Materials

Hastelloy C-276

• Manufacturing Considerations:

  • Nickel-Molybdenum-Chromium alloy with tungsten.

  • Good workability for machining and forming compared to some other superalloys.

  • Often used for bolts, studs, nuts, and fasteners requiring uniform corrosion resistance.

• Performance in Fasteners:

  • Outstanding resistance to strong oxidizers, chlorides, and reducing environments.

  • Excellent performance in wet chlorine gas, hypochlorite, and chlorine dioxide.

  • Resists pitting, stress corrosion cracking, and crevice corrosion.

• Applications:

  • Fasteners for chemical processing, pollution control, paper pulp bleaching systems, and marine environments.

  • A go-to Hastelloy grade for general severe corrosion service.

Hastelloy C-22

• Manufacturing Considerations:

  • Nickel-Chromium-Molybdenum-Tungsten alloy with more chromium and molybdenum than C-276.

  • Similar machining characteristics to C-276.

• Performance in Fasteners:

  • Superior resistance to oxidizing environments (nitric acid, ferric & cupric salts) compared to C-276.

  • Excellent in mixed acid and oxidizing chemical streams.

  • Highly resistant to localized corrosion (pitting and crevice).

• Applications:

  • Engineered fasteners for chemical reactors, scrubbers, flue gas systems, and pharmaceutical processing.

  • Preferred when oxidizers + chlorides are both present.

Hastelloy B (B-2 / B-3 series)

• Manufacturing Considerations:

  • Nickel-Molybdenum alloy (less chromium than C-series).

  • More limited weldability and formability compared to C-grades.

• Performance in Fasteners:

  • Excellent resistance to hydrochloric acid and strong reducing acids.

  • Very poor resistance to oxidizing environments — can fail rapidly if exposed.

• Applications:

  • Specialized fasteners and components in hydrochloric acid service.

  • Rarely chosen for general-purpose fasteners due to limited versatility.