Inconel and Hastelloy are both nickel-chromium-molybdenum-based alloys. They are all corrosion-resistant and extremely strong metals. Hastelloy has greater molybdenum content than Inconel, although Inconel has a higher chromium concentration. This sets them apart in terms of corrosion resistance in different situations.
What is Hastelloy?
Hastelloy is an alloy of nickel and molybdenum. It is available in several grades, including nickel chromium molybdenum alloys. Although each Hastelloy grade was developed for a distinct use, they are all extremely corrosion-resistant. Hastelloy is strengthened and hardened at high temperatures, making it perfect for welding applications. It’s easy to shape and build. They can be forged and cold-worked because of their flexibility. Hastelloy is a suitable choice for high-temperature applications because of its outstanding resistance to strongly oxidizing and reducing chemicals. In the chemical and petrochemical sectors, pipes and valves are widely used. It works well in heat exchangers, pressure vessels, and nuclear and chemical reactors.
Forging Inventory of Nickel Alloys
- ALLOY B2
- ALLOY C
- ALLOY C276
- ALLOY N
- ALLOY S
- ALLOY W
- ALLOY X
Hastelloy Chemical Composition
| Alloy* | C% | Co% | Cr% | Mo% | V% | W% | Ai% | Cu% | Nb % | Ti% | Fe% | Ni% | Other% |
| Hastelloy B | 0.1 | 1.25 | 0.6 | 28 | 0.3 | – | – | – | – | – | 5.5 | rest/bal | Mn 0.80; Si 0.70 |
| Hastelloy B2 / Hastelloy B-2 | 0.02 | 1 | 1 | 26.0-30.0 | – | – | – | – | – | – | 2 | rest/bal | Mn 1.0, Si 0.10 |
| Hastelloy C | 0.07 | 1.25 | 16 | 17 | 0.3 | 40 | – | – | – | – | 5.75 | rest/bal | Mn 1.0; Si 0.70 |
| Hastelloy C4 / Hastelloy C-4 | 0.015 | 2 | 14.0-18.0 | 14.0-17.0 | – | – | – | – | – | 0..70 | 3 | rest/bal | Mn 1.0 ; Si 0.08 |
| Hastelloy C276 / Hastelloy C-276 | 0.02 | 2.5 | 14.0-16.5 | 15.0-17.0 | 0.35 | 3.0-4.5 | – | – | – | – | 4.0-7.0 | rest/bal | Mn 1.0; Si 0.05 |
| Hastelloy F | 0.02 | 1.25 | 22 | 6.5 | – | 0.5 | – | – | 2.1 | – | 21 | rest/bal | Mn 1.50; Si 0.50 |
| Hastelloy G | 0.05 | 2.5 | 21.0-23.5 | 5.5-7.5 | – | 1 | – | 1.5-2.5 | 1.7-2.5 | – | 18.0-21.0 | rest/bal | Mn 1.0-2.0; P0.04; Si 1.0; |
| Hastelloy G2 / Hastelloy G-2 | 0.03 | – | 23.0-26.0 | 5.0-7.0 | – | – | – | 0.70-1.20 | – | 0.70-1.50 | rest/bal | 47.0-52.0 | Mn 1.0; Si 1.0 |
| Hastelloy N | 0.06 | 0.25 | 7 | 16.5 | – | 0.2 | – | 0.1 | – | – | 3 | rest/bal | Mn 0.40; Si 0.25; B 0.01 |
| Hastelloy S | 0.02 | 2 | 15.5 | 14.5 | 0.6 | 1 | 0.2 | – | – | – | 3 | rest/bal | Mn 0.50; Si 0.40; B0.0009; La 0.02 |
| Hastelloy W | 0.06 | 1.25 | 5 | 24.5 | – | – | – | – | – | – | 5.5 | rest/bal | Mn 0.050; Si 0.50 |
| Hastelloy X | 0.1 | 1.5 | 22 | 9 | – | 0.6 | – | – | – | 18.5 | – | rest/bal | Mn 0.6; Si 0.60 |
Hastelloy Melting Point, Density and Tensile Strength
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation | |
| C22 | 8.69 g/cm3 | 1399 °C (2550 °F) | Psi – 1,00,000 , MPa – 690 | Psi – 45000 , MPa – 310 | 45 % |
| C276 | 8.89 g/cm33 | 1370 °C (2500 °F) | Psi – 1,15,000 , MPa – 790 | Psi – 52,000 , MPa – 355 | 40% |
| B2 | 9.2 g/cm3 | 1370 °C (2550 °F) | Psi – 1,15,000 , MPa –760 | Psi – 52,000 , MPa – 350 | 40% |
| B3 | 9.2 g/cm3 | 1370 °C (2550 °F) | Psi – 1,15,000 , MPa –760 | Psi – 52,000 , MPa – 350 | 40% |
| C4 | 8.64 g/cm3 | 1350-1400 °C | 783 | 365 | 55% |
| Hybrid BC1 | 8.83 g/cm³ | 1343 – 1443°C | 725 | 310 | 40% |
| X | 8.22 g/cm³ | 1355°C | 655 MPa | 240 MPa | 35% |
Hastelloy Equivalent Grades
| STANDARD | WERKSTOFF NR. | UNS | GOST | AFNOR | JIS | OR | EN |
| Hastelloy C22 | 2.4602 | N06022 | – | – | NW 6022 | – | NiCr21Mo14W |
| Hastelloy C276 | 2.4819 | N10276 | ХН65МВУ | – | NW 0276 | ЭП760 | NiMo16Cr15W |
| Hastelloy B2 | 2.4617 | N10665 | |||||
| Hastelloy B3 | 2.4600 | N10675 | |||||
| Hastelloy C4 | 2.4610 | N06455 | |||||
| Hastelloy C-22HS | – | N07022 | |||||
| Hastelloy C2000 | 2.4675 | N06200 | |||||
| Hastelloy Hybrid BC1 | 2.4708 | N10362 | |||||
| Hastelloy X | 2.4665 | N06002 |
What is Inconel?
Inconel is a corrosion-resistant and oxidation-resistant alloy suited for high-temperature and high-pressure purposes. When Inconel alloy is treated, a thick, persistent oxide layer forms, protecting the surface from further damage. The strength of Inconel varies with temperature. Depending on the alloy, it produces high-temperature strength by solid solution strengthening or precipitation hardening. Inconel is a metal used extensively for high-temperature purposes.
Inconel Material Specification
Inconel Chemical Composition
| Inconel | Element (% by mass) | ||||||||||||||
| Ni | Cr | Fe | Mo | Nb | Co | Mn | Cu | Al | Ti | Si | C | S | P | B | |
| 600 | 72.0 | 14.0–17.0 | 6.0–10.0 | 1.0 | 0.5 | 0.5 | 0.15 | 0.015 | |||||||
| 617 | 44.2–56.0 | 20.0–24.0 | 3.0 | 8.0–10.0 | 10.0–15.0 | 0.5 | 0.5 | 0.8–1.5 | 0.6 | 0.5 | 0.15 | 0.015 | 0.015 | 0.006 | |
| 625 | 58.0 | 20.0–23.0 | 5.0 | 8.0–10.0 | 3.15–4.15 | 1.0 | 0.5 | 0.4 | 0.4 | 0.5 | 0.1 | 0.015 | 0.015 | ||
| 690 | 59.5 | 30 | 9.2 | 0.35 | 0.01 | 0.02 | 0.35 | 0.019 | 0.003 | ||||||
| 718 | 50.0–55.0 | 17.0–21.0 | balance | 2.8–3.3 | 4.75–5.5 | 1.0 | 0.35 | 0.2–0.8 | 0.65–1.15 | 0.3 | 0.35 | 0.08 | 0.015 | 0.015 | 0.006 |
| X-750 | 70.0 | 14.0–17.0 | 5.0–9.0 | 0.7–1.2 | 1.0 | 1.0 | 0.5 | 0.4–1.0 | 2.25–2.75 | 0.5 | 0.08 | 0.01 | |||
Inconel Melting Point, Density and Tensile Strength
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation | |
| 600 | 8.47 g/cm3 | 1413 °C (2580 °F) | Psi – 95,000 , MPa – 655 | Psi – 45,000 , MPa – 310 | 40 % |
| 601 | 8.1 g/cm3 | 1411 °C (2571 °F) | Psi – 80,000 , MPa – 550 | Psi – 30,000 , MPa – 205 | 30 % |
| 617 | 8.3g/cm³ | 1363°C | ≥ 485 MPa | ≥ 275 MPa | 25 % |
| 625 | 8.4 g/cm3 | 1350 °C (2460 °F) | Psi – 135,000 , MPa – 930 | Psi – 75,000 , MPa – 517 | 42.5 % |
| 690 | 8.3g/cm³ | 1363°C | ≥ 485 MPa | ≥ 275 MPa | 25 % |
| 718 | 8.2 g/cm3 | 1350 °C (2460 °F) | Psi – 135,000 , MPa – 930 | Psi – 70,000 , MPa – 482 | 45 % |
| 725 | 8.31 g/cm3 | 1271°C-1343 °C | 1137 MPa | 827 MPa | 20 % |
| X-750 | 8.28 g/cm3 | 1430°C | 1267 MPa | 868 MPa | 25 % |
Inconel Equivalent Grades
| STANDARD | WERKSTOFF NR. | UNS | GOST | AFNOR | JIS | BS | EN | OR |
| Inconel 600 | 2.4816 | N06600 | МНЖМц 28-2,5-1,5 | NC15FE11M | NCF 600 | NA 13 | NiCr15Fe | ЭИ868 |
| Inconel 601 | 2.4851 | N06601 | XH60BT | NC23FeA | NCF 601 | NA 49 | NiCr23Fe | ЭИ868 |
| Inconel 617 | 2.4663 | N06617 | ||||||
| Inconel 625 | 2.4856 | N06625 | ХН75МБТЮ | NC22DNB4M | NCF 625 | NA 21 | NiCr22Mo9Nb | ЭИ602 |
| Inconel 690 | 2.4642 | N06690 | ||||||
| Inconel 718 | 2.4668 | N07718 | ||||||
| Inconel 725 | – | N07725 | ||||||
| Inconel X-750 | 2.4669 | N07750 |
Mechanical Behavior
Inconel and Hastelloy are both solid solution-reinforced alloys with equivalent mechanical properties. It’s just that they use a lot of different solid solution-strengthening components.
Application
As shown, both alloys have a wide variety of functions. And, to a large extent, their applicability range is extremely close. This does not, however, mean that the two alloys can be used alternately. According to the application environment, various alloys should be employed in the same application.
In oil and gas applications, for example, the subsurface environment of various oil fields varies greatly. Inconel is a superior choice when oil fields are subjected to an oxidising environment. In oil fields with declining conditions, Hastelloy should be used.
Hastelloy will cost a little extra because molybdenum is more costly than chromium. Their prices, on the other hand, are not vastly different.
Conclusion
Corrosion resistance is strong in both Inconel and Hastelloy. Inconel is a better choice for oxidising environments. Hastelloy C-276 is preferable for decreasing conditions.
Both alloys are strengthened by a solid solution. Even though the components with a solid solution-strengthening effect are different, the mechanical characteristics of the two are very similar. The two alloys have similar application ranges but serve distinct functions in the same application.
