HASTELLOY® alloy B-3


Alloy B-3® is a nickel-molybdenum solid solution strengthened super-alloy with a nominal chemical composition of 65% nickel and 28% molybdenum with additions of iron, manganese, tungsten, and cobalt. It is commonly referred to by the tradename Hastelloy® B-3 and the universal designation UNS N10675. B-3® is known for its resistance to reducing acids, particularly hydrochloric and sulfuric, and also has good thermal stability.



Alloy B-3® is resistant to non-oxidizing acids, including hydrochloric, sulfuric, and phosphoric acids. However, B-3® has a low chromium content and should not be used in oxidizing acids or salts. The molybdenum content in B-3® confers resistance to chloride-induced localized corrosion, including chloride stress corrosion cracking and chloride-induced pitting and crevice corrosion.


B-3® does not possess good oxidation resistance and is limited to a maximum service temperature of 800°F (427°C).


B-3® is typically provided in the low-strength annealed condition. It maintains excellent toughness at cryogenic temperatures.


B-3® cannot be strengthened by heat treating. It is typically annealed at 1950°F (1065°C) followed by rapid cooling. B-3® should not be exposed to temperatures in the range of 1100°F – 1500°F (593°C – 815°C) for extended periods, as deleterious phases can form in the microstructure leading to cracking. B-3® is a solid solution alloy and does not respond to age hardening.


B-3® can be cold worked or hot worked through standard methods using common techniques. B-3® is prone to rapid work-hardening, and intermediate annealing treatments may be needed to recover ductility. Solution annealing should be conducted after cold working for optimum corrosion resistance.


B-3® is used in the chemical process industry to handle concentrated acids and other aggressive media. Other uses include heat-treating fixtures, aerospace, food processing, oil & gas, aerospace, and nuclear power generation. CRA offers specialty alloy B-3® seamless pipe & tube for use in multiple industries and applications, including:

Chemical Processing, Aerospace, Food Processing, Oil & Gas, Nuclear Power Generation, Heat-treating Fixtures