Principal Features

Excellent High-Temperature Strength, Low Thermal Expansion Characteristics, and Good Oxidation Resistance

HAYNES® 242® alloy (UNS N10242) 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 1200 – 1300°F (649 – 704°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 (816°C). Other attractive features include excellent low cycle fatigue properties, very good thermal stability, and resistance to high-temperature fluorine and fluoride environments.  HAYNES® 244® alloy has been developed as an upgrade from 242® alloy, with enhanced tensile and creep properties up to 1400°F (760°C), as well as a lower coefficient of thermal expansion.

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 aero and industrial gas turbine engines. It may 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.

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).

*Please contact our technical support team if you have technical questions about this alloy.

Nominal Composition

Weight %
Nickel Balance
Molybdenum 25
Chromium 8
Iron 2 max.
Cobalt 1 max.
Manganese 0.8 max.
Silicon 0.8 max.
Aluminum 0.5 max.
Carbon 0.03 max.
Boron 0.006 max.

Thermal Expansion

HAYNES® 242® alloy exhibits significantly lower thermal expansion characteristics than most nickel-base high-temperature alloys in the range of temperature from room temperature to 1600°F (871°C). Although its expansion is greater than that for alloy 909 below 1000°F (538°C), at higher temperatures, the difference narrows considerably.

Total Thermal Expansion, Room to Elevated Temperature

Mean Coefficient of Thermal Expansion

The following compares the mean coefficient of expansion for several alloys:

Alloy
Mean Coefficient of Expansion from RT to Temperature, in./in/-°F (mm/mm-°C) x10-6
1000°F 538°C 1100°F 593°C 1200°F 649°C 1300°F 704°C 1400°F 760°C
in./in/-°F x10-6
mm/mm-°C x10-6
in./in/-°F x10-6
mm/mm-°C x10-6
in./in/-°F x10-6
mm/mm-°C x10-6
in./in/-°F x10-6
mm/mm-°C x10-6
in./in/-°F x10-6
mm/mm-°C x10-6
909 5 9 5.4 9.7 5.8 10.4 6.2 11.2 6.6 11.9
242® 6.8 12.2 6.8 12.3 7 12.6 7.2 13 7.7 13.9
B 6.7 12 6.7 12 6.7 12 6.9 12.4 7.1 12.8
N 7.3 13.1 7.4 13.3 7.5 13.5 7.6 13.7 7.8 14
S 7.4 13.2 7.5 13.5 7.6 13.7 7.8 14 8 14.4
X 8.4 15.1 8.5 15.3 8.6 15.5 8.6 15.7 8.8 15.8

Tensile Properties

Bar and Rings – Annealed and Aged

Test Temperature Yield Strength 0.2% Offset Ultimate Tensile Strength Elongation Reduction in Area
°F °C ksi MPa ksi MPa % %
RT RT 122.4 845 187.4 1290 33.7 45.7
200 93 110.4 760 180.7 1245 31.7 47.0
400 204 102.3 705 173.5 1195 33.0 51.8
600 316 96.5 665 168.6 1160 33.4 48.4
800 427 86.3 595 161.3 1110 37.6 45.9
1000 538 78.3 540 156.3 1080 38.3 49.9
1200 649 82.7 570 144.9 1000 33.2 41.1
1400 760 44.9 310 106.2 730 44.3 54.1
1600 871 44.8 310 72.5 500 49.7 85.1
1800 982 30.6 210 42.0 290 54.0 97.8

RT= Room Temperature

Comparison of Yield Strengths and Elongations*

HAYNES® 242® alloy exhibits much higher yield strength than typical solid-solution-strengthened nickel-base alloys, such as HASTELLOY® S alloy, but also possesses excellent ductility in the fully heat-treated condition. This can translate into excellent containment characteristics for gas turbine rings and casings, particularly when coupled with 242 alloy’s lower expansion coefficient and excellent ductility retention following thermal exposure. This combination is also well suited for a range of fastener and bolting applications up to 1300°F (705°C).


*Plate material or manufacturer’s data.

Hot-Rolled Plate – Annealed and Aged (a)

Test Temperature Yield Strength 0.2% Offset Ultimate Tensile Strength Elongation Reduction in Area
°F °C ksi MPa ksi MPa % %
RT RT 126 868 193 1330 36
400 204 101 696 176 1213 43 52
800 427 91 627 165 1137 45 52
1000 538 89 613 164 1130 44 51
1100 593 89 613 160 1102 44 51
1200 649 87 599 141 971 29 31
1300 704 73 503 118 813 28 30
1400 760 48 331 94 648 93 71

Cold-Rolled Sheet- Annealed and Aged (a)

Test Temperature Yield Strength 0.2% Offset Ultimate Tensile Strength Elongation
°F °C ksi MPa ksi MPa %
RT RT 120 827 187 1288 38
1000 538 106 730 165 1137 31
1100 593 102 703 150 1034 18
1200 649 96 661 135 930 14
1300 704 83 572 109 751 10
1400 760 57 393 92 634 98

(a)Average of two tests per heat, two heats of each product form. Solution Annealed + Aged 1200ºF-48 h.

Cold-Reduced Sheet- As Cold-Worked and Cold-Worked Plus Aged

HAYNES® 242® alloy has excellent strength and ductility as a cold-reduced and directly aged product. Coupled with its low thermal expansion characteristics, this makes it an excellent choice for fasteners and springs.

Test Temperature 0.2% Yield Strength Ultimate Tensile Strength Elongation
°F °C ksi MPa ksi MPa %
M.A. RT RT 65.3 450 137.6 950 47
M.A. + 20% C.W. RT RT 139.5 960 169.6 1170 20
M.A. + 40% C.W. RT RT 181.3 1250 217.9 1500 8
M.A. + Age RT RT 130.0 895 192.0 1325 32
M.A. + 20% C.W. + Age RT RT 173.0 1195 209.5 1445 21
M.A. + 40% C.W. + Age RT RT 219.7 1515 244.7 1685 11
M.A. + 40% C.W. + Age 1100 595 191.4 1320 201.9 1390 11
M.A. + 40% C.W. + Age 1200 649 145.9 1005 198.7 1370 8
M.A. + 40% C.W. + Age 1300 705 134.3 925 183.7 1265 11
M.A. + 40% C.W. + Age 1400 760 94.1 650 156.0 1075 32

*RT= Room Temperature

Comparative Fastener Alloy Tensile Properties*

HAYNES® 242® alloy compares very favorably with other cold-worked and directly aged fastener alloys. The graphs below present comparative room temperature tensile properties for 40% cold-reduced and aged sheet product.

Creep and Stress-Rupture Strength

HAYNES® 242® alloy is an 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 (705°C), where its strength is as much as double that for typical solid-solution strengthened alloys.

Comparison of 100 Hour Stress-Rupture Strengths*

*Alloy B and Alloy N sheet products. All others hot forged or rolled plate, bar, and rings.

242® Plate, Age-Hardened

Temperature Creep Approximate Initial Stress to Produce Specified Creep in
10 Hours 100 Hours 1,000 Hours 10,000 Hours
°F °C % ksi MPa ksi MPa ksi MPa ksi MPa
1000 538 0.5
1
R 153 1055 138 952 122 841 109 752
1100 593 0.5 75 517
1 79 545
R 126 869 112 772 100 690 85 586
1200 649 0.5 82 565 62 427 38 262
1 85 586 66 455 42 290
R 105* 724* 91 627 75 517 48 331
1300 704 0.5 72 496 48 331 33 228 13* 90*
1 75 517 53 365 37 255 17* 117*
R 87* 600* 66 455 44 303 25 172
1400 760 0.5 24 165 12 83
1 27 186 15 103 8.0 55
R 46 317 29 200 18 124

*Significant extrapolation

242® Sheet, Age-Hardened

Temperature Creep Approximate Initial Stress to Produce Specified Creep in
10 Hours 100 Hours 1,000 Hours
°F °C % ksi MPa ksi MPa ksi MPa
1000 538 0.5
1
R 133 917 125 862
1100 593 0.5 97 669
1 102 703
R 117 807 110 758
1200 649 0.5 79 545 58 400
1 82 565 62 427
R 110* 758* 90 621 69 476
1300 704 0.5 59 407 44 303 33 228
1 64 441 47 324 35 241
R 80 552 57 393 41 283
1400 1400 0.5 21 145 12* 83*
1 24 165 14 97
R 41 283 25 172 15 103

*Significant extrapolation

Fatigue Properties

Strain-Controlled LCF Properties (Hot-Rolled Plate)

HAYNES® 242® alloy exhibits excellent low cycle fatigue properties at elevated temperature. Results shown below are for strain-controlled tests run in the temperature range from 800 to 1400°F (425 to 760°C). Samples were machined from plate. Tests were run with fully reversed strain (R=-1) at a frequency of 20 cpm (0.33 Hz).

Stress-Controlled Notched 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 (Kt=2.18). Loading was uniaxial cycling with an R-ratio of 0.05 stress and a cycle frequency of 20 cpm (0.33 Hz).

Maximum Stress Cycles to Failure at 1200°F (650°C), NF
ksi MPa 242® 909
110 760 845 2,835
100 690 12,220 22,568
95 655 32,587 13,796
90 620 76,763 55,679; 40,525
85 585 297,848 47,707; 43,701
80 550 304,116* 129,573**

* No crack observed at 198,030 cycles. 8 mil (200μm) crack observed at 200,000 cycles.
**No crack observed at 45,800 cycles. 8 mil (200μm) crack observed at 47,770 cycles.

Impact Strength

Product Form Condition Test Temperature Impact Strength
°F °C ft-lbf J
Plate Solution Annealed RT RT 198 268
Plate Solution Annealed -320 -196 150 203
Bar Solution Annealed RT RT 401 544
Bar Solution Annealed -320 -196 343 465
Plate Age Hardened* RT RT 91 123
Ring Annealed + Age Hardened* RT RT 51 69

*Aged hardened:  1200°F (649°C) / 24 h / Air Cool

Hot Hardness Data

The following are results from standard vacuum furnace hot hardness tests. Values are given in originally measured DPH (Vickers) units and conversions to Rockwell C/B scale.

Alloy 800°F (425°C) 1000°F (540°C) 1200°F (650°C) 1400°F (760°C) 1600°F (870°C)
Vickers Rockwell Vickers Rockwell Vickers Rockwell Vickers Rockwell Vickers Rockwell
242® 271 26 HRC 263 24 HRC 218 95 HRBW 140 75 HRBW 78
6B 269 26 HRC 247 22 HRC 225 98 HRBW 153 81 HRBW 91
25 171 87 HRBW 160 83 HRBW 150 80 HRBW 134 74 HRBW 93
188 170 86 HRBW 159 83 HRBW 147 77 HRBW 129 72 HRBW 89
230® 142 77 HRBW 139 76 HRBW 132 73 HRBW 125 70 HRBW 75
556® 132 73 HRBW 129 72 HRBW 118 67 HRBW 100 56 HRBW 67

HRBW = Hardness Rockwell “B”, Tungsten Indentor.
HRC = Hardness Rockwell “C”.

Thermal Stability

HAYNES® 242® alloy 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).

Comparative Retained Ductility and Impact Strength

Room-Temperature Tensile Elongation

Room Temperature Impact Strength

Room-Temperature Properties after Exposure at 1200°F (649°C)*

Exposure Time 0.2% Offset Yield Strength Ultimate Tensile Strength Elongation Reduction of Area Charpy V-Notch Strength
h ksi MPa ksi MPa % % ft.-lbs. J
0 110 758 179 1234 39 44 66 89
1000 119 820 194 1338 28 38 41 56
4000 122 841 196 1351 25 37 31 42
8000 121 834 193 1331 24 39 26 35

*Samples age hardened 1200°F (649°C) 24 h.
Duplicate tests.

Physical Properties

Physical Property British Units Metric Units
Density RT
0.327 lb/in3
RT
9.05 g/cm3
Melting Range 2350-2510°F - 1290-1375°C -
Electrical Resistivity RT 48.0 µohm-in RT 122.0 µohm-cm
200°F 48.5 µohm-in 100°C 123.4 µohm-cm
400°F 49.3 µohm-in 200°C 125.1 µohm-cm
600°F 50.0 µohm-in 300°C 126.7 µohm-cm
800°F 50.6 µohm-in 400°C 128.0 µohm-cm
1000°F 51.1 µohm-in 500°C 129.5 µohm-cm
1200°F 51.7 µohm-in 600°C 130.6 µohm-cm
1400°F 52.4 µohm-in 700°C 132.0 µohm-cm
1600°F 51.3 µohm-in 800°C 132.4 µohm-cm
1800°F 50.4 µohm-in 900°C 129.8 µohm-cm
- - 1000°C 127.6 µohm-cm
Thermal Diffusivity RT
4.7 x 10-3 in2/s
RT
30.5 x 10-3 cm2/s
200°F
5.1 x 10-3 in2/s
100°C
32.9 x 10-3 cm2/s
400°F
5.6 x 10-3 in2/s
200°C
35.9 x 10-3 cm2/s
600°F
6.1 x 10-3 in2/s
300°C
39.0 x 10-3 cm2/s
800°F
6.6 x 10-3 in2/s
400°C
41.9 x 10-3 cm2/s
1000°F
7.2 x 10-3 in2/s
500°C
45.0 x 10-3 cm2/s
1200°F
7.9 x 10-3 in2/s
600°C
48.1 x 10-3 cm2/s
1400°F
7.2 x 10-3 in2/s
700°C
51.2 x 10-3 cm2/s
1600°F
7.0 x 10-3 in2/s
800°C
44.2 x 10-3 cm2/s
1800°F
7.6 x 10-3 in2/s
900°C
46.6 x 10-3 cm2/s
- - 1000°C
49.6 x 10-3 cm2/s
Thermal Conductivity RT
75.7 Btu-in/ft2-hr-°F
RT 11.3 W/m-ºC
200°F
83.6 Btu-in/ft2-hr-°F
100°C 12.6 W/m-ºC
400°F
96.1 Btu-in/ft2-hr-°F
200°C 14.2 W/m-ºC
600°F
108.5 Btu-in/ft2-hr-°F
300°C 15.9 W/m-ºC
800°F
120.9 Btu-in/ft2-hr-°F
400°C 17.5 W/m-ºC
1000°F
133.3 Btu-in/ft2-hr-°F
500°C 19.2 W/m-ºC
1200°F
145.7 Btu-in/ft2-hr-°F
600°C 20.9 W/m-ºC
1400°F
158.2 Btu-in/ft2-hr-°F
700°C 22.5 W/m-ºC
1600°F
170.6 Btu-in/ft2-hr-°F
800°C 24.2 W/m-ºC
1800°F
183.0 Btu-in/ft2-hr-°F
900°C 25.8 W/m-ºC
- - 1000°C 27.5 W/m-ºC
Specific Heat RT 0.092 Btu/lb-°F RT 386 J/Kg-ºC
200°F 0.097 Btu/lb-°F 100°C 405 J/Kg-ºC
400°F 0.100 Btu/lb-°F 200°C 419 J/Kg-ºC
600°F 0.103 Btu/lb-°F 300°C 431 J/Kg-ºC
800°F 0.106 Btu/lb-°F 400°C 439 J/Kg-ºC
1000°F 0.110 Btu/lb-°F 500°C 451 J/Kg-ºC
1200°F 0.118 Btu/lb-°F 600°C 470 J/Kg-ºC
1400°F 0.144 Btu/lb-°F 700°C 595 J/Kg-ºC
1600°F 0.146 Btu/lb-°F 800°C 605 J/Kg-ºC
1800°F 0.150 Btu/lb-°F 900°C 610 J/Kg-ºC
- - 1000°C 627 J/Kg-ºC
Mean Coefficient of Thermal Expansion 70-200°F 6.0 µin/in-°F 25-100°C 10.8 µm/m-°C
70-400°F 6.3 µin/in-°F 25-200°C 11.3 µm/m- °C
70-600°F 6.5 µin/in-°F 25-300°C 11.6 µm/m-°C
70-800°F 6.7 µin/in-°F 25-400°C 11.9 µm/m-°C
70-1000°F 6.8 µin/in-°F 25-500°C 12.2 µm/m-°C
70-1100°F 6.8 µin/in-°F 25-600°C 12.3 µm/m-°C
70-1200°F 6.9 µin/in-°F 25-650°C 12.4 µm/m-°C
70-1300°F 7.2 µin/in-°F 25-700°C 13.0 µm/m-°C
70-1400°F 7.7 µin/in-°F 25-750°C 13.7 µm/m-°C
70-1600°F 8.0 µin/in-°F 25-800°C 14.0 µm/m-°C
70-1800°F 8.3 µin/in-°F 25-900°C 14.5 µm/m-°C
- - 25-1000°C 15.0 µm/m- °C
Dynamic Modulus of Elasticity RT
33.2 x 106 psi
RT 229 GPa
200°F
32.7 x 106 psi
100°C 225 GPa
400°F
31.8 x 106 psi
200°C 219 GPa
600°F
30.8 x 106 psi
300°C 213 GPa
800°F
29.7 x 106 psi
400°C 206 GPa
1000°F
28.6 x 106 psi
500°C 199 GPa
1200°F
27.6 x 106 psi
600°C 193 GPa
1400°F
25.7 x 106 psi
700°C 185 GPa
1600°F
24.0 x 106 psi
800°C 172 GPa
1800°F
22.4 x 106 psi
900°C 163 GPa
- - 1000°C 152 GPa

RT= Room Temperature

Oxidation Resistance

HAYNES® 242® alloy exhibits very good oxidation resistance at temperatures up to 1500°F (815°C), and should not require protective coatings for continuous or intermittent service at these temperatures. The alloy is not specifically designed for use at higher temperatures, but can tolerate short-term exposures.

Comparative Oxidation-Resistance in Flowing Air at 1500°F (815°C) for 1008 Hours*

Alloy Metal Loss Average Metal Affected
mils µm mils µm
242® 0.0 0 0.5 13
S 0.0 0 0.5 13
X 0.1 3 1.1 28
N 0.4 10 1.2 30
B 7.2 183 8.2 208
909 4.4 112 19.4 493

*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.

Comparative Oxidation Resistance in Flowing Air, 10 Months (7200 h), Cycled Every Two Months**

Alloy 800°F (427°C) 1000°F (538°C) 1200°F (649°C)
Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected
mils μm mils μm mils μm mils μm mils μm mils μm
718 0 0 0 0 0 0 0.1 3 0 0 0.2 5
242® 0 0 0 0 0 0 0.1 3 0 0 0.3 8
263 0 0 0 0 0 0 0.1 3 0 0 0.3 8

** 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 every two months.

Comparative Burner Rig Oxidation-Resistance at 1400°F (760°C) for 500 Hours***

Alloy Metal Loss Average Metal Affected
mils µm mils µm
N 0.7 18 0.8 20
242® 1.1 28 1.2 30
B 1.8 46 2.6 66
909 0.3 8 10.8 275

***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 reinserted into the flame tunnel.

Microstructures shown relate to the burner rig oxidation test data shown above for three of the materials evaluated. The black area shown at the top of the pictures for 242® alloy and alloy B represent thickness loss during the test. The alloy 909 apparently exhibited only minor thickness loss. This is believed to be a consequence of the sample actually swelling during the exposure due to oxygen absorption. The sample also developed a very thick, coarse scale and extensive internal oxidation. There was also evidence of significant cracking in the alloy 909 specimen due to the thermal cycling, even though the test samples were not constrained.

Schematic Representation of Metallographic Technique used for
Evaluating Oxidation Tests

Resistance to High-temperature Fluoride Environments

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® 242® alloy is in that category, 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® 12.6 0.3
S 15.8 0.4
N 15.8 0.4
625 47.2 1.2
230® 70.9 1.8
C-22® 78.7 2.0
600 141.7 3.6

Comparative Resistance to KCl-KF-NaF Mixed Salts

Samples were exposed to a mixture of KCl-KF-NaF salts for a total of 40 hours in service. Temperature was cycled from 1290 to 1650°F (700-900°C) during the course of the exposure.

Resistance to Molten Salt

Samples were partially submerged in molten flux at 1250°F for 1200 hours. Flux consisted of boric acid, boron elemental, potassium fluoride, potassium tetraborate tetrahydrate, potassium fluoborate, potassium hydrogen difluoride, and potassium pentaborate.

Alloy Corrosion Rate
mils / 24 h µm / 24 h
242® 0.5 13
N 0.6 15
C-276 0.9 23

Resistance to Nitriding

HAYNES® 242® alloy have 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.

HAYNES® 242® alloy Resistance to Nitriding

Alloy
Nitrogen Absorption (mg/cm2)
214® 0.3
242® 0.7
600 0.9
230® 1.4
X 3.2
800H 4.0
316 SS 6.0
304 SS 7.3
310 SS 7.7

Resistance to Salt Spray Corrosion

HAYNES® 242® alloy 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 Affected
mils µm mils µm
S 0.10 2.5 0.20 5.1
242® 0.15 3.8 0.30 7.6
B 0.20 5.1 0.30 7.6
909 0.40 10.2 0.20 30.5

Resistance to Hydrogen Embrittlement

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 Ratio of Notched Tensile Strength, Hydrogen/Air
psi MPa Kt
Waspaloy 7,000 48 6.3 .78
625 5,000 34 8.0 .76
242® 5,000 34 8.0 .74
718 10,000 69 8.0 .46
R-41 10,000 69 8.0 .27
X-750 7,000 48 6.3 .26

Aqueous Corrosion Resisitance

Although not specifically designed for use in applications which require resistance to aqueous corrosion, 242® alloy does exhibit resistance in some media which compares favorably with that exhibited by traditional corrosion-resistant alloys. Data shown for 242® alloy was generated for samples tested in the mill annealed condition.

Corrosive Media Temperature Exposure Corrosion Rate, Mils/year (mm/year)
242® B-2 C-22® N
°F °C h mils mm mils mm mils mm mils mm
5% HF 175 79 24 14 0.36 12 0.30 25 0.64 20 0.51
48% HF 175 79 24 32 0.81 25 0.64 27 0.69 31 0.79
70% HF 125 52 24 35 0.89 66 1.68 32 0.81 48 1.22
10% HCI Boiling 24 22 0.56 7 0.18 400 10.16 204 5.18
20% HCl Boiling 24 41 1.04 15 0.38 380 9.65
55% H3PO4 Boiling 24 3 0.08 4 0.10 9 0.23
85% H3PO4 Boiling 24 4 0.10 4 0.10 120 3.05
10% H2PO4 Boiling 24 2 0.05 2 0.05 11 0.28 46 1.17
50% H2PO4 Boiling 24 5 0.13 1 0.03 390 9.91
99% ACETIC Boiling 24 <1 <0.03 1 0.03 Nil

Solution Annealed Tensile

Room temperature tensile properties of material in mill annealed condition

Form 0.2% Yield Strength Ultimate Tensile Strength Elongation Reduction of Area
ksi MPa ksi MPa % %
Sheet 60.7 419 131.8 909 65.6
Plate 60.3 416 131.1 904 65.5 71.6
Bar 60.5 417 131.0 903 66.5 77.1

Hardness and Grain Size

Solution Annealed Room Temperature Hardness

Form Hardness, HRBW Typical ASTM Grain Size
Sheet 92 5 – 6.5
Plate 94 4 – 6.5
Bar 90 3.5 – 6

HRBW= Hardness Rockwell “B”, Tungsten Indentor.

Fabrication and Welding

HAYNES® 242® alloy 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 (1038-1121°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, etc. prior to welding. Because of the alloy’s high nickel content, the weld puddle will be somewhat “sluggish” relative to steels. To avoid lack of fusion and incomplete penetration defects, the root opening and bevel should be sufficiently open.

Filler Metals

HAYNES® 242® alloy should be joined using matching filler metal. If shielded metal arc welding is used, HASTELLOY® W alloy coated electrodes are suggested. Please click here or see the Haynes Welding SmartGuide for more information.

Postweld Heat Treatment

HAYNES® 242® alloy 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 mechanical properties.

Typical root, face, and side
bends (L to R) for welded
242® alloy 0.5-inch (13 mm)
plate and matching filler
metal. Bend radius was 1.0
inch (25 mm).

Machining

HAYNES® 242® alloy 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 results may be achieved 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.

Specifications and Codes

Specifications

HAYNES® 242® alloy (N10242)
Sheet, Plate & Strip SB 434/B 434P= 44
Billet, Rod & Bar SB 573/B 573B 472P= 44
Coated Electrodes
Bare Welding Rods & Wire SFA 5.14/ A 5.14 (ERNiMo-12)F= 44
Seamless Pipe & Tube SB 622/B 622P= 44
Welded Pipe & Tube SB 619/B 619SB 626/B 626P= 44
Fittings SB 366/B 366P= 44
Forgings SB 564/B 564P= 44
DIN
Others

Codes

HAYNES® 242® alloy (N10242)
ASME Section l
Section lll Class 1
Class 2
Class 3
Section lV HF-300.2
Section Vlll Div. 1 1000°F (538°C)1
Div. 2
Section Xll
B16.5
B16.34
B31.1
B31.3

1Plate, Sheet, Bar, Forgings, fittings, welded pipe/tube, seamless pipe/tube

Disclaimer

Haynes International makes all reasonable efforts to ensure the accuracy and correctness of the data displayed on this site but makes no representations or warranties as to the data’s accuracy, correctness or reliability. All data are for general information only and not for providing design advice. Alloy properties disclosed here are based on work conducted principally by Haynes International, Inc. and occasionally supplemented by information from the open literature and, as such, are indicative only of the results of such tests and should not be considered guaranteed maximums or minimums.  It is the responsibility of the user to test specific alloys under actual service conditions to determine their suitability for a particular purpose.

For specific concentrations of elements present in a particular product and a discussion of the potential health affects thereof, refer to the Safety Data Sheets supplied by Haynes International, Inc.  All trademarks are owned by Haynes International, Inc., unless otherwise indicated.

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