Alloy B2 (UNS N10665 / W.Nr. 2.4617) is a solid solution strengthened, nickel-molybdenum alloy, typically used in extreme reducing conditions. B2 has significantly lower carbon, silicon and iron compared to its’ predecessor, Alloy 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 Alloy B2 and Alloy B-3 Today, Alloy B2 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.
Alloy B2 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.
Available Product Forms:
Plate, Sheet, Bar, Pipe
Specifications
Hastelloy B-2 is covered by the following specifications:
UNS N10665
Plate, Sheet, Strip: ASTM B333, ASME SB333,
Bar: ASTM B 335, ASME SB335, (DUAL CERTIFIED TO ASTM B564, ASME
SB564 ON 3-1/2 DIA. AND UP)
Welded Pipe: ASTM B619, ASME SB619, CLASS I or II, (ABOVE 8 SCH 40) ASTM
B775, ASME SB775,
Seamless Pipe: ASTM B622, ASME SB622
Chemical Composition
Cr…………….1.00 Max.
Mo…………. 26.0 to 30.0
Mn…………..1.00 Max.
Fe…………… 2.00 Max.
Si……………..0.10 Max.
C……………. 0.02 Max.
P………………0.040 Max.
Co………….. 1.00 Max.
S………………0.030 Max.
