HAYNES® 556® is an iron–nickel–chromium–cobalt alloy designed for high-heat, corrosive-duty service. It delivers solid strength at elevated temperatures while standing up well to oxidizing conditions and harsh process atmospheres such as carburizing, sulfidizing, and chlorine-containing environments. It’s also recognized for performance in molten salt exposure (including chloride-based salts) and for resisting attack in contact with molten zinc—making it a practical option where temperature, chemistry, and durability must all be managed together.
Nickel Systems supports customers sourcing high-performance fasteners for severe service applications—helping engineers and procurement teams match the right material to the job and keep projects moving. If you’re specifying HAYNES® 556® for heat- and corrosion-exposed hardware, our team can help streamline selection, availability, and delivery so you can maintain equipment integrity and uptime with confidence.
The tables below provide a quick-reference overview of the key physical, mechanical, and chemical properties for HAYNES® 556® alloy (UNS R30556). For full details—including additional conditions, product forms, and processing guidance—please download the complete datasheet. .
This technical information applies specifically to HAYNES® 556® material manufactured by Haynes International. HAYNES® and HAYNES® 556® are registered trademarks of Haynes International website. If your application requires this specific producer/brand, please indicate it at the time of quotation.
| Physical Property | Imperial Units | Metric Units | ||
|---|---|---|---|---|
| Density | RT | 0.297 lb/in3 | RT | 8.23 g/cm3 |
| Melting Range | 2425-2580°F | – | 1330-1415°C | – |
| Electrical Resistivity | RT | 35.7 µohm-in | RT | 95.2 µohm-cm |
| 200°F | 38.7 µohm-in | 100°C | 98.6 µohm-cm | |
| 400°F | 40.5 µohm-in | 200°C | 102.6 µohm-cm | |
| 600°F | 42.1 µohm-in | 300°C | 106.5 µohm-cm | |
| 800°F | 43.5 µohm-in | 400°C | 109.5 µohm-cm | |
| 1000°F | 44.7 µohm-in | 500°C | 112.5 µohm-cm | |
| 1200°F | 45.7 µohm-in | 600°C | 115.1 µohm-cm | |
| 1400°F | 46.6 µohm-in | 700°C | 117.2 µohm-cm | |
| 1600°F | 47.3 µohm-in | 800°C | 119.0 µohm-cm | |
| 1800°F | 48.0 µohm-in | 900°C | 120.7 µohm-cm | |
| 2000°F | 48.6 µohm-in | 1000°C | 122.3 µohm-cm | |
| – | – | 1100°C | 123.7 µohm-cm | |
| Thermal Diffusivity | RT | 4.5 x 10-3 in2/s | RT | 28.7 x 10-3 cm2/s |
| 200°F | 4.8 x 10-3 in2/s | 100°C | 31.2 x 10-3 cm2/s | |
| 400°F | 5.3 x 10-3 in2/s | 200°C | 34.2 x 10-3 cm2/s | |
| 600°F | 5.8 x 10-3 in2/s | 300°C | 37.0 x 10-3 cm2/s | |
| 800°F | 6.3 x 10-3 in2/s | 400°C | 39.7 x 10-3 cm2/s | |
| 1000°F | 6.7 x 10-3 in2/s | 500°C | 42.3 x 10-3 cm2/s | |
| 1200°F | 7.1 x 10-3 in2/s | 600°C | 44.8 x 10-3 cm2/s | |
| 1400°F | 7.5 x 10-3 in2/s | 700°C | 47.0 x 10-3 cm2/s | |
| 1600°F | 7.7 x 10-3 in2/s | 800°C | 48.8 x 10-3 cm2/s | |
| 1800°F | 8.0 x 10-3 in2/s | 900°C | 50.3 x 10-3 cm2/s | |
| 2000°F | 8.2 x 10-3 in2/s | 1000°C | 51.6 x 10-3 cm2/s | |
| – | – | 1100°C | 52.8 x 10-3 cm2/s | |
| Thermal Conductivity | RT | 77 Btu-in/ft2-hr-°F | RT | 11.1 W/m-°C |
| 200°F | 90 Btu-in/ft²-hr-°F | 100°C | 13.1 W/m-°C | |
| 400°F | 107 Btu-in/ft²-hr-°F | 200°C | 15.4 W/m-°C | |
| 600°F | 122 Btu-in/ft²-hr-°F | 300°C | 17.3 W/m-°C | |
| 800°F | 135 Btu-in/ft²-hr-°F | 400°C | 19.0 W/m-°C | |
| 1000°F | 148 Btu-in/ft²-hr-°F | 500°C | 20.8 W/m-°C | |
| 1200°F | 160 Btu-in/ft²-hr-°F | 600°C | 22.4 W/m-°C | |
| 1400°F | 173 Btu-in/ft²-hr-°F | 700°C | 24.0 W/m-°C | |
| 1600°F | 185 Btu-in/ft²-hr-°F | 800°C | 25.5 W/m-°C | |
| 1800°F | 197 Btu-in/ft²-hr-°F | 900°C | 27.2 W/m-°C | |
| 2000°F | 210 Btu-in/ft²-hr-°F | 1000°C | 28.9 W/m-°C | |
| – | – | 1100°C | 30.4 W/m-°C | |
| Specific Heat | RT | 0.111 Btu/lb-°F | RT | 464 J/kg·°C |
| 200°F | 0.113 Btu/lb-°F | 100°C | 475 J/kg·°C | |
| 400°F | 0.118 Btu/lb-°F | 200°C | 493 J/kg·°C | |
| 600°F | 0.122 Btu/lb-°F | 300°C | 508 J/kg·°C | |
| 800°F | 0.126 Btu/lb-°F | 400°C | 523 J/kg·°C | |
| 1000°F | 0.130 Btu/lb-°F | 500°C | 538 J/kg·°C | |
| 1200°F | 0.133 Btu/lb-°F | 600°C | 552 J/kg·°C | |
| 1400°F | 0.135 Btu/lb-°F | 700°C | 561 J/kg·°C | |
| 1600°F | 0.140 Btu/lb-°F | 800°C | 570 J/kg·°C | |
| 1800°F | 0.147 Btu/lb-°F | 900°C | 595 J/kg·°C | |
| 2000°F | 0.152 Btu/lb-°F | 1000°C | 618 J/kg·°C | |
| – | – | 1100°C | 638 J/kg·°C | |
| Mean Coefficient of Thermal Expansion | 70-200°F | 8.1 µin/in-°F | 25-100°C | 14.7 x 10-6 m/m·°C |
| 70-400°F | 8.2 µin/in-°F | 25-200°C | 14.9 x 10-6 m/m·°C | |
| 70-600°F | 8.4 µin/in-°F | 25-300°C | 15.1 x 10-6 m/m·°C | |
| 70-800°F | 8.6 µin/in-°F | 25-400°C | 15.4 x 10-6 m/m·°C | |
| 70-1000°F | 8.8 µin/in-°F | 25-500°C | 15.7 x 10-6 m/m·°C | |
| 70-1200°F | 9.0 µin/in-°F | 25-600°C | 16.1 x 10-6 m/m·°C | |
| 70-1400°F | 9.2 µin/in-°F | 25-700°C | 16.4 x 10-6 m/m·°C | |
| 70-1600°F | 9.4 µin/in-°F | 25-800°C | 16.7 x 10-6 m/m·°C | |
| 70-1800°F | 9.5 µin/in-°F | 25-900°C | 17.0 x 10-6 m/m·°C | |
| 70-2000°F | 9.6 µin/in-°F | 25-1000°C | 17.1 x 10-6 m/m·°C | |
| – | – | 25-1100°C | 17.1 x 10-6 m/m·°C | |
| Dynamic Modulus of Elasticity | RT | 29.7 x 106 psi | RT | 205 GPa |
| 200°F | 29.1 x 106 psi | 100°C | 200 GPa | |
| 400°F | 28.2 x 106 psi | 200°C | 195 GPa | |
| 600°F | 26.9 x 106 psi | 300°C | 187 GPa | |
| 800°F | 25.6 x 106 psi | 400°C | 179 GPa | |
| 1000°F | 24.4 x 106 psi | 500°C | 172 GPa | |
| 1200°F | 23.1 x 106 psi | 600°C | 164 GPa | |
| 1400°F | 21.8 x 106 psi | 700°C | 155 GPa | |
| 1600°F | 20.9 x 106 psi | 800°C | 148 GPa | |
| 1800°F | 20.1 x 106 psi | 900°C | 143 GPa | |
| – | – | 1000°C | 138 GPa | |
RT= Room Temperature
| Test Temperature | 0.2% Yield Strength | 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 |
| 400 | 204 | 102.3 | 705 | 173.5 | 1195 | 33 | 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 | 290 | 54 | 97.8 |
*RT= Room Temperature
| 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 |
| 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 1200°F-48 hr.
| 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 | 895 | 192 | 1325 | 32 |
| M.A. + 20% C.W. + Age | RT | RT | 173 | 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 | 1075 | 32 |
RT= Room Temperature
M.A.= Solution Anneal
C.W. = Cold Work
Age = Standard aging treatment
Haynes® 556® is built for high-temperature strength plus high-temperature corrosion resistance. It performs especially well in sulfidizing, carburizing, and chlorine-bearing atmospheres, while also offering good oxidation resistance and strong fabricability (forming/welding).
Haynes® 556® alloy (UNS R30556) is an iron–nickel–chromium–cobalt alloy designed for service in moderately to severely corrosive, elevated-temperature environments. It’s also been shown to resist attack from molten chloride salts (and other salts) and molten zinc, which is a key reason it’s often selected for harsh thermal/process-duty hardware and fixtures.
From a thermal-use standpoint, Haynes® 556® shows good resistance in oxidizing environments and can be used for long-term exposure up to about 2000°F (1095°C) (with higher temperatures possible for shorter durations depending on conditions/design).
This alloy is also known as:
This material is composed of the following elements:
Specification note: Chemical limits for UNS R30556 are defined by product standards (for example, ASTM specifications that include UNS R30556 such as ASTM B435 for plate/sheet/strip). If your application requires a specific specification revision, melt practice, or tighter chemistry, include that in your RFQ so it’s confirmed on the material test report (MTR).
Haynes® 556® is frequently used where heat + corrosive combustion/process environments drive material selection. Common uses include:
Nickel Systems provides a comprehensive range of Haynes® 556® fasteners. Our offerings include:
We offer full material traceability and conform to rigorous quality standards, supporting both one-off needs and high-volume industrial projects.
