Hastelloy B-2 (UNS N10665 / W.Nr. 2.4617)
Hastelloy B-2 (UNS N10665 / W.Nr. 2.4617) is a solid solution strengthened, nickel-molybdenum alloy, typically used in extreme reducing conditions. Hastelloy B-2 has significantly lower carbon, silicon and iron compared to its’ predecessor, Hastelloy B (UNS N10001), making the alloy less susceptible to decreased corrosion resistance in the weld zone, in the as-welded condition. Controlling other alloying elements such as iron and chromium solved other issues concerning fabricability. Stringent chemistry control along with years of development has resulted in the alloy used today, both in Hastelloy B-2 and Hastelloy B-3 Today, Hastelloy B-2 with restricted chemistry can be used in the welded condition and is less susceptible to SCC under many conditions. As always, care must taken in selecting the right alloy for the desired application.
Hastelloy B-2 should not be used at temperatures between 1000°F and 1600°F as the alloy forms secondary phases that could decrease the ductility of the material.
Equivalent Grades
| Trademark | GB | GOST | ASTM | UNS | DIN | W.Nr. | NF | BS | JIS | SS |
| Hastelloy B-2 | NS3202 | – | Hastelloy B-2 | N10665 | NiMo28
Nicrofer 6928 | 2.4617 | – | NA44 | – | – |
Chemical Composition, %
| Alloy | C | Si | Mn | P | S | Cr | Ni | Mo | Cu | Fe |
| Hastelloy B-2 | ≤0.02 | ≤0.10 | ≤1.00 | ≤0.04 | ≤0.03 | ≤1.00 | Bal | 26.0-30.0 | ≤0.20 | ≤2.00 |
Typical Physical and Mechanical Properties (RT, Solution annealed)
| Density, g/cm3 | Melting Point, ℃ | Tensile Strength, MPa | Yield Strength, MPa | ELongation, % | Hardness, HB |
| 8.08 | 1380-1420 | 885 | 400 | 58 | – |
Available Products and Specifications
| Rod, Bar, Wire and Forgings | ASTM B335, ASME SB335, ASTM B366, ASME SB366, ASTM B564, ASME SB564, ASTM B472, ASME SB472 |
| Plate, Sheet and Strip | ASTM B333, ASME SB333 |
| Pipe and Tube | ASTM B622, ASME SB622, ASTM B619, ASME SB619 |
| Welding Product | AWS A5.11 (ENiMo-10), AWS A5.14 (ERNiMo-10) |
| Others | ASTM B366, ASME SB366, ASTM B564, ASME SB564 |
Features
- Controlling the minimum content of iron and chromium elements to prevent the formation of Ni4Mo in β phase
- Excellent corrosion resistance to reduced environment
- Excellent resistance to medium concentration of sulfuric acid and many non oxidizing acid corrosiveness
- Good resistance to chloride ion reduction stress corrosion cracking (SCC)
- Excellent ability to resist various kinds of organic acid corrosion
Applications
- Superior resistance to hydrochloric acid, aluminum chloride catalysts and other strongly reducing chemicals.
- Excellent high-temperature strength in inert and vacuum atmospheres.
