Specifications
- Bolts: ASTM A193 & ASME SA193 GRADE B8R
- Nuts: ASTM A194 & ASME SA194 GRADE 8R
- Bar: ASTM A276 & A479
- W-Nr 1.7440
Nitronic 50 is a durable austenitic stainless steel used for anti-galling applications with greater corrosion resistance than 304 or 316 stainless steel with nearly twice the yield strength. It has excellent mechanical properties at low and high-temperature ranges. Nickel Systems stocks threaded rod/studs and nuts in Nitronic 50 ranging from 1/2”-13 to 3/4”-10 in both finished and heavy pattern certified to ASTM A194 Grade 8r. Most designs of a gall-resistant joint require only one component to be gall resistant.
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Density, g/cm3 (lbs/in.3) | 24 °C (75 °F) | 7.88 (0.285) |
Electrical Resistivity, µΩ•cm | 21 °C (70 °F) | 82 |
Condition | Typical Magnetic Permeability at Field Strength of | ||
50 Oer (3978 A/m) | 100 Oer (7957 A/m) | 200 Oer (15 914 A/m) | |
Annealed | 1.004 | 1.004 | 1.004 |
Cold Drawn 27% | 1.004 | 1.004 | 1.003 |
Cold Drawn 56% | 1.004 | 1.004 | 1.004 |
Cold Drawn 75% | 1.004 | 1.004 | 1.004 |
*Average of duplicate tests on mill-annealed sheet samples using the Curie Force Method.
Temperature, °C (°F) | Magnetic Mass Susceptibility, χ, 10-6 cm3/g | Typical Magnetic Permeability, µ |
22 (72) | 21.5 | 1.0021 |
-23 (-9) | 22.5 | 1.0022 |
-73 (-99) | 25.0 | 1.0025 |
-123 (-189) | 28.5 | 1.0028 |
-173 (-279) | 35.5 | 1.0035 |
-223 (-369) | 54.0 | 1.0053 |
-240 (-400) | 74.0 | 1.0073 |
-258 (-432) | 61.0 | 1.0060 |
Note that the magnetic susceptibility of NITRONIC 50 peaks at approximately -240 °C (-400 °F). This phenomenon is independent of field strength.
Condition | Size, mm (in.) | Ultimate Tensile Strength, MPa (ksi) | 0.2% Yield Strength, MPa (ksi) | Elongation % in 4D0 | Reduction of Area, % | Rockwell Hardness Max. | Impact Strength and Lateral Expansion, -196 °C (-321 °F) | Impact Strength -60 °C (-76 °F), J (ft•lbs) | Lateral Expansion -60 °C (-76 °F), mm (in.) | |
J (ft•lbs) | mm (in.) | |||||||||
Annealed | all | 690 (100) | 415 (60) | 35 | 55 | C35 | 27 (20) | 0.381 (0.015) | 20 (15) | 0.381 (0.015) |
HS | 0 -50.8 (0 – 2) | 930 (135) | 800 (116) | 20 | 50 | C35 | 27 (20) | no minimum guaranteed, but production aims for 0.381 mm min | 20 (15) | 0.381 (0.015) |
HS | > 50.8 – 76.2 (> 2 – 3) | 800 (116) | 515 (75) | 25 | 50 | C35 | 27 (20) | 20 (15) | 0.381 (0.015) | |
HS | > 76.2 – 203.2 (> 3 – 8) | 700 (102) | 415 (60) | 30 | 50 | C35 | 27 (20) | 20 (15) | 0.381 (0.015) | |
SHS | 0 – 50.8 (0 – 2) | 930 (135) | 800 (116) | 25 | 50 | C35 | 27 (20) | 20 (15) | 0.381 (0.015) | |
SHS | > 50.8 – 145 (> 2 – 5.7) | 900 (131) | 725 (105) | 25 | 50 | C35 | 27 (20) | 20 (15) | 0.381 (0.015) |
Condition | Size, mm (in.) | UTS, MPa (ksi) | 0.2% YS, MPa (ksi) | Elongation % in 4D0 | Reduction of Area, % | Rockwell Hardness Max. | Impact Strength and Lateral Expansion, -196 °C (-321 °F) | Impact Strength -60 °C (-76 °F), J (ft•lbs) | Lateral Expansion -60 °C (-76 °F), mm (in.) | ||
J (ft•lbs) | mm (in.) | ||||||||||
Annealed | 25.4 (1) | 25.4 (1) | 827 (120) | 414 (60) | 50 | 70 | B98 | 68 (50) | >0.381 (0.015) | >20 (15) | >0.381 (0.015) |
HS | >50.8 (2) | ≤101.6 (4) | 937 (136) | 731 (106) | 33 | 66 | C28 | 68 (50) | >0.653 (0.026) | >20 (15) | >0.381 (0.015) |
SHS | >50.8 (2) | ≤101.6 (4) | 1009 (146) | 830 (120) | 27 | 63 | C32 | 50 (37) | >0.427 (0.017) | >20 (15) | >0.381 (0.015) |
Condition | Test Temperature, °C (°F) | UTS, MPa (ksi) | 0.2% YS, MPa (ksi) | Elongation % in 4D0 | Reduction of Area, % |
Annealed 1066 °C (1950 °F) Bars 19.1 – 31.8 mm (0.75 – 1.25 in.) Diameter |
24 (75) | 855 (124) | 538 (78) | 41 | 68 |
93 (200) | 772 (112) | 455 (66) | 41 | 68 | |
204 (400) | 703 (102) | 400 (58) | 38 | 67 | |
316 (600) | 676 (98) | 372 (54) | 38 | 64 | |
427 (800) | 648 (94) | 345 (50) | 40 | 63 | |
538 (1000) | 614 (89) | 331 (48) | 37 | 63 | |
649 (1200) | 552 (80) | 303 (44) | 37 | 63 | |
732 (1350) | 469 (68) | 290 (42) | 43 | 72 | |
816 (1500) | 345 (50) | 221 (32) | 60 | 85 | |
Annealed 1121 °C (2050 °F) Bars 25.4 – 38.1 mm (1 – 1.5 in.) Diameter |
24 (75) | 807 (117) | 414 (60) | 45 | 71 |
93 (200) | 738 (107) | 338 (50) | 44 | 71 | |
204 (400) | 662 (96) | 262 (38) | 44 | 70 | |
316 (600) | 634 (92) | 241 (35) | 43 | 68 | |
427 (800) | 614 (89) | 234 (34) | 44 | 66 | |
538 (1000) | 579 (84) | 221 (32) | 41 | 67 | |
649 (1200) | 510 (74) | 214 (31) | 38 | 64 | |
732 (1350) | 455 (66) | 214 (31) | 37 | 62 | |
816 (1500) | 359 (52) | 207 (30) | 41 | 61 |
Average of triplicate tests from each of three heats.
Condition | Test Temperature, °C (°F) | Stress for Failure, MPa (ksi) | ||
100 Hours | 1,000 Hours | 10,000 Hours (estimated) | ||
Annealed 1066 °C (1950 °F) Bars 19.1 – 31.8 mm (0.75 – 1.25 in.) Diameter |
538 (1000) | 627 (91) | 607 (88) | 496 (72) |
593 (1100) | 496 (72) | 427 (62) | 324 (47) | |
649 (1200) | 379 (55) | 262 (38) | 152 (22) | |
732 (1350) | 145 (11) | 82.7 (12) | 41.4 (6) | |
816 (1500) | 69.0 (10) | 25.5 (3.7) | 9.0 (1.3) | |
Annealed 1121 °C (2050 °F) Bars 25.4 – 38.1 mm (1 – 1.5 in.) Diameter |
538 (1000) | – | – | – |
593 (1100) | 488 (65) | 372 (54) | 296 (43) | |
649 (1200) | 345 (50) | 283 (41) | 224 (32.5) | |
732 (1350) | 200 (29) | 103 (15) | 58.6 (8.5) | |
816 (1500) | 89.6 (13) | 44.8 (6.5) | 241 (3.5) |
Average of tests from three heats.
Condition | Test Temperature, °C (°F) | Stress for Min Creep Rate, MPa (ksi) | |
0.0001% per Hour | 0.00001% per Hour | ||
Annealed 1121 °C (2050 °F) | 593 (1100) | 283 (41) | 238 (34.5) |
649 (1200) | 152 (22) | 110 (16) |
Test from one heat.
Cold Reduction % | UTS, MPa (ksi) | 0.2% YS, MPa (ksi) | Elongation % in 4D0 | Reduction of Area, % |
15 | 1138 (165) | 986 (143) | 23 | 56 |
30 | 1338 (194) | 1200 (174) | 15 | 49 |
45 | 1489 (216) | 1351 (196) | 11 | 45 |
60 | 1613 (234) | 1489 (216) | 9 | 42 |
75 | 1696 (246) | 1613 (234) | 8 | 39 |
Average of duplicate tests. Starting size 6.35 mm (0.25 in.) dia. rod annealed at 1121 °C (2050 °F).
Test Temperature, °C (°F) | UTS, MPa (ksi) | 0.2% YS, MPa (ksi) | Elongation % in 4D0 | Reduction of Area, % |
-73 (-100) | 1007 (146) | 586 (85) | 50 | 65 |
-196 (-320) | 1558 (226) | 883 (128) | 41 | 51 |
Average of duplicate tests.
Test Temperature, °C (°F) | Impact – Charpy V. Notch, J (ft•lbs) | |
Annealed at 1121 °C (2050 °F) | Simulated HAZ | |
24 (75) | 230 (170) | 230 (170) |
-73 (-100) | 156 (115) | 156 (115) |
-196 (-320) | 68 (50) | 68 (50) |
Heat treated at 677 °C (1250 °F) for 1 hour to simulate the heat-affected zone of heavy weldments. Average of duplicate test.
Diameter Bar, mm (in.) | Cold Reduction % | UTS, MPa (ksi) | 0.2% YS, MPa (ksi) | Elongation % in 4D0 | Reduction of Area % | Rockwell Hardness | Charpy Impact, J (ft•lbs) | ||
Test Temperature, °C (°F) | |||||||||
27 (80) | -40 (-40) | -79 (-110) | |||||||
19.05 (0.75) | 0 | 804 (116.6) | 397 (57.6) | 47 | 71 | B91 | 314 (232) | – | – |
19.05 (0.75) | 13 | 982 (142.5)
973 (141.1) |
869 (126.0) 844 (122.5) |
31 31 |
67 66 |
C30 | 157 (116) 156 (115) |
– | – |
16.51 (0.65) | 28 | 1086 (157.6) 1076 (156.0) |
1058 (153.4) 1036 (150.6) |
2124 | 64 64 |
C34 | 133 (98) 123 (91) |
100 (74) 73 (54) |
– |
19.05 (0.75) | 46 | 1282 (185.9) 1263 (183.1) |
1268 (183.8) 1245 (180.6) |
18 16 |
58 58 |
C36 | 73 (54) 71 (53) |
65 (48) 58 (43) |
51 (38) 53 (39) |
Condition | Bar Diameter, mm (in.) | Fatigue Strength at 108 Reversals of Stress, MPa (ksi) | |
Tested in Air* | Tested in Seawater** | ||
Annealed 1121 °C (2050 °F) | 25.4 (1) | 290 (42) | 152 (22) |
Annealed 1066 °C (1950 °F) | 25.4 (1) | 324 (47) | — |
High-Strength (HS) Bars (Hot Rolled Unannealed) | 25.4 (1) | 469 (68) | 124 (18) |
63.5 (2.5) | 400 (58) | 103 (15) | |
102 (4 | 303 (44) | 103 (15) |
*R R Moore specimens tested at room temperature. ** McAdam specimens tested in ambient temperature seawater (11 – 31 °C) at LaQue Corrosion Laboratory Wrightsville Beach, N.C. Tests from one heat for each size and condition.
Condition | UTS, MPa (ksi) | Double Shear, MPa (ksi) | Shear/Tensile Ratio, % |
Annealed 1066 °C (1950 °F) | 869 (126) | 598 (86.8) | 69 |
Annealed 1121 °C (2050 °F) | 779 (113) | 541 (78.5) | 69.5 |
Average of duplicate tests.
Modulus of Elasticity in Tension (E), GPa (Mpsi) | Modulus of Elasticity in Torsion (G), GPa (Mpsi) | Poisson’s Ratio |
199 (28.9) | 74.5 (10.8) | 0.312 |
Average of duplicate tests.
Temperature, °C (°F) | Young’s Modulus in Tension | Poisson’s Ratio | |
GPa | Mpsi | ||
22 (72) | 199 | 28.9 | 0.312 |
93 (200) | 192 | 27.8 | 0.307 |
149 (300) | 186 | 27.0 | 0.303 |
204 (400) | 180 | 26.1 | 0.299 |
260 (500) | 174 | 25.3 | 0.295 |
315 (600) | 170 | 24.6 | 0.291 |
371 (700) | 165 | 24.0 | 0.288 |
Tests performed on sheet samples in the longitudinal direction using strain gauges.
Condition | UTS – Smooth, MPa (ksi) | UTS – Notched, MPa (ksi) |
Annealed 1121 °C (2050 °F) | 790 (114.5) | 1069 (155) |
Annealed 1066 °C (1950 °F) | 830 (120.5) | — |
High-Strength (HS) bars | 1041 (151.0) | 1355 (196.5) |
Average of duplicate tests using notched specimens with a stress-concentration factor of kt = 1.3.
Temperature, °C (°F) | Coefficient of Thermal Expansion | |
µm/m/K | μin./in./°F | |
21 – 93 (70 – 200) | 16.2 | 9.0 |
21 – 204 (70 – 400) | 16.6 | 9.2 |
21 – 316 (70 – 600) | 17.3 | 9.6 |
21 – 427 (70 – 800) | 17.8 | 9.9 |
21 – 538 (70 – 1000) | 18.4 | 10.2 |
21 – 649 (70 – 1200) | 18.9 | 10.5 |
21 – 760 (70 – 1400) | 19.4 | 10.8 |
21 – 871 (70 – 1600) | 20.0 | 11.1 |
*Average of duplicate tests.
Temperature, °C (°F) | Contraction Parts Per Million, (ppm) | Mean Expansion Coefficient Between T and 24 °C (75 °F) | |
ppm/°C | ppm/°F | ||
-41 (-41) | 948 | 14.61 | 8.17 |
-46 (-51) | 1016 | 14.53 | 8.06 |
-51 (-60) | 1074 | 14.34 | 7.95 |
-62 (-80) | 1237 | 14.40 | 7.98 |
-73 (-100) | 1398 | 14.43 | 7.99 |
-87 (-125) | 1560 | 14.07 | 7.80 |
-101 (-150) | 1723 | 13.80 | 7.66 |
-117 (-178) | 1951 | 13.84 | 7.71 |
-129 (-200) | 2079 | 13.60 | 7.56 |
-143 (-225) | 2231 | 13.37 | 7.44 |
-162 (-260) | 2333 | 12.55 | 6.96 |
-196 (-320) | 2542 | 11.56 | 6.44 |
Temperature, °C (°F) | Thermal Conductivity*, W/m/K (BTU/hr/ft/in./°F) |
21 (70) | — |
149 (300) | 15.6 (108) |
316 (600) | 17.9 (124) |
482 (900) | 20.3 (141) |
649 (1200) | 23.0 (160) |
816 (1500) | 25.2 (175) |
*Average of duplicate tests.
Alloy (Rockwell Hardness) Versus | Alloy K 500 (C34) | NITRONIC 50 (C28) | Type 316 | NITRONIC 50 (B95) |
Type 316 (B91) | 33.78 | 10.37 | 12.51 (B91) | 4.29 |
17-4 PH (C43) | 34.08 | 12.55 | 18.50 (B91) | 5.46 |
Cobalt Alloy 6B (C48) | 18.78 | 3.26 | 5.77 (B72) | 1.85 |
Type 431 (C42) | 26.40 | 6.73 | 5.03 (B72) | 3.01 |
Ti-6AI-4V (C36) | 17.19 | 6.27 | 6.31 (B72) | 4.32 |
Alloy K-500 (C34) | 30.65 | 34.98 | 33.78 (B91) | 22.87 |
NITRONIC 50 (C28) | 34.98 | 9.37 | 10.37 (B72) | 4.00 |
NITRONIC 60 (B95) | 22.87 | 4.00 | 4.29 (B91) | 2.79 |
Test Conditions: Taber Met-Abrader machine, 12.7 mm (0.5 in.) crossed (90°) cylinders, dry. 71 N load (16 lbs), 105 RPM, room temperature. 120 gm surface finish, 10 000 cycles degreased, duplicates weight loss corrected for density differences.
Alloy | Weight Loss, mg |
NITRONIC 50 | 30 |
Type 316 | 100 |
Data provided by outside laboratory per ASTM G32 Test Method.
Test Medium | Corrosion Rates(1) | ||
NITRONIC 50 Bar Annealed 1066 °C (1950 °F), g/mm2 (g/in.2) | NITRONIC 50 Bar Annealed 1121 °C (2050 °F), g/mm2 (g/in.2) | NITRONIC 50 HighStrength (HS) Bar (3), g/mm2 (g/in.2) | |
10% FeCl3, 25C-Plain(2) | 0.6 (< 0.001) | 0.6 (< 0.001) | 0.6 (< 0.001) |
10% FeCl3, 25C-creviced(2) | 0.6 (< 0.001) | 0.6 (< 0.001) | 0.6 (< 0.001) |
mm/y (MPY(4)) | mm/y (MPY(4)) | mm/y (MPY(4)) | |
1% H2 SO4, 80 °C | < 0.03 (< 1) | < 0.03 (< 1) | < 0.03 (< 1) |
2% H2 SO4, 80 °C | < 0.03 (< 1) | < 0.03 (< 1) | < 0.03 (< 1) |
5% H2 SO4, 80 °C | < 0.03 (< 1) | < 0.03 (< 1) | < 0.03 (< 1) |
10% H2 SO4, 80 °C | — | 0.71 (28) | — |
20% H2 SO4, 80 °C | — | 3.38 (133) | — |
1% H2 SO4, Boiling | — | 0.69 (27) | — |
2% H2 SO4, Boiling | — | 1.63 (64) | — |
5% H2 SO4, Boiling | 4.93 (194) | 3.33 (131) | 7.52 (296) |
10% H2 SO4, Boiling | — | 9.04 (356) | — |
20% H2 SO4, Boiling | — | 41.66 (1640) | — |
1% HCL, 35 °C | < 0.03 (< 1) | < 0.03 (< 1) | < 0.03 (< 1) |
2% HCL, 35 °C | 0.61 (24) | < 0.03 (< 1) | 0.69 (27) |
1% HCL, 80 °C | — | < 0.03 (< 1) | 6.07 (239) |
2% HCL, 80 °C | — | 11.15 (439) | 11.48 (452) |
65% HNO3, Boiling | 0.25 (10) | 0.18 (7) | — |
70% H3 PO4, Boiling | 5.16 (203) | 3.91 (154) | — |
33% Acetic Acid, Boiling | < 0.03 (< 1) | < 0.03 (< 1) | < 0.03 (< 1) |
20% Formic Acid, Boiling | — | < 0.03 (< 1) | — |
40% Formic Acid, Boiling | — | 0.81 (32) | — |
10% HNO3 + 1% HF, 35 °C | — | 0.18 (7) | — |
10% HNO3 + 1% HF, 80 °C | — | 1.75 (69) | — |
(1)Immersion test performed on 15.9 mm (0.625 in.) diameter x 15.9 mm (0.625 in.) long machined cylinders. Results are average of five 48-hour periods. Specimens tested at 35 and 80 °C were intentionally activated for third, fourth, and fifth periods. Where both active and passive conditions occurred, only active rates are shown. (2)Exposure for 50 hours with rubber bands on some specimens to produce crevices. (3)Corrosion rates for hot rolled bars. For other mill products, contact AK Steel International. (4)Mils Per Year (MPY) = 0.001 in. per year.
Test Medium | NITRONIC 50 As-Cast, mm/y (MPY) | NITRONIC 50 Cast + Annealed 1121 °C (2050 °F), mm/y (MPY) |
10% FeCl3 – Uncreviced 50 hrs, Room Temperature | — | 0.6 g/mm2 (< 0.001 g/in.2) |
10% FeCl3 – Crevices 50 hrs, Room Temperature | — | 187 g/mm2 (0.029 g/in.2) |
5% H2 SO4 , 80 °C | 2.41 (95) | 2.06 (81) |
5% H2 SO4 , Boiling | — | 10.62 (418) |
1% HCL, 35 °C | < 0.03 (< 1) | < 0.03 (< 1) |
70% H3 PO4 Boiling | — | 2.11 (83) |
All test performed on 15.9 mm (0.625 in.) diameter x 15.9 mm (0.625 in.) long machined cylinders. Except for the ferric chloride tests, all results are the average of five 48-hour periods. Specimens tested at 35 and at 80 °C were intentionally activated for the third, fourth, and fifth periods. Where both active and passive periods occurred, only active rates are shown.
Huey Test | % Ferrite | |
Annealed*, mm/y (MPY) | Sensitized#, mm/y (MPY) | |
0.15 (6) | 0.18 (7.20) | Nil |
0.12 (4.8) | 0.46 (18.0) | 4 |
*1121 °C (2050 °F) – 30 Minute-Water Quenched #1121 °C (2050 °F) – 30 Minute-Water Quenched + 677 °C (1250 °F) – 30 Minute – Air Cooled. Even sensitized cast NITRONIC 50 Stainless Steel has an acceptable intergranular corrosion rate less than 0.61 mm/y (24 MPY) with up to 4% ferrite present.
INTERGRANULAR ATTACK RESISTANCE OF ARMCO NITRONIC 50 BAR PER ASTM A262
Condition | Practice B Ferric Sulfate, mm/y (MPY) | Practice E Copper-Copper Sulfate |
Annealed 1066 °C (1950 °F) | 0.30 (12.0) | Passed |
Annealed 1066 °C (1950 °F) + 677 °C (1250 °F) – 1 hr – A.C. | 1.16 (45.6) | Passed |
Annealed 1121 °C (2050 °F) | 0.27 (10.8) | Passed |
Annealed 1121 °C (2050 °F) + 677 °C (1250 °F) – 1 hr – A.C. | 0.67 (26.4) | Passed |
High-Strength (Bar Mill) | 0.94 (37.2) | Passed |
High-Strength (Precision Rotary Forging, PRF): Edge | 0.40 (15.6) | Passed |
High-Strength (Precision Rotary Forging, PRF): Intermediate | 0.37 (14.4) | Passed |
High-Strength (Precision Rotary Forging, PRF): Center | 0.34 (13.2) | Passed |
Alloy | Condition | Time to Failure, Hours Under Stress of | ||
517 MPa (75 ksi) | 345 MPa (50 ksi) | 172 MPa (25 ksi) | ||
Type 304 | Annealed | 0.2 | 0.3 | 0.8 |
Type 316 | Annealed | 0.8 | 2.5 | 7.0 |
NITRONIC 50 | Annealed | 0.4 | 1.2 | 5.0 |
NITRONIC 50 | High-Strength | 1.2 | 1.5 | 6.0 |
NITRONIC 50 | Cold Drawn | 1.2 | 2.6 | 3.3 |
Alloy | Condition | Rockwell Hardness, C | 0.2% YS, MPa (ksi) | Time to Failure, hr, Under Stress, MPa (ksi) | ||||||
1034 (150) | 965 (140) | 862 (125) | 690 (100) | 517 (75) | 345 (50) | 172 (25) | ||||
NITRONIC 50 | Annealed 1066 °C (1950 °F) | 22 | 488 (67) | — | — | — | > 1000 | > 1000 | > 1000 | — |
High-Strength (HS)(3) 25.4 mm (1 in.) dia. | 33 | 931 (135) | — | 204 | 320 | > 1000 | > 1000 | — | — | |
High-Strength (HS)(3) 25.4 mm (1 in.) dia. | 35 | 1007 (146) | — | 358 | — | — | — | — | — | |
High-Strength (HS)(3) 25.4 mm (1 in.) dia. | 36 | 993 (144) | 170(2) | > 1000 | > 1000 | > 1000 | — | — | — | |
Cold Drawn 9.5 mm (0.375 in.) dia. | 41 | 993 (144) | > 1000 | — | — | > 1000 | — | — | — | |
17-4 PH | H 1150D | 32.5 | 758 (110) est | — | — | — | — | 9.5 | 16 | 225 |
H 1150M | 29 | 586 (85) | — | — | — | — | 13.5 | 29 | 850 |
(1)Longitudinal tensile specimens tested according to NACE TM0177. (2)Ductile creep failure. (3)For hot rolled bars only.