour exposure at 1200°F (650°C).
Room-Temperature Properties After Exposure at 1200°F (650°C)*
|
Exposure Time Hours |
Ultimate |
0.2%
Yield |
Elongation |
Reduction |
Charpy |
|
|
Ksi (MPa) |
Ksi (MPa) |
% |
% |
Ft.-lbs. |
Joules |
|
|
0 |
179 (1235) |
110 (760) |
39 |
44 |
66 |
90 |
* Samples machined from plate after exposure. Duplicate tests.
|
Temperature, °F |
British Units |
Temperature, °C |
Metric Units |
|
|
Density |
Room |
0.327 lb/cubic in |
Room |
9.05 g/cubic cm |
|
Melting Range |
2350-2510 |
1290-1375 |
||
|
Electrical Resistivity |
Room |
48.0
Mu.ohm-in. |
Room |
122.0
Mu.ohm-in. |
|
Thermal Diffusivity |
Room |
4.7 x 10(-3)
in²/sec. |
Room |
30.5 x 10(-3)
cm²/sec. |
|
Thermal Conductivity |
Room |
75.7 BTU-in./ft²
hr.-°F |
Room |
11.3
W/m-K |
|
Specific Heat |
Room |
0.092
Btu/lb.-°F |
Room |
386
J/Kg-K |
|
Mean Coefficient of
|
70-200 |
6.0
microin/in.-°F |
25-100 |
10.8
Mu.m/m-°C |
Dynamic Modulus of Elasticity
|
Temperature, °F |
Dynamic Modulus
of |
Temperature, °C |
Dynamic Modulus
of |
|
Room |
33.2 |
Room |
229 |
Haynes alloy 242 exhibits very good oxidation resistance at temperature up to 1500°F (815°C), and should not require protective coating for continuous or intermittent service at these temperatures. The alloy is not specifically designed for use at highter temperatures, but can tolerate short-term exposures.
Comparative Burner Rig Oxidation-Resistance at 1400°F (760°C) for 500 Hours.
|
Alloy |
Metal Loss |
Average Metal Affected |
Maximum Metal Affected |
|||
|
Mils |
Mu.m |
Mils |
Mu.m |
Mils |
Mu.m |
|
|
HASTELLOY Alloy
N |
0.7 |
18 |
0.8 |
20 |
1.2 |
30 |
Oxidation Test Parameters
Burner rig oxidation tests were conducted by exposing samples 3/8 inch x 2.5 inches x thickness (9mm x 64mm x thickness), in a rotating holder, to the products of combustion of No. 2 fuel oil burned at a ratio of air to fuel of about 50:1 (Gas velocity was about 0.3 mach). Samples were automatically removed from the gas stream every 30 minutes and fan-cooled to near ambient temperature and then reinsured into the flame tunnel.
Comparative Oxidation-Resistance in Flowing Air At 1500°F (815°C) For 1008 Hours*
|
Alloy |
Metal Loss |
Average Metal Affected |
||
|
Mils |
Mu.m |
Mils |
Mu.m |
|
|
242
alloy |
0.0 |
0 |
0.5 |
13 |
* Coupons exposed to flowing air at a velocity of 7.0 feet/minute (2.1m/minute) past the samples. Samples cycled to room temperature once-a-day.
Research has shown that materials which have high molybdenum content and low chromium content are generally superior to other materials in resisting high-temperature corrosion in fluorine-containing environments. Haynes alloy 242 is in that catergory, and displays excellent resistance to both fluoride gas and fluoride salt environments.
Comparative Resistance to 70% HF At 1670°F (910°C) For 136 Hours
|
Alloy |
Thickness Loss |
|
|
Mils |
mm |
|
|
242
alloy |
12.6 |
0.3 |
Haynes alloy 242 has very good resistance to nitriding environments. Tests were performed in flowing ammonia at 1800°F (980°C) for 168 hours. Nitrogen absorption was determined by chemical analysis before and after exposure and knowledge of the specimen area.
|
Alloy |
Nitrogen Absorption |
|
(mg/cm²) |
|
|
HAYNES alloy
214 |
0.3 |
Haynes alloy 242 exhibits good resistance to corrosion by sodium-sulfate-containing sea water environment at 1200°F (650°C). Tests were performed by heating specimens to 300°F (150°C), spraying with a simulated sea water solution, cooling and storing at room temperature for a week, heating to 1200°F (650°C) for 20 hours in still air; cooling to room temperature, heating and spraying again at 300°F (150°C), and storing at room temperature for a week.
|
Alloy |
Metal Loss |
Maximum
Metal |
||
|
Mils |
Mu.m |
Mils |
Mu.m |
|
|
HASTELLOY alloy
S |
0.10 |
2.5 |
0.20 |
5.1 |
Notched room-temperature tensile tests performed in hydrogen and air reveal that 242 alloy is roughly equivalent to alloy 625 in resisting hydrogen embrittlement, and appears to be superior to many important materials. Tests were performed in MIL-P27201B grade hydrogen, with a crosshead speed of 0.005 in./min. (0.13 mm/min.).
|
Alloy |
Hydrogen Pressure |
Kt |
Ratio of
Notched |
|
|
Psi |
MPa |
|||
|
WASPALOY alloy
|
7,000 |
48 |
6.3 |
.78 |
Although not specifically designed for use in applications which require resistance to aqueous corrosion, 242 alloy does exhibit resistance in some media wich compares favorably with that exhibited by traditional corrosion-resistance alloys. Data shown for 242 alloy was generated for samples tested in the mill annealed condition.
|
Corrosive |
Temperature |
Exposure |
Corrosion Rate, Mils/year (mm/year) |
|||
|
242 alloy |
alloy B-2 |
C-22 alloy |
alloy N |
|||
|
5% HF |
175 (79) |
24 |
14
(0.36) |
12 (0.30) |
25 (0.64) |
20 (0.51) |
Haynes alloy 242 has excellent
forming and welding characteristics. It may be hot-worked at
temperatures in the range of about 1800-2250°F (980-1230°C)
provided the entire piece is soaked for a time sufficient to bring it
uniformly to temperature. Initial breakdown is normally performed at
the higher end of the range, while finishing is usually done at the
lower temperatures to afford grain refinement.
As a consequence of
its good ductility, 242 alloy is also readily formed by cold-working.
All hot- or cold-worked parts should be annealed at 1900-2050°F
(925-1120°C) and cooled by air cool or faster rate before aging
at 1200°F (650°C) in order to develop the best balance of
properties.
The alloy can be welded by a variety of processes,
including gas tungsten arc, gas metal arc, and shielded metal arc.
High heat input processes such as submerged arc and oxyacetalyne
welding are not recommended.
Welding Procedures
Welding
procedures common to most high-temperature, nickel-base alloys are
recommended. These include use of stringer beads and an interpass
temperature less than 200°F (95°C). Preheat is not required.
Cleanliness is critical, and careful attention should be given to the
removal of grease, oil, crayon marks, shop dirt, ect. prior to
welding. Because of the alloy's high nickel content, the weld puddle
will be somewhat "sluggish" relavive to steels. To avoid
lack of fusion and incomplete penetration defects, the root opening
and bevel should be sufficiently open.
Filler Metals
Haynes
alloy 242 should be joined using matching filler metal. If shielded
metal arc welding is used, HASTELLOY alloy W coated electrodes are
suggested.
Post-Welded Heat Treatment
HAYNES alloy 242
is normally used in the fully-aged condition. However, following
forming and welding, a full solution anneal is recommended prior to
aging in order to develop the best joint and overall fabrication
properties.
Welding can be a safe occupation.
Those in the welding industry, however, should be aware of the
potential hazards associated with welding fumes, gases, radiation,
electric shock, heat, eye injuries, burns, etc. Also, local,
municipal, state, and federal regulations (such as those issued by
OSHA) relative to welding and cutting processes should be
considered.
Nickel-, cobalt-, and iron-base alloy products may
contain, in varying concentrations, the following elemental
constituents: aluminum, cobalt, chromium, copper, iron, manganese,
molybdenium ,nickel and tungsten. For specific concentrations of
these and other elements present, refer to the Material Safety Data
Sheets (MSDS) H3095 and H1072 for the product.
Inhalation of metal
dust or fumes generated form welding, cutting, grinding, melting, or
dross handling of these alloys may cuase adverse health effects such
as reduced lung function, nasal and mucous membrane irritation.
Exposure to dust or fumes which may be generated in working with
these alloys may also cause eye irritation, skin rash and effects on
other organ systems.
The operation and maintenance of welding and
cutting equipment should conform to the provisions of American
National Standard ANSI/AWS Z49.1, "Safety in Welding and
Cutting". Attention is especially called to Section 7
(Protection of Personnel) and 8 (Health Protection and Ventilation)
of ANSI/AWS Z49.1. Mechanical ventilation is advisable and under
certain conditions such as a very confined space, is necessary during
welding or cutting operations, or both, to prevent possible exposure
to hazardous fumes, gases, or dust that may occur.
HAYNES alloy 242 may be machined in either the solution-annealed or aged conditions. Carbide tools are recommended. In the annealed condition (Rb 95-100 typical hardness) the alloy is somewhat "gummy". Better result may be achiedved by performing machining operations on material in the age-hardened condition (Rc 35-39 typical hardness). Finish turning has been successfully done employing carbide tools with a depth of cut in the range of 0.010-0.020 inch (0.25-0.50 mm), rotation speeds of 200-400 rpm, 40-80 sfm, and a water-base lubricant.